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Anatomy for Dental Medicine Second Edition

ERRNVPHGLFRVRUJ

Edited by Eric W. Baker, MA, MPhil Departm ent of Basic Science and Craniofacial Biology New York Universit y College of Dentistry New York, New York

Based on the w ork of Michael Schuenke, MD, PhD Institute of Anatomy Christian Albrecht Universit y Kiel Ot to-Hahn-Plat z 8 D-24118 Kiel Erik Schulte, MD Departm ent of Functional and Clinical Anatomy Universit y Medicine Johannes Gutenberg Universit y Saarstrasse 19-21 D-55099 Mainz Udo Schumacher, MD, FRCPath, CBiol, FSB, DSc Institute of Anatomy and Experim ent al Morphology Center for Experim ent al Medicine Universit y Cancer Center Universit y Medical Center Hamburg-Eppendorf Martinistrasse 52 D-20246 Hamburg

Illustrations by Markus Voll Karl Wesker Thiem e New York • Stut tgart • Delhi • Rio de Janeiro

Vice Presid en t an d Ed itor ial Director, Ed u cat ion al Prod u ct s: An n e T. Vin n icom be Develop m en t al Ed itor: Ju lie O’Meara Ed itor ial Assist an t: Hu vie Wein reich Prod u ct ion Ed itor: Barbara A. Ch er n ow In ter n at ion al Prod u ct ion Director: An d reas Sch aber t Sen ior Vice Presid en t , Ed itor ial an d E-Prod u ct Develop m en t: Cor n elia Sch u lze In ter n at ion al Market ing Director: Fion a Hen d erson Director of Sales, Nor t h Am er ica: Mike Rosem an Sen ior Vice Presid en t an d Ch ief Op erat in g O ce: Sarah Van d erbilt Vice Presid en t : Br ian D. Scan lan Illu st rat ion s: Marku s Voll an d Karl Wesker Com p ositor: Agn ieszka & Mar t in Walet zko, Leon berg, Ger m any

Copyr igh t ©2015 by Th iem e Me d ical Pu blish ers, In c

Librar y of Congress Cat alogin g-in -Pu blicat ion Dat a An atom y for d en t al m ed icin e. An atom y for d en t al m ed icin e / ed ited by Er ic W. Baker ; based on t h e w ork of Mich ael Sch u en ke, Er ik Sch u lte, Ud o Sch u m ach er ; illu st rat ion s by Marku s Voll, Karl Wesker. Secon d ed it ion . p . ; cm . Preced ed by: Head an d n eck an atom y for d en t al m ed icin e / ed ited by Er ic W. Baker. 2010. In clu d es bibliograp h ical referen ces an d in d ex. Su m m ar y: “Th is sin gle-volu m e text at las covers d en t al st u d en t ’s n eed s across all for m at s of an atom y ed u cat ion . It in clu d es an ap p en d ix on t h e an atom y of d en t al local an est h esia, on e of t h e cr it ical ap p licat ion s of h ead an d n eck an atom y. Th ere are also ap p en d ices t h at in clu d e fact u al-t yp e qu est ion s to test recall of in for m at ion an d clin ical vign et te-st yle qu est ion s t h at test com p reh en sion an d ap p licat ion . Th ese ap p en d ices in clu d e fu ll an sw er exp lan at ion s. Th ere are also over 400 n ew illu st rat ion s, su m m ar y t ables, d en t ally-relevan t clin ical correlat ion s, rad iograp h s, an d fu ll-color p h otograp h s”--Provid ed by p u b lish er. ISBN 978-1-62623-085-9 (p ap erback) I. Baker, Er ic W. (Er ic W illiam ), 1961- , ed itor. II. Sch ü n ke, Mich ael. III. Sch u lte, Er ik. IV. Sch u m ach er, Ud o. V. Tit le. [DNLM: 1. Head --an atom y & h istology--At lases. 2. Den t ist r y--At lases. 3. Neck--an atom y & h istology--At lases. W E 17] QM535 611’.910223--d c23 2014041067

Pr in ted in Ch in a by Everbest Pr in t ing Ltd ISBN 978-1-62623-085-9 Also available as an e-book: eISBN 978-1-62623-086-6

54321

Im p or t an t n ote: Med icin e is an ever-ch anging scien ce u n d ergoin g con t in u al d evelop m en t . Research an d clin ical exp er ien ce are con t in u ally exp an d in g ou r kn ow ledge, in p ar t icu lar ou r kn ow ledge of p rop er t reat m en t an d d r ug t h erapy. In sofar as t h is book m en t ion s any d osage or ap p licat ion , read ers m ay rest assu red t h at t h e au t h ors, ed itors, an d p u blish ers h ave m ad e ever y e or t to en su re t h at su ch referen ces are in accord an ce w it h th e state o f kn o w le dge at th e tim e o f pro du ctio n o f th e bo o k. Never t h eless, t h is d oes n ot involve, im p ly, or exp ress any gu aran tee or resp on sibilit y on t h e p ar t of t h e p u blish ers in resp ect to any d osage in st r u ct ion s an d for m s of ap p licat ion s st ated in t h e book. Eve ry use r is re qu e ste d to exam in e carefu lly t h e m an u fact u rer’s lea et s accom p anyin g each d r ug an d to ch eck, if n ecessar y in con su lt at ion w it h a p hysician or sp ecialist , w h et h er t h e d osage sch ed u les m e n t ion ed t h erein or t h e con t rain d icat ion s st ated by t h e m an u fact u rers d i er from t h e st atem en t s m ad e in t h e p resen t book. Su ch exam in at ion is p ar t icu larly im p or t an t w it h d r ugs t h at are eit h er rarely u sed or h ave been n ew ly released on t h e m arket . Ever y d osage sch ed u le or ever y for m of ap p licat ion u sed is en t irely at t h e u ser’s ow n r isk an d resp on sibilit y. Th e au t h ors an d p u blish ers requ est ever y u ser to rep or t to t h e p u blish ers any d iscrep an cies or in accu racies n ot iced . If er rors in t h is w ork are fou n d after p u blicat ion , er rat a w ill be p osted at w w w .t h iem e.com on t h e p rod u ct d escr ipt ion p age. Som e of t h e p rod u ct n am es, p aten t s, an d registered d esign s refer red to in t h is book are in fact registered t rad em arks or p rop r iet ar y n am es even t h ough sp eci c referen ce to t h is fact is n ot alw ays m ad e in t h e text . Th erefore, t h e ap p earan ce of a n am e w it h ou t d esign at ion as p rop r iet ar y is n ot to be con st r u ed as a rep resen t at ion by t h e p u blish er t h at it is in t h e p u blic d om ain .

Th is book, in clu d in g all p ar t s t h ereof, is legally p rotected by copyr igh t . Any u se, exp loit at ion , or com m ercializat ion ou t sid e t h e n ar row lim it s set by copyr igh t legislat ion , w it h ou t t h e p u blish e r’s con se n t , is illegal an d liable to p rosecu t ion . Th is ap p lies in p ar t icu lar to p h otost at rep rod u ct ion , copyin g, m im eograp h in g, p rep arat ion of m icro lm s, an d elect ron ic dat a p rocessin g an d storage.

To m y w on derful w ife, Am y Cu rran Baker, an d m y aw e-in spiring daugh ters, Ph oebe an d Claire

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIII Acknowledgm ent s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XV Acknowledgm ent s from the First Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XVII

Head 1

Embryolog y of the He ad & Ne ck Germ Layers & the Developing Em bryo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Developm ent of the Brain & Spinal Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Developm ent & Derivatives of the Pharyngeal (Branchial) Arches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Developm ent & Derivatives of the Pharyngeal Pouches, Mem branes, & Cleft s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Developm ent of the Tongue & Thyroid Gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Developm ent of the Face . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Developm ent of the Palate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2

Cranial Bones Developm ent of the Cranial Bones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Skull: Lateral View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Skull: Anterior View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Skull: Posterior View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Calvaria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Skull Base: Exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Skull Base: Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Sphenoid Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Tem poral Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Occipit al Bone & Ethm oid Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Zygom atic (Malar) Bone & Nasal Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Maxilla & Hard Palate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Mandible & Hyoid Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Mandible: Age-related Changes & Mandibular Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Neurovascular Pathways through the Skull Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Muscles of the Head: Origins & Insertions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3

Vasculature & Lymphatics of the He ad & Ne ck Arteries of the Head & Neck: Overview & Subclavian Artery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 External & Internal Carotid Arteries: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 External Carotid Artery: Anterior & Medial Branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 External Carotid Artery: Posterior Branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 External Carotid Artery: Term inal Branches (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 External Carotid Artery: Term inal Branches (II) & Anastom oses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Internal Carotid Artery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Veins of the Head & Neck: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Super cial Veins of the Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Deep Veins of the Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Lym phatics of the Head & Neck (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Lym phatics of the Head & Neck (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

VII

ERRNVPHGLFRVRUJ

Contents

4

Ne uroanatomy & Inne rvation of the He ad & Ne ck Organization of the Nervous System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Spinal Cord: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Spinal Cord: Circuitry & Spinal Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Organization of the Brain & Cerebellum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Telencephalon (I): Overview, Basal Ganglia, & Neocortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Telencephalon (II): Allocortex & Lim bic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Diencephalon: Overview & Developm ent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Diencephalon: Thalam us & Hypothalam us . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Brainstem : Organization & External Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Mesencephalon & Pons: Transverse Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Medulla Oblongat a: Transverse Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Cerebrospinal Fluid (CSF) Spaces & Ventricles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Arteries of the Brain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Veins of the Brain: Super cial & Deep Veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Blood Vessels of the Brain: Cerebrovascular Disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Meninges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Sensory Pathways (Exluding the Head) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Sensory Pathways: Pain Pathways in the Head & the Central Analgesic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Motor Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Autonom ic Nervous System (I): Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Autonom ic Nervous System (II): Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Cranial Nerves: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 Cranial Nerve Nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 CN I & II: Olfactory & Optic Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 CN III, IV, & VI: Oculom otor, Trochlear, & Abducent Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 CN V: Trigem inal Nerve, Nuclei, & Divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 CN V1 : Trigem inal Nerve, Ophthalm ic Division . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 CN V2 : Trigem inal Nerve, Maxillary Division . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 CN V3 : Trigem inal Nerve, Mandibular Division . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 CN VII: Facial Nerve, Nuclei & Internal Branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 CN VII: Facial Nerve, External Branches & Ganglia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 CN VIII: Vestibulocochlear Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 CN IX: Glossopharyngeal Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 CN X: Vagus Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 CN XI & XII: Accessory Spinal & Hypoglossal Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Regions of the Head 5

Face & Scalp Muscles of the Face . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Muscles of Facial Expression: Calvaria, Ear, & Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Muscles of Facial Expression: Mouth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 Neurovascular Topography of the Anterior Face & Scalp: Super cial Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Neurovascular Topography of the Lateral Head: Super cial Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Neurovascular Topography of the Lateral Head: Interm ediate & Deep Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

6

Te mporal, Infrate mporal, & Pte ryg opalatine Fossae Tem poral & Infratem poral Fossae: Content s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Infratem poral Fossa: Content s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Muscles of Mastication: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 Muscles of Mastication: Deep Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Tem porom andibular Joint (TMJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

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Tem porom andibular Joint (TMJ): Biom echanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Pterygopalatine Fossa: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Topography of the Pterygopalatine Fossa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

7

Nose & Nasal Cavity Nose: Nasal Skeleton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Overview of the Nasal Cavit y & Paranasal Sinuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Nasal Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Mucosa of the Nasal Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Nose & Paranasal Sinuses: Histology & Clinical Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 Olfactory System (Sm ell) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

8

Oral Cavity & Pharynx Oral Cavit y: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 Vasculature of the Oral Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 Innervation of the Oral Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Teeth in situ & Term inology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 Structure of the Teeth & Periodontium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 Maxillary Perm anent Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 Mandibular Perm anent Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Deciduous Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Radiographs of Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 Lingual Mucosa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 Glossal Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Neurovasculature of the Tongue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 Gust atory Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Floor of the Oral Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 Salivary Glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Hard & Soft Palates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 Pharynx: Divisions & Content s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 Muscles of the Pharynx (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 Muscles of the Pharynx (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Muscles of the Pharynx (III) & Innervation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 Neurovascular Topography of the Pharynx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Potential Tissue Spaces in the Head & Spread of Dent al Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

9

Orbit & Eye Bones of the Orbit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 Com m unications of the Orbit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 Extraocular Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 Innervation of the Extraocular Muscles (CN III, IV, & VI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 Neurovasculature of the Orbit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 Topography of the Orbit (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 Topography of the Orbit (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Lacrim al Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Eyeball . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Eye: Blood Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 Eye: Lens & Cornea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248 Eye: Iris & Ocular Cham bers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 Eye: Retina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 Visual System (I): Overview & Geniculate Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 Visual System (II): Lesions & Nongeniculate Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 Visual System (III): Re exes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 Visual System (IV): Coordination of Eye Movem ent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

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10

Ear Overview & External Ear (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 External Ear (II): Auricle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 Middle Ear (I): Tym panic Cavit y & Pharyngot ym panic Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Middle Ear (II): Auditory Ossicles & Tym panic Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 Inner Ear (I): Overview & Innervation (CN VIII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 Arteries & Veins of the Middle & Inner Ear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 Inner Ear (II): Auditory Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 Auditory Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 Inner Ear (III): Vestibular Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 Vestibular Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

Neck 11

Bo nes, Lig ame nts, & Muscles o f the Ne ck Vertebral Colum n & Vertebrae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 Cervical Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Joint s of the Cervical Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288 Ligam ent s of the Vertebral Colum n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 Ligam ent s of the Cervical Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 Ligam ent s of the Craniovertebral Joint s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 Muscles of the Neck: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 Muscles of the Neck & Back (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 Muscles of the Neck & Back (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 Muscles of the Posterior Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 Intrinsic Back Muscles (I): Erector Spinae & Interspinales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304 Intrinsic Back Muscles (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 Intrinsic Back Muscles (III): Short Nuchal & Craniovertebral Joint Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 Prevertebral & Scalene Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 Suprahyoid & Infrahyoid Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

12

Ne urovascular Topog raphy of the Ne ck Arteries & Veins of the Neck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 Cervical Plexus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316 Cervical Regions (Triangles) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 Cervical Fasciae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 Anterior Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 Root of the Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 Lateral Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326 Deep Lateral Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 Posterior Neck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 Peripharyngeal Space (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332 Peripharyngeal Space (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334

13

Larynx & Thyroid Gland Larynx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 Laryngeal Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 Larynx: Neurovasculature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 Larynx: Topography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 Endotracheal Intubation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344 Thyroid & Parathyroid Glands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

X

ERRNVPHGLFRVRUJ

Contents

Sectional Anatomy 14

Se ctional Anatomy of the Head & Ne ck Coronal Sections of the Head (I): Anterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 Coronal Sections of the Head (II): Posterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 Coronal MRIs of the Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352 Coronal MRIs of the Neck (I): Anterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 Coronal MRIs of the Neck (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 Coronal MRIs of the Neck (III): Posterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 Transverse Sections of the Head (I): Cranial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 Transverse Sections of the Head (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 Transverse Sections of the Head (III): Caudal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 Transverse Sections of the Neck (I): Cranial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 Transverse Sections of the Neck (II): Caudal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368 Transverse MRIs of the Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370 Transverse MRIs of the Oral Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372 Transverse MRIs of the Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 Sagit t al Sections of the Head (I): Medial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 Sagit t al Sections of the Head (II): Lateral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 Sagit t al MRIs of the Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 Sagit t al MRIs of the Neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

Rest of Body Anatomy 15

Re st o f Body Anatomy Upper Lim b Clavicle & Scapula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 Hum erus & Glenohum eral Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 Bones of Forearm , Wrist, & Hand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388 Muscles of the Shoulder (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390 Muscles of the Shoulder (II) & Arm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 Muscles of the Forearm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394 Muscles of the Wrist & Hand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 Arteries & Veins of the Upper Lim b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398 Brachial Plexus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 Thorax Thoracic Skeleton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402 Muscles & Neurovascular Topography of the Thoracic Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404 Fem ale Breast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406 Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 Neurovasculature of the Diaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410 Divisions of the Thoracic Cavit y & Lym phatics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 Thoracic Vasculature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 Nerves of the Thoracic Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 Mediastinum : Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418 Mediastinum : Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 Heart: Surfaces & Cham bers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422 Heart: Valves, Arteries, & Veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424 Heart: Conduction & Innervation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 Pre- & Postnat al Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428 Esophagus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430

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Contents

Pleura . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432 Lungs in situ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434 Pulm onary Arteries & Veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 Abdom en Surface Anatomy & Muscles of the Abdom inal Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438 Arteries of the Abdom inal Wall & Abdom en . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440 Divisions of the Abdom inopelvic Cavit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442 Peritoneal Cavit y, Greater Sac, & Mesenteries (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444 Stom ach & Om ent al Bursa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446 Mesenteries (II) & Bowel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448 Liver, Gallbladder, & Biliary Tract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 Abdom inal Aort a & Celiac Trunk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452 Superior & Inferior Mesenteric Arteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454 Veins of the Abdom en . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456 Interior Vena Cava & Inferior Mesenteric Veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458 Autonom ic Plexuses & Sectional Anatomy of the Abdom en . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460 Pelvis Pelvic Girdle & Ligam ent s of the Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462 Content s of the Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464 Arteries & Veins of the Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466

Appendices Appendix A Anatomy of Local Anesthesia for Dentistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470 Appendix B Factual Questions & Answer Explanations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488 Appendix C Clinical Questions & Answer Explanations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523

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Preface Before em barkin g on t h e secon d ed it ion of An atom y for Dent al Med icin e, w e sought to n d out h ow an atom y is cu r rent ly bein g t aught in Nor t h Am er ica. We con su lted m em bers of t h e Am er ican Dent al Edu cat ion Associat ion (ADEA) an d read t h eir Basic Scien ce Su r vey Ser ies for Dent ist r y, a ser ies of rep or t s t h at clar ify t h is ver y issue. W h at w e fou n d out is t h at teach in g t im e is bein g squ eezed an d m an y in st it ut ion s h ave com bin ed cou rses t h at w ere on ce st an d-alon e, e.g., em br yology, h istology, an d n eu roan atom y, in to t h e an at om y cou rse. Ar m ed w it h t h is kn ow ledge w e set out to creat e a sin gle-volu m e text at las t h at w ou ld cover dent al st u dent ’s n eed s across all for m at s of an atom y edu cat ion , a feat t h at w e t h in k w e h ave ach ieved w it h t h is secon d e d it ion . Som e key feat u res ret ain ed from t h e rst ed it ion are: • Organ ized in a u ser-fr ien d ly for m at in w h ich each t w op age spread is a self cont ain ed gu ide to a sp e ci c top ic. • In t u it ively ar ran ged to facilit ate lear n in g. Coverage of each region begin s by d iscu ssin g t h e bon es an d joint s an d t h en add s t h e m u scles, t h e vascu lat u re, an d t h e n er ves. Th is in for m at ion is t h en integrated in t h e top ograph ic n eu rovascu lar an atom y coverage t h at follow s. • Feat u res large, fu ll- color, h igh ly det ailed ar t w ork w it h clear an d t h orou gh labelin g an d descr ipt ive capt ion s, plu s nu m erou s sch em at ics to elu cid ate con cep t s an d t ables to su m m ar ize key in for m at ion for review an d referen ce. • In clu des a fu ll ch apter devoted to se ct ion al an atom y w it h rad iograph ic im ages to dem on st rate an atom y as seen in t h e clin ical set t in g. Th e secon d ed it ion h as t w o n ew ch apters: an em br yology ch apter t h at int roduces dent al st u dent s to all of t h e m ajor

con cep t s t h at t h ey n eed t o be fam iliar w it h , an d t h at put s an at om ical con cept s from lat er ch ap t ers in con t ext; an d a ch apt er t h at covers t h e an atom y of t h e rest of bod y, w h ich in cludes coverage of t h e upp er lim b, t h ora x, abdom en , an d p elvis (t h e back is covered in ch ap ter 11 w it h t h e n eck). In add it ion , w e in creased ou r coverage of n eu roan atom y su ch t h at it sh ou ld be su cient to m eet den t al st u dent ’s n eeds. In t h is secon d ed it ion w e also rear ran ged m ater ial into a m ore region al approach t hu s en h an cin g it s u sefu ln ess as a com p an ion t o lect u re-based m at er ial an d to d issect ion cou rses. How ever, w e also ret ain ed a syst em ic an at om y approach at t h e begin n in g of t h e at las t h at allow s cer t ain topics t o be presen t ed m ore clearly w h ile provid in g a good ent r y p oint for t h e n ovice lear n er. Ot h er n ot able ch an ges to t h e secon d ed it ion in clu de a n ew app en d ix on t h e an at om y of den t al local an est h esia, w h ich is on e of t h e cr it ical applicat ion s of h ead an d n eck an at om y. Th ere are also app en d ices t h at in clu de fact u al-t yp e qu est ion s to test recall of in for m at ion an d clin ical vign et te-st yle quest ion s t h at t est com preh en sion an d applicat ion . Th ese app en d ices in clu de fu ll an sw er explan at ion s. Th ere is also over 400 n ew illu st rat ion s, su m m ar y t ables, dent allyrelevant clin ical cor relat ion s, rad iograph s, an d fu ll- color ph ot ograph s. Th e text , ar t w ork, an d labels h ave been t h orough ly up d ated , an d w e w elcom e t h e cont inu in g supp or t of t h ose m em bers of t h e m ed ical an d den t al com m u n it y w h o aler t u s t o any issu es an d keep u s on ou r t oes! All-in -all, w e h ave t aken ou r ver y w ell-received rst e d it ion an d given it even m ore relevan ce an d app eal su ch t h at it sh ou ld ser ve dent al st u dent s, an d ot h er st u dent s for w h om t h e h ead an d n eck h old s p ar t icu lar relevan ce, w ell for m any e ect ive years of st udyin g to com e.

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Acknow ledgments For t h eir invalu able in put an d advice in resh apin g t h is secon d ed it ion , t h an ks to

For t h eir cont r ibut ion to ph otograph ic coverage of t h e an atom y of dent al local an est h esia, t h an ks to

• Dr. Roger A. Dash n er, Clin ical An atom ist an d CEO, Advan ced An atom ical Ser vices, Colu m bu s, Oh io

• Dr St an ley P. Freem an , Dr Br ian S. Du ch an , Alison Sm it h , Jazm in Sm it h , an d Br idget Bieler of West p or t Dent al Associates.

• Dr. Dorot hy Bu rk, Associate Professor of Biom ed ical Scien ces, Un iversit y of t h e Paci c Ar t hu r A. Dugon i Sch ool of Dent ist r y, San Fran cisco, Califor n ia • Dou glas Gou ld , Ph D, Professor, Oaklan d Un iversit y W illiam Beau m ont Sch ool of Med icin e, Roch ester, Mich igan • Dr St an ley P. Freem an , DDS, FACD, FICD, Cou rse Director an d Professor of Dent al An at om y, Colu m bia Sch ool of Den t ist r y, New York • Dr. Bob Hutch in s, Professor of Biom ed ical Scien ces, TX A&M Un iversit y, Baylor College of Dent ist r y, Dallas, TX (recent ly ret ired) • Dr. Geo roy Noel, Assist ant Professor an d Direct or of Division of An atom ical Scien ces, McGill Un iversit y, Mont real, Quebe c, Can ad a • Ju st in Gorgi Ph D, Associate Un iversit y, Glen d ale, Ar izon a

Professor,

Midw esten

• Mich elle Sin gleton , Ph .D., Professor of An atom y, Ch icago College of Osteop at h ic Med icin e, Midw ester n Un iversit y, Dow n ers Grove, Illin ois • Dr Nicole Her r in g, Assist ant Professor of An atom ical Scien ces an d Neu robiology, Un iversit y of Lou isville, Lou isville, Ken t u cky

In add it ion to t h ose w h o h elp ed w it h t h e rst ed it ion of t h is at las, I w ou ld like to t h an k m y follow in g colleagu es at New York Un iversit y for t h eir assist an ce w it h t h is secon d ed it ion: Dr. Rich ard Cot t y, Dr. Elisabet h Lop ez, an d Dr. Joh an n a Warsh aw for t h eir in st r u m ent al cont r ibut ion s in review in g an d com m ent in g on t h e n ew (an d old) m at er ial; Dr. Jean Pier re Sain t-Jean n et for h is exp er t opin ion s relat ed t o t h e exp an ded n eu roan at om y coverage in t h is ed it ion; Dr. Ken n et h Allen for h is review of t h e coverage of t h e an atom y of local an est h esia; Dr. Ken n et h Fleish er for h is assist an ce w it h t h e ph otograph ic coverage of t h e an atom y of den t al local an est h esia; Dr. Elen a Cu n n in gh am an d Mr. Josh u a Joh n son for provid in g in valu able su ggest ion s on h ow to im prove t h e at las; Dr. Nicola Par t r idge, ch air of t h e dep ar t m ent of basic scien ce an d cran iofacial biology, for h er ent hu siast ic supp or t for t h e n ew ed it ion; Dr. Lou is Ter racio (w h o I egregiou sly m ist aken ly failed to ackn ow ledge in t h e rst add it ion) for h is on goin g m en tor in g an d overall supp or t of t h is cu r ren t academ ic en deavor an d all t h in gs relat ed t o an at om ical edu cat ion at NYUCD; an d last but n ot least m y st udent s at NYUCD for provid in g con st r u ct ive feedback in h ow to im prove t h e rst ed it ion .

For t h e clin ical vign et te-st yle qu est ion s an d t h e fact u al-t yp e qu est ion s, resp ect ively, t h an ks to

I w ou ld on ce again like to t h an k m y colleagu es at Th iem e Publish ers w h o so d iligent ly research ed t h e m arket an d cam e up w it h an am bit iou s plan for t h is secon d ed it ion . My t h an ks go to An n e T. Vin n icom be, Vice President an d Ed itor ial Direct or, Edu cat ion al Produ ct s, for h er t ireless w ork, on goin g supp or t , an d con t in u ou s ch am pion in g of t h is at las; Dr Ju lie O’Meara, Developm ent al Ed itor, w h o ed ited an d develop ed t h e m anu scr ipt m ore t h an eit h er of u s envisaged at t h e st ar t an d w h ose en t h u siasm an d kn ow ledge (as a den t ist h erself) h as t aken t h is ed it ion to a n ew level; Hu vie Wein reich for h er ed itor ial assist an ce; an d Barbara Ch er n ow, Product ion Ed itor, w h o m an aged to t ake all of t h e elem ent s w e gave h er an d produ ce t h is st u n n in g at las.

• Dr. Law ren ce C. Zoller , Professor of Biom ed ical Scien ces , UNLV Sch ool of Den t al Med icin e , Las Vegas, Nevad a

Eric W . Bak er

• Dr Rit a Hard im an , Lect u rer in Oro-facial an d Head an d Neck An at om y, Melbou r n e Dent al Sch ool, Un iversit y of Melbou r n e, Park ville, Au st ralia • Br ian R. MacPh erson , Ph D, Professor an d Vice- Ch air, Dep ar t m en t of An atom y an d Neu robiology, Un iversit y of Ken t u cky College of Med icin e, Lexin gton , Ken t ucky. • Hen r y Ed in ger, Ph .D., Director of Educat ion al Program s, Dep ar t m en t of Ph ar m acology & Physiology, Rutgers-New Jersey Med ical Sch ool, New ark, New Jersey

• Fran k J. Daly, Ph .D., Associat e Professor of An atom y, Un iversit y of New En glan d College of Osteop at h ic Med icin e, Biddeford , Main e

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Acknow ledgments from the First Edition Su san a Tejad a, class of 2010, Boston Un iversit y Sch ool of Dent al Med icin e; Dr. Nor m an F. Capra, Dep ar t m ent of Neu ral an d Pain Scien ces, Un iversit y of Mar ylan d Dent al Sch ool, Balt im ore, Mar ylan d; Dr. Bob Hutch in s, Associate Professor, Dep ar t m ent of Biom ed ical Scien ces, Baylor College of Dent ist r y, Dallas, Texas; Dr. Br ian R. MacPh erson , Professor an d Vice- Ch air, Dep ar t m ent of An atom y an d Neu robiology, Un iversit y of Kent u ck y, Lexin gton , Kent ucky; an d Dr. Nich olas Pet er Piesco, Associat e Professor, Dep ar t m en t of Oral Med icin e, Un iversit y of Pit t sbu rgh , Pit t sbu rgh , Pen n sylvan ia. I w ou ld like to t h an k m y colleagu es at New York Un iversit y w h o assist ed m e in t h is en deavor: Professor Ter r y Har r ison , Dep ar t m ent of Ant h rop ology, for foster in g m y interest s in com p arat ive an at om y an d in st illin g an appreciat ion for det ail an d accu racy in an atom ical descr ipt ion; Dr. Rich ard Cot t y for h is keen eye in lookin g over t h e sect ion al an at om y in t h is at las; Dr. Phyllis Slot t , Dr. Elen a Cu n n in gh am , Dr. Avelin Malyan go, an d Dr. Joh an n a Warsh aw for assist an ce in all t h in gs an atom y related , in clu d in g cou n t less d iscu ssion s on all asp ect s of cu r ren t an atom ical edu cat ion an d t h e n eed for a det ailed h ead an d n eck an at om y at las. Fin ally, I w ou ld like to t h an k Dr. In der Sin gh for m entor in g m e as an an atom ist an d ser vin g as an in spirat ion al an atom y professor.

I w ou ld like to t h an k m y colleagues at Th iem e Publish ers w h o so profession ally facilit at ed t h e rst ed it ion of t h is at las. I can n ot t h an k en ou gh , Cat h r in E. Schu lz, MD, Ed it or ial Direct or Edu cat ion al Produ ct s, for askin g m e t o advise Th iem e an d t h en invit in g m e t o creat e t h is at las. I w ish to ext en d ver y sp ecial t h an ks an d appreciat ion t o Br idget Qu een an , Developm en t al Ed it or, w h o ed it ed an d develop ed t h e m anu scr ipt w it h an out st an d in g t alent for visu alizat ion an d in t u it ive ow of in for m at ion . I am also ver y grat efu l t o h er for catch in g m any det ails alon g t h e w ay w h ile alw ays p at ient ly resp on d in g to requ est s for ar t w ork an d labelin g ch an ges. Th an ks t o Ju lie O’Meara, Developm en t al Ed it or, for join in g t h e team in t h e cor rect ion ph ase. Sh e graciou sly rem in ded m e of dead lin es, w h ile alw ays bein g available t o t roublesh oot problem s. Fin ally cord ial t h an ks to Elsie St arb ecker, Sen ior Produ ct ion Ed it or, w h o w it h great care an d sp eed p rodu ced t h is at las w it h it ’s over 9 0 0 illu st rat ion s. Th eir h ard w ork h as m ade t h is book a realit y. Eric W . Bak er

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Head 1

Embryolog y of the He ad & Ne ck Germ Layers & the Developing Em bryo Developm ent of the Brain & Spinal Cord Developm ent & Derivatives of the Pharyngeal (Branchial) Arches Developm ent & Derivatives of the Pharyngeal Pouches, Mem branes, & Cleft s Developm ent of the Tongue & Thyroid Gland Developm ent of the Face Developm ent of the Palate

2

3

2 4

4 6 8 10 12 14

Cranial Bones Developm ent of the Cranial Bones Skull: Lateral View Skull: Anterior View Skull: Posterior View Calvaria Skull Base: Exterior Skull Base: Interior Sphenoid Bone Tem poral Bone Occipit al Bone & Ethm oid Bone Zygom atic (Malar) Bone & Nasal Bone Maxilla & Hard Palate Mandible & Hyoid Bone Mandible: Age-related Changes & Mandibular Fractures Neurovascular Pathways through the Skull Base Muscles of the Head: Origins & Insertions

16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46

Vasculature & Lymphatics of the He ad & Ne ck Arteries of the Head & Neck: Overview & Subclavian Artery External & Internal Carotid Arteries: Overview External Carotid Artery: Anterior & Medial Branches External Carotid Artery: Posterior Branches External Carotid Artery: Term inal Branches (I) External Carotid Artery: Term inal Branches (II) & Anastom oses Internal Carotid Artery Veins of the Head & Neck: Overview Super cial Veins of the Head Deep Veins of the Head

Lym phatics of the Head & Neck (I) Lym phatics of the Head & Neck (II)

48 50 52 54 56 58 60 62 64 66

68 70

Ne uroanatomy & Inne rvation of the He ad & Ne ck Organization of the Nervous System Spinal Cord: Overview Spinal Cord: Circuitry & Spinal Nerves Organization of the Brain & Cerebellum Telencephalon (I): Overview, Basal Ganglia, & Neocortex Telencephalon (II): Allocortex & Lim bic System Diencephalon: Overview & Developm ent Diencephalon: Thalam us & Hypothalam us Brainstem : Organization & External Structure Mesencephalon & Pons: Transverse Sections Medulla Oblongata: Transverse Sections Cerebrospinal Fluid (CSF) Spaces & Ventricles Arteries of the Brain Veins of the Brain: Super cial & Deep Veins Blood Vessels of the Brain: Cerebrovascular Disease Meninges Sensory Pathways (Exluding the Head) Sensory Pathways: Pain Pathways in the Head & the Central Analgesic System Motor Pathways Autonom ic Nervous System (I): Overview Autonom ic Nervous System (II): Connections Cranial Nerves: Overview Cranial Nerve Nuclei CN I & II: Olfactory & Optic Nerves CN III, IV, & VI: Oculom otor, Trochlear, & Abducent Nerves CN V: Trigem inal Nerve, Nuclei, & Divisions CN V1 : Trigem inal Nerve, Ophthalm ic Division CN V2 : Trigem inal Nerve, Maxillary Division CN V3 : Trigem inal Nerve, Mandibular Division CN VII: Facial Nerve, Nuclei & Internal Branches CN VII: Facial Nerve, External Branches & Ganglia CN VIII: Vestibulocochlear Nerve CN IX: Glossopharyngeal Nerve CN X: Vagus Nerve CN XI & XII: Accessory Spinal & Hypoglossal Nerves

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72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140

1. Embryology of the Hea d & Neck

Hea d

Germ Layers & the Developing Embryo Cranial Cut edge of am nion

Cranial Neural plate

Cut edge of am nion

Neural groove

Plane of section in d Prim itive node with prim itive groove A Neural fold

Neural plate Neural groove

Plane of section in e

Neural folds

Som ites Neural folds

Prim itive node

Primitive streak Caudal

B

Neural groove

Amnion Amniotic cavity

Ectoderm Interm ediate mesoderm

Notochord

Endoderm

Dorsal aorta (paired)

Yolk sac D

Prim itive streak

Cut edge of amnion

Prim itive heart

Plane of section in f

Somites

Am nion

Amniotic cavity

Som ites

Lateral plate m esoderm

Som atopleura

Yolk sac

C

Fig. 1.1   Embryonic developme nt (after Sadler) Age in postovulatory days. A-C Posterior (dorsal) view after rem oval of the am nion. D-E Schem atic cross sections of the corresponding stages at the horizont al planes of section m arked in A to C. Gastrulation occurs in week 3 of hum an em bryonic developm ent. It produces three germ layers in the em bryonic disk: ectoderm (light grey), m esoderm (red), and endoderm (dark grey). A, D Day 19, the three layers are visible in the em bryonic disk. The am nion form s the am niotic cavit y dorsally, and the endoderm encloses

Neural crest

Amnion Amniotic cavity

Neural tube Surface ectoderm

Pair of somites

Gut tube

Splanchnopleura

E

Open caudal part of neural tube Caudal

Neural groove

Future gut tube

Neural folds

Closure of neural tube

Caudal

Site of fusion of neural folds to close neural tube

Paraxial m esoderm

Cranial

Yolk sac F

Intraem bryonic coelom (future body cavity)

the yolk sac. The neural tube is developing in the area of the neural plate. B, E Day 20, the rst som ites have form ed, and the neural groove is beginning to close to form the neural tube, with initial folding of the em bryo. C, F Day 22, eight pairs of som ites ank the partially closed neural tube, which has sunk below the ectoderm . The yolk sac elongates ventrally to form the gut tube and yolk sac. At the sites where the neural folds fuse to close the neural tube, cells form a bilateral neural crest that det aches from the surface and m igrates into the m esoderm .

Ta ble 1.1 Di e re ntiation of g e rm laye rs Ge rm laye r

Embryonic structure

Adult de rivative

Ectoderm

Neural tube

Brain, retina, spinal cord

Neural crest

Surface ectoderm

Neural crest of the head

Sensory and parasym pathetic ganglia, enteric nervous system , parafollicular cells, sm ooth m uscle, pigm ent cells, carotid body, cartilage, connective tissue, dentine and cem entum of the teeth, derm is and subcut aneous tissue of the head

Neural crest of the trunk

Sensory and autonom ic ganglia, peripheral glia, adrenal m edulla, pigm ent cells, intram ural plexuses

Placodes

Anterior pituit ary, cranial sensory ganglia, olfactory epithelium , inner ear, lens Epithelium of the oral cavit y, salivary glands, nasal cavities, paranasal sinuses, lacrim al passages, external auditory canal, epiderm is, hair, nails, cut aneous glands

Mesoderm

Paraxial

Som ites

Corium of skin (from derm atom e), m usculature (from m yotom e), vertebral colum n (from sclerotom e)

Axial

Notochord

Extraocular m uscles

Interm ediate Lateral plates

Endoderm

Intestinal tube

Kidneys, gonads, renal and genit al excretory duct s Visceral

Heart, blood vessels, sm ooth m uscle, bowel wall, blood, adrenal cortex, visceral serosa

Pariet al

Sternum , lim bs without m uscles, derm is and subcut aneous tissue of the anterolateral body wall, sm ooth m uscle, connective tissue, pariet al serosa Epithelium of the bowel, respiratory tract, digestive glands, pharyngeal glands, pharyngot ym panic (auditory) tube, t ym panic cavit y, urinary bladder, parathyroid glands, thyroid gland

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Hea d

Migrating sclerotome cells

Neural tube

Dermatome Myotom e

Aorta

Surface ectoderm

A Posterior horns of spinal cord

Posterior root

1. Embryology of the Hea d & Neck

Fig. 1.2 Somatic muscle  developme nt Age in post ovulat ory days. Each som it e divid es int o a de rm at om e (cut ane ous), m yot om e (m uscular), and scle rot om e (ve rt eb ral) at around day 22 (se e Fig 1.1). A Day 28, scle rot om es m igrat e t o form t he ve rt eb ral colum n around t he not chord (prim it ive sp inal cord). B Day 30, all 34 or 35 som it e pairs have form e d. The ne ural t ube diffe re nt iat es int o a p rim it ive spinal cord. Mot or and se nsory ne urons diffe re nt iat e in t he ant e rior and p ost e rior horns of t he sp inal cord, resp e ct ively. C By day 40, t he post e rior and ant e rior root s form t he m ixe d sp inal ne rve. The post e rior branch sup plies t he e piaxial m uscles (fut ure int rinsic back m uscles); t he ant e rior branch supplies t he hypaxial m uscles (ant e rior m uscles, including all m uscles e xce pt t he int rinsic b ack m uscles). D We ek 8, t he e p iaxial and hypaxial m uscles have diffe re nt iat e d int o t he skelet al m uscles of t he t runk. Cells from t he scle rot om es also m igrat e int o t he lim bs. During t his m igrat ion, t he spinal ne rves form t he p le xuses (ce rvical, b ranchial, and lum b osacral), which inne rvat e t he m uscles of t he ne ck, upp e r lim b, and lowe r lim b, resp e ct ively.

Anterior horns of spinal cord

B Posterior root (with ganglion)

Posterior ram us (to epaxial muscles)

Anterior ram us (to hypaxial m uscles)

Pharyngeal arches

C Vertebra (sclerotom e derivative)

Epaxial muscles (intrinsic back m uscles)

Optic vesicles

Cardiac prom inence

Vertebral colum n

Connecting stalk (with um bilical vessels) Lim b buds

Epiderm is and derm is (derm atom e derivative) D Hypaxial muscles (trunk and lim bs)

Fig. 1.3 5-w e ek-old e mbryo The hum an e m bryo at 5 we eks has a crown-rum p le ngt h of approxim at ely 5 t o 7 m m . The um bilical cord, which at t aches t he e m bryo t o t he m ot he r, is se e n. The fut ure ce reb ral he m isphe res form along wit h t he eye, ear, pharyngeal arches (which form a large port ion of t he st ruct ures of t he head and ne ck), heart (which will st art beat ing at around we ek 6), ne ural t ube, and lim b buds.

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1. Embryology of the Hea d & Neck

Hea d

Development of the Brain & Spinal Cord Notocord Surface ectoderm Notocord

Neural tube

Neural crest cells

Neural plate

Epiderm is

Neural folds Neural groove Neural crest

Fig. 1.4   Developme nt of the  ne ural tube  and ne ural crest (after Wolpert) The tissues of the nervous system orginate em bryonically from the posterior surface ectoderm .The notochord in the m idline of the body induces the form ation of the neural plate, which lies above the notochord, and of the neural crest s, which are lateral to the notochord. With further developm ent, the neural plate deepens at the center to form the neural groove, which is anked on each side by the neural folds. Later the groove deepens and closes to form the neural tube, which sinks below the ectoderm . The neural tube is the structure from

which the central nervous system (CNS) − the brain and spinal cord− develops (further developm ent of the spinal cord is shown in Fig . 1.5, further brain developm ent in Fig. 1.7). Failure of the neural groove to close com pletely will leave an anom alous cleft in the vertebral colum n, known as spina bi da. The adm inistration of folic acid to potential m others around the tim e of conception can reduce the incidence of spina bi da by 70%. Cells that m igrate from the neural crest develop into various structures, including cells of the peripheral nervous system (PNS), such as Schwann cells, and the pseudounipolar cells of the spinal ganglion (see Fig . 1.6).

Roof plate Alar plate Zone of autonom ic neurons A

Basal plate Floor plate

Roof plate White matter Zone of autonom ic neurons B

Alar plate

Posterior root

Basal plate

Spinal ganglion

Sprouting afferent axons of the posterior root in the spinal ganglion

Floor plate

White matter

Interneuron Posterior horn

Lateral horn

Central horn Anterior horn C

Fig. 1.5   Di e re ntiation of the  ne ural tube  in the  spinal cord during  developme nt Cross-section, superior view. A Early neural tube. B Interm ediate St age. C Adult spinal cord. The neurons that form the basal plate are e erent (m otor neurons), while the neurons that form the alar plate are a erent (sensory neurons). In the future thoracic, lum bar, and sacral spinal cord, there is another zone bet ween them that gives rise to sym pathetic (autonom ic) e erent neurons. The roof plate and the oor plate do not form neurons.

A

Sprouting efferent axons of the anterior root

B

Anterior root

Fig. 1.6   Developme nt of a pe riphe ral ne rve A erent (sensory) axons (blue) and e erent (m otor) axons (red) sprout from the neuronal cell bodies during early em bryonic developm ent. A Prim ary a erent neurons develop in the spinal ganglion, and alpha m otor neurons develop from the basal plate of the spinal cord. B The interneurons (black), which functionally interconnect the a erent and e erent neurons, develop at a later st age.

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Hea d

Cerebellum

Cervical flexure

Mesencephalon

Medulla oblongata

Cranial flexure Diencephalon

Pons

Telencephalon

Optic cup A

Telodiencephalic sulcus

Mesencephalon

Telecephalon

Cerebellum

Diencephalon

Mam illary tubercle

Pituitary prim ordium

Medulla oblongata Pons

Olfactory bulb B

Telencephalon Mesencephalon Insula Cerebellum Diencephalon Pons C

Medulla oblongata

1. Embryology of the Hea d & Neck

Fig. 1.7   Developme nt of the  brain A Em bryo with the greatest length (GL) of 10 m m at the beginning of the 2nd m onth of developm ent. Even at this st age, we can see the differentiation of the neural tube into segm ent s that will generate various brain regions. • • • • •

Red: telencephalon (cerebrum ) Yellow: diencephalon Dark blue: m esencephalon (m idbrain) Light blue: cerebellum Gray: pons and m edulla oblongat a

Note: The telencephalon outgrows all of the other brain structures as developm ent proceeds. B Em bryo with a GL of 27 m m near the end of the 2nd m onth of developm ent (end of the em bryonic period). The telencephalon and the diencephalon have enlarged. The olfactory bulb is developing from the telencephalon, and the prim ordium of the pituit ary gland is developing from the diencephalon. C Fetus with a GL of 53 m m in approxim ately the 3rd m onth of developm ent. By this st age the telencephalon has begun to cover the other brain areas. The insula is still on the brain surface but will subsequently be covered by the hem ispheres (com pare with D). D Fetus with GL of 27 cm (270 m m ) in approxim ately the 7th m onth of developm ent. The cerebrum (telencephalon) has begun to develop well-de ned gyri and sulci.

Telencephalon Insula

Eye

Cerebellum Pons D

Medulla oblongata

Ta ble 1.2 Developme nt of the  brain Primary ve sicle

Neural tube

Prosencephalon (forebrain)

Re g ion

Structure

Telencephalon

Cerebral cortex, white m at ter, basal ganglia

Diencephalon

Epithalam us (pineal gland), dorsal thalam us, subthalam us, hypothalam us

Mesencephlon (m idbrain)* Rhom bencephalon (hindbrain)

Tectum , tegm entum , cerebral peduncles

Metencephalon

Myelencephalon

Cerebellum

Cerebellar cortex, nuclei, peduncles

Pons*

Nuclei, ber tract s

Medulla oblongat a*

*The m esencephalon, pons, and m edulla oblongat a are collectively known as the brainstem .

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1. Embryology of the Hea d & Neck

Hea d

Development & Derivatives of the Pharyngeal (Branchial) Arches

Maxillary prom inence

Pharyngeal arches

Ectoderm al pharyngeal cleft Neural tube

Endodermal pharyngeal pouch

Pharyngeal gut

Prosencephalon

Pharyngeal arches

Cardiac and liver prom inence Connecting stalk with allantois

Optic vesicle

Fig. 1.8   Head and ne ck re g ion of a 5-w e ek-old e mbryo, show ing  the  pharyng eal (branchial) arches and cle fts Left lateral view. The pharyngeal arches are instrum ent al in the developm ent of the face, neck, larynx, and pharynx. Developm ent of the pharyngeal arches begins in the 4th week of em bryonic life as cells m igrate from the neural crest to the future head and neck region. Within 1 week, a series of four oblique ridges ( rst through fourth pharyngeal arches) form that are located at the level of the cranial segm ent of the foregut and are separated externally by four deep grooves (pharyngeal cleft s). The pharyngeal arches and cleft s are prom inent features of the em bryo at this st age.

Limb buds

Fig. 1.9   Cross se ction through an e mbryo at the  level of the  pharyng eal gut (after Drews) Left superior oblique view. Due to the craniocaudal curvature of the em bryo, the cross section passes through the pharyngeal arches and pharyngeal gut as well as the prosencephalon and spinal cord. The pharyngeal gut is bounded on both sides by the pharyngeal arches, which cont ain the m esoderm al core. They are covered externally by ectoderm and internally by endoderm . Ectoderm al pharyngeal cleft s and endoderm al pharyngeal pouches lie directly opposite one another. Because the em bryo is curved craniocaudally, the pharyngeal gut and pharyngeal arches overlie the prom inence of the rudim ent ary heart and liver.

Neural tube

Neural tube Cartilage rod Pharyngeal arch artery Posterior aorta Pharyngeal gut

Posterior root Anterior root Pharyngeal arch nerve

Anterior aorta

A

Cartilage rod Cleft B

Pouch Pharyngeal gut

Artery Nerve Cleft (ectoderm)

Fig. 1.10   Structure  of the  pharyng eal arches (after Sadler) A Cross section through a pharyngeal arch and the neural tube, showing the pharyngeal arch cartilage and artery. B Oblique cross section through a pharyngeal arch and the neural tube, showing the pharyngeal arch nerves. C Blow up of section in B, showing the relationship of pharyngeal arch cartilage, artery, and nerve in the pharyngeal arches. The pharyngeal arches are covered externally by ectoderm (blue) and internally by endoderm (green). Each pharyngeal arch contains an arch artery, an arch nerve, and a cartilaginous skeletal elem ent, all of which

Pouch (endoderm ) C

Arch (mesenchym e)

are surrounded by m esenchym e and m uscular tissue. The external grooves are called the pharyngeal cleft s, and the internal grooves are called the pharyngeal pouches.

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Hea d

Fig. 1.11   The  arrang e me nt and de rivatives  o f the  pharyng eal arche s (after Sadler and Drews) A The pharyngeal arches with the associated pharyngeal arch nerves B The m andibular nerve (CN V3 ), facial nerve (CN VII), glossopharyngeal nerve (CN IX), and vagus nerve (CN X) derived from the pharyngeal arch nerves C Muscles derived from the pharyngeal arches D Skeletal and ligam ent atous elem ent s derived from the pharyngeal arches

1. Embryology of the Hea d & Neck

First pharyngeal arch with pharyngeal arch nerve (m andibular arch) Second pharyngeal arch with pharyngeal arch nerve (hyoid arch) Third pharyngeal arch with pharyngeal arch nerve Fourth and sixth pharyngeal arches with pharyngeal arch nerve (fifth rudim entary only)

A

Mandibular nerve (from trigem inal nerve)

Muscles of facial expression

Tem poralis

Meckel’s Sphenom andibular ligament Malleus cartilage Incus

Posterior auricular m uscle Facial nerve (cranial nerve VII)

Styloid process, tem poral bone

Occipitalis Masseter

Glossopharyngeal nerve (cranial nerve IX)

B

C Laryngeal nerve (from vagus nerve)

Stapes

Digastric, anterior belly

Nerves

Digastric, posterior belly

Stylohyoid ligam ent

Infrahyold muscles

Greater horn of hyoid bone

Stylopharyngeus Musculature

D Lesser horn of hyoid bone

Cricoid cartilage

Thyroid cartilage

Skeletal and ligamentous elements

Ta ble 1.3 De rivatives of the  pharyng e al arches Pharyng e al arch

Muscles*

Skeletal and lig ame nto us ele me nts

Ne rve  accompanying  arch

1

Muscles of m astication • Tem poralis • Masseter • Lateral pt yergoid • Medial pterygoid Mylohyoid Digastric, anterior belly Tensor t ym pani Tensor veli palatini

Maxilla Mandible Zygom atic bone Palatine bone Vom er Squam ous part, tem poral bone Malleus and incus Meckel’s cartilage Sphenom andibular ligam ent Anterior ligam ent of m alleus

Mandibular n. (CN V3 )

2

Muscles of facial expression St ylohyoid Digastric, posterior belly St apedius

St apes St yloid process, tem poral bone Lesser horn, hyoid bone Upper part, hyoid bone

Facial n. (CN VII)

3

St ylopharyngeus

Greater horn, hyoid bone Lower part, hyoid bone

Glossopharyngeal n. (CN IX)

4 and 6

Pharyngeal m uscles • Levator veli palatini • Uvular m uscle • Palatoglossus • Salpingopharyngeus • Palatopharyngeus • Pharyngeal constrictors

Laryngeal skeleton • Thyoid cartilage • Cricoid cartilage • Arytenoid cartilage • Corniculate cartilage • Cuneiform cartilage

Vagus n. (CN X)

Laryngeal m uscles • Thyroarytenoid • Vocalis • Lateral cricoarytenoid • Cricothyroid • Oblique arytenoids • Transverse arytenoids • Posterior arytenoids • Aryepiglot tis • Thyroepiglot tis

Abbreviation: CN, cranial nerve. *All branchial skelet al m uscles

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1. Embryology of the Hea d & Neck

Hea d

Development & Derivatives of the Pharyngeal Pouches, Membranes, & Clefts 

Pharyngeal arches 1st pharyngeal cleft

1

Prim ative t ympanic cavit y 1st pharyngeal pouch 2

Pharyngot ympanic (auditory) tube

External auditory m eatus

2nd pharyngeal pouch

Palatine tonsil

3rd pharyngeal pouch

Inferior parathyroid gland

3

2nd, 3rd, 4th pharyngeal clefts

4

Thym us

Cervical sinus

4th pharyngeal pouch

Superior parathyroid gland

5th pharyngeal pouch

Ultimobranchial body A

B

Pharyngeal cavit y Oral cavit y 1

Thyroid gland 2

3

4 Trachea Lung bud

Fig. 1.12   Developme nt of the  pharyng eal  pouches, me mbranes,  and cle fts A Schem atic view of developing pharyngeal pouches and cleft s. B Schem atic view of adult structures form ed by pharyngeal pouches. C Three-dim ensional represent ation of the pharyngeal pouches and their relationship to the oral cavit y, pharyngeal cavit y, and structures of the neck. The pharyngeal pouches are paired, diverticula-like outpouchings of the endoderm al pharyngeal gut. A tot al of four distinct pharyngeal pouches develop on each side; the fth is often absent or rudim ent ary. The pharyngeal pouches develop into the t ym panic cavit y and the endocrine glands in the neck. The rst pharyngeal cleft develops into the external acoustic m eatus. The second pharyngeal arch grows over the third and fourth pharyngeal arches and as it does so it buries the second, third, and fourth pharyngeal cleft s. Rem nant s of these cleft s form the cervical sinus, which is norm ally obliterated. The pharyngeal m em branes separate the pharyngeal pouches from the pharyngeal cleft s in the developing em bryo. They collectively develop into the t ym panic m em brane.

Esophagus C

Thyroid gland anlage First aortic arch

Fig. 1.13   Pharyng eal pouches and the  aortic arch (after Sadler) The aortic arches (pharyngeal arch arteries) arise from the paired em bryonic anterior aort a and run bet ween the pharyngeal pouches. They open posteriorly into the posterior aort a, which is also paired. The denitive aortic arch develops from the fourth aortic arch on the left side. Note: The pouch protruding from the roof of the oral cavit y is called Rathke’s pouch (precursor of the anterior pituitary). Note also the lung bud extending anteriorly from the pharyngeal gut, and the prim ordial (anlage) of the thyroid gland.

Internal carotid artery Rathke’s pouch Anterior aorta

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Third aortic arch with associated artery

Fourth aortic arch artery (future aortic arch) Tracheal anlage with lung bud Posterior aorta Esophagus

Hea d

1. Embryology of the Hea d & Neck

Ta ble 1.4 De rivatives of the  pharyng e al pouche s Pouch

Ge rm laye r

Embryonic structure

Adult structure

1

Endoderm

Tubot ym panic recess

Epithelium of the pharyngot ym panic (auditory) tube Tym panic cavit y

2

Prim itive palatine tonsils

Tonsilar fossa Epithelium of the palatine tonsil

3

Divides into a posterior and an anterior part at it s dist al end

Inferior parathyroid gland (from posterior part) Thym us (from anterior part)

4

Divides into a posterior and a anterior part at it s dist al end

Superior parathyroid gland (from posterior part) Ultim obranchial body (from anterior part). This is later incorporated in thyroid gland and gives rise to the parafollicular or C cells, which secrete calcitonin.

Ta ble 1.5 De rviative  of the  pharyng eal me mbranes Me mbranes

Ge rm laye rs

Adult structure

1 to 4

Com posed externally of ectoderm and internally of endoderm . The intervening core consist s of m esoderm and neural crest cells.

Tym panic m em brane

Ta ble 1.6 De rivatives of the  pharyng e al cle fts Cle ft

Ge rm laye r

Adult structure

1

Ectoderm

External acoustic m eatus

2 to 4

Cervical sinus, which is rapidly obliterated by the 2nd pharyngeal arch, which grows over cleft s 2 to 4

Treache r Co llins syndro me is a rare autosom al dom inant craniofacial defect involving the structures derived from the rst pharyngeal arch. It is characterized by m alar hypoplasia (underdevelopm ent or incom plete developm ent of the cheek), m andibular hypoplasia, downslanting eyes, eyelid colobom a (notching of the lower eyelids), and m alform ed external ears. It m ay also be associated with cleft palate, hearing loss (due to defect s in the ossicles), vision loss, and di cult y breathing (dyspnea). Treatm ent will depend on the severit y of the defect s but will involve a m ultidisciplinary team of clinicians.

Pie rre -Ro bin syndro me is characterized by an abnorm ally sm all m andible (m icrognathia). As a result, the tongue m usculature is unsupported by the m andible, allowing it to displace posteriorly, partially obstructing the airway, resulting in dyspnea (shortness of breath). This posterior displacem ent of the tongue (glossoptosis) is also responsible for cleft palate because it prevent s the palatal shelves from fusing (see Figs. 1.21 and 1.22). Initial treatm ent involves surgery to repair the cleft palate to im prove feeding and speech developm ent.

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Hea d

1. Embryology of the Hea d & Neck

Development of the Tongue & Thyroid Gland

Lateral lingual swelling

Body of tongue

Tuberculum im par

Foram en cecum Copula (hypobranchaial em inence) Epiglot tal swelling

Term inal sulcus

Foram en cecum

Palatine tonsil Root of tongue

Laryngeal oriface

Laryngeal orifice Arytenoid swellings

Epiglot tis

Arytenoid swelling

A

Fig. 1.14   Developme nt of the  tong ue A Early tongue developm ent, around week 4. B Late tongue developm ent, around week 8. The tongue develops within the pharynx. While the m usculature of the tongue is derived from som ites, the tongue develops from the four pharyngeal (lingual) swellings. Three swellings are associated with the 1st arch and one, with the 3rd, 4th, and 6th arches. The t wo lateral and one m idline swelling (the tuberculum im par) from the 1st pharyngeal arch contribute to the developm ent of the anterior t wo thirds of the tongue. The single m idline swelling (the hypobranchial em inence [copula]) from the 3rd, 4th, and 6th arches contributes to the develop m ent of the posterior one third of the tongue. A U-shaped sulcus develops around the tongue allowing it to m ove freely, except in one area, which is the lingual frenulum , which anchors the tongue to the oor of the oral cavit y. The lingual m ucosa derived from the 1st arch swelling that covers the anterior t wo thirds of the tongue is innervated by the m andibular divi-

B

sion of the trigem inal nerve; the lingual m ucosa derived from the 3rd, 4th, and 6th arch swellings receives sensory innervation from both CN IX (hypoglossal nerve) and CN X (vagus nerve). The V-shaped term inal sulcus (sulcus term inalis) separates the anterior t wo thirds of the tongue from the posterior one third. Located at the vertex of the term inal sulcus, bet ween the tuberculum im par and the hypobranchial em inence, the foram en cecum m arks the site of exit for the thyroid gland from the oor of the inside of the pharynx to an extrapharyngeal location. Ankyloglossia (tongue-tie) is a congenit al anom aly in which the lingual frenulum is unusually short or thick, thereby tethering the ventral surface of the tip of the tongue to the oor of the m outh. Clinical features include restricted elevation, protrusion, and side-to-side m ovem ent of the tongue, and dem onstration of a heart-shaped tongue on protrusion. It m ay be noticed as di cult y feeding in infant s. Treatm ent, when required, involves a frenectomy, where the frenulum is incised, releasing the tongue.

Ta ble 1.7 De rivation of the  tong ue Pharyng e al arch

Embryonic structure (s)

Adult structure

Inne rvatio n

1

Two lateral lingual swellings Tuberculum im par

Anterior t wo thirds of the tongue

GSA: lingual branch of the m andibular division of the trigem inal n. (CN V3 )

2

Is obliterated by the 3rd arch and therefore does not contribute to the adult tongue Hypobranchial em inence (m inor involvem ent)

-

-

3

Hypobranchial em inence

Posterior one third of the tongue

GSA: glossopharyngeal n. (CN IX) SVA: glossopharyngeal n. (CN IX)

4

Hypobranchial em inence Epiglot tic swelling Arytenoid swelling Laryngotracheal groove

Root of the tongue

GSA: internal laryngeal branch of the vagus n. (CN X) SVA: internal laryngeal branch of the vagus n. (CN X)

Abbreviations: GSA, general som atic a erent ; SVA, special visceral a erent

Ta ble 1.8 De rvivation of the  skeletal muscle s of the  tong ue Muscle  orig in

Muscle s

Cranial ne rve s

Som ites (from myotom es)

Intrinsic m uscles of the tongue Extrinsic m uscles of the tongue (genioglossus, st yloglossus, and hyoglossus; not palatoglossus)

Hypoglossal n. (CN XII)

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Hea d

Pharyngotympanic (auditory) tube

Tym panic cavity External auditory meatus

Foram en cecum

Palatine tonsil Parathyroid glands, superior pair Parathyroid glands, inferior pair

Thyroid gland

Ultim obranchial body Thym us

Foram en cecum

Fig. 1.15   Migration of the  pharyng eal arch tissues (after Sadler) Anterior view. During em bryonic developm ent, the epithelium from which the thyroid gland form s m igrates from it s site of origin on the basal m idline of the tongue to the level of the rst tracheal cartilage, where the thyroid gland is located in postnat al life. As the thyroid tissue buds o from the tongue base, it leaves a vestigial depression on the dorsum of the tongue, the foram en cecum . The parathyroid glands are derived from the 4th pharyngeal arch (superior pair) or the 3rd pharyngeal arch (inferior pair), which also gives rise to the thym us. The ultim obranchial body, whose cells m igrate into the thyroid gland to form the calcitonin-producing C cells, or parafollicular cells, is derived from the 5th vestigial pharyngeal arch. The lat ter arch is the last to develop and is usually considered part of the 4th pharyngeal arch. The external auditory m eatus is derived from the 1st pharyngeal cleft, the t ym panic cavit y and pharyngot ym panic tube from the 1st pharyngeal pouch, and the palatine tonsil from the 2nd pharyngeal pouch. Ectopic thyroid is a rare condition in which the entire thyroid gland or thyroid tissues are not found in their norm al position in the neck, i.e., is inferolateral to the thyroid cartilage. Dentist s m ay encounter this as a rm m idline m ass, which m ay appear as light pink to bright red, and m ay be regular or irregular on the dorsal tongue, just posterior to the foram en cecum (the em bryonic origin of the thyroid gland). This is known as a lingual thyroid and represent s approxim ately 90% of ectopic thyroid cases. Sym ptom s of lingual thyroid m ay include cough, pain, di cult y swallowing (dysphagia), di cult y speaking (dysphonia), and di cult y breathing (dyspnea).

Foram en cecum Lateral neck cyst s

Thyroglossal duct

Hyoid Carotid bifurcation

Hyoid Median neck cyst s

Thyroid cartilage

Pyramidal lobe

Hyoid

Thyroid cartilage

Pyram idal lobe

Thyroid

Thyroid

Fistulas tract

Thyroid Sternocleidom astoid

Trachea A

1. Embryology of the Hea d & Neck

Trachea B

Fig. 1.16   Location of cysts and  stulas in the  ne ck A Median cyst s. B Median stulas. C Lateral stulas and cyst s. A, B Me dian cysts and  stulas in the  ne ck are rem nant s of the thyro glossal duct. Failure of this duct to regress com pletely m ay lead to the form ation of a m ucus- lled cavit y (cyst), which present s clinically as a palpable, uctuant, m idline swelling in the neck at around the level of the hyoid bone. It is seen to m ove upward on swallowing or protrusion of the tongue due to the connection of the tongue with the duct. Sym ptom s m ay include dyspnea (di cult y breathing), dysphagia (di cult y swallowing), and pain (only if the cyst becom es infected).

Trachea C

C Late ral cysts and  stulas in the  ne ck are anom alous rem nant s of the duct al portions of the cervical sinus, which form s as a result of tissue m igrations during em bryonic developm ent. If epithelium -lined rem nant s persist, neck cyst s (right) or stulas (an abnorm al com m unication bet ween structures; left) m ay appear in postnat al life. A com plete stula opens into the pharynx and onto the surface of the skin, whereas an incom plete (blind) stula is open at one end only. The external ori ce of a lateral cervical stula is t ypically lo cated at the anterior border of the sternocleidom astoid m uscle.

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Hea d

1. Embryology of the Hea d & Neck

Development of the Face

Frontonasal prom inence Maxillary prom inence Strom odeum Mandibular prom inence Cardiac prom inence Medial nasal prom inence A

Lateral nasal prom inence

Frontonasal prom inence

Frontonasal prom inence Eye

Nasal pit Maxillary prom inence Mandibular prom inence

Nasal pit

Naso-optic furrow

Lateral nasal prom inence

Strom odeum

Medial nasal prom inence

B

Eye Naso-optic furrow Strom odeum

C

Lateral nasal prom inence Eye

Medial nasal prom inence

Eye

Maxillary prom inence

Naso-optic furrow

D

Mandibular prom inence

Naso-optic furrow Philtrum

E

Fig. 1.17   Developme nt of the  face  (after Sadler) A Anterior view at 24 days. The surface ectoderm of the 1st pharyngeal arch invaginates to form the stromodeum, which is a depression bet ween the forebrain and the pericardium in the em bryo. It is the precursor of the m outh, oral cavit y, and the anterior pituit ary gland. At this st age, the strom odeum is separated from the prim itive pharynx by the buccopharyngeal (oropharyngeal) m em brane. This m em brane later breaks down and the strom odeum becom e continuous with the pharynx. The strom odeum is surrounded by ve neural-crest-cell−derived m esenchym al swellings, known as prominences, which contribute to the developm ent of the face. B Anterior view at 5 weeks. Nasal placodes, ectoderm al thickenings, form on each side of the frontonasal prom inence. Invagination of the nasal placodes into the frontonasal prom inence leads to the form ation of the lateral and m edial nasal prom inences. The placodes now lie in the oor of a depression known as the nasal pit. The m axillary prom inences continue to increase in size and m erge laterally with the m andibular prom inences to form the cheek. Medially, the m axillary prom inences com press the m edial nasal prom inences toward the m idline. A furrow (the naso -optic furrow) separates the nasal processes from the m axillary process. Ectoderm from the oor of the nasolacrim al groove (nasooptic furrow) will give rise to the nasolacrim al duct that connect s the orbit with the nasal cavit y; the t wo prom inences will join to close the groove and create the nasolacrim al canal.

C Anterior view at 6 weeks. The m edial nasal swellings enlarge, grow m edially, and m erge with each other to form the interm axillary segm ent. D Anterior view at 7 weeks. The m edial nasal processes have fused with each other along the m idline and with the m axillary processes and their lateral m argins. E Anterior view at 10 weeks. Cell m igration is com plete.

Ta ble 1.9 Promine nces contributing  to facial structures Promine nce

Facial structure

Frontonasal prom inence

Forehead, nose, m edial and lateral nasal prom inences

Maxillary prom inences

Cheeks, lateral part s of the upper lip

Medial nasal prom inences

Philtrum of the upper lip, crest and tip of nose

Lateral nasal prom inences

Alae of nose

Mandibular prom inences

Lower lip

*The frontonasal prom inence is a single unpaired structure; all other prom inences listed as paired.

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Hea d

1. Embryology of the Hea d & Neck

Wall of brain

Nasal pit Oronasal m em brane

Breakdown of oronasal m em brane

Medial nasal prom inence

Medial nasal prom inence

Tongue A

Tongue

Oral cavit y

B

Oral cavit y

Olfactory fibers Conchae

Olfactory fibers Nasal cham ber Prim itive choana Prim ary palate

Prim ary palate Upper lip

Tongue

Lower lip

Secondary palate Definitive choana

Mandible C

D

Fig. 1.18   Developme nt of the  nasal cavity Sagit t al section of em bryo. At week 6, the prim itive nasal cavit y is sep arated from the oral cavit y by the oronasal m em brane (A), which then breaks down (B), leaving the nasal and oral cavities in open connection by week 7 (C). In week 9, the nasal cavit y and oral cavit y are in their denitive arrangem ent (D), separated by the prim ary and secondary palate with choanae at their junction in the pharynx. The lateral walls of Fig. 1.19   Developme nt of the  eyes and e ars At about 22 days, the eyes and ears begin to develop. The eyes develop laterally in the em bryo but during growth m ove m edially to occupy their fam iliar position on the face. The auricle of the ear is form ed from six swellings, known as auricular hillcocks, from the rst and second pharyngeal pouches. The germ layers that contribute to the eyes and ears are listed in Table  1.10.

the nasal cavit y develop the superior, m iddle, and inferior conchae. The ectoderm al epithelium in the roof of the nasal cavit y becom es the specialized olfactory epithelium . The olfactory cells within the olfactory epithelium give rise to the olfactory nerve bers (CN I) that grow into the olfactory bulb. The nasal septum (not shown) develops as a downgrowth of the m erged m edial nasal prom inences. It fuses with the palatine process by weeks 9 to 12.

Oral cavit y

Left eye Nodules that form auricle

Ta ble 1.10 De rivation of the  structures of the  eye  and e ar Ge rm laye r

Maxillary prom inence

Structure

Eye Surface ectoderm

Nasolacrim al groove

Corneal and conjunctival epithelium , lens, lacrim al glands, t arsal glands

Neural crest cell ecto derm (neuroectoderm )

Retina, optic nerve (CN I), iris

Mesenchym e

Corneal strom a, sclera, choroid, iris, part s of vitrous, ciliary m uscle, m uscles lining the anterior cham ber

Opening of left nasal sac (future naris) Cardiac prom inence

Second pharyngeal arch Third pharyngeal arch First pharyngeal arch

Ear Ectoderm

External acoustic m eatus

Endoderm

Auricle

Mesenchym e

Vestibulocochlear organ

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Hea d

1. Embryology of the Hea d & Neck

Development of the Palate Frontal area

Medial nasal prom inence Lateral nasal prom inence Right eye

Nasal cavit y

Left eye

Nasal septum

Nasal septum

Oronasal m embrane

Maxillary prom inence (1st arch)

Roof of stomodeum (base of skull)

Lateral palatine process (1st arch)

Palatine shelf Tongue

Fig. 1.20   Palate  formation, 7- to 8-w e ek-old e mbryo Inferior view. Before the palate has form ed, the oral cavit y is open to the nasal cavit y. The nasal septum can be seen as well as the oronasal m em brane, which will ultim ately form the choana. Developm ent of the palate begins during week 5, but fusion of it s part s is not com plete until week 12. The m ost critical period for palate developm ent is bet ween the end of week 6 and the beginning of week 9. The palate form s from t wo m ajor part s, the prim ary and secondary palates. The prim ary palate is derived from the wedge-shaped interm axillary segm ent, which is form ed by the m erging of the t wo m edial nasal prom inences. The secondary palate is derived from t wo shelf-like outgrowths of the m axillary prom inence, which, at this stage, are directed downward beside the tongue (rem oved).

Fig. 1.21   Elevation of the  palatine  shelves The palatine shelves, which form the secondary palate, are seen at around 6 weeks and are directed obliquely downward on each side of the tongue. At around 7 weeks, the palatine shelves ascend to a horizont al position above the tongue and fuse.

Prim ary palate Secondary palate Contact and fusion

Nasal septum

A

B

C

D

Fig. 1.22   Fusion and me rg ing  of the  palatine  shelves Fusion of the palate begins at around 9 weeks and is com pleted posteriorly by week 12. (A) The prim ary palate and both halves of the secondary palate m igrate toward each other as indicated by the arrows. (B) They cont act and fuse at a point (m arked by the incisive foram en)

and m erge anteriorly and posteriorly, as shown in (C) and (D). The prim ary and secondary palates ossify, form ing the hard palate. The posterior portions of the palatine shelves do not becom e ossi ed but extend beyond the nasal septum to form the soft palate and uvula.

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Hea d

Prim ary palate

Incisive foram en

Naris (nostril)

1. Embryology of the Hea d & Neck

Maxilla

Unilateral, com plete cleft lip

Unilateral, com plete cleft of lip, alveolus, and prim ary palate

Upper lip

A

Uvula Prim ary palate

D

Secondary palate

B

C

Philtrum

Bilateral complete cleft of lip, alveolus, and prim ary palate

E

Cleft of secondary palate

Fig. 1.23   Formation of facial clefts (after Sadler) Inferior view. Cleft s ( ssures or openings) can involve the lips and/or the palate. Cleft s are classi ed as isolated (cleft lip or cleft palate), unilateral or bilateral, and as com plete (when they cross the nasal philtrum ) or incom plete (if they do not cross the nasal philtrum ). A Normal lips and palate , in which the m axillary prom inences and m edial nasal prom inences have m erged to form the upper lip and prim ary palate. The prim ary palate has also fused with the palatine processes of the m axillary prom inences (secondary palate) to form the com plete, uni ed, hard palate. The posterior portion of the secondary palate is unossi ed and form s the soft palate and uvula. B Unilate ral, co mple te  cleft lip result s from failure of fusion of the m axillary prom inence with the m edial nasal prom inence on the affected side. C Unilate ral, co mple te  cleft lip, alve olus, and primary palate (part of palate anterior to the incisive foram en) result s from failure of fusion

F

Unilateral, complete cleft of lip, alveolus and palate (prim ary and secondary palate)

of the m axillary prom inence with the m edial nasal prom inence on the a ected side. D Bilate ral, comple te  cleft lip, alve olus, and primary palate result from failure of the m axillary prom inences to fuse with the m edial nasal prom inences on both sides. E Cle ft of se condary palate (part of palate posterior to the incisive fo ram en) result s from incom plete fusion of the t wo lateral palatine processes. F Unilate ral, comple te  cleft lip and complete  cleft palate (involving both prim ary and secondary palate) result from failure of fusion of the m axillary prom inence with the m edial nasal prom inence and failure of fusion of the t wo lateral palatine processes on the a ected side. Cleft lip and palate can cause di cult y in eating and speaking, and result in failure to thrive in infant s. Treatm ent by a m ultidisciplinary team of healthcare professionals principally involves corrective surgery, which is usually perform ed bet ween 6 and 12 m onths of age, often followed by surgical revisions, speech therapy, and orthodontic therapy.

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Hea d

2. Cra nia l Bones

Development of the Cranial Bones

Fig. 2.1 Bones of the skull Left lateral view. The skull form s a bony capsule that encloses the brain and viscera of the head. The bones of the skull are divided into t wo part s. The viscerocranium (orange), the facial skeleton, is form ed prim arily from the pharyngeal (branchial) arches (see pp. 6 and 7). The neurocranium (gray), the cranial vault, is the bony capsule enclosing the brain. It is divided into t wo part s based on ossi cation (see Fig. 2.2). The cartilaginous neurocranium undergoes endochondral ossi cation to form the base of the skull. The membranous neurocranium undergoes intram em branous ossi cation.

Fig. 2.2 Ossi cation of the  cranial bones Left lateral view. The bones of the skull develop either directly or indirectly from m esenchym al connective tissue. The bones of the desm ocranium (gray) develop directly via intram em branous ossi cation of m esenchym al connective tissue. The bones of the chondrocranium (blue) develop indirectly via endochondral ossi cation of hyaline cartilage. Note: The skull base is form ed exclusively by the chondrocranium . Elem ent s form ed via intram em branous and endochondral ossi cation m ay fuse to form a single bone (e.g., the elem ent s of the occipit al, tem poral, and sphenoid bones contributing to the skull base are cartilaginous, while the rest of the bone is m em branous).

Ta ble 2.1 Developme nt of the skull Embryo nic orig ins

Adult bone

Ossi catio n

Maxilla

I

Nasal bone

I

Lacrim al bone

I

Vom er

I

Palatine bone

I

Zygom atic bone

I

Tem poral bone (t ym panic part)

I

Mandible

I

Malleous

E

Incus

E

St apes

E

Tem poral bone (st yloid process)

E

Hyoid bone (superior part, lesser horn)

E

Hyoid bone (inferior part, greater horn)

E

Sphenoid bone (pterygoid process)

E

Front al bone

I

Tem poral bone (squam ous part)

I

Ethm oid bone

E

Sphenoid bone

E

Ethm oid bone

E

Sphenoid bone

E

Occipit al bone (lower portion)

E

Tem poral bone (petrom astoid part)

E

Viscerocranium

Neural crest, pharyngeal (branchial) arches

1st pharyngeal arch, m axillary prom inence

1st pharyngeal arch, m andibular prom inence

2nd pharyngeal arch

3rd pharyngeal arch Neural crest Membranous neurocranium

Neural crest Paraxial m esoderm Cartilaginous neurocranium

Neural crest Paraxial m esoderm

Abbreviations: I, intram em branous; E, endochondral. Note: Tubular (long) bones undergo endochondral ossi cation. The clavicle is the only exception. Congenit al defect s of intram em branous ossi cation therefore a ect both the skull and clavicle (cleidocranial dysostosis).

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2. Cra nia l Bones

Anterior fontanelle Anterior fontanelle

Coronal suture Sphenoid (anterolateral) fontanelle

Posterior fontanelle

Frontal suture

Lam bdoid suture

Coronal suture

Mastoid (posterolateral) fontanelle

A

Fig. 2.3 Cranial sutures (craniosynostoses) and fontanelles A Left lateral view of neonat al skull. B Superior view of neonat al skull. The at cranial bones grow as the brain expands; thus the sutures bet ween them rem ain open after birth. In the neonate, there are six areas

Pterion

Sagit tal suture Posterior fontanelle

B

(font anelles) bet ween the still-growing cranial bones that are occupied by unossi ed brous m em brane. The posterior font anelle provides a reference point for describing the position of the fet al head during childbirth. The anterior font anelle provides access for drawing cerebro spinal uid (CSF) sam ples in infant s (e.g., in suspected m eningitis).

Coronal suture

Coronal suture Sagit tal suture

Sphenofrontal suture

Squam ous suture Lam bdoid suture Lam bdoid suture

Lam bda

Asterion

B

Bregm a

Sphenosquam ous suture

A

Fig. 2.4 Sutures in the  adult skull A Left lateral view. B Superior view. Synost osis (t he fusion of t he cranial bones along t he sut ures) occurs d uring adult hood. Alt hough t he e xact t im es of closure vary,

t he orde r (sag it t al, coronal, lam bd oid) d oes not . Closure of each font anelle yield s a part icular junct ion (se e Table  2.2 ). Pre m at ure closure of t he cranial sut ures produces charact e rist ic d eform it ies (se e Fig . 2 .1 1, p. 22).

Ta ble 2.2 Closure  of sutures and fontanelle s Fontanelle

Ag e  at closure

Suture

Ag e  at o ssi cation

1 Posterior fontanelle

2–3 m onths (lam bda)

Front al suture

Childhood

2 Sphenoid (anterolateral) font anelles

6 m onths (pterion)

Sagit t al suture

20–30 years old

2 Mastoid (posterolateral) font anelles

18 m onths (asterion)

Coronal suture

30–40 years old

1 Anterior font anelle

36 m onths (bregm a)

Lam bdoid suture

40–50 years old

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Skull: Lateral View

Temporal bone, squam ous part Frontal bone

Parietal bone

Sphenoid bone, greater wing

Ethm oid bone

Lacrim al bone

Nasal bone

Zygom atic bone

Maxilla Occipital bone

Temporal bone, petrom astoid part Mandible Tem poral bone, t ym panic part

Fig. 2.5 Cranial bones Left lateral view.

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Pterion

2. Cra nia l Bones

Coronal suture

Frontal bone

Squam ous suture Parietal bone

Sphenoparietal suture Sphenofrontal suture Sphenosquam ous suture Supraorbital foram en Glabella Sphenoid bone, greater wing Ethm oid bone Lacrim al bone Zygom atic bone, temporal process

Nasal bone Zygom atic bone, frontal process

Temporal bone, zygom atic process

Infraorbital foram en Anterior nasal spine Maxilla, zygom atic process

Lam bdoid suture Mastoid foram en

Mastoid process Tym panom astoid fissure

St yloid process Articular tubercle (articular em inence)

Mandible, body Obligue line

Mental protuberance

Mental foram en

Asterion

External acoustic m eatus Postglenoid tubercle

Zygom atic arch Mandible, ram us

Zygom atic bone

Fig. 2.6 Skull (cranium) Left lateral view. This view displays the greatest num ber of cranial bones (indicated by di erent colors in Fig. 2.5). The zygom atic arch is

form ed by the zygom atic process of the tem poral bone and the tem poral process of the zygom atic bone, which are united by an oblique suture.

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Skull: Anterior View

Sphenoid bone, lesser wing Frontal bone Parietal bone

Sphenoid bone, greater wing Nasal bone

Temporal bone

Ethm oid bone, m iddle nasal concha

Sphenoid bone, greater wing

Zygom atic bone Inferior nasal concha Maxilla

Mandible

Fig. 2.7 Cranial bones. Anterior view.

I

II

III

Fig. 2.8 Le  Fort classi cation of midfacial fracture s The fram elike construction of the facial skeleton leads to characteristic pat terns of fracture lines in the m idfacial region (Le Fort I, II, and III). Le Fo rt I: This fracture line runs across the m axilla and above the hard palate. The m axilla is separated from the upper facial skeleton, disrupt ing the integrit y of the m axillary sinus (low transverse fracture). Le Fort II: The fracture line passes across the nasal root, ethm oid bone, m axilla, and zygom atic bone, creating a pyramid fracture that disrupt s the integrit y of the orbit. Le Fo rt III: The facial skeleton is separated from the base of the skull. The m ain fracture line passes through the orbit s, and the fracture m ay additionally involve the ethm oid bones, front al sinuses, sphenoid sinuses, and zygom atic bones.

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Glabella Superciliary arch

Nasion

Frontal bone

Maxilla, frontal process

Frontal incisure (notch)

Tem poral bone Supraorbital foram en

Supraorbital m argin

Sphenoid bone, greater wing

Nasal bone Sphenoid bone, lesser wing

Tem poral bone Orbit

Ethm oid bone, perpendicular plate

Sphenoid bone, greater wing

Infraorbital m argin

Zygom atic bone, frontal process

Ethm oid bone, m iddle nasal concha

Piriform (anterior nasal) aperture Maxilla, zygom atic process

Vom er Inferior nasal concha

Infraorbital foram en

Anterior nasal spine Mandible, ram us

Interm axillary suture

Oblique line

Maxilla, alveolar process Mandible, body

Mental foram en

Mental protuberance

Mental tubercles

Fig. 2.9 Skull Anterior view. The boundaries of the facial skeleton (viscerocranium ) can be clearly appreciated in this view. The bony m argins of the anterior nasal aperture m ark the st art of the respiratory tract in the skull. The nasal cavit y, like the orbit s, cont ains a sensory organ (the olfactory m ucosa). The paranasal sinuses are shown schem atically in Fig.

7.8, p. 175. The anterior view of the skull also displays the three clinically im portant openings through which sensory nerves pass to supply the face: the supraorbital foram en, infraorbit al foram en, and m ent al foram en.

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Skull: Posterior View

Parietal bone

Occipital bone

Temporal bone, squam ous part

Temporal bone, petrom astoid part

Vom er

Sphenoid bone

Palatine bone

Maxilla Mandible

Fig. 2.10 Cranial bones. Posterior view.

A

B

C

D

Fig. 2.11 Pre mature  closure  of cranial sutures The prem ature closure of a cranial suture (craniosynostosis) m ay lead to characteristic cranial deform ities: A B C D

Sagit t al suture: scaphocephaly (long, narrow skull). Coronal suture: oxycephaly (pointed skull). Front al suture: trigonocephaly (triangular skull). Asym m etrical suture closure, usually involving the coronal suture: plagiocephaly (asym m etric skull).

A

B

Fig. 2.12 Hydroce phalus and microce phaly A Hydroce phalus: When the brain becom es dilated due to cerebro spinal uid (CSF) accum ulation before the cranial sutures ossify, the neurocranium will expand, whereas the facial skeleton rem ains unchanged. B Microce phaly: Prem ature closure of the cranial sutures result s in a sm all neurocranium with relatively large orbit s.

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Parietal foram ina

Lam bda Sagit tal suture

Parietal bone

Parietal em inence

Lam bdoid suture Occipital bone Temporal bone, squam ous part

Suprem e nuchal line

Temporal bone, petrous part

Asterion Superior nuchal line

External occipital protuberance (inion)

Median nuchal line (external occipital crest)

Mastoid foram ina Mastoid notch

Inferior nuchal line

Temporal bone, m astoid process

Vom er

Temporal bone, st yloid process

Occipital condyle Palatine bone

Sphenoid bone, pterygoid process

Mandible, ram us

Mandibular foram en

Maxilla, palatine process

Mylohyoid groove Incisive fossa

Mandible, body

Subm andibular fossa Mylohyoid line

Digastric fossa

Genial (m ental) spines

Fig. 2.13 Skull Posterior view. The occipit al bone, which is dom inant in this view, articulates with the parietal bones, to which it is connected by the lam bdoid suture. Worm ian (sutural) bones are isolated bone plates often found in the lam bdoid suture. The cranial sutures are a special t ype of syndes-

m osis (i.e., ligam entous at t achm ent s that ossify with age). The outer surface of the occipit al bone is contoured by m uscular origins and insertions: the inferior, superior, m edian, and suprem e nuchal lines.

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Calvaria

Nasal bone

Frontal bone

Parietal bone

Occipital bone

Fig. 2.14 Bones of the  calvaria External surface, superior view.

Diploic veins

Em issary vein Endosteal layer of dura m ater

Scalp Outer table Diploë Dural sinus

Inner table Dura m ater

Arachnoid granulations

Meningeal layer of dura m ater Falx cerebri

Fig. 2.15 The  scalp and calvaria The three-layered calvaria consist s of the outer t able, the diploë, and the inner t able. The diploë has a spongy structure and cont ains red (blood-form ing) bone m arrow. With a plasm acytom a (m alignant transform ation of cert ain white blood cells), m any sm all nest s of tum or cells m ay destroy the surrounding bony trabeculae, and radiographs will dem onstrate m ultiple lucent areas (“punched-out lesions”) in the skull.

Fig. 2.16 Se nsitivity of the  inne r table  to trauma  The inner t able of the calvaria is very sensitive to external traum a and m ay fracture even when the outer t able rem ains int act (look for corresponding evidence on CT im ages).

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Nasal bone Bregm a

Frontal bone

Coronal suture

Parietal bone

Sagit tal suture

Frontal bone

Frontal crest

Frontal sinus Groove for superior sagit tal sinus

Superior and inferior temporal lines A

Parietal foram en

Occipital bone

Lam bdoid suture

Meningeal grooves Parietal bone

Granular foveolae

Fig. 2.17 Exte rnal and inte rnal surface  of the  calvaria The external surface of the calvaria (A) is relatively sm ooth, unlike it s internal surface (B). It is de ned by the frontal, parietal, and occipit al bones, which are interconnected by the coronal, sagit tal, and lambdoid sutures. The sm ooth external surface is interrupted by the pariet al foram ina, which gives passage to the parietal em issary veins (see Fig. 3.24, p. 67). The internal surface of the calvaria bears a num ber of pit s and grooves: • Granular foveolae (sm all pit s in the inner surface of the skull caused by saccular protrusions of the arachnoid m em brane [arachnoid granulations] covering the brain) • Groove for the superior sagit t al sinus (a dural venous sinus of the brain, see Fig . 3.22, p. 66)

B Groove for superior sagit tal sinus

Parietal foram en

• Arterial grooves (which m ark the positions of the arterial vessels of the dura m ater, such as the m iddle m eningeal artery, which supplies m ost of the dura m ater and overlying bone) • Frontal crest (which gives at t achm ent to the falx cerebri, a sickleshaped fold of dura m ater bet ween the cerebral hem ispheres).

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Skull Base: Exterior Median palatine suture Transverse palatine suture

Teeth Palatine process Maxilla Zygom atic process Zygom atic bone

Palatine bone

Frontal bone

Inferior nasal concha

Sphenoid bone

Vom er

Tem poral bone, zygom atic process

Lateral and m edial pterygoid plates

Tem poral bone, squam ous part

Spheno-occipital synchrondrosis

Tem poral bone, t ympanic part

Occipital condyle

Mastoid process Tem poral bone, petrom astoid psrt

Foram en m agnum

Occipital bone Parietal bone

Fig. 2.18 Bones of the  skull base External surface, inferior view. The base of the skull is com posed of a m osaic-like assem bly of various bones.

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Incisive fossa (opening of incisive foram ina) Posterior nasal spine

Palatine bone Inferior orbital fissure

Greater palatine foramen Lesser palatine foramen

Zygom atic arch

Infratemporal crest Scaphoid fossa

Pteryoid ham ulus Medial and lateral pteryoid plates

Sphenoidal foramen

Pharyngeal canal

Foram en ovale

Vomerovaginal canal

Foram en spinosum

Pharyngeal tubercle

Foram en lacerum Petrotympanic fissure

Mandibular (glenoid) fossa Occipital condyle

Carotid canal

Stylom astoid foram en

Jugular foram en Tym panic canaliculus

Mastoid (digastric) incisure (Posterior) condylar canal Mastoid foram en

Inferior nuchal line

Median nuchal line

Superior nuchal line External occipital protuberance (inion)

Suprem e nuchal line

Fig. 2.19 Skull base External surface, inferior view. Note the openings that transm it nerves and vessels. With abnorm alities of bone growth, these openings m ay rem ain too sm all or m ay becom e narrowed, com pressing the neuro-

vascular structures that pass through them . The sym ptom s associated with these lesions depend on the a ected opening. All of the structures depicted here will be considered in m ore det ail in subsequent pages.

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Skull Base: Interior

Frontal bone

Ethm oid bone

Sphenoid bone Temporal bone, squam ous part Temporal bone, petrom astoid part

Parietal bone Occipital bone

Fig. 2.20 Bones of the  skull base Internal surface, superior view.

Jugum sphenoidale

Anterior cranial fossa

Anterior cranial fossa Sphenoid bone, lesser wing

Dorsum sellae

Middle cranial fossa

Foram en magnum

Petrous ridge (crest)

Middle cranial fossa

Posterior cranial fossa

Posterior cranial fossa B

A

Fig. 2.21 The  cranial fossae A Skull base, internal surface, superior view. B Skull base, m idsagit tal section. The interior of the skull base is deepened to form three successive fossae: the anterior, m iddle, and posterior cranial fossae. These depressions becom e progressively deeper in the frontal-to-occipital direction, form ing a terraced arrangem ent that is displayed m ost clearly in B.

Foram en m agnum

The cranial fossae are bounded by the following structures: • Anterior to m iddle: lesser wings of the sphenoid bone and the jugum sphenoidale • Middle to posterior: superior border (ridge) of the petrous part of the tem poral bone and the dorsum sellae

Fig. 2.22   Common fracture  lines of skull base  Internal surface, superior view. In response to m asticatory pressures and other m echanical stresses, the bones of the skull base are thickened to form “pillars” along the principal lines of force. The intervening areas that are not thickened are sites of predilection for bone fractures, resulting in the t ypical pat terns of skull base fracture lines shown here in red. An analogous phenom enon of t ypical fracture lines is found in the m idfacial region (see the anterior views of Le Fort fractures on p. 20).

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Frontal crest

2. Cra nia l Bones

Frontal sinus

Chiasm atic groove

Ethm oid bone, cribriform plate

Optic canal

Ethm oid bone, crista galli

Anterior clinoid process

Frontal bone

Foram en ovale

Sphenoid bone, lesser wing

Foram en spinosum

Sphenoid bone, greater wing

Arterial groove Foram en lacerum

Sphenoid bone, hypophyseal fossa

Hiatus of facial canal

Posterior clinoid process

Clivus

Groove for lesser petrosal nerve

Petro-occipital fissure

Temporal bone, petrous part

Hypoglossal canal

Internal acoustic m eatus

Groove for sigm oid sinus

Jugular foram en Foram en m agnum Cerebellar fossa Internal occipital crest

Groove for transverse sinus

Internal occipital protuberance Cerebral fossa

Fig. 2.23 Skull base Internal surface, superior view. The openings in the interior of the base of the skull do not always coincide with the openings visible on the exterior because som e neuro vascular structures change direction when passing through the bone or pursue a relatively long intraosseous course. An exam ple of this is the internal acoustic m eatus, through which the facial nerve, am ong other structures, passes from the interior of the skull into the petrous part of the tem poral bone. Most of it s bers then leave the petrous bone through the st ylom astoid foram en, which is visible from the external aspect (see Fig.4.87, p. 131, and Fig . 2.45, p. 44, for further det ails).

located in the anterior, m iddle, or posterior cranial fossa. The arrangem ent of the cranial fossae is shown in Fig . 2.21. The cribriform plate of the ethm oid bone connect s the nasal cavit y with the anterior cranial fossa and is perforated by num erous foram ina for the passage of the olfactory bers (see Fig . 7.22, p. 180). Note: Because the bone is so thin in this area, a front al head injury m ay easily fracture the cribriform plate and lacerate the dura m ater, allowing cerebrospinal uid (CSF) to enter the nose. This poses a risk of m eningitis, as bacteria from the nonsterile nasal cavit y m ay enter the sterile CSF.

In learning the sites where neurovascular structures pass through the base of the skull, it is helpful initially to note whether these sites are

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Sphenoid Bone

Palatine bone Sphenoid bone

Vom er

Occipital bone

Temporal bone

A

Frontal bone Sphenoid bone

Parietal bone

Occipital bone

Tem poral bone

B Parietal bone

Fig. 2.24 Position of the sphe noid bone in the skull The sphenoid bone is the m ost structurally com plex bone in the hum an body. It m ust be viewed from various aspect s in order to appreciate all it s features (see also Fig. 2.25): A Skull base, e xte rio r. The sphenoid bone com bines with the occipital bone to form the load-bearing m idline structure of the skull base. B Skull base, inte rio r. The lesser wing of the sphenoid bone form s the boundary bet ween the anterior and m iddle cranial fossae. The openings for the passage of nerves and vessels are clearly displayed (see det ails in Fig. 2.45). C Left late ral view . Portions of the greater wing of the sphenoid bone can be seen above the zygom atic arch, and portions of the pterygoid process can be seen below the zygom atic arch.

Frontal bone

Sphenoid bone, greater wing

C

Fig. 2.25 Isolate d sphe noid bone A Infe rio r view  (it s position in situ is shown in Fig. 2.24). This view dem onstrates the m edial and lateral plates of the pterygoid process. Bet ween them is the pterygoid fossa, which is occupied by the m edial pterygoid m uscle. The foram en spinosum and foram en ovale provide pathways through the base of the skull (see also in C). B Ante rior view . This view illustrates why the sphenoid bone was originally called the sphecoid bone (“wasp bone”) before a transcription error turned it into the sphenoid (“wedge-shaped”) bone. The apertures of the sphenoid sinus on each side resem ble the eyes of the wasp, and the pterygoid processes of the sphenoid bone form it s dangling legs, bet ween which are the pterygoid fossae. This view also displays the superior orbit al ssure, which connect s the m iddle cranial fossa with the orbit on each side. The t wo sphenoid sinuses are separated by an internal septum (see Fig. 7.11, p. 175).

Pterygoid process

Tem poral bone

C  Supe rior view . The superior view displays the sella turcica, whose central depression, the hypophyseal fossa, cont ains the pituit ary gland. The foram en spinosum , foram en ovale, and foram en rotundum can be identi ed. D Po ste rior view . The superior orbit al ssure is seen clearly in this view, whereas the optic canal is alm ost com pletely obscured by the anterior clinoid process. The foram en rotundum is open from the m iddle cranial fossa to the pterygopalatine fossa of the skull (the foram en spinosum is not visible in this view; com pare with A). Because the sphenoid and occipit al bones fuse together during pubert y (“tribasilar bone”), a suture is no longer present bet ween the t wo bones. The cancellous trabeculae are exposed and have a porous appearance.

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Superior orbital fissure

Lesser wing

Sphenoid crest

2. Cra nia l Bones

Aperture of sphenoid sinus Greater wing Foram en rotundum

Greater wing

Medial plate Lateral plate Temporal surface

Pterygoid process

Foram en ovale Foram en spinosum

A

Pterygoid ham ulus

Body

Pterygoid fossa Lesser wing

Sphenoid crest

Aperture of sphenoid sinus

Orbital surface Temporal surface

Superior orbital fissure Greater wing

Foram en rotundum

Pterygoid canal

Pterygoid fossa

B

Lesser wing

Medial plate

Optic canal

Pterygoid ham ulus

Jugum sphenoidale

Lateral plate

Pterygoid process

Superior orbital fissure

Greater wing Chiasm atic groove Foram en rotundum Foram en ovale

Anterior clinoid process

Foram en spinosum C

Sella turcica

Hypophyseal fossa

Posterior clinoid process Lesser wing

Optic canal

Posterior clinoid process Superior orbital fissure

Anterior clinoid process

Greater wing, cerebral surface Foram en rotundum

Pterygoid canal

Cancellous trabeculae

Foram en ovale D

Pterygoid fossa

Dorsum sellae

Medial plate Lateral plate

Pterygoid process

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Temporal Bone

Parietal bone

Fig. 2.26 Position of the  te mporal bone  in the  skull Left lateral view. The tem poral bone is a m ajor component of the base of the skull. It form s the capsule for the auditory and vestibular apparatus and bears the articular fossa of the tem porom andibular joint (TMJ).

Temporal bone Occipital bone

Zygom atic bone

Sphenoid bone, greater wing

Sphenoid bone

Zygom atic bone, temporal process

Squam ous part

Tympanic part

Mandibular fossa

Petrom astoid part

St yloid process

Sphenoid bone

Squam ous part Petrom astoid part

Occipital bone Parietal bone Occipital bone A

B

Fig. 2.27 Te mporal bone  in the  skull A Internal view. B Inferior view. The tem poral bone, develops from four centers that fuse to form a single bone: • The squamous part (light green) includes the articular fossa (m andibular [glenoid] fossa) of the tem porom andibular joint (TMJ).

Chorda t ympani

Facial nerve

Mastoid air cells

Tym panic m em brane Pharyngot ympanic (auditory) tube Internal carotid artery Internal jugular vein

Mastoid process

• The petromastoid part (pale green) cont ains the auditory and vestib ular apparatus. • The tympanic part (darker green) form s large portions of the external auditory canal. • The styloid process develops from cartilage derived from the second pharyngeal arch and is a site of m uscle at t achm ent.

Fig. 2.28   Proje ction of clinically important structures onto the  left  te mporal bo ne The t ympanic m em brane is shown translucent in this lateral view. Because the petrous bone contains the m iddle and inner ear and the t ym panic membrane, a knowledge of it s anatomy is of key importance in otological surgery. The internal surface of the petrous bone has openings (see Fig. 2.29) for the passage of the facial nerve, internal carotid artery, and internal jugular vein. A ne nerve, the chorda t ympani, passes through the t ympanic cavit y and lies medial to the t ympanic membrane. The chorda t ympani arises from the facial nerve, which is susceptible to injury during surgical procedures (see p. 131). The m astoid process of the petrous bone form s air- lled chambers, the m astoid cells, that vary greatly in size. Because these chambers comm unicate with the middle ear, which in turn com municates with the nasopharynx via the pharyngot ympanic (auditory or Eustachian) tube, bacteria in the nasopharynx m ay pass up the pharyngot ympanic tube and gain access to the m iddle ear. From there they m ay pass to the mastoid air cells and nally enter the cranial cavit y, causing meningitis.

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Postglenoid tubercle

Zygom atic process

Temporal surface

External acoustic opening Articular tubercle (articular em inence)

Mastoid foram en

Mandibular (glenoid) fossa

External acoustic m eatus

Petrot ympanic fissure

Tympanom astoid fissure St yloid process

A

Zygom atic process

Tym panic canaliculus

Articular tubercle (articular em inence)

Mastoid process

Mandibular (glenoid) fossa

Arcuate em inence

Groove for m iddle m eningeal arteries

Carotid canal

External acoustic m eatus

St yloid process

Petrous ridge (groove for superior petrosal sinus)

Mastoid process

Jugular fossa Mastoid canaliculus

Mastoid notch

St ylom astoid foram en Occipital groove

Mastoid foram en

Aqueduct of the vestibule B

Zygom atic process Internal acoustic m eatus Mastoid foram en

C

Petrous apex

Groove for sigm oid sinus

St yloid process

Fig. 2.29 Left te mporal bone A Lateral view . An em issary vein passes through the m astoid foram en (external ori ce shown in A, internal ori ce in C), and the chorda t ym pani passes through the m edial part of the petrot ym panic ssure. The m astoid process develops gradually in life due to traction from the sternocleidom astoid m uscle and is pneum atized from the inside (see Fig. 2.28). B  Infe rior view . The shallow articular fossa of the tem porom andibular joint, the m andibular (glenoid) fossa, is clearly seen from the inferior view. The facial nerve em erges from the base of the skull through

the st ylo m astoid foram en. The initial part of the superior jugular bulb is adherent to the jugular fossa, and the internal carotid artery passes through the carotid canal to enter the skull. C Me dial view . This view displays the internal ori ce of the m astoid foram en and the internal acoustic m eatus. The facial nerve and vestibulocochlear nerve are am ong the structures that pass through the internal m eatus to enter the petrous bone. The part of the petrous bone shown here is also called the petrous pyramid, whose apex (often called the “petrous apex”) lies on the interior of the base of the skull.

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Occipital Bone & Ethmoid Bone

Occipital squam a

Hypoglossal (anterior condylar) canal Foram en m agnum

Fig. 2.30   Position of the  occipital bone  in the  e xte rio r skull base Inferior view. B

Jugular notch

Posterior condylar canal Jugular process

Basilar part

Hypoglossal (anterior condylar) canal

Groove for superior sagit tal sinus

Pharyngeal tubercle

Foram en m agnum Posterior condylar canal

Groove for transverse sinus

Cruciform em inence

Internal occipital crest

Inferior nuchal line

External occipital crest (m edian nuchal line)

A

Internal occipital protuberance

Occipital condyle

Posterior condylar canal

Foram en m agnum

Superior nuchal line

External occipital protuberance (inion)

Suprem e nuchal line

Fig. 2.31 Isolate d occipital bone A Infe rio r view . This view shows the basilar part of the occipit al bone, whose anterior portion is fused to the sphenoid bone. The condylar canal term inates posterior to the occipit al condyles, and the hypoglossal canal passes superior and opens anterior to the occipital condyles. The condylar canal is a venous channel that begins in the sigm oid sinus and ends in the occipit al vein. The hypoglossal canal cont ains a venous plexus in addition to the hypoglossal nerve (CN XII). The pharyngeal tubercle gives at t achm ent to the pharyngeal raphe, and the external occipit al protuberance provides a palpable bony landm ark on the occiput.

Jugular process

C

Basilar part

B  Left late ral view . The extent of the occipital squam a, which lies above the foram en m agnum , is clearly appreciated in this view. The internal openings of the condylar canal and hypoglossal canal are visible along with the jugular process, which form s part of the wall of the jugular foram en (see p. 27). C  Inte rnal surface. The grooves for the dural venous sinuses of the brain can be identi ed in this view. The cruciform em inence overlies the con uence of the superior sagit t al sinus and transverse sinuses. The con guration of the em inence shows that in som e cases the sagit tal sinus drains predom inantly into the left transverse sinus.

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Fig. 2.32   Position of the  ethmoid bone  in the  inte rior skull base Superior view. The superior part of the ethm oid bone form s part of the anterior cranial fossa, and it s inferior portions contribute structurally to the nasal cavities and orbit. The ethm oid bone is bordered by the front al and sphenoid bones.

2. Cra nia l Bones

Fig. 2.33 Position of the  e thmoid bone  in the  facial skeleton  Anterior view. The ethm oid bone is the central bone of the nose and paranasal sinuses. It also form s the m edial wall of each orbit.

Perpendicular plate

Crista galli

Crista galli Cribriform plate

Ethm oid air cells

Orbital plate

A

Crista galli

Orbital plate

B Anterior ethm oid foram en

Ethm oid air cells Superior m eatus

Middle concha

Crista galli

Posterior ethm oid foram en

Ethm oid air cells

Perpendicular plate

Orbital plate Superior concha

Ethm oid bulla Perpendicular plate

Middle concha

Uncinate process

D

C

Fig. 2.34 Isolate d e thmoid bone A Supe rio r view . This view dem onstrates the crista galli, which gives at tachm ent to the falx cerebri and the horizont ally directed cribriform plate. The cribriform plate is perforated by foram ina through which the olfactory bers pass from the nasal cavit y into the anterior cranial fossa (see Fig. 7.22, p. 180). With it s num erous foram ina, the cribriform plate is a m echanically weak structure that fractures easily in response to traum a. This t ype of fracture is m anifested clinically by CSF leakage from the nose (“runny nose” in a patient with head injury). B  Ante rior view . The anterior view displays the m idline structure that separates the t wo nasal cavities: the perpendicular plate. Note also the m iddle nasal concha, which is part of the ethm oid bone (of the conchae, only the inferior nasal concha is a separate bone), and the ethm oid cells, which are clustered on both sides of the m iddle con-

Ethm oid infundibulum

Middle concha

Perpendicular plate

chae. C  Left late ral view . Viewing the bone from the left side, we observe the perpendicular plate and the opened anterior ethm oid cells. The orbit is separated from the ethm oid cells by a thin sheet of bone called the orbit al plate. D Po ste rio r view . This is the only view that displays the uncinate process, which is alm ost com pletely covered by the m iddle concha when in situ. It partially occludes the entrance to the m axillary sinus, the sem ilunar hiatus, and it is an im port ant landm ark during endoscopic surgery of the m axillary sinus. The narrow depression bet ween the m iddle concha and uncinate process is called the ethm oid infundibulum . The front al sinus, m axillary sinus, and anterior ethm oid air cells open into this “funnel.” The superior concha is located at the posterior end of the ethm oid bone.

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Zygomatic (Malar) Bone & Nasal Bone

Maxilla

Sphenoid bone, greator wing

Zygom atic bone Sphenoid bone

Frontal bone Tem poral bone

Maxilla, orbital surface Zygom atic bone Maxilla

Tem poral bone, zygomatic process B

A

Fig. 2.35   Zyg omatic bone  in the  skull A Left lateral view. B Inferior view. The zygom atic (m alar) bone, or zygom a, is im port ant in determ ining the width and m orphology of the face and is a m ajor but tress bet ween the m axilla and the skull. In addition, it form s a signi cant portion of the oor and lateral walls of the orbit. The zygom a cont ains foram ina that transm it the zygom aticofacial and zygom aticotem poral arteries

and the corresponding nerves (from the m axillary nerve [CN V2 ]) . Muscles that at t ach along the zygom atic arch include the m asseter, zygo m aticus m ajor, and som e bers of the tem poralis fascia. The Whitnall tubercle, which is the at t achm ent site for the lateral canthal tendon, is located on the zygom a. This tendon is crucial in m aint aining the contour of the eye.

Maxillary process

Frontal process Infraorbital m argin

Tem poral surface

Maxillary process

Zygom aticofacial foram en

Temporal process

Tem poral process

B

A

Fig. 2.36   Isolate d zyg omatic bone A Inferior view. B Left lateral view. The zygom a is a subst antial bone but it s prom inent position on the face leaves it vulnerable to fracture following traum a. Traum a that transm it s m inim al force to the zygom a m ay cause a non-displaced fracture at the suture lines. Greater force, for exam ple, following a m otor vehicle accident, will result in displacem ent of the bone and involvem ent of the orbit al rim and oor, the zygom aticofront al suture, the zygom aticom axillary but tress, and the zygom atic arch. Sym ptom s of zygom a fracture include pain, facial bruising and swelling, a at tened m alar em inence, diplopia (double vision), trism us (lock jaw), and al-

tered m astication (due to m asseteric spasm or interference of the norm al m echanism of the coronoid process by bony fragm ent s), loss of sensation below the orbit (due to infraorbit al nerve involvem ent), and ipsilateral epist axis (nosebleed) (due to laceration of the m ucosa of the m axillary sinus). Nondisplaced fractures do not require treatm ent. Displaced fractures com m only require open reduction and xation, with reconstruction of the orbit. Displacem ent of the zygom atic arch m ay be reduced by the Gillies technique, in which an incision is m ade over the tem poralis m uscle and an instrum ent is slid under the arch and hooked and the arch is elevated into it s norm al position.

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2. Cra nia l Bones

Frontal bone

Nasion Nasal bones Foram en for em issary vein

Lacrim al bone

Maxilla, orbital surface

Zygom atic bone, orbital surface

Maxilla, frontal process

Ethm oid bone

Vom er

Fig. 2.37   Nasal bone  in the  skull Anterior view. Fractures of the nasal bones are com m on following facial traum a, for exam ple, m otor vehicle accident s, sport s injuries, or ght s. This is due both to the prom inence of the nose and the fragilit y of the nasal bones. Sym ptom s of nasal fractures include pain, bruising, swelling, epistaxis

(nosebleeds), and deform it y of the nose. The patient m ay also experience di cult y breathing. Minor nasal fractures require no treatm ent while those that cause deform it y will require m anual realignm ent. More severe nasal fractures, for exam ple, those involving the nasal septum or other facial bones will require surgery.

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Maxilla & Hard Palate

Maxilla Zygom atic bone

Palatine bone

Nasal bone Lacrim al bone Ethmoid bone Zygom atic bone

Vom er

Maxilla

B

A

Fig. 2.38 Maxilla and hard palate  in skull A Anterior view. B Exterior of skull base, inferior view.

Frontal process

Orbital surface

Infraorbital groove

Infraorbital foram en

Zygom atic process

Anterior nasal spine

Interm axillary suture Alveolar process

A Fossa for lacrim al sac Canine fossa

Canine eminence

Incisive fossa Orbital surface

Frontal process

Infraorbital groove Facial surface

Infraorbital foram en

Zygom atic process Posterior superior alveolar foram ina

Anterior nasal spine

Infratemporal surface Tuberosity

B

Fig. 2.39 Isolate d maxilla A Anterior view. B Left lateral view.

Canine eminence

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Canine fossa

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Fig. 2.40 Bone s of the  hard palate A Superior view. The upper part of the m axilla is rem oved. The oor of the nasal cavit y shown here and the roof of the oral cavit y (B) are form ed by the union of the palatine processes of the t wo m axillary bones with the horizont al plates of the t wo palatine bones. Cleft palate result s from a failed fusion of the palatine processes at the m edian palatine suture (see p. 15). B Inferior view. The nasal cavit y com m unicates with the nasopharynx via the choanae, which begin at the posterior border of the hard palate. The t wo nasal cavities com m unicate with the oral cavit y via the incisive canals (A), which com bine and em erge at the incisive foram en. C Oblique posterior view. This view illustrates the close anatom ic relationship bet ween the oral and nasal cavities. Note: The pyram idal process of the palatine bone is integrated into the lateral pterygoid plate of the sphenoid bone. The palatine m argin of the vom er articulates with the hard palate along the nasal crest. Tori are bony exostoses (lum ps) that can be found on both jaws. Torus palatinus occurs in the center of the hard palate; torus m andibularis occurs in the lingual prem olar or m olar region of the m andible. Tori are com pletely benign but m ay cause problem s for denture retention, in which case they can be surgically excised.

2. Cra nia l Bones

Anterior nasal spine (cut)

Incisive canal

Maxillary sinus

Nasal crest (cut)

Maxilla, palatine process

Palatine bone, perpendicular plate

Transverse palatine (palatom axillary) suture

Palatine bone, horizontal plate

Greater palatine canal

Palatine bone, pyram idal process

Medial pterygoid plate, sphenoid bone

Lateral pterygoid plate, sphenoid bone

Palatine bone, posterior nasal spine

A

Incisive fossa (opening of incisive foram ina)

Palatine process of m axilla

Transverse palatine suture

Median (interm axillary) palatine suture

Greater palatine foram en

Interpalatine suture

Lesser palatine foram en Inferior orbital fissure

Maxillary tuberosit y Medial pterygoid plate

Pyram idal process of palatine bone

Pterygoid fossa

Choana Posterior nasal spine

Lateral pterygoid plate Scaphoid fossa

B

Anterior clinoid process

Septum of sphenoid sinus

Pterygoid canal

Foram en ovale

Foram en spinosum

Optic canal

Superior orbital fissure

Ostium of sphenoid sinus

Middle nasal concha

Pterygoid fossa

Ethm oid bone, perpendicular plate

Inferior orbital fissure

Maxilla, zygom atic process Inferior nasal concha

Choana (external nares) Vom er Median palatine (interm axillary) suture C

Vom er

Lateral pterygoid plate Medial pterygoid plate Incisive fossa

Pterygoid ham ulus Palatine process of m axilla

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Mandible & Hyoid Bone Head (condyle) of m andible Neck of m andible

Pterygoid fovea

Internal oblique ridge

External oblique ridge

Oblique line

Coronoid process

Ram us of m andible

Mental protuberance

Head (condyle) of m andible Alveolar process

Mental foram en

Coronoid process

Alveoli (tooth sockets) Lingula

A

Mental tubercles

Body of m andible

Internal oblique ridge

Mandibular foram en Mylohyoid groove

Mandibular notch

Head (condyle) of m andible

Coronoid process

Pterygoid fovea Condylar process

Sublingual fossa

Subm andibular fossa

Mandibular foram en

B

Lingula

Superior and inferior m ental spines (genial tubercles)

Digastric fossa

Mylohyoid line

Ram us of m andible

Alveolar process Mental protuberance

Angle Mental tubercle

C

Mental foram en

Body of m andible

Oblique line

External oblique ridge

Fig. 2.41 Mandible A Ante rior view . The m andible is connected to the viscerocranium at the tem porom andibular joint, whose convex surface is the head of the m andibular condyle. This “head of the m andible” is situated atop the vertical (ascending) ram us of the m andible, which joins with the body of the m andible at the m andibular angle. The teeth are set in the alveolar processes (alveolar part) along the upper border of the m andibular body. This part of the m andible is subject to t ypical age-related changes as a result of dent al developm ent (see Fig . 2.43). The m ent al branch of the trigem inal nerve exit s through the m ent al foram en. The location of this foram en is im port ant in clinical exam inations, as the tenderness of the nerve to pressure can be tested at that location. B  Posterior view. The m andibular foram en is particularly well displayed in this view. It transm it s the inferior alveolar nerve, which supplies sensory innervation to the m andibular teeth. Its term inal branch em erges from the m ental foram en. The m andibular foram en

and the m ental foram en are interconnected by the m andibular canal. C  Oblique  left late ral view . This view displays the coronoid process, the condylar process, and the m andibular notch bet ween them . The coronoid process is a site for m uscular at t achm ent s, and the condylar process bears the head of the m andible, which articulates with the articular disk in the m andibular (glenoid) fossa of the tem poral bone. A depression on the m edial side of the condylar process, the pterygoid fovea, gives at t achm ent to portions of the lateral pterygoid m uscle. D Supe rior view . This view displays the retrom olar fossa, retrom olar triangle, and buccal shelf. The retrom olar fossa is the insertion point for som e bers of the tem poralis m uscle. Lower dentures should be designed to avoid this area so that they are not dislodged during m astication. The buccal shelf (as a prim ary bearer of stress) and the retrom olar triangle are areas that are utilized to provide support for lower dentures.

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2. Cra nia l Bones

Head (condyle) of m andible Pterygoid fovea Mandibular foram en Lingula Coronoid process

Retrom olar fossa Retrom olar triangle Buccal shelf

Angle of mandible

Molars Genial spines

Premolars

Interalveolar septum

Canine

Incisors D

Lesser horn

A

Greater horn

Body

Lesser horn

B

Greater horn

Body

Lesser horn

Greater horn

C

Fig. 2.42 Hyoid bone A Anterior view. B Posterior view. C Oblique left lateral view. The hyoid bone is suspended by m uscles and ligam ent s bet ween the oral oor

and the larynx. The greater horn and body of the hyoid bone are palpable in the neck. The physiological m ovem ent of the hyoid bone can be palpated during swallowing.

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Mandible: Age -related Changes & Mandibular Fractures

A

B

C

Fig. 2.43 Ag e -relate d chang es in the  mandible The structure of the m andible is greatly in uenced by the alveolar process the teeth. Because the angle of the m andible adapt s to changes in the alveolar process, the angle bet ween the body and ram us also varies with age-related changes in the dentition. The angle m easures approxim ately 150 degrees at birth and approxim ately 120 to 130 degrees in adult s, decreasing to 140 degrees in the edentulous m andible of old age. A At birth the m andible is without teeth, and the alveolar process has not yet form ed. B In childre n the m andible bears the deciduous teeth. The alveolar process is still relatively poorly developed because the deciduous teeth are considerably sm aller than the perm anent teeth. C  In adults the m andible bears the perm anent teeth, and the alveolar process is fully developed. D In old ag e with resorption of the alveolar process, the m andible is edentulous (toothless).

D

Note: The resorption of the alveolar process with aging age leads to a change in the position of the m ental foram en (which is norm ally lo cated below the second prem olar tooth, as in C). This change m ust be t aken into account in surgery or dissections involving the m ental nerve. The alveolar process is the portion of the m axilla and m andible that support s the root s of the teeth. It is com posed of t wo part s, the alveolar bone proper and the supporting bone. The alveolar bone proper lines the tooth socket s (alveoli). Supporting bone consist s of cortical plates of com pact bone on the inner and outer surfaces of the m axilla and m andible and the intervening spongy bone bet ween the cortical plates and alveolar bone proper. Alveolar bone is subject to resorption following tooth loss (a norm al physiological process) and in certain disease st ates (e.g., abscess form ation, cyst s, osteoporosis). Basal bone is that portion of the m axilla and m andible deep to the alveolar bone. It is not subject to resorption.

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2. Cra nia l Bones

Head of m andible Coronoid process

Ram us of m andible

Angle of m andible

Alveolar process

A

Mental foram en

Mental protuberance

Body of m andible

Plate

B

Fig. 2.44 Mandibular fracture Anterior view. A Mandibular fracture. B Reduction and xation of m andibular fracture. Mandibular fracture is a com m on injury, for exam ple, following m otor vehicle accident s, ght s, or sporting accident s, due to the prom inence of the m andible and it s relative lack of support. Most fractures occur in the body (~ 30%), condyle (~ 25%), angle (~ 25%), and sym physis (~ 17%). To avoid m isdiagnosis of the injury, the history should include not just inform ation about the current injury but inform ation about previous m andibular traum a or tem porom andibular joint (TMJ) dysfunction. Determ ine the patency of the airway and the presence of other injuries (facial lacerations, swellings, or hem atom as). Inspect intraoral tissuesa for bruising, which, if present, is suggestive of a fracture of the body or sym physis. Palpate the m andible from the sym physis to the angle, noting any swelling, tenderness, or step deform ities. Next palpate the condyle through the external acoustic m eatus; tenderness m ay indicate a fracture at this site. Note any deviation on opening the m outh. With condylar fractures, the m andible deviates toward the side of the fracture. Note also any obstruction to m outh

opening, e.g., trism us (lock jaw due to spasm of the m uscles of m astication) or im paction of the coronoid process. Now evaluate the occlusion. If the teeth do not occlude as norm al, this is highly suggestive of m andibular fracture, although this can also occur following tooth subluxation (loosening) or TMJ injury. Note any areas of altered sensation (paresthesia, dysesthesia, or anesthesia). The lat ter is suggestive of a fracture dist al to the m andibular foram en. Following this, the m andible should be grasped at either side of the suspected fracture and gently m anipulated to assess m obilit y. Con rm the diagnosis via either radiography or CT scans. Treat with antibiotics to prevent infection, followed by reduction (to the patient’s norm al occlusion) and surgical xation of the fracture. The xation m ethod depends on m any factors including the t ype and site of fracture and m ay involve the use of bars, wires, or plates for interm axillary xation. The double m andibular fracture shown here is treated in a t wo-step process. First, the fracture at the m idline is xated with m et al plates followed by the angle fracture. Note that t wo plates provide m uch m ore st abilit y than a single plate.

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Neurovascular Pathw ays through the Skull Base Cribriform plate

Incisive canal

Nasopalatine nerve , greater palatine artery

Olfactory nerve , anterior and posterior ethmoidal art e rie s

Greater palatine foramen

Optic canal

Greater palatine nerve and artery

Optic nerve , ophthalm ic artery

Lesser palatine foramina

Superior orbital fissure Superior ophthalm ic vein

Abducent nerve

Lacrimal nerve

Nasociliary nerve

Lesser pala tine nerve and art e ry

Oculom otor nerve

Foramen lacerum Deep petrosal nerve, greater petrosal nerve

Frontal nerve Trochlear nerve

Foramen spinosum Foramen rotundum

Middle meningeal artery, meningeal br. of mandibular nerve (CN V3 )

Maxillary nerve (CN V2) Foramen ovale

Carotid canal

Mandibular nerve (CN V3 ), lesser petrosal nerve, accessory meningeal artery

Internal carotid artery, internal carotid sympathetic plexus

Carotid canal Petrotympanic fissure

Internal carotid artery, internal carotid sym pathetic plexus

Anterior t ympanic artery, chorda t ympani

Foramen spinosum

Middle meningeal artery, meningeal br. of mandibular nerve (CN V3 )

Stylomastoid foramen Facial nerve, st ylomastoid artery

Hiatus of canal for lesser petrosal nerve

Jugular foramen Lesser petrosal nerve, superior t ym panic artery

Sigm oid sinus Glossopharyngeal nerve

Hiatus of canal for greater petrosal nerve

Vagus nerve

Greater petrosal nerve

Inferior petrosal sinus

Internal acoustic meatus

Posterior m eningeal artery

Accessory nerve

Labyrinthine art e ry and vein Mastoid foramen

Vestibulocochlear nerve

Em issary vein

Facial nerve

Hypoglossal canal

Jugular foramen Internal jugular vein Glossopharyngeal nerve Vagus nerve

Hypoglossal nerve, venous plexus of hypoglossal canal

Foramen magnum

Accessory nerve Inferior petrosal sinus

Spinal vein

Posterior spinal artery

Accessory nerve

Posterior m eningeal art e ry

Anterior spinal artery

Medulla oblongata

Vertebral artery

Fig. 2.45  Passage of neurovascular structures through the skull base A Cranial cavit y (interior of skull base), superior view. B Exterior of skull base, inferior view. This im age and the corresponding t able only address structures entering and exiting the skull. Many neuro vascular structures pass through

Condylar canal Condylar em issary vein

bony canals within the skull (to pterygopalatine fossa, infratem poral fossa, etc.). Note: The deep petrosal nerve and greater petrosal nerve travel over the surface of foram en lacerum but not through it.

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2. Cra nia l Bones

Ta ble 2.3 Ope nings in the  skull base Cranial cavity

Ope ning

Transmitte d structures Ne rve s

Arte ries and ve ins

Inte rnal view , base  o f the  skull

Anterior cranial fossa

Cribriform plate

• CN I (olfactory bers collected to form olfactory n.)

• Anterior and posterior ethm oidal aa. (from ophthalm ic a.) • Ethm oidal vv. (to superior ophthalm ic v.)

Middle cranial fossa

Optic canal

• CN II (optic n.)

• Ophthalm ic a. (from internal carotid a.)

Superior orbit al ssure

• • • •

• Superior and inferior ophthalm ic vv. (to cavernous sinus) (Note: The inferior ophthalm ic v. also drains through the inferior orbit al ssure to the pterygoid plexus.)

Foram en rotundum *

• CN V2 (m axillary n.)

Foram en ovale

• CN V3 (m andibular n.) • Lesser petrosal n. (CN IX)

• Accessory m eningeal a. (from m andibular part of m axillary a.)

Foram en spinosum

• CN V3 , recurrent m eningeal branch

• Middle m eningeal a. (from mandibular part of m axillary a.)

Carotid canal

• Carotid plexus (postganglionic sym pathetics from superior cervical ganglion)

• Internal carotid a.

Hiatus of canal for greater petrosal n.

• Greater petrosal n. (CN VII)

• Super cial petrosal a. (from m iddle m eningeal a.)

Hiatus of canal for lesser petrosal n.

• Lesser petrosal n. (CN IX)

• Superior t ym panic a. (from m iddle m eningeal a.)

Internal acoustic m eatus

• CN VII (facial n.) • CN VIII (vestibulocochlear n.)

• Labyrinthine a. (from vertebral a.) • Labyrinthine vv. (to superior petrosal or transverse sinus)

Jugular foram en

• CN IX (glossopharyngeal n.) • CN X (vagus n.) • CN XI (accessory n., cranial root)

• • • •

Hypoglossal canal

• CN XII (hypoglossal n.)

• Venous plexus of hypoglossal canal

Foram en m agnum

• Medulla oblongat a with m eningeal coverings • CN XI (accessory n.)

• Vertebral aa. • Anterior and posterior spinal aa. (from vertebral a.) • Em issary vv.

Posterior cranial fossa

CN III (oculom otor n.) CN IV (trochlear n.) CN VI (abducent n.) CN V1 (ophthalm ic n.) divisions (lacrim al, front al, and nasociliary nn.)

Internal jugular v. (bulb) Sigm oid sinus (to bulb of internal jugular v.) Posterior m eningeal a. (from ascending pharyngeal a.) Inferior petrosal sinus

Exte rnal aspe ct, base  o f the  skull (w he re  di e re nt from inte rnal aspe ct)

Incisive canal

• Nasopalatine n. (from CN V2 )

• Branch of greater palatine a.

Greater palatine foram en

• Greater palatine n. (from CN V2 )

• Greater palatine a. (from pterygopalatine part of m axillary a. or descending palatine a.)

Lesser palatine foram en

• Lesser palatine n. (from CN V2 )

• Lesser palatine aa. (from pterygopalatine part of m axillary a. or as branch of greater palatine a. or descending palatine a.)

Foram en lacerum **

• Deep petrosal n. (from superior cervical ganglion via carotid plexus) • Greater petrosal n. (from CN VII)

Petrot ym panic ssure

• Chorda t ym pani (from CN VII)

• Anterior t ympanic a. (from m andibular part of m axillary a.)

St ylom astoid foram en

• Facial n. (CN VII)

• St ylom astoid a. (from posterior auricular a.)

(Posterior) condylar canal

• Condylar em issary v. (to sigm oid sinus)

Mastoid foram en

• Mastoid em issary v. (to sigm oid sinus)

*The external opening of the foram en rotundum is located in the pterygopalatine fossa, which is located deep on the lateral surface of the base of the skull and is not visible here. **Structures travel over the superior surface of the foramen lacerum , not through it, from external to internal (with the exception of lymphatic vessels and em issary veins).

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Muscles of the Head: Origins & Insertions The bony origins and insertions of the m uscles are indicated by color shading : origins (red) and insertions (blue).

Muscles of facial expression (CN VII)

Sternocleidomastoid and trapezius (CN XI)

Occipitalis (occipitofrontalis, occipital belly)

Sternocleidom astoid

Corrugator supercilii Orbicularis oculi

Trapezius

Orbital part Lacrim al part

Levator labii superioris alaeque nasi Nuchal muscles, intrinsic back muscles (dorsal rami of cervical nerves)

Zygom aticus major Zygom aticus m inor Levator anguli oris

Sem ispinalis capitis Transverse part Alar part

Obliquus capitis superior

Depressor septi nasi

Rectus capitis posterior m ajor

Nasalis

Orbicularis oris

Rectus capitis posterior m inor

Buccinator Mentalis

Muscles of mastication (CN V3 )

Orbicularis oris

Splenius capitis Longissim us capitis

Masseter Depressor labii inferioris

Lateral pterygoid (see B and C)

Depressor anguli oris

Tem poralis

Platysma

Medial pterygoid (see B and C)

A

Lateral pterygoid, superior head* Temporalis

Fig. 2.46   Origins and insertions on the skull A Left lateral view. B Inner surface of right hem im andible. C Inferior view of skull base. Note: The st ylohyoid, st yloglossus, and st ylo pharyngeus originate on the st yloid process.

Lateral pterygoid, inferior head

Buccinator

Medial pterygoid

Genioglossus Mylohyoid Geniohyoid B

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Digastric, anterior belly *Prim arily insert s into articular disk.

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2. Cra nia l Bones

Muscles of mastication (CN V3 )

Masseter Medial pterygoid Lateral pterygoid Temporalis

Tensor veli palatini (CN V3 ) Levator veli palatini (pharyngeal plexus) St ylopharyngeus (CN IX)

St yloglossus (CN XII) St ylohyoid Digastric, posterior belly (CN VII)

Prevertebral muscles (anterior rami of cervical spinal nerve and cervical plexus)

Nuchal muscles, intrinsic back muscles (posterior rami of spinal cervical nerves)

Rectus capitis lateralis Longus capitis

Splenius capitis

Rectus capitis anterior

Longissim us capitis Obliquus capitis superior Rectus capitis posterior m ajor

Sternocleidomastoid and trapezius (CN XI)

Rectus capitis posterior m inor

Sternocleidom astoid

Sem ispinalis capitis

Trapezius C

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3. Vascula ture & Lympha tics of the Hea d & Neck

Arteries of the Head & Neck: Overview & Subclavian Artery

Angular artery Superficial temporal artery Posterior auricular artery Superior labial artery

Maxillary artery Occipital artery Ascending pharyngeal artery

Inferior labial artery

Facial artery

Facial artery

Internal carotid artery Carotid bifurcation with carotid body

Lingual artery Superior thyroid artery

Vertebral artery

Superior laryngeal artery External carotid artery Com m on carotid artery

Thyrocervical trunk Subclavian artery

Fig. 3.1 Ove rview of the arte ries of the head and ne ck Left lateral view. The left com m on carotid artery arises from the aortic arch; the right com m on carotid artery from the brachiocephalic trunk. Each com m on carotid artery divides into an internal carotid artery and an external carotid artery at the carotid bifurcation, which is at the approxim ate level of the fourth cervical vertebra. The carotid body is lo-

cated at the carotid bifurcation. It contains the chem oreceptors that respond to oxygen de ciency in the blood (hypoxia) and to changes in pH (both are im port ant in the regulation of breathing). The internal carotid artery does not branch further before entering the skull, where it m ainly supplies blood to the brain. It also gives o branches that sup ply areas of the facial skeleton that em erge from the cranium .

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3. Vascula ture & Lympha tics of the Hea d & Neck

Basilar artery

Transverse foram en

Ascending cervical artery Inferior thyroid artery

Vertebral artery

Transverse cervical artery

Left com m on carotid artery Internal thoracic artery

Thyrocervical trunk Suprascapular artery

Left subclavian artery

Interscalene space

Fig. 3.2 Subclavian arte ry and its branches Anterior view. The subclavian artery distrib utes a num ber of branches to structures located at the base of the neck and in the region of the thoracic inlet. Note that the branches of the subclavian artery m ay arise in a variable sequence. After em erging from the thoracic inlet, the subclavian artery passes through the interscalene space (bet ween the anterior scalene and m iddle scalene) and on into the axilla as the axillary artery. Each vertebral artery arises from the posterior aspect of the subclavian artery on each side and ascends through the foram ina in the transverse processes of the cervical vertebrae (C6–C1). After entering the skull through the foram en m agnum , the vertebral arteries unite to form the basilar artery and contribute to the form ation of both the cerebral arteries, form ing anastom oses (circle of Willis) that have m ajor clinical im portance in supplying the blood to the brain.

Brachiocephalic trunk

Ta ble 3.1 Branches of the subclavian arte ry Arte ry

Branch

Subclavian a.

Internal t horacic a. Vertebral a.

Thyrocervical trunk

Costocervical trunk

Dorsal scapular a. (descending scapular a.)*

Furthe r branches

Re g ions supplie d Internal anterior chest wall

Meningeal branches

Falx cerebelli

Posterior spinal a.

Posterior spinal cord, especially the posterior colum ns; m edulla oblongat a (nucleus coneatus and nucleus gracilis)

Anterior spinal a.

Meninges; anterior spinal cord; m edulla oblongat a (dorsal m otor nucleus of CN X, nucleus am biguus, spinal accessory nucleus and hypoglossal nucleus)

Posterior inferior cerebellar a.

Cerebellum , m edulla oblongat a (cochlear nucleus, vestibular nucleus, dorsal m otor nucleus of CN X, nucleus am biguous)

Inferior thyroid a.

Inferior portion of thyroid gland and larynx, upper trachea, upper esophagus, deep neck m uscles

Suprascapular a.

Supraspinatus and infraspinat us m uscles, shoulder joint

Transverse cervical a.

Trapezius m uscle and surrounding tissues

Deep cervical a.

Muscles at the root of the neck

Suprem e intercost al a.

Posterior part of the 1 st and 2 nd intercost als spaces Levator scapulae, rhom boid and trapezius m uscles

* Arises from the subclavian a. in around t wo thirds of individuals and from the transverse cervical a. in the rem aining one third.

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3. Vascula ture & Lympha tics of the Hea d & Neck

External & Internal Carotid Arteries: Overview

Dorsal nasal artery Superficial temporal artery

Ophthalm ic artery

Angular artery

Posterior auricular artery

Ascending pharyngeal artery

Maxillary artery

Occipital artery

Internal carotid artery

Facial artery

External carotid artery

Lingual artery

Superior thyroid artery

Vertebral artery

Com m on carotid artery

Subclavian artery

Fig. 3.3 Arte ries of the head Left lateral view. The com m on carotid artery divides into the internal carotid artery (purple) and the external carotid artery (gray) at the carotid bifurcation (at the level of the C4 vertebra, bet ween the thyroid cartilage and hyoid bone). The external carotid artery divides into eight m ajor branches that supply the scalp, face, and structures of the head and neck. These eight branches can be arranged into four groups: anterior (red), m edial (blue), posterior (green), and term inal (yellow). The internal carotid artery does not branch before entering the skull. It gives o branches within the cranial cavit y.

The ophthalm ic branch of the internal carotid artery provides branches that will anastom ose with branches of the facial artery on the face (see Fig. 3.12). A carotid bruit is a noise (“swooshing” sound) caused by turbulent blood ow in the carotid artery. It is suggestive of carotid artery stenosis (narrowing) due to atherosclerosis (hardening of the arteries). It is best heard with the stethoscope placed over the carotid bifurcation (at the upper border of the thyroid cartilage). Surgical intervention is necessary for those with >60% lum en stenosis, which is indicated by im aging.

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Ta ble 3.2 Branches of the e xte rnal carotid and inte rnal carotid arte ries Arte ry

Branch

Re g ions supplie d

External carotid a.*(gray)

Superior thyroid a. (red)

Larynx, thyroid gland, pharynx, sternocleidom astoid m uscle

Ascending pharyngeal a. (blue)

Muscles of the pharyngeal wall, m ucosa of the m iddle ear, dura, posterior cranial fossa

Lingual a. (red)

Floor of the oral cavit y, tongue, sublingual gland, epiglot tis, suprahyoid m uscles

Facial a. (red)

Super cial face, subm andibular gland, pharyngeal wall, soft palate, palatine tonsils, anterior belly of digastric, mylohyoid, nose and nasal septum

Occipit al a. (green)

Scalp in occipit al region; posterior neck m uscles

Posterior auricular a. (green)

Tym panic cavit y, posterior auricle, parotid gland, posterior scalp

Maxillary a. (yellow)

Mandibular and m axillary dentition, m uscles of m astication, posterom edial facial skeleton, nasal cavit y, face, and m eninges

Super cial tem poral a. (yellow)

Scalp of forehead and vertex, soft tissue below zygom atic arch, m asseter, parotid gland, external orbit al wall, orbicularis oculi

Caroticot ym panic arteries

Pharyngot ym panic (auditory) tube and anterior wall of t ym panic cavit y

Artery of pterygoid canal

Anastom osis with external carotid a.

Superior and inferior hypophyseal aa.

Pituit ary gland

Cavernous sinus branch

Anastom osis with external carotid a.

Anterior m eningeal branch

Meninges of the anterior cranial fossa

Ganglionic branch

Trigem inal ganglion

Ophthalm ic a.

Optic n., optic chiasm , optic tract, retina, extraocular m uscles, eyelids, lacrim al gland, forehead, ethm oidal air cells, front al sinus, lateral nasal wall, dorsum of the nose, and m eninges

Anterior cerebral a.

Medial aspect of front al and pariet al lobes, corpus callosum

Middle cerebral a.

Front al, pariet al, and tem poral lobes

Posterior com m unicating a.

Anastom osis with cerebral aa. as part of Circle of Willis

Anterior choroidal a.

Choroid plexus of the lateral and 3 rd ventricle, optic chiasm and optic tract, internal capsule, lateral geniculate body, globus pallidus, caudate nucleus, hippocam pus, am ygdale, subst antia nigra, red nucleus, crus cerebelli

Internal carotid a. (purple)

* Anterior branches of external carotid artery are red; m edial branches are blue; posterior branches are green; and term inal branches are yellow ** There is also an artery of the pterygoid canal from the 3 rd part of the m axillary artery.

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3. Vascula ture & Lympha tics of the Hea d & Neck

External Carotid Artery: Anterior & Medial Branches Inferior t ympanic artery

Posterior m eningeal artery

Deep lingual artery

Sublingual artery

Dorsal lingual branches Lingual artery Suprahyoid branch Ascending pharyngeal artery

Superior laryngeal artery

Pharyngeal branches

External carotid artery Superior thyroid artery

Lingual artery External carotid artery Internal carotid artery

Infrahyoid branch

Sternocleidom astoid branch

Superior thyroid artery

Fig. 3.5 Lingual arte ry and its branches Left lateral view. The lingual artery is the second anterior branch of the external carotid artery. It has a relatively large caliber, providing the tongue and oral cavit y with it s rich blood supply. It also gives o branches to the tonsils.

Lateral glandular branch

Superior laryngeal artery Cricothyroid branch Anterior glandular branch

Com m on carotid artery

Thyroid im a artery

Fig. 3.4 Supe rior thyroid and asce nding pharynge al arte ries Left lateral view. The superior thyroid artery is t ypically the rst branch to arise from the external carotid artery. One of the anterior branches, it supplies the larynx (via the superior laryngeal branch) and thyroid gland. The ascending pharyngeal artery springs from the m edial side of the external carotid artery, usually arising above the level of the superior thyroid artery.

Ta ble 3.3 Branche s of the supe rior thyroid, lingual, and asce nding pharyng e al arte ries Branch of e xte rnal carotid a.

Furthe r branche s

Re g ion supplie d

Superior thyroid a.

Superior laryngeal a.

Larynx

Glandular branches

Thyroid gland

Sternocleidom astoid branch

Sternocleidom astoid m uscle

Muscular branches

Pharynx

Infrahyoid branch

Region of thyrohoid m em brane

Cricothyroid branch

Region of the cricothyroid m em brane

Suprahyoid branch

Suprahyoid m uscles

Dorsal lingual branches

Base of tongue, epiglot tis

Sublingual a.

Sublingual gland, tongue, oor of the oral cavit y

Deep lingual a.

Tongue

Pharyngeal branches

Muscles of the pharyngeal wall

Inferior t ym panic a.

Mucosa of m iddle ear

Posterior m eningeal a.

Dura; posterior cranial fossa

Lingual a.

Ascending pharyngeal a.

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3. Vascula ture & Lympha tics of the Hea d & Neck

Dorsal nasal artery*

Angular artery Superficial temporal artery

Infraorbital artery

Maxillary artery Superior labial artery

Ascending pharyngeal artery Tonsillar artery

Inferior labial artery

Ascending palatine artery

Mental artery

Facial artery Lingual artery

Fig. 3.6 Facial arte ry and its branches Left lateral view. The facial artery has four cervical and four facial branches. The four cervical branches (ascending palatine, tonsillar, glandular, and subm ental arteries) arise in the neck before the facial artery crosses the m andible to reach the face. The four facial branches (inferior and superior labial, lateral nasal, and angular arteries) supply the supercial face. Branches of the facial artery anastom ose with branches of the internal carotid artery as well as other branches derived from the external carotid artery (see Fig 3.12, p. 59).

Internal carotid artery Subm ental artery Glandular branches

Com m on carotid artery

Superior thyroid artery

*Branch of ophthalm ic artery

Ta ble 3.4 Branches of the facial arte ry Course: The facial artery arises from the external carot id artery in the carot id triangle of the neck. It then passes superiorly im m ediately deep to the posterior belly of digastric and the st ylohyoid. It runs along the subm andibular gland then loops under and over the body of the m andible at the anterior border of t he m asseter. It then runs anterosuperiorly across t he cheek to the angle of the m outh and then cont inues superiorly along the side of the nose. It term inates as the angular artery along the m edial aspect of the orbit. At it s term ination, the angular artery anastom oses wit h the dorsal nasal artery. Branch

Re g ion supplie d

Cervical branches Ascending palat ine a.

Pharyngeal wall, soft palate, pharyngot ym panic tube, palatine tonsils, pharynx

Tonsillar a.

Palatine tonsils and oropharynx

Glandular branch

Subm andibular gland

Subm ent al a.

Anterior belly of digastric, m ylohyoid, subm andibular gland

Facial branches Inferior labial a.

Lower lip

Superior labial a.

Upper lip; nasal septum (via sept al branches)

Lateral nasal a.

Dorsum of the nose

Angular a.

Root of the nose

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External Carotid Artery: Posterior Branches

Posterior branch

Occipital branches

Superficial temporal artery

Occipital artery

Descending branch

Maxillary artery

Posterior auricular artery Ascending pharyngeal artery Occipital artery

Facial artery Lingual artery

Internal carotid artery Superior thyroid artery

External carotid artery Com m on carotid artery

Fig. 3.7 Branches of the occipital arte ry The occipit al artery generally arises from the external carotid artery, just opposite the origin of the facial artery and just inferior to the posterior belly of the digastric m uscle (not shown). The artery passes posteriorly and near it s origin is crossed laterally by the hypoglossal nerve (not shown). In it s course to the posterior of the occiput, the occipit al artery passes lateral to the internal carotid artery (at the sam e tim e that it is passing lateral to both the internal jugular vein and cranial

nerves CN X and CN XI--not shown). At the base of the skull, the occipit al artery passes m edial to the m astoid process, travelling in the occipit al groove. Branches of the occipital artery anastom ose with branches of both the posterior auricular and super cial tem poral arteries. On the posterior aspect of the cranium , the artery converges with the greater occipital nerve (not shown). The occipit al artery gives rise to eight nam ed branches (see Table 3.5).

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Fig. 3.8 Branches of the poste rior auricular arte ry The posterior auricular artery arises from the external carotid artery as the last branch before the origin of it s t wo term inal branches (m axillary and super cial tem poral arteries). It arises superior to the posterior belly of digastric. In it s course the posterior auricular artery travels deep to the parotid gland and ascends along the lateral aspect of the st yloid process of the tem poral bone. The artery then passes superiorly bet ween the m astoid process and the posterior aspect of the auricle. It gives rise to 5 nam ed branches (see Table 3.5).

3. Vascula ture & Lympha tics of the Hea d & Neck

Auricular branch Posterior auricular artery Posterior t ym panic artery Parotid branch

External carotid artery

Occipital artery

Ta ble 3.5 Branches of the occipital and poste rior auricular arte ries Branch

Furthe r branches

Re g ion supplie d

Occipit al a.

Muscular branch

Regional m uscles including posterior belly of digastric and st ylohyoid

Sternocleidom astoid branch

Sternocleidom astoid

Descending branch

Posterior neck m uscles

Meningeal branch

Structures internal and external to jugular foram en

Mastoid branch

Mastoid air cells and dura

Auricular branch

Auricle (m edial side)

Occipit al branches

Scalp of occipit al region

St ylom astoid a.*

Facial n. in facial canal; t ym panic cavit y

St ylom astoid a.*

Facial n. in facial canal; t ym panic cavit y

Occipit al branch

Occiput

Muscular branches

Posterior belly of digastric and st ylohyoid

Parotid branch

Parotid gland

Auricular branch

Posterior side of auricle

Posterior auricular a.

* The st ylom astoid a. has a variable origin; it arises from the occipit al a. t wo thirds of the tim e and the posterior auricular a. one third of the tim e.

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External Carotid Artery: Terminal Branches (I) The t wo term inal branches of the external carotid artery are the m axillary artery and the super cial tem poral artery. They divide within the subst ance of the parotid gland. The m axillary artery is the largest of

the t wo term inal branches. It supplies the m axilla and m andible (including the teeth), the m uscles of m astication, the palate, the nose, and the dura covering the brain.

Infraorbital artery

Sphenopalatine artery Deep tem poral arteries Posterior superior alveolar artery

Anterior and m iddle superior alveolar arteries

Pterygoid (m uscular) branch Middle m eningeal artery Deep auricular artery Anterior t ympanic artery Superficial temporal artery Posterior auricular artery Maxillary artery Masseteric artery Buccal artery Occipital artery

A

Facial artery

Fig. 3.9 Maxillary arte ry Left lateral view. A Schem atic. B Course of the m axillary artery. The m axillary artery can be divided into three part s: m andibular (blue), pterygoid (green), and pterygopalatine (yellow). See Table 3.6.

Anastom otic branch with lacrim al artery

Frontal branch

Middle m eningeal artery

B

Mental branch

Mylohyoid branch

Inferior alveolar artery

Ascending pharyngeal artery Lingual artery Superior thyroid artery

Parietal branch

Petrous branch

Fig. 3.10 Middle me ning eal arte ry Medial view of right m iddle m eningeal artery. The m iddle m eningeal artery arises from the m andibular portion of the m axillary artery. It passes through the foram en spinosum into the m iddle cranial fossa. Despite it s nam e, it supplies blood not just to the m eninges, but also to the overlying calvaria. Rupture of the m iddle m eningeal artery by head traum a result s in an epidural hem atom a (see Fig. 4.58, p. 103).

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Ta ble 3.6 Branches of the maxillary arte ry Branch

Course

Distribution

Mandibular part (blue): Also known as the bony part or 1st part, this portion runs m edial to the neck of the m andible and gives o 5 m ajor branches, all of which enter bone. Inferior alveolar a.

Gives o a lingual and a mylohyoid branch before entering the m andibular foram en to travel along the m andibular canal; it split s into 2 term inal branches (incisive and m ent al)

Mandibular m olars and prem olars with associated gingiva, m andible

• Lingual branch

Lingual m ucous m em brane

• Mylohyoid branch

Mylohyoid

• Incisive branch

Mandibular incisors

• Ment al branch

Chin

Anterior t ym panic a.

Runs through the petrot ym panic ssure along with the chorda t ym pani

Middle ear

Deep auricular a.

Travels through the wall of the external acoustic m eatus

Lateral t ym panic m em brane, skin of external acoustic m eatus

• Branch to tem porom andibular joint

Tem porom andibular joint

Middle m eningeal a.

Runs through the foram en spinosum to the m iddle cranial cavit y

Bones of the cranial vault, dura of anterior and m iddle cranial fossae

Accessory m eningeal a.

Runs through the foram en ovale to the m iddle cranial fossa

Medial and lateral pterygoid, tensor veli palatini, sphenoid bone, dura, trigem inal ganglion

Pterygoid part (green): Also known as the m uscular part or 2nd part, this portion runs bet ween the tem poralis and lateral pterygoid. It gives o 5 m ajor branches, all of which supply m uscle. Masseteric a.

Runs through the m andibular incisure (notch)

Masseter, tem porom andibular joint

Deep tem poral aa.

Consist of anterior, m iddle, and posterior branches, which course deep to the tem poralis

Tem poralis

Lateral pterygoid a.

Runs directly to the lateral pterygoid m uscle

Lateral pterygoid

Medial pterygoid a.

Runs directly to the m edial pterygoid m uscle

Medial pterygoid

Buccal a.

Accom panies the buccal n.

Buccal m ucosa and skin, buccinator

Pterygopalatine part or 3rd part (yellow): This portion runs through the pterygom axillary ssure to enter the pterygopalatine fossa. It gives o 6 m ajor branches, which accom pany the branches of the m axillary nerve (CN V2 ).* Posterior superior alveolar a.

Runs through the pterygom axillary ssure; m ay arise from the infraorbit al a.

Maxillary m olars and prem olars, with associated gingiva; m axillary sinus

Infraorbit al a.

Runs through the inferior orbit al ssure into the orbit, where it runs along the infraorbit al groove and canal, exiting onto the face via the infraorbit al foram en

Cheek, upper lip, nose, lower eyelid

• Anterior and m iddle superior alveolar aa.

Maxillary teeth and m axillary sinus

• Greater palatine a.: runs via the greater (anterior) palatine canal; in the canal it gives o several lesser palatine aa.; continues through greater palatine foram en onto hard palate

Roof of hard palate, nasal cavit y (inferior m eatus), m axillary gingiva

• Lesser palatine aa.: runs via the lesser palatine foram en

Soft palate

• Anastom osing branch: runs via the incisive canal; joins with the sphenopalatine a.

Nasal septum

Descending palatine a.

Sphenopalatine a.

Runs via the sphenopalatine foram en to the nasal cavit y; gives o posterior lateral nasal branches, then travels to the nasal septum , where it term inates as posterior sept al branches • Posterior lateral nasal aa.: anastom ose with the ethm oidal aa. and nasal branches of the greater palatine a.

Nasal air sinuses (front al, m axillary, ethm oidal, and sphenoidal)

• Posterior sept al branches: anastom ose with the ethm oidal arteries on the nasal septum

Nasal conchae and nasal septum

A. of the pterygoid canal

Runs through the pterygoid canal

Pharyngot ym panic tube, t ym panic cavit y, upper pharynx

Pharyngeal a.

Runs through the palatovaginal canal

Nasopharynx, sphenoidal sinus, and pharyngot ympanic tube; m ucosa of nasal cavit y

*All branches are nam ed for the nerve they travel with except for the sphenopalatine artery, which travels with the nasopalatine nerve.

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External Carotid Artery: Terminal Branches (II) & Anastomoses Fig. 3.11 Supe r cial te mporal arte ry Left lateral view. The super cial tem poral artery is the second of the t wo term inal branches of the external carotid artery. Particularly in elderly or cachectic patient s, the often tortuous course of the frontal branch of this vessel can be easily traced across the tem ple. Tem poral arteritis (giant cell arteritis, cranial arteritis) is an in am m atory condition a ecting the m edium -sized arteries that supply the tem ple region, scalp, eyes, and optic nerves. The average age of onset of this condition is 70 years and it a ect s wom en t wice as com m only as m en. Sym ptom s m ay begin as general m alaise and progress rapidly to headaches, tenderness of the scalp, severe pain in the tem ple region, transient blurred vision, diplopia (double vision), ptosis (droop ing eyelid), neck pain, and jaw claudication (pain on jaw m anipulation, e.g., during eating, due to ischem ia of the m asseter m uscle). It is diagnosed by blood test s that indicate an inam m atory process is ongoing and by biopsy of the tem poral artery (de nitive test). If not treated prom ptly (usually before biopsy result s con rm the condition), then it m ay cause painless loss of vision in the a ected eye that is usually perm anent. Having tem poral arteritis also increases the risk of stroke and aortic aneurysm . Treatm ent is with corticosteroids, often long-term .

Parietal bone branch

Frontal branch

Middle temporal artery

Zygom aticoorbital artery Transverse facial artery

Superficial temporal artery Maxillary artery External carotid artery

Ta ble 3.7 Branche s of the  supe r cial te mporal arte ry Branch

Furthe r branche s

Re g io n supplie d

Super cial tem poral a.

Transverse facial a.

Soft tissues below zygom atic arch, parotid gland, m asseter m uscle

Anterior auricular a.

External auditory m eatus, anterior area of auricle

Middle tem poral a.

Tem poralis

Zygom atico-orbit al a.

Lateral external orbit al wall and obicularis oculi

Front al (anterior) branches

Scalp of forehead

Pariet al (posterior) branches

Scalp of vertex

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Superficial temporal artery, frontal branch Supratrochlear artery

Dorsal nasal artery

Supraorbital artery Lateral palpebral arteries Medial palpebral arteries Superficial temporal artery

Lateral nasal artery

Infraorbital artery

Angular artery

Superior and inferior labial arteries

Facial artery

Mental artery External carotid artery

Fig. 3.12 Anastomoses of the e xte rnal carotid and inte rnal carotid arte ries Branches of the external carotid artery (e.g., facial artery [red], supercial tem poral artery [yellow], and infraorbital arteries [yellow]) and the internal carotid artery (e.g., dorsal nasal and supraorbit al arteries [purple]) anastom ose in cert ain facial regions to ensure blood ow to the face and head. Anastom oses occur bet ween the angular artery and dorsal nasal artery and bet ween the super cial tem poral artery and supraorbit al artery. Due to the extensive arterial anastom oses, facial injuries tend to bleed profusely but also heal quickly.

Lateral posterior nasal arteries

Infraorbital artery

Posterior septal branches

Sphenopalatine artery

Sphenopalatine artery

Artery of pterygoid canal

Artery of pterygoid canal

Descending palatine artery

Descending palatine artery Lesser palatine artery

Dental branches

Anterior superior alveolar artery

Greater palatine artery

Fig. 3.13 Infraorbital arte ry Left lateral view. The infraorbit al artery arises from the pterygopalatine part of the m axillary artery (a term inal branch of the external carotid artery), and the supraorbit al artery (not shown) arises from the internal carotid artery (via the ophthalm ic branch). These vessels therefore provide a path for potential anastom osis bet ween the internal and external carotid arteries on the face.

Fig. 3.14 Sphe nopalatine arte ry Medial view of right nasal wall and right sphenopalatine artery. The sphenopalatine artery enters the nasal cavit y through the sphenopalatine foram en. The anterior portion of the nasal septum cont ains a highly vascularized region (Kiesselbach’s area), which is supplied by both the posterior sept al branches of the sphenopalatine artery (external carotid artery) and the anterior sept al branches of the anterior ethm oidal artery (internal carotid artery via ophthalm ic artery). When severe nasopharyngeal bleeding occurs, it m ay be necessary to ligate the m axillary artery in the pterygopalatine fossa.

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Internal Carotid Artery Fig. 3.15 Ove rview of the inte rnal carotid arte ry The internal carotid artery branches from the com m on carotid artery at the level of the carotid bifurcation (C4 vertebral level). It s extracranial part gives o no branches. The internal part has four anatom ical part s that supply blood to the brainstem and brain (see Fig 3.16).

Supraorbital artery

Posterior com m unicating artery

Ophthalm ic artery

Supratrochlear artery

Internal carotid artery

Dorsal nasal artery

Basilar artery Posterior ethm oidal artery

External carotid artery

Internal carotid artery

Superior thyroid artery

Carotid bifurcation

Vertebral artery

Subclavian artery

Fig. 3.16 Subdivisions of the inte rnal carotid arte ry Anatom ical segm ent s of the internal carotid artery and their branches. The internal carotid artery is distributed chie y to the brain but also supplies extracerebral regions of the head. It consist s of four part s (listed from bot tom to top): • • • •

Ophthalm ic artery

Anterior choroidal artery Posterior com m unicating artery Superior hypophyseal artery

Cerebral part

Basal tentorial branch

Cervical part Petrous part Cavernous part Cerebral part

The petrous part of the internal carotid artery (traversing the carotid canal) and the cavernous part (traversing the cavernous sinus) have a role in supplying extracerebral structures of the head. They give o additional sm all branches that supply local structures and are usually nam ed for the areas they supply. Of the branches not supplying the brain, of special im port ance is the ophthalm ic artery, which arises from the cerebral part of the internal carotid artery. Note: The ophthalm ic artery form s an anastom osis with the artery of the pterygoid canal derived from the m axillary artery.

Marginal tentorial branch Cavernous part

Inferior hypophyseal artery Trigem inal ganglion branch

Neural branch

Meningeal branch

Petrous part Caroticot ympanic arteries

Cavernous sinus branch Artery of pterygoid canal

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Middle cerebral arteries

Posterior cerebral arteries

Anterior cerebral arteries

Posterior com m unicating arteries

Anterior com m unicating arteries

Basilar artery Internal carotid arteries Vertebral arteries

Anterior cerebral artery

Anterior com m unicating artery A

Middle cerebral artery

Posterior com m unicating artery Com m on carotid arteries

Internal carotid artery

Posterior cerebral artery

Basilar artery B

Fig. 3.17 Blood supply to the brain A Schem atic of circle of Willis in situ. B Schem atic of isolated circle of Willis. The brain is supplied by four arteries that leave the root of the neck separately, the left and right internal carotid arteries and the left and right vertebral arteries. However, the vertebral arteries converge to

form the basilar artery and so only three arteries reach the base of the brain, where they form the circle of Willis. The circle of Willis is a m eans by which the brain can receive blood when one or m ore of it s m ajor arterial contributors becom es narrowed or blocked, for exam ple, by an em boli, possibly preventing ischem ic stroke.

Ta ble 3.8 Contribution of the inte rnal carotid arte ry to the blood supply of the eye, nose, face, and surrounding areas Course: The ophthalm ic artery branches from the internal carotid artery (ICA) just after the ICA passes through the cavernous sinus. It runs along the m edial side of the anterior clinoid process passing anteriorly through the optic canal with the optic nerve. It then courses in the m edial wall of the orbit . The t wo term inal branches of the ophthalm ic artery are the dorsal nasal and supratrochlear arteries. Orig in

Arte ry

Ophthalm ic a. (branch of internal carotid artery)

Ocular branches

Re g ion supplie d

Central artery of the retina

Retina

Anterior ciliary a.

Eyeball

Long and short posterior ciliary aa.

Eyeball

Orbital branches Lacrim al a.

Lacrim al glands, eyelids, and conjunctiva

Muscular aa.

Extraocular m uscles

Middle palpebral a.

Eyelids

Posterior ethm oidal a.

Ethm oidal air cells, posterosuperior nasal septum , part of sphenoid sinus and m eninges

Anterior ethm oidal a.

Ethm oidal air cells, anterosuperior nasal septum , lateral nasal wall, and anterior cranial fossa

Supratrochlear a.

Muscles and skin of the m edial forehead, and front al sinus

Supraorbit al a.

Muscles and skin of the forehead, and front al sinus

Meningeal a.

Middle cranial fossa

Dorsal nasal a.

Region along the bridge of the nose

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Veins of the Head & Neck: Overview Superior sagit tal sinus

Superficial temporal vein Confluence of the sinuses

Cavernous sinus

Transverse sinus Sigm oid sinus External Facial vein

Internal

Jugular veins

Anterior Suprascapular vein

Left brachiocephalic vein

Subclavian vein

A Pterygoid plexus

Superior and inferior ophthalm ic veins Angular vein Deep temporal veins

Superficial temporal vein Maxillary vein Occipital vein Posterior auricular vein

Facial vein

Fig. 3.18 Ve ins of the head and ne ck Left lateral view. The principal vein of the head and neck is the internal jugular vein. This drains blood from both the exterior and the interior of the skull (including the brain) in addition to receiving venous blood from the neck. It receives blood from the com m on facial vein (form ed by the union of the facial vein and the anterior division of the retrom andibular vein), the lingual, superior thyroid, and m iddle thyroid veins, and the inferior petrosal sinus. Enclosed in the carotid sheath, the internal jugular vein descends from the jugular foram en to it s union with the subclavian vein to form the brachiocephalic vein. The external jugular vein receives blood from the posterior division of the retrom andibular vein and the posterior auricular vein. The occipital vein norm ally drains to the deep cervical veins. The subclavian vein in the thorax can be catheterized in acutely ill or chronically ill patient s to provide a fast and st able route for adm inistering m edication, uids, and nutrition, and for m easuring central oxygen saturation and central venous pressure (to quantify their uid st atus). This

Retrom andibular vein Superior thyroid vein Subm ental vein Internal jugular vein External jugular vein

Anterior jugular vein

Left brachiocephalic vein B

is called central venous catheterization or a “central line.” Other large veins in the neck (e.g., the internal jugular vein), thorax (e.g., the axillary vein), or the groin (e.g., the fem oral vein) can also be catheterized in this way.

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Suprascapular vein Subclavian vein

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Supratrochlear vein Superior ophthalm ic vein

Supraorbital vein

3. Vascula ture & Lympha tics of the Hea d & Neck

Sphenoidal em issary vein Maxillary vein Cavernous sinus Dural sinuses

Superficial temporal vein Sigm oid sinus

Inferior ophthalm ic vein Facial vein

Retrom andibular vein

Deep facial vein Pterygoid plexus

Posterior auricular vein

Anterior division of retrom andibular vein

Posterior division of retrom andibular vein

Dorsal lingual vein

Occipital vein

Deep lingual vein Anterior jugular vein

Lingual vein

Internal jugular vein

Exterm al jugular vein

Com m on facial vein

Fig. 3.19 Ve ins of the head: ove rview The super cial veins of the head com m unicate with each other and with the dural sinuses via the deep veins of the head (pterygoid plexus and cavernous sinus). The pterygoid plexus connect s the facial vein and the retrom andibular vein (via the deep facial vein and m axillary vein, respectively). The cavernous sinus connect s the facial vein to the sigm oid sinus (via the ophthalm ic veins and the petrosal sinuses, respectively). Cavernous sinus throm bosis is the form ation of a throm bus (blood

clot) in the cavernous sinuses. It usually occurs secondary to an infection in the nasal sinuses, teeth, ears, eyes, or the skin of the face. The infective organism is t ypically staphlococcus aureus, but it can also be caused by streptococci, pneum ococci, and fungi. Signs and sym ptom s include headache, eye pain, exophthalm os (bulging eyeball), ptosis (drooping eyelid), vision loss, sluggish pupillary responses, and lim it ation of m ovem ent of the eye due to paralysis of the oculom otor, trochelar and abducent nerves. It m ay progress to m eningitis or sepsis.

Ta ble 3.9 Ve nous drainag e of the head and ne ck Ve in

Location

Tributarie s

Re g io n draine d

Internal jugular v.

Within carotid sheath

Com m on facial v. — Facial v. — Retrom andibular v., anterior division Pharyngeal vv. Lingual v. Superior and m iddle thyroid vv.

Skull, anterior and lateral face, oral cavit y, external pharynx, neck

Sigm oid sinus and inferior petrosal sinuses

Interior of skull (including brain)

Retrom andibular v., posterior division

Lateral skull

Posterior auricular v.

Occiput

Super cial veins in subm andibular region

Anterior neck

External jugular v.

Anterior jugular v.

Within super cial cervical fascia

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Super cial Veins of Head Pterygoid plexus Superior and inferior ophthalm ic veins External nasal vein Angular vein Deep temporal veins

Superficial temporal vein Maxillary vein

Deep facial vein

Occipital vein Posterior auricular vein

Inferior labial vein Facial vein

Retrom andibular vein Superior thyroid vein Subm ental vein Internal jugular vein Retrom andibular vein, anterior division

External jugular vein

Com m on facial vein

Fig. 3.20 Ve nous drainag e to the common facial ve in The com m on facial vein is form ed by the union of the facial vein and the anterior division of the retrom andibular vein. These trib ut aries com bine to drain m uch of the face, eye, and oral cavit y (see Table 3.10). The com m on facial vein em pties into the internal jugular vein. Note: The course of veins is highly variable.

Anterior jugular vein

Left brachiocephalic vein

Suprascapular vein Subclavian vein

Ta ble 3.10 Tributaries of the common facial ve in Course: tribut aries of the com m on facial vein course parallel to the branches of the m axillary a. Tributary

Furthe r tributaries

Re g io n draine d

Facial v.

Angular v.*

Anterior scalp, forehead, upper and lower eyelids, conjunctiva, root of the nose, cavernous sinus (via com m unication with ophthalm ic vein)

External nasal v.

External nose

Superior labial v.

Upper lip

Inferior labial v.

Lower lip

Deep facial vein (from pterygoid plexus)

Contributes to drainage from pterygoid plexus (see m axillary vein below)

Parotid vv.

Parotid region

External palatine (paratonsillar) v.

Soft palate and tonsils

Subm ent al v.

Mylohyoid region

Subm andibular v.

Subm andibular gland

Maxillary v. (from pterygoid plexus)

Orbit and eye, m uscles of m astication, m uscles of facial expression, buccal m ucosa and skin, hard palate, soft palate, teeth and their associated gingival, subm andibular, sublingual, and parotid glands, tem porom andibular joint, chin, nasal air sinuses (front al, m axillary, ethm oidal, and sphenoidal), nasal conchae, nasal septum , external acoustic m eatus, t ym panic m em brane

Super cial tem poral v.

Anterior auricle, tem ple region, and scalp

Retrom andibular v., anterior division

* The angular vein is form ed by the con uence of the supratrochlear and subraorbit al vv.

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Pterygoid plexus Superior and inferior ophthalm ic veins Angular vein

Deep temporal veins

Superficial temporal vein Maxillary vein Occipital vein Posterior auricular vein

Facial vein

Retrom andibular vein, posterior division Superior thyroid vein Subm ental vein Internal jugular vein External jugular vein

Fig. 3.21 Ve nous drainag e to the e xte rnal jug ular ve in The external jugular vein receives blood from the posterior auricular vein, the posterior division of the retrom andibular vein, the posterior external jugular vein, the transverse cervical vein, and the suprascapular vein. These tribut aries com bine to drain the face and super cial neck (see Table 3.11). The external jugular vein drains into the subclavian vein.

Anterior jugular vein

Suprascapular vein

Left brachiocephalic vein

Subclavian vein

Ta ble 3.11 Tributaries of the e xte rnal jug ular ve in Course: Arises at the con uence of posterior auricular vein and the posterior division of the retrom andibular vein within the subst ance of the parotid gland, at the level of the angle of the m andible. It travels inferiorly within super cial cervical fascia to drain into the subclavian vein. Tributary

Furthe r tributarie s

Re g io n draine d

Posterior auricular v.

Retrom andibular v., posterior division

Posterior auricle, external acoustic m eatus, t ym panic m em brane, posterior scalp, parotid gland Maxillary v.

Orbit and eye, m uscles of m astication, m uscles of facial expression, buccal m ucosa and skin, hard palate, soft palate, teeth and their associated gingival, subm andibular, sublingual, and parotid glands, tem porom andibular joint, chin, nasal air sinuses (front al, m axillary, ethm oidal, and sphenoidal), nasal conchae, nasal septum , external acoustic m eatus, t ym panic m em brane

Super cial tem poral v.

Anterior auricle, super cial face

Posterior external jugular v.

Skin and super cial m uscles in the upper and back part of the neck

Transverse cervical v.

Trapezius m uscle and surrounding tissue

Suprascapular v.

Supraspinatus and infraspinatus m uscles; shoulder joint

Anterior jugular v.

Super cial part s of the anterior neck

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Deep Veins of the Head Parietal em issary vein

Inferior sagit tal sinus

Superior sagit tal sinus

Basilar vein

Straight sinus

Frontal vein

Superior petrosal sinus

Superior ophthalm ic vein Angular vein

Occipital em issary vein

Inferior ophthalm ic vein

Occipital vein Confluence of the sinuses

Cavernous sinus

Posterior auricular vein

Venous plexus of foram en ovale

Sigm oid sinus

Pterygoid plexus

Mastoid em issary vein

Inferior petrosal sinus

Condylar em issary vein

Maxillary vein

Deep cervical vein

Com m on facial vein Vertebral vein

External jugular vein

Fig. 3.22 Ve nous drainag e of the he ad The super cial veins of the head have extensive connections with the deep veins of the head and the dural sinuses. The m eninges and brain are drained by the dural sinuses, which lie within the skull. Em issary

Retrom andibular vein Facial vein

Internal jugular vein

veins connect the super cial veins of the skull directly to the dural sinuses. In addition, the deep veins of the head (e.g., pterygoid plexus) are interm ediaries bet ween the super cial veins of the face and the dural venous sinuses.

Ta ble 3.12 Ve nous anastomoses as portals of infe ction The extracranial veins of the head are connected to the deep veins and dural sinuses. Patient s who sust ain m idfacial fractures m ay bleed profusely due to the extensive venous anastom oses. Because the veins are generally valveless, extracranial bacteria m ay m igrate to the deep veins, causing infections (e.g., bacteria from boils on the upper lip or nose m ay enter the angular vein and travel to the cavernous sinus). Bacteria in the cavernous sinus m ay cause throm bosis. Extracranial ve in

Co nne cting ve in

Ve nous sinus

Angular v.

Superior ophthalm ic v.

Cavernous sinus

Vv. of palatine tonsil

Pterygoid plexus, inferior ophthalm ic v.

Super cial tem poral v.

Pariet al em issary v.

Superior sagit t al sinus

Occipit al v.

Occipit al em issary v.

Transverse sinus, con uence of the sinuses

Mastoid em issary v.

Sigm oid sinus

Posterior auricular v. External vertebral venous plexus

Condylar em issary v.

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Supratrochlear vein

Supraorbital vein

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Deep Cavernous temporal veins sinus

Superficial temporal vein Sphenoidal em issary veins

Superior ophthalm ic vein

Superior and inferior petrosal sinuses

Angular vein

Sigm oid sinus

Facial vein Deep facial vein

Pterygoid plexus Maxillary vein Retrom andibular vein Posterior division of retrom andibular vein Internal jugular vein Anterior division of retrom andibular vein Com m on facial vein Facial vein

Lingual vein

External palatine vein

Fig. 3.23 De e p ve ins of the he ad Left lateral view. The pterygoid plexus is a venous net work situated behind the m andibular ram us and em bedded in the pterygoid m uscles. Because the veins of the face have no valves (sm all valves m ay be present but are generally nonfunctional), the m ovem ent of the pterygoid m uscles forces blood from the pterygoid plexus into the jugular veins.

The pterygoid plexus is linked to the facial vein via the deep facial vein and to the retrom andibular vein via the m axillary vein. The plexus is also linked to the cavernous sinus via the sphenoidal em issary vein. The cavernous sinus receives blood from the superior and inferior ophthalm ic veins. Parietal em issary vein

Superior sagit tal sinus Confluence of the sinuses Occipital em issary vein

Fig. 3.24 Ve ins of the occiput Posterior view. The dural sinuses are the series of venous channels that drain the brain. The super cial veins of the occiput com m unicate with the dural sinuses by way of the em issary veins. The em issary veins enter a sim ilarly nam ed foram en to com m unicate with the dural sinuses.

Venous plexus around the foram en m agnum Venous plexus of the hypoglossal nerve canal External vertebral venous plexus

Transverse sinus

Mastoid em issary vein Condylar em issary vein Internal jugular vein Occipital vein

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Lymphatics of the Head & Neck (I) A distinction is m ade bet ween regional lym ph nodes, which are associated with a particular organ or region and constitute their prim ary ltering st ations, and collecting lym ph nodes, which usually receive lym ph from m ultiple regional lym ph node groups. Lym ph from the head and neck region, gathered in scat tered regional nodes, ows through it s system of deep cervical collecting lym ph nodes into the right and left

Retroauricular lymph nodes

Occipital lymph node

jugular trunks, each closely associated with it s corresponding internal jugular vein. The jugular trunk on the right side drains into the right lym phatic duct, which term inates at the right jugulosubclavian junction. The jugular trunk on the left side term inates at the thoracic duct, which em pties into the left jugulosubclavian junction (see Fig. 12.16).

Superficial parotid lym ph nodes

Mastoid lymph nodes

Fig. 3.25 Supe r cial ce rvical lymph nodes Right lateral view. Enlarged cervical lym ph nodes are a com m on nding at physical exam ination. The enlargem ent of cervical lym ph nodes m ay be caused by in am m ation (usually a painful enlargem ent) or neoplasia (usually a painless enlargem ent) in the area drained by the nodes. The super cial cervical lym ph nodes are prim ary drainage locations for lymph from adjacent areas or organs.

Deep parotid lymph nodes

Anterior superficial cervical lymph nodes Lateral superficial cervical lymph nodes

Fig. 3.26 De e p ce rvical lymph nodes Right lateral view. The deep lym ph nodes in the neck consist m ainly of collecting nodes. They have m ajor clinical im portance as potential sites of m etastasis from head and neck tum ors. A ected deep cervical lym ph nodes m ay be surgically rem oved (neck dissection) or m ay be treated by regional irradiation. For this purpose, the Am erican Academy of Otolaryngology—Head and Neck Surgery has grouped the deep cervical lym ph nodes into six levels (Robbins 1991): I Subm ent al and subm andibular lym ph nodes II– IV Deep cervical lym ph nodes along the internal jugular vein (lateral jugular lym ph nodes): – II Deep cervical lym ph nodes (upper lateral group) – III Deep cervical lym ph nodes (m iddle lateral group) – IV Deep cervical lym ph nodes (lower lateral group) V Lym ph nodes in the posterior cervical triangle VI Anterior cervical lym ph nodes

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II

I

V III

IV

VI

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Occipital

Parotidauricular

Buccal

Facial

Nuchal Jugulofacial venous junction

Subm entalsubm andibular

Parallel to internal jugular vein

Laryngotracheothyroidal

Along the accessory nerve

Fig. 3.27 Dire ctions of lymphatic drainag e in the ne ck Right lateral view. Underst anding this pat tern of lym phatic ow is critical to identifying the location of a potential cause of enlarged cervical lym ph nodes.There are t wo m ain sites in the neck where the lym phatic pathways intersect: • Jugulofacial venous junction: Lym phatics from the head pass obliquely downward to this site, where the lym ph is redirected vertically downward in the neck. • Jugulosubclavian venous junction: The m ain lym phatic trunk, the thoracic duct, term inates at this central location, where lym ph collected from the left side of the head and neck region is com bined with lym ph draining from the rest of the body. If only peripheral nodal groups are a ected, this suggest s a localized disease process. If the central groups (e.g., those at the venous junctions) are a ected, this usually signi es an extensive disease process. Central lym ph nodes can be obt ained for diagnostic evaluation by prescalene biopsy.

Jugulosubclavian venous junction

Axillary

Right lym phatic duct

3. Vascula ture & Lympha tics of the Hea d & Neck

B

Thoracic duct

F B C D A

F

Fig. 3.28 Relationship of the ce rvical nodes to the syste mic lymphatic circulatio n Anterior view. The cervical lym ph nodes m ay be involved by diseases that are not prim ary to the head and neck region, because lym ph from the entire body is channeled to the left and right jugulosubclavian junctions (red circles). This can lead to retrograde involvem ent of the cervical nodes. The right lymphatic duct term inates at the right jugulosubclavian junction, the thoracic duct at the left jugulosubclavian junction. Besides cranial and cervical tributaries, the lym ph from thoracic lym ph nodes (m ediastinal and tracheobronchial) and from abdom inal and caudal lym ph nodes m ay reach the cervical nodes by way of the thoracic duct. As a result, diseases in those organs m ay lead to cervical lym ph node enlargem ent. For exam ple, gastric carcinom a m ay m et ast asize to the left supraclavicular group of lym ph nodes, producing an enlarged sentinel node that suggest s an abdom inal tum or. System ic lym phom as m ay also spread to the cervical lym ph nodes by this pathway.

E

E

C

D

Fig. 3.29 Syste matic palpation of the ce rvical lymph nodes The cervical lym ph nodes are system atically palpated during the physical exam ination to ensure the detection of any enlarged nodes. Panel A shows the sequence in which the various nodal groups are successively palpated. The exam iner usually palpates the subm ent alsubm andibular group rst (B), including the m andibular angle (C), then proceeds along the anterior border of the sternocleidom astoid m uscle (D). The supraclavicular lym ph nodes are palpated next (E), followed by the lym ph nodes along the accessory nerve and the nuchal group of nodes (F). If lym ph nodes are palpable, the following characteristics should be noted and described: size (<1 cm in diam eter is norm al), pain/tenderness (suggestive of in am m ation), consistency (soft nodes suggest inam m ation; rm , rubbery nodes suggest lym phom a; stony-hard nodes m ay be a sign of cancer), location of lym phadenopathy, and whether it is localized or generalized as this m ay help aid diagnosis.

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Lymphatics of the Head & Neck (II)

Posterior zone

Anterior zone

External auditory canal

Superficial parotid lymph nodes

Mastoid lymph nodes (retroauricular)

Parotid fascia

Lower zone

Deep parotid lymph nodes Internal jugular vein

Fig. 3.30 Auricle and e xte rnal auditory canal: lymphatic drainag e Right ear, oblique lateral view. The lym phatic drainage of the ear is divided into three zones, all of which drain directly or indirectly into the deep cervical lym ph nodes along the internal jugular vein. The lower zone drains directly into the deep cervical lym ph nodes. The anterior zone rst drains into the parotid lym ph nodes, the posterior zone into the m astoid lym ph nodes.

Parotid gland

Deep cervical lym ph nodes

Deep cervical lymph nodes Lingual vein Submental lym ph nodes

Jugulofacial venous junction

Subm andibular lymph nodes Upper cervical lymph nodes

Subm andibular lymph nodes

Lower cervical lymph nodes Internal jugular vein Jugular lymph nodes A

B

Fig. 3.31 Lymphatic drainag e  of the  tong ue  and oral  oor A Left lateral view. B Anterior view. The lym phatic drainage of the tongue and oral oor is m ediated by subm ent al and subm andibular groups of lym ph nodes that ultim ately drain into the lym ph nodes along the internal jugular vein (A, jugular

lym ph nodes). Because the lym ph nodes receive drainage from both the ipsilateral and contralateral sides (B), tum or cells m ay becom e widely dissem inated in this region (e.g., m et astatic squam ous cell carcinom a, especially on the lateral border of the tongue, frequently m etast asizes to the opposite side).

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Ta ble 3.13 Lymphatic drainage of the head and ne ck Note: Lym phatic drainage of the oral cavit y is in bold. Re g io n

Node (s)

Se condary no de (s)

Occipit al region of the scalp and upper neck

Occipit al nodes

Super cial cervical nodes

Scalp in tem poropariet al region, posterior surface of the ear, and skin in m astoid region

Mastoid nodes (retroauricular)

Super cial and deep cervical nodes

Anterior pariet al region of the scalp, anterior surface of the ear, external acoustic m eatus, face, and buccal muco sa

Supe r cial parotid no des (preauricular)

De e p parotid and de e p ce rvical no des

External acoustic m eatus, pharyngot ym pranic (auditory) tube, m iddle ear

Deep parotid nodes

Deep cervical nodes

Nasal cavit y, paranasal sinuses, hard palate (rarely), soft palate , nasopharynx, oropharynx, and auditory tubes

Retropharyng e al no des

De e p ce rvical nodes

Supe r cial face  and che ek

Buccal no des

Submandibular no des

Upper lip, lateral part of the lower lip, cheek, nasal vestibule, anterior nasal cavit y, g ing ivae, te eth, medial canthus, hard palate, so ft palate, ante rio r pillar, ante rio r part o f the to ng ue, submandibular and subling ual g lands, and  oor of mouth

Submandibular no des

De ep ce rvical no des

Chin, m iddle part of the lower lip, anterior g ing ivae, tip of tong ue, and ante rior  oor of mouth

Submental no des

Submandibular and de ep cervical no des

Oral cavity, oropharynx, nasopharynx, laryngopharynx, , larynx, and parotid

Jug ulo dig astric no des

De e p ce rvical node s

Subm ent al region, head and neck above this level

Jugulo -om ohyoid nodes

Deep cervical nodes

Esophagus, larynx, trachea, and thyroid gland

Juxt avisceral nodes (prelaryngeal, pretracheal, and paratracheal)

Deep cervical nodes

Skin and m uscles of the anterior infrahyoid region of the neck

Anterior jugular nodes

Deep cervical nodes

Inferior part of the ear and parotid region

External jugular nodes Tracheal nodes

Deep cervical nodes

Lungs, upper esophagus, part of the larynx below the vocal folds

Tracheal nodes

Bronchom ediastinal trunk

Lateral part of the neck, anterior thoracic wall, m am m ary gland

Transverse cervical nodes

Jugular lym phatic trunk, or right lym phatic trunk, or thoracic duct

Most of the lym ph from the head and neck ultim ately drains to the super cial or deep cervical nodes then into the jugular lym phatic trunk. Som e lym ph also drains into the bronchom ediastinal trunk. These trunks both em pt y into either the thoracic duct or right lym phatic duct and into the venous system .

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Organization of the Nervous System Fig. 4.1 Ne rvous syste m A Anterior view. B Posterior view. The nervous system is a collection of neurons that can be divided anatom ically into t wo groups:

Cerebrum Cranial nerves

Brain

• Ce ntral ne rvous syste m (CNS, pink): Brain and spinal cord. • Pe riphe ral ne rvous syste m (PNS, yellow): Nerves em erging from the CNS. These are divided into t wo t ypes depending on their site of em ergence: ◦ Cranial nerves: 12 pairs of nerves em erge from the brain (telencephalon, diencephalon, and brainstem only). These nerves m ay contain sensory and/or m otor bers. ◦ Spinal ne rves: 31 pairs of nerves em erge from the spinal cord. Spinal nerves cont ain both sensory and m otor bers that em erge from the spinal cord as separate root s and unite to form the m ixed nerve. In certain regions, the spinal nerves m ay com bine to form plexuses (e.g., cervical, brachial, or lum bosacral).

Cerebellum

Brachial plexus Spinal nerves Spinal cord Spinal cord Spinal nerve

Lum bosacral plexus Cauda equina

B

A

Afferent (sensory)

Efferent (motor)

Joint s, skin, skeletal m uscle

Skeletal m uscle

Som atosensory fibers

Somatic

Som atom otor fibers

CNS

Autonomic (visceral)

Viscerosensory fibers

Viscerom otor fibers

Glands, sm ooth m uscle, cardiac m uscle

Viscera, vessels

Fig. 4.2 Organization of the ne rvous syste m The nervous system is a vast net work that can be divided according to t wo criteria: 1. Type of inform ation: A erent (sensory) cells and pathways receive inform ation and transm it it to the CNS. E erent (m otor) cells and pathways convey inform ation from the CNS.

2. Destination/origin: The som atic division of the nervous system prim arily m ediates interaction with the external environm ent. These processes are often volunt ary. The autonom ic (visceral) nervous system prim arily m ediates regulation of the internal environm ent. These processes are frequently involunt ary. These t wo criteria yield four t ypes of nerve bers addressed above that connect the CNS to the PNS.

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Fig. 4.3 Ne urons (ne rve cells) The nervous system is com posed of neurons (nerve cells) and supporting neuroglial cells, which vastly outnum ber them (10 to 1). Each neuron cont ains a cell body (som a) with one axon (projecting segm ent) and one or m ore dendrites (receptor segm ent s). The release of neurotransm it ters at synapses creates an excit atory or inhibitory post synaptic potential at the t arget neuron. If this exceeds the depolarization threshold of the neuron, the axon “ res,” initiating the release of a transm it ter from it s presynaptic knob (bouton).

Receptor segm ent Presynaptic terminal (bouton) Dendrite

Transm ission segm ent

Som a

Axon hillock

Axodendritic synapse

Axon

Term inal segment Axoaxonal Synapse

Axosomatic synapse

CNS

Oligodendrocyte

PNS

Nucleus Schwann cells

Fig. 4.4 Myelination Cert ain glial cells with lipid-rich m em branes m ay myelinate axons (nerve bers). Myelination electrically insulates axons, thereby increasing im pulse conduction speed. In the central nervous system , one oligodendrocyte myelinates one internode on m ultiple axons; in the peripheral nervous system , one Schwann cell myelinates one internode on a single axon.

Unmyelinated axons

Node of Ranvier

Myelinated axon

Axon

Schwann cell nucleus

Myelin sheath

Ta ble 4.1 Cells of the ce ntral ne rvous syste m (CNS) and pe riphe ral ne rvous syste m (PNS) Cell type

Function

Neurons (CNS and PNS)

Im pulse form ation, im pulse conduction, inform ation processing

Glial cells Astrocytes (CNS only)

Maint ain a const ant internal m ilieu in the CNS, help form the blood brain-barrier, phagocytosis of non-functioning synapses, scar form ation in the CNS (e.g., following cerebral infarction [Stroke] or in m ultiple sclerosis), absorb excess neurotransm it ters and K+

Microglial cells (CNS only)

Cells specialized for phagocytosis and antigen processing ; secrete cytokines and growth factors

Oligodendrocytes (CNS only)

Form myelin sheaths in the CNS

Ependym al cells (CNS only)

Line cavities in the CNS

Cells of the choroid plexus (CNS only)

Secrete cerebrospinal uid (CSF)

Schwann cells (PNS only)

Form myelin sheaths in the PNS

Satellite cells (PNS only)

Modi ed Schwann cells; surround the cell body of neurons in PNS ganglia

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Spinal Cord: Overview

C1 spinal nerve

Medulla oblongata

Atlas (C1)

Anterior spinal artery

Anterior spinal veins

Pia m ater

Subarachnoid space

Arachnoid m ater Vertebra prominens (C7)

Spinal cord

Posterior root Spinal ganglion Posterior ram us

Cervical enlargem ent

T1 spinal nerve

Subdural space Dura m ater

Anterior root

Anterior ram us White and gray ram i com m unicantes Spinal nerve

Denticulate ligam ent Anterior rootlets

Lum bosacral enlargem ent T12 vertebra

L1 spinal nerve

Fig. 4.6 Spinal cord and its me ning eal laye rs Posterior view. The dura mater is opened and the arachnoid is sectioned. The spinal cord, like the brain, is covered by three meninges. The outerm ost layer, the tough dura m ater, extends from the foram en magnum to the sacrum and coccyx. The m iddle layer, the arachnoid m ater, loosely envelopes the spinal cord and extends from foram en magnum to around the S2 vertebral level. The inner layer, the pia mater, closely invests the spinal cord and the anterior spinal artery.

Conus m edullaris

Spinal ganglia Cauda equina

L5 vertebra S1 spinal nerve

Dura m ater Arachnoid m ater

Sacral hiatus

Fig. 4.5 Spinal cord in situ Posterior view with vertebral canal windowed. The spinal cord is located in the vertebral foram en and extends from the m edulla oblongata to around the level of T12/ L1. It gives o 31 pairs of spinal nerves. The cervical enlargement corresponds with the at tachm ents of the large nerves that supply the upper limbs. It extends from about C3 to T1. Similarly, the lumbosacral enlargement corresponds with the at tachments of the large nerves that supply the lower lim bs. The posterior and anterior spinal nerve roots extending from the lower end of the spinal cord are collectively known as the cauda equina. During lumbar puncture at this level, a needle introduced into the subarachnoid space (lumbar cistern) normally slips past the spinal nerve roots without injuring them (see Fig. 4.9).

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T12 Conus m edullaris (adult)

Epidural space Subarachnoid space

Posterior internal vertebral venous plexus

Arachnoid m ater Dura m ater

L1 Denticulate ligam ent Intervertebral foram en

Posterior root Anterior root

Spinal ganglion Spinal nerve

Vertebral a. Vertebral veins

Anterior internal vertebral venous plexus

Conus m edullaris (newborn) Dural sac (lum bar cistern)

Sympathetic chain

Root sleeve

Fig. 4.7 Spinal cord in the ve rtebral canal Transverse section at the level of the C4 vertebra, viewed from above. The spinal cord occupies the center of the vertebral foram en and is anchored within the subarachnoid space to the spinal dura m ater by the denticulate ligam ent. The root sleeve, an outpouching of the dura m ater in the intravertebral foram en, contains the spinal ganglion and the posterior and anterior root s of the spinal nerve. The spinal dura m ater is bounded externally by the epidural space, which contains venous plexuses, fat, and connective tissue. The epidural space extends upward as far as the foram en m agnum , where the dura becom es fused to the cranial periosteum . Fig. 4.8 Ag e -relate d chang es of spinal co rd levels Anterior view. As an individual grows, the longitudinal growth of the spinal cord increasingly lags behind that of the vertebral colum n. At birth the dist al end of the spinal cord, the conus m edullaris, is at the level of the L3 vertebral body (where lum bar puncture is contraindicated). The spinal cord of a tall adult ends at the T12/ L1 level, whereas that of a short adult extends to the L2/ L3 level. The dural sac always extends into the upper sacrum . It is im port ant to consider these anatom ical relationships during lum bar puncture. It is best to introduce the needle at the L3/ L4 interspace (see Fig . 4.9).

Conus m edullaris Cauda equina 1

Filum term inale

2

Sacral hiatus

A

B

3

Fig. 4.9 Lumbar puncture, e pidural anesthesia, and lumbar anesthesia In preparation for a lumbar puncture, the patient bends far forward to separate the spinous processes of the lum bar spine. The spinal needle is usually introduced bet ween the spinous processes of the L3 and L4 vertebrae. It is advanced through the skin and into the dural sac (lum bar cistern, see Fig. 4.8) to obtain a CSF sam ple. This procedure has num erous applications, including the diagnosis of m eningitis. For e pidural anesthesia, a catheter is placed in the epidural space without penetrating the dural sac (1). Lumbar anesthesia is induced by injecting a local anesthetic solution into the dural sac (2). Another option is to pass the needle into the epidural space through the sacral hiatus (3).

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Spinal Cord: Circuitry & Spinal Nerves

Nuclear column

Anterior root

Peripheral n.

Posterior horn (sensory)

Plexus

Lateral horn (viscerom otor)

Multisegm ental m uscle innervation

Afferent nuclei

Anterior horn (m otor)

Efferent nuclei

Columns

Spinal cord segm ent

Nuclei

Fig. 4.10 Organization of the gray matte r Left oblique anterosuperior view. The gray m at ter of the spinal cord is divided into three colum ns (horns). A erent (blue) and e erent (red) neurons within these colum ns are clustered according to function.

Ascending tract s (afferent)

Lateral funiculus

Anterior funiculus

Descending tract s (efferent)

Funiculi

Fig. 4.11 Muscle inne rvation Indicator m uscles are innervated by m otor neurons in the anterior horn of one spinal cord segm ent. Most m uscles (m ultisegm ental m uscles) receive innervation from a m otor colum n, a vertical arrangem ent of m otor nuclei spanning several segm ent s.

Interfascicular fasciculus (only in cervical cord)

Posterior funiculus

Monosegm ental m uscle innervation

Septom arginal fasciculus (only in thoracic cord)

Philippe-Gom bault triangle (only in sacral cord)

Longitudinal fasciculus of posterior colum n Lateral fasciculus proprius Sulcom arginal fasciculus

Tracts

Fig. 4.12   Re e xes Principal intrinsic fascicles of the spinal cord. Muscular function at the unconscious (re ex) level is controlled by the gray m at ter of the spinal cord. The intrinsic fascicles are the conduction apparatus of the intrinsic circuit s, allowing axons to ascend and descend to coordinate spinal re exes for m ultisegm ent al m uscles.

Fig. 4.13 Se nsory and motor syste ms White m at ter of the spinal cord. The white m at ter of the spinal cord cont ains ascending tract s (a erent tract s) and descending tract s (efferent tract s), which are the CNS equivalent of peripheral nerves. The sensory system (see pp. 104, 105 and m otor system (see pp. 108, 109) are so functionally interrelated they m ay be described as one (sensorim otor system ).

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Posterior rootlets

Gray m at ter, posterior horn

Posterior root (with spinal ganglion) Spinal nerve

White m at ter Posterior ram us

Gray m at ter, anterior horn

Anterior ram us Gray ram us com m unicans

Anterior root

White ram us com m unicans

Meningeal branch

Anterior rootlet s

Splanchnic nerves

Sympathetic ganglion

Fig. 4.14 Spinal cord se g me nt The spinal cord consists of 31 segments, each innervating a speci c area of the skin (a dermatome) of the head, trunk, or limbs. A erent (sensory) posterior rootlets and e erent (motor) anterior rootlets form the posterior and anterior roots of the spinal nerve for that segment. The t wo roots fuse to form a mixed (motor and sensory) spinal nerve that exits the intervertebral foramen and immediately thereafter divides into an anterior and posterior ramus (or branch). Spinal cord segment C1

Vertebra

T2

Atlas (C1) Axis (C2)

S1

L5

L1

C2

T1

Cervical cord lesion

C3 C8 T1

C4

C7 T1

C5

Thoracic cord lesion

C6

S5 T1 T12 L1 S1

T12

C7

L1

Lum bar cord lesion

C8

L5

Conus/cauda equina lesion

S1

A

Coccyx

C

B

Fig. 4.15   Spinal cord se g me nts, de rmatomes, and e e cts of spinal  co rd lesio ns The spinal cord is divided into four major regions: cervical, thoracic, lumbar, and sacral. The regions of the spinal cord are designated by colors: red, cervical; brown, thoracic; green, lumbar; blue, sacral. A Spinal cord segments. Initially spinal nerves pass out above the vertebrae for which they are numbered. However, since there is an 8th cervical spinal nerve but no 8th cervical vertebra, C8 passes out above the

vertebral level T1, and the spinal nerve for T1 and following pass out below the vertebral level for which they are named. B Dermatome, bandlike areas of skin receiving sensory innervation from a single pair of spinal nerves (from a single segment of the spinal cord). Note: Spinal nerve C1 is purely motor; consequently there is no C1 dermatome. C E ects of lesions in each region of the spinal cord.

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Organization of the Brain & Cerebellum

Central sulcus Insula

A

B

Lateral sulcus

Frontal pole Cingulate gyrus

Olfactory bulb and tract nerve (CN I)

Corpus callosum Parietooccipital sulcus

Optic nerve (CN II) Pituitary gland Mam m illary body

Septum pellucidum

Mesencephalon

C

D

Fornix

Occipital pole

Fig. 4.16 The brain A Lateral view of the left hemisphere. B Lateral view of the retracted left hemisphere. C Lateral view of a sagit tal section of the right hemisphere. D Basal (inferior) view with the brainstem removed. The brain is divided in four major parts: telencephalon (cerebrum), diencephalon, brainstem, and cerebellum. The telencephalon (cerebrum) is the large outer portion of the brain, consisting of t wo hemispheres separated by a longitudinal ssure (see D). The telencephalon is divided into ve lobes: frontal, parietal, temporal, occipital, and insular. The surface

Longitudinal cerebral fissure

contours of the cerebrum are de ned by convolutions (gyri) and depressions (sulci). The central sulcus, an important reference point on the cerebrum, separates the precentral gyrus from the postcentral gyrus. The precentral gyrus mediates voluntary motor activit y, and the postcentral gyrus mediates the conscious perception of body sensation. Sulci may be narrowed and compressed in brain edema, due to excessive uid accumulation in the brain, and are enlarged in brain atrophy (e.g., Alzheimer disease), due to tissue loss from the gyri.

Ta ble 4.2 Functions of the ce rebrum (tele nce phalon) Brain structure

Lo be

Function

Cerebrum (telencephalon)

Front al

Motor m ovem ent ; m otor aspect of speech (Broca’s area); reasoning ; personalit y; problem solving

Pariet al

Sensory perceptions related to pain, tem perature, touch, and pressure; spatial orient ation and perception; sensory aspect of language (Wernicke’s area)

Tem poral

Auditory perceptions; learning ; m em ory

Occipit al

Vision

Insula

Associated with visceral functions, e.g., t aste

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Interm ediate parts

Anterior lobe

Prim ary fissure Culm en

Quadrangular lobule Simple lobule Superior sem ilunar lobule Verm is

Posterior lobe

A

Folium of verm is Inferior sem ilunar lobule

Superior m edullary Central velum lobule Superior cerebellar peduncle Middle cerebellar peduncle

Horizontal fissure

• The primary ssure separates the anterior lobe of the cerebellum from the posterior lobe. • The posterolateral ssure separates the posterior lobe of the cerebellum from the occulonodular lobe.

Lingula 4th ventricle

Inferior cerebellar peduncle

Nodule Flocculus

Horizontal fissure Uvula verm is B

Flocculonodular lobe

Intermediate part s

Pyram id Vallecula of verm is

Tonsil

Fig. 4.17 Ce rebellum A Superior view. B Anterior view. The cerebellum is part of the motor system. It cannot initiate conscious movements by itself but is responsible for unconscious coordination and ne control of muscle actions. Grossly, the cerebellar surface presents a much ner arrangement of gyri and sulci than the cerebrum, providing an even greater expansion of its surface area. Externally the cerebellum consists of t wo large lateral masses, the cerebellar hemispheres, and a central part, called the vermis. Cerebellar ssures further subdivide the cerebellum into lobes:

Peduncle of flocculus

The cerebellum is connected to the brainstem by three cerebellar peduncles (superior, middle, and inferior), through which the a erent and e erent tracts enter and leave the cerebellum (see Fig 4.18). The superior medullary velum stretches bet ween the superior cerebellar peduncles and forms part of the roof of the fourth ventricle. The cerebellar tonsils protrude downward near the midline on each side, almost to the foramen magnum at the base of the skull (not shown). Increased intracranial pressure may cause the cerebellar tonsils to herniate into the foramen magnum, impinging on vital centers in the brainstem and posing a threat to life.

Superior cerebellar peduncle Anterior spinocerebellar tract

Inferior cerebellar peduncle

Middle cerebellar peduncle Trigem inal n. (CN V)

Fig. 4.18 Ce rebellar pe duncles Left lateral view. The substantial mass of the peduncles re ects the extensive neural connections they carry. The cerebellum requires these numerous connections because it is the integrating center for the control of ne movements. It contains and processes vestibular and proprioceptive a erents and modulates motor nuclei in other brain regions and in the spinal cord.

Vestibulocochlear n. (CN VIII) Facial n. (CN VII) Central tegm ental tract Olive

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Telencephalon (I): Overview, Basal Ganglia, & Neocortex

Cerebral cortex Caudate nucleus

Corpus striatum

Putam en

Basal ganglia

Globus pallidus White mat ter Claustrum Amygdala

Diencephalon

Fig. 4.19 Divisions of the tele nce phalon Coronal section, anterior view. The telencephalon is divided into the cerebral cortex, white mat ter, and basal ganglia. The cerebral cortex is further divided into the allocortex and neocortex. The allocortex consists of the olfactory cortex and hippocampus. The neocortex is remainder and the largest portion of the cerebral cortex. Thalam us Lateral ventricle

Caudate nucleus

Putam en

Lateral ventricle (anterior horn) Caudate nucleus (head)

Anterior crus Internal capsule

Genu Posterior crus

Putam en

External capsule

Globus pallidus

Claustrum Extrem e capsule

Thalam us Caudate nucleus (tail)

Forceps m ajor (occipitalis) Lateral ventricle (posterior horn)

Fig. 4.20 Basal ganglia Transverse section through the cerebrum at the level of the corpus striatum, superior view. The basal ganglia consists of the caudate nucleus, putamen, and globus pallidus and are an essential component of the extrapyramidal motor system, which controls involuntary movement and

re exes and coordinates complex movements (see p.108). The caudate nucleus and putamen, which are separated from each other by the brous white mat ter of the internal capsule, together constitute the corpus striatum. De ciency of dopamine in the basal ganglia is responsible for Parkinson disease.

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Central sulcus

6

3

1

2

4

8 5 9

7

31 24 23

10

Parieto-occipital sulcus

33 32

19

Calcarine sulcus

30 12

18

25

11

17

34 28

37

20

18

38

19

A Central sulcus

3

1

2

6 8 4 7

9 40 46

10

39

44 41 45

19

42

22

11 38

21 18 37

20

B

17

Lateral sulcus

Fig. 4.21   Brodmann areas in the  ne ocorte x A Medial view of midsagit tal section of the right cerebral hemisphere; B Lateral view of the left cerebral hemisphere. The surface of the brain consists macroscopically of lobes, gyri, and sulci. Microscopically, however, subtle di erences can be found in the distribution of the cortical neurons, and some of these di erences do not conform to the gross surface anatomy of the brain. Portions of the cerebral cortex that have the same basic microscopic features are called cortical areas or cortical elds. This organization into cortical areas is based on the distribution of neurons in the di erent layers of the cortex (cytoarchitectonics). In the brain map shown above, these areas are indicated by different colors. Although the size of the cortical areas may vary bet ween individuals, the brain map pictured here is still used today as a standard

reference chart. It has long been thought that the map (created by Korbinian Brodmann) accurately re ects the functional organization of the cortex, and indeed, modern imaging techniques have shown that many of the cytologically de ned areas are associated with speci c functions. There is no need, of course, to memorize the location of all the cortical areas, but the following areas are of special interest: • Areas 1, 2, and 3: primary somatosensory cortex • Area 4: primary motor cortex • Area 17: primary visual cortex (striate area, the extent of which is best appreciated in the midsagit tal section) • Areas 41 and 42: auditory cortex

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Telecephalon (II): Allocortex & Limbic System

Olfactory bulb Olfactory tract Olfactory trigone Periarchicortex

Olfactory tract Paleo- Periarchicortex cortex

Archicortex

Archicortex

Fig. 4.22   Allocorte x A Left lateral view of the right hem isphere. B Basal (inferior) view. The allocortex consist s of the olfactory cortex (blue) and the hippocam pus (pink). The olfactory cortex is involved with processing the sense of sm ell. It receives sensory a erent im pulses directly from the

olfactory bulb, unlike all other sensory a erent im pulses that reach the cerebral cortex via the dorsal thalam us. The hippocam pus is an im port ant area for inform ation integration and m em ory. Dam age to the hippocam pus, which occurs early in Alzheim er disease, contributes to m em ory loss and disorient ation.

Cingulate gyrus (lim bic lobe) Fornix

Corpus callosum

Indusium griseum

Colum n of fornix

Fimbria of hippocampus

Anterior comm issure

Mam m illary body

Hippocam pus

Fig. 4.23 Left hippocampal formation Lateral view. Most of the left hem isphere has been dissected away, leaving only the corpus callosum , fornix, and hippocam pus. The intact right hem isphere is visible in the background. The hippocam pal form ation is an im port ant com ponent of the limbic system (see Fig . 4.24). It consist s of three part s:

The ber tract of the fornix connect s the hippocam pus to the m am m illary body. The hippocam pus integrates inform ation from various brain areas and in uences endocrim e, visceral, and em otional processes via it s e erent output. It is particulary associated with the est ablishm ent of short-term m em ory. Lesions of the hippocam pus can therefore cause speci c de cit s in m em ory form ation.

• subiculum (not shown), • hippocam pus proper, and • dent ate gyrus (not shown).

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Fornix Corpus callosum

Mam m illary body

Hippocam pus B

A

Fig. 4.24 Limbic syste m A Midsagit t al section, left lateral view. B Hippocam pus, left anterior oblique view. The lim bic system , which exchanges and integrates inform ation bet ween the telencephalon, diencephalon, and m esencephalon, regulates drive and a ective behavior. It plays a crucial role in m em ory

and learning. The amygdala ( , one of the subcortical nuclei) is an im port ant structure for the processing of em otions. It is involved in the ight-or- ght response and in sexual pleasure. Dysfunction of the amygdala has been linked to conditions such as anxiet y, depression, post-traum atic stress disorder, and phobias.

Ta ble 4.3 Structures of the limbic syste m Oute r arc

Inne r arc*

Subco rtical nucle i

Parahippocam pal gyrus

Hippocam pal form ation (hippocam pus, entorhinal area of parahippocam pal gyrus)

Amygdala

Indusium griseum

Fornix

Dorsal tegm ental nuclei

Subcallosal (paraolfactory) area

Sept al area (septum )

Habenular nuclei Interpeduncular nuclei

Cingulate (lim bic) gyrus

Paraterm inal gyrus

Mam m illary bodies Anterior thalam ic nuclei

* The inner arc also cont ains the diagonal band of Broca (not shown).

Em otional drive

Limbic system

Hypothalamus Hom eostasis

Circulatory and respiratory hom eostasis

Medulla oblongata

Spinal cord Spinal reflexes Target organs

Fig. 4.25 Limbic re g ulation of the pe riphe ral autonomic ne rvous syste m The lim bic system receives a erent feedback signals from it s t arget organs. See Fig 4.68 for a diagram of the autonom ic nervous system .

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Diencephalon: Overview & Development Hypothalam ic sulcus (ventral diencephalic sulcus)

Corpus callosum

Thalam us

Choroid plexus

Fornix Interthalam ic adhesion

Anterior com m issure

Stria m edullaris thalam i

Preoptic area

Pineal (epiphysis)

Hypothalam us Supraoptic recess Infundibular recess

Cerebellum

Infundibulum

Anterior lobe of pituitary gland (adenohypophysis) Posterior lobe of pituitary gland (neurohypophysis)

Tuber cinereum

Third ventricle

Mam m illary body

Cerebral peduncle

Tegm entum

A

Cerebral aqueduct

Quadrigem inal plate, superior and inferior colliculi

Mesencephalon

Fig. 4.26 The die nce phalon A Diencephalon and brainstem in situ, midsagit tal section of the right hemisphere viewed from the left side. B Left lateral view with telencephalon removed. The diencephalon is located below the corpus callosum, part of the telencephalon, and above the mesencephalon (midbrain). The lateral wall of the third ventricle, visible here, forms the medial boundary of the diencephalon. The thalamus makes up four fths of the entire diencephalon, but the only parts of the diencephalon that can be seen externally are the hypothalamus (visible from the basal aspect) and portions of the epithalamus (pineal gland, visible from the occipital aspect). The diencephalon is involved in endocrine functioning and autonomic coordination of the pineal gland, the poste-

rior lobe of the pituitary gland (neurohypophysis), and the hypothalamus. It also acts as a relay station for sensory information and somatic motor control (via the thalamus). Visible in B are the thalamus, the lateral geniculate body, and the optic tract. The lateral geniculate body and optic tract are components of the visual pathway. Note: The retina and associated optic nerve form an anterior extension of the diencephalon and therefore are colored blue here, which departs from the convention of yellow for nerves. The optic tract marks the lateral boundary of the diencephalon. It winds around the cerebral peduncles, which are part of the adjacent mesencephalon (midbrain).

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Corpus callosum

Thalam us

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Lateral geniculate body

Pulvinar Pineal Optic tract Optic nerve Infundibulum Mam millary body

Brachium of inferior colliculus

Cerebellum B

Ta ble 4.4 Functions of the die nce phalon Part

Structures

Function

Epithalam us

Pineal gland Habenulae

Regulation of circadian rhyt hm s; linking of olfactory system to brain

Thalam us

Thalam us

Relay center for the som atosensory system and part s of the m otor system

Subthalam us

Subthalam ic nucleus Zona incert a (not shown) Globus pallidus

Relay of sensory inform ation (som atom otor zone of diencephalon)

Hypothalam us

Optic chiasm , optic tract Tuber cinereum (not shown) Posterior lobe of pit uit ary gland (neurohypophsis) Mam m illary bodies

Coordination of autonom ic nervous system with endocrine system ; participation in visual pathway

Telencephalon

Diencephalon

Caudate nucleus

Anterior group of nuclei Internal m edullary lam ina

Lateral ventricle

Reticular nucleus of thalamus

Corpus callosum

Medial group of nuclei

Choroid plexus

Paraventricular nuclei

Putam en

Third ventricle

Globus pallidus. lateral segment

Mam m illothalamic fasciculus

Globus pallidus, medial segm ent

Subthalamic nucleus

Hippocam pus

Optic tract Mam m illary body Mesencephalon Substantia nigra

Fig. 4.27 Inte rnal structure of the die nce phalon and tele ce phalon Coronal section at the level of the mammillary bodies.

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Diencephalon: Thalamus & Hypothalamus Cerebral cortex

Lateral dorsal nucleus

Thalam us Synapse

Dorsal m edial nucleus

Anterior thalam ic nuclei

Intralam inar nuclei

Lateral posterior nucleus

Centrom edian nucleus

Ventral anterior nucleus Ventral lateral nucleus

Neuron

Ventral intermediate nucleus

Descending tract

Ascending tract

Pulvinar

Ventral posterolateral nucleus Ventral posterom edial nucleus Lateral geniculate body

Fig. 4.28 Functional organization of the thalamus Almost all of the sensory pathways are relayed via the thalamus and project to the cerebral cortex. Consequently, a lesion of the thalamus or its cortical projection bers caused by a stroke or other disease leads to sensory disturbances. Although a di use kind of sensory perception may take place at the thalamic level (especially pain perception), cortical processing (by the telencephalon) is necessary in order to transform unconscious perception into conscious perception. The olfactory system is an exception to this rule, although its olfactory bulb is still an extension of the telencephalon. Note: Major descending motor tracts from the cerebral cortex generally bypass the thalamus.

Fig. 4.29 Spatial arrang e me nt of the thalamic nucle ar g ro ups Left thalamus viewed from the lateral and occipital aspect. The thalamus is a collection of approximately 120 nuclei that process sensory information. They are broadly classi ed as speci c or nonspeci c: • Speci c nuclei and the bers arising from them (thalamic radiation) have direct connections with speci c areas of the cerebral cortex. The speci c thalamic nuclei are subdivided into four groups: • Anterior nuclei (yellow) • Medial nuclei (red) • Ventrolateral nuclei (green) • Dorsal nuclei (blue). The dorsal nuclei are in contact with the me-

Medial geniculate body

dial and lateral geniculate bodies. Located beneath the pulvinar, these t wo nuclear bodies contain the nuclei of the medial and lateral geniculate bodies, and are collectively called the metathalamus. Like the pulvinar, they belong to the category of speci c thalamic nuclei. • Nonspeci c nuclei have no direct connections with the cerebral cortex. Part of a general arousal system, they are connected directly to the brainstem. The only nonspeci c nuclei shown in this diagram (orange) are the centromedian nucleus and the intralaminar nuclei.

Ta ble 4.5 Clinically important conne ctions of the thalamic nucle i Thalamic a e re nt

Thalamic nucle us

Thalamic e e re nts

Mam m illary body (m am m allothalam ic fasciclus)

Anterior nucleus (NA)

Cingulate gyrus (lim bic system )

Cerebellum , red nucleus

Ventral lateral nucleus (VL)

Prem otor cortex

Posterior funiculus, lateral funiculus (som atosensory input from lim bs and trunk)

Ventral posterolateral nucleus (VPL)

Postcentral gyrus (sensory cortex)

Trigem inothalam ic tract (som atosensory input from head)

Ventral posterom edial nucleus (VPM)

Postcentral gyrus (sensory cortex)

Inferior brachium (part of auditory pathway)

Medial geniculate nucleus (body) (MGB)

Transverse tem poral gyri (auditory cortex)

Optic tract

Lateralgeniculate nucleus (body) (LGB)

Striate area (visual cortex)

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Paraventricular nucleus

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Hypothalam ic sulcus

Fornix

Fornix

Dorsom edial nucleus

Paraventricular nucleus

Preoptic nucleus

Area lateralis Area m edialis

Supraoptic nucleus

b c

Ventrom edial nucleus

Optic chiasm

B

Supraoptic nucleus

Dorsomedial nucleus

Optic chiasm

A

Area dorsalis

Fornix

Infundibular nucleus Anterior lobe of pituitary gland

Third ventricle

Area lateralis

Optic tract

Posterior lobe of pituitary gland

Tuberal nuclei

Mam millary body

Posterior nucleus

Fig. 4.30 Nucle i in the rig ht hypothalamus A Midsagit tal section of the right hemisphere viewed from the medial side. B, C Coronal sections. The hypothalamus is a small nuclear complex located ventral to the thalamus and separated from it by the hypothalamic sulcus. Despite its small size, the hypothalamus is the command center for all autonomic functions in the body. Only a few of the larger, more clinically important hypothalmic nuclei are mentioned in this unit. Three groups of nuclei are listed below in an oral-to-caudal sequence, and their functions are brie y described: • The anterior (rostral) group of nuclei (green) synthesizes the hormones released from the posterior lobe of the pituitary gland, and consists of the: – preoptic nucleus, – paraventricular nucleus, and – supraoptic nucleus. • The middle (tuberal) group of nuclei (blue) controls hormone release from the anterior lobe of the pituitary gland, and consists of the: – dorsomedial nucleus, – ventromedial nucleus, and

C

Tuberal nuclei Ventrom edial nucleus

Third ventricle

– tuberal nuclei. • The posterior (mammillary) group of nuclei (red) activates the sympathetic nervous system when stimulated. It consists of the: – posterior nucleus and – mammillary nuclei located in the mammillary bodies. The coronal section (C) shows the further subdivision of the hypothalamus by the fornix into lateral and medial zones. The three nuclear groups described above are part of the medial zone, whereas the nuclei in the lateral zone are not subdivided into speci c groups (e.g., the area lateralis takes the place of a nucleus. Bilateral lesions of the mammillary bodies and their nuclei are manifested by Korsako syndrome, which is frequently associated with alcoholism (cause: vitamin B1 [thiamine] de ciency). The memory impairment that occurs in this syndrome mainly a ects shortterm memory, and the patient may ll in the memory gaps with fabricated information. A major neuropathological nding is the presence of hemorrhages in the mammillary bodies, which are sectioned at autopsy to con rm the diagnosis.

Ta ble 4.6 Functions of the hypothalamus Re g io n o r nucle us

Functio n

Lesion

Anterior preopt ic region

Maint ains const ant body tem perature

Central hypotherm ia

Posterior region

Responds to tem perature changes, e.g., sweating

Hypotherm ia

Midanterior and posterior regions

Activate sym pat hetic nervous system

Autonom ic dysfunction

Paraventricular and anterior regions

Activate parasym pathetic nervous system

Autonom ic dysfunction

Supraopt ic and paraventricular nuclei

Regulate water balance

Diabetes insipidus Hyponatrem ia (low Na +)

Anterior nuclei

Regulate appetite and food int ake

Lesion of m edial part causes obesit y Lesion of lateral part causes anorexia and em aciation

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Brainstem: Organization & External Structure

Diencephalon Cerebral aqueduct

Mesencephalon

Cerebellum

Pituitary gland

Fourth ventricle

Pons

Medulla oblongata

Rhomboid fossa

Nucleus of oculom otor nerve

Nuclear region for visual orientation in space, autonom ic center for coordinating food intake

Fig. 4.31 Division of the brainste m into levels Midsagit tal section. The brainstem is divided macroscopically into three levels, with the bulge of the pons marking the boundary lines bet ween the parts:

Nucleus of trochlear nerve

• Mesencephalon (midbrain) • Pons • Medulla oblongata

Trigem inal m otor nucleus

The three levels are easily distinguished from one another by gross visual inspection, although they are not di erentiated in a functional sense. The functional organization of the brainstem is determined chie y by the arrangement of the cranial nerve nuclei (see pp. 116, and 117). Given the close proximit y of nuclei and large ber tracts in this region, even a small lesion of the brainstem (e.g., hemorrhage, tumor) may lead to extensive and complex alterations of sensorimotor function.

Nucleus of abducent nerve Facial nucleus Nuclear region for swallowing Dorsal m otor (vagal) nucleus Pneum otaxic region, acoustic and vestibular orientation in space

Nucleus of hypoglossal nerve

Nuclear region for vasomotor control Nucleus am biguus

Area postrema

Nuclear region for inspiration

Nuclear region for expiration

Fig. 4.32 Structural-functional relationships in the re ticular fo rmatio n Midsagit tal section of the brainstem viewed from the left side. While the cranial nerve nuclei, substantia nigra, and red nucleus have well-de ned boundaries, as we have seen, the reticular formation (light green) is a relatively di use net work of nerve cells and bers in the brainstem, occupying the areas bet ween the cranial nerve nuclei described above. It can be roughly divided into t wo main groups of nuclei: • Medial group (speci c nuclei labeled in the diagram): nuclei containing large neurons whose axons form long ascending and descending tracts. • Lateral group (not individually labeled in the diagram): nuclei containing small neurons whose axons usually stay within the brainstem. They are therefore called “association areas.” Besides respiratory and circulatory regulation, the di use neuronal network of the reticular formation performs many other important autonomic functions.

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Oculom otor nerve (CN III)

Interpeduncular fossa

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Quadrigem inal plate, superior colliculus Pineal

Cerebral peduncle

Brachium of superior colliculus

Brachium of inferior colliculus

Quadrigem inal plate, inferior colliculus

Pons Trigem inal nerve, motor root

Superior m edullary velum Trochlear nerve

Trigem inal nerve (CN V) Abducent nerve (CN VI) Facial nerve (CN VII) Nervus interm edius Vestibulocochlear nerve (CN VIII)

Olive

Glossopharyngeal nerve (CN IX)

Pyram id of m edulla oblongata

Vagus nerve (CN X) Hypoglossal nerve (CN XII)

Trigeminal nerve

Rhomboid fossa

Medial em inence

Inferior cerebellar peduncle

Middle cerebellar peduncle

Vestibular area

Facial colliculus

Striae medullaris Taenia cinerea

Decussation of pyramids

A

Cerebral peduncle

B

Superior colliculus Inferior colliculus Trochlear nerve

Trigem inal nerve, m otor root

Trigone of vagus nerve

Tubercle of nucleus gracilis

C1 spinal nerve, ventral root

Brachium of inferior colliculus

Pons

Trigone of hypoglossal nerve

Tubercle of nucleus cuneatus

Anterior m edian fissure

Accessory nerve (CN XI)

Superior cerebellar peduncle

Trigem inal nerve, sensory root

Middle cerebellar peduncle Inferior cerebellar peduncle

Vestibulocochlear nerve Facial nerve

Lateral aperture

Abducent nerve

Vagus nerve

Nervus interm edius

Accessory nerve

Glossopharyngeal nerve Hypoglossal nerve Olive C1 spinal nerve, ventral root C

Superior cerebellar peduncle

Posterolateral sulcus Anterolateral sulcus

Fig. 4.33 Brainste m A Anterior view. The sites of entry and emergence of the ten pairs of true cranial nerves (III—XII) are particularly well displayed in this view. Note: The ophthalmic nerve (CN I) is a derivative of the telecephalon; the optic nerve (CN II) is a derivative of the diencephalon. Note also the site below the pyramids where the pyramidal bers cross over the midline from each side (decussation of the pyramids). Most of the axons of the large motor pathway for the trunk and limbs cross to the opposite side at this level. The cranial nerves are discussed in detail on pages 114 to 141. B Posterior view. Since the cerebellum has been removed, we can see the rhomboid fossa, which forms the oor of the fourth ventricle. The surface of the fossa is raised by several cranial nerve nuclei, which bulge into the fourth ventricle. The cerebellum is connected to the brainstem by three cerebellar peduncles on each side: • Superior cerebellar peduncle • Middle cerebellar peduncle • Inferior cerebellar peduncle The superior and inferior cerebellar peduncles border portions of the rhomboid fossa and thus contribute to the boundaries of the fourth ventricle. C Left lateral view. In addition to the cerebellar peduncles, this view displays the superior and inferior colliculi. Together with their counterparts on the right side, the colliculi form the quadrigeminal plate (see B), which is a prominent structure of the mesencephalon. The t wo superior colliculi are part of the visual pathway, while the inferior colliculi are part of the auditory pathway. The trochlear nerve (CN IV) runs forward below the inferior colliculus, and is the only cranial nerve that emerges from the posterior side of the brainstem. The olive appears as a prominence on the side of the medulla oblongata. The nuclei within the olive function as a relay station for the motor system.

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Mesencephalon & Pons: Transverse Sections

Fig. 4.34 Transve rse se ction throug h the mese nce phalo n (midbrain) Superior view. Nuclei: The most rostral cranial nerve nucleus is the relatively small nucleus of the oculomotor nerve. In the same transverse plane is the mesencephalic nucleus of the trigeminal nerve; other trigeminal nuclei can be identi ed in sections at lower levels (see Fig 4.36). Unique in the CNS, the mesencephalic nucleus of the trigeminal nerve contains displaced pseudounipolar sensory neurons, closely related to the PNS neurons of the trigeminal ganglion (both populations are derived embryonically from the neural crest). The peripheral processes of these mesencephalic neurons are proprioceptors in the muscles of mastication. The superior collicular nucleus is part of the visual system. The red nucleus and substantia nigra are involved in coordination of motor activit y. The red nucleus and all of the cranial nerve nuclei are located in the tegmentum of the mesencephalon, the superior colliculus is in the tectum (roof) of the mesencephalon, and the substantia nigra is in the cerebral peduncle. Di erent parts of the reticular formation, a diffuse aggregation of nuclear groups (see p. 88), are visible here and in sections below. Tracts: The tracts at this level run anterior to the nuclear regions. Prominent descending

Fig. 4.35 Transve rse se ction through the uppe r po ns Superior view. Nuclei: The only cranial nerve nucleus appearing in this plane of section is the mesencephalic trigeminal nucleus. It can be seen that the bers from the nucleus of the trochlear nerve (CN IV) cross to the opposite side (decussate) while still within the brainstem. Tracts: The ascending and descending tract systems are the same as in Figs 4.34 and 4.36. The pyramidal tract appears less compact at this level compared with the previous section due to the presence of intermingled pontine nuclei. This section cuts the tracts (mostly efferent) that exit the cerebellum through the superior cerebellar peduncle. The lateral lem niscus at the posteiror surface of the section is part of the auditory pathway. The relatively large medial longitudinal fasciculus extends from the mesencephalon (see Fig 4.34) into the spinal cord. It interconnects the brainstem nuclei and contains a variet y of bers that enter and emerge at various levels (“highway of the brainstem nuclei”). The smaller dorsal longitudinal fasciculus connects hypothalamic nuclei with the parasympathetic cranial nerve nuclei. The size and location of the nuclei of the reticular formation, which here are shown

Spinotectal tract

Superior collicular nucleus

A B C

Mesencephalic nucleus of trigem inal nerve

Lateral spinothalam ic tract

D

Cerebral aqueduct Central sym pathetic tract

Brachium of inferior colliculus Reticular formation

Nucleus of oculom otor nerve

Corticopontine tract: tem poropontine and parietopontine fibers

Medial longitudinal fasciculus

Red nucleus

Pyram idal tract: corticonuclear and corticospinal fibers

Substantia nigra

Corticopontine tract

Medial lem niscus

Oculom otor nerve

Tectospinal tract

tracts seen at this level include the pyramidal tract and the corticonuclear bers that branch from it. Ascending tracts visible at this level include the lateral spinothalamic tract and the medial lemniscus, both of which terminate in the thalamus.

Mesencephalic nucleus of trigem inal nerve Lo cu s ce ru le u s Superior cerebellar peduncle Lateral lem niscus Lateral trigem inal lem niscus Lateral spinothalam ic tract

Trochlear nerve Ce re b ra l aqueduct Dorsal longitudinal fasciculus Medial longitudinal fasciculus Central tegm ental tract Tectospinal tract

Rubrospinal tract

Reticular formation

Medial lem niscus

Pyramidal tract

graphically within a compact area, vary with the plane of the section. This diagram indicates only the approximate location of the reticular formation, and other smaller nuclei and bers may be found within these regions.

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Superior cerebellar peduncle

Superior m edullary velum

Anterior spinocerebellar tract

Fourth ventricle

Principal sensory nucleus of trigem inal nerve

Central sympathetic tract

Spinal nucleus of trigem inal nerve

Medial longitudinal fasciculus

Motor nucleus of trigem inal nerve

Reticular formation

Central tegm ental tract

Tectospinal tract

Lateral lem niscus Lateral spinothalam ic tract

Trigem inal nerve Medial lem niscus

Pyramidal tract

Fig. 4.36 Transve rse se ction throug h the midportion of the pons Nuclei: The trigeminal nerve leaves the brainstem at the midlevel of the pons, its various nuclei dominating the pontine tegmentum. The principal sensory nucleus of the trigeminal nerve relays a erents for touch and discrimination, while its spinal nucleus relays pain and temperature bers. The trigeminal motor nucleus contains the motor neurons for the mus-

Superior vestibular nucleus

Fastigial nucleus

cles of mastication. Tracts: This section cuts the anterior spinocerebellar tract, which passes to the cerebellum, immediately dorsal to the pons. CSF space : At this level the cerebral aqueduct has given way to the fourth ventricle, which appears in cross section. It is covered dorsally by the medullary velum.

Em boliform nucleus

Inferior vestibular nucleus

Globose nucleus Dentate nucleus

Lateral vestibular nucleus

Fourth ventricle

Medial vestibular nucleus

Nucleus of abducent nerve

Solitary tract

Medial longitudinal fasciculus

Central sympathetic tract

Tectospinal tract

Spinal tract of trigem inal nerve

Vestibulocochlear nerve

Anterior spinocerebellar tract

Facial nerve Trapezoid body

Facial nucleus Central tegm ental tract

Superior olivary nucleus Rubrospinal tract

Lateral spinothalam ic tract

Fig. 4.37 Transve rse se ction throug h the low e r pons (D) Nuclei: The lower pons contains a number of cranial nerve nuclei including the nuclei of the vestibulocochlear and abducent nerves, and the facial (motor) nucleus. The rhomboid fossa is covered dorsally by the cerebellum, whose nuclei also appear in this section—the fastigial nucleus,

emboliform nucleus, globose nucleus, and dentate nucleus. Tracts: The trapezoid body with its subnuclei is an important relay station and crossing point in the auditory pathway. The central tegmental tract is an important pathway in the motor system.

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Medulla Oblongata: Transverse Sections Dorsal vagal nucleus

Nucleus of hypoglossal nerve

Rhom boid fossa

Inferior cerebellar peduncle A B C D

Solitary tract Anterior cochlear nucleus Spinal nucleus of trigem inal nerve

Medial longitudinal fasciculus

Central sym pathetic tract

Vestibulocochlear nerve, cochlear root Vagus nerve

Nucleus am biguus Rubrospinal tract

Tectospinal tract

Anterior spinocerebellar tract

Inferior olivary nucleus

Lateral spinothalam ic tract

Reticular formation

Medial lem niscus

Fig. 4.38 Transve rse se ction throug h the uppe r me dulla oblongata (A) Nuclei: The nuclei of the hypoglossal nerve, vagus nerve, vestibulocochlear nerve, and the spinal nucleus of the trigeminal nerve appear in the posterior part of the medulla oblongata. The inferior olivary nucleus, which belongs to the motor system, is located in the anterior part of the medulla oblongata. The reticular formation is interposed bet ween the cranial nerve nuclei and the inferior olivary nucleus. It appears in all the

Dorsal vagal nucleus

Hypoglossal nerve

transverse sections of this section. Tracts: Most of the ascending and descending tracts are the same as in Fig 4.37. A new structure appearing at this level is the inferior cerebellar peduncle, through which a erent tracts pass to the cerebellum. CSF space : The oor of the fourth ventricle is the rhom boid fossa, which m arks the dorsal boundary of this section.

Choroid plexus

Rhomboid fossa

Solitary tract Nucleus of hypoglossal nerve

Spinal nucleus of trigem inal nerve

Medial longitudinal fasciculus

Central sym pathetic tract Nucleus am biguus

Vagus nerve

Posterior spinocerebellar tract

Tectospinal tract

Rubrospinal tract

Inferior olivary nucleus

Lateral spinothalam ic tract Reticular formation Pyram idal tract

Fig. 4.39 Transve rse se ction just above the middle of the me dulla oblo ng ata (B) Nuclei: The only cranial nerve nuclei visible at this level are those of the hypoglossal nerve, vagus nerve, and trigeminal nerve, appearing in the posterior medulla. The lower portion of the inferior olivary nucleus appears in the anterior medulla. Tracts: The ascending and descending tracts are the same as in Fig 4.37.

Medial lem niscus

Hypoglossal nerve

Ascending sensory tracts (from nuclei gracilis and cuneatus) decussate in the medial lemniscus. The solitary tract carries the gustatory bers of cranial nerves V, VII, and X. Posterolateral to it is the nucleus of the solitary tract (not shown). The pyramidal tract again appears as a compact structure at this level due to the absence of interspersed nuclei and decussating bers.

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Nucleus cuneatus

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Nucleus gracilis

Solitary tract

Accessory nucleus cuneatus Spinal nucleus of trigem inal nerve

Central canal

Posterior spinocerebellar tract

Nucleus of accessory nerve

Reticular formation

Medial longitudinal fasciculus

Central sym pathetic tract

Accessory nerve

Rubrospinal tract

Nucleus of hypoglossal nerve

Lateral spinothalam ic tract

Hypoglossal nerve

Pyramidal tract

Tectospinal tract

Fig. 4.40 Transve rse se ction just below the middle of the me dulla o blong ata (C) Nuclei: The nuclei of the hypoglossal, vagus, and trigeminal nerves appear at this level. The irregular outline of the inferior olivary nucleus is still just visible in the anterior medulla. The nuclei that relay signals from the posterior funiculus—the nucleus cuneatus and nucleus gracilis—ap-

Nucleus cuneatus

Medial lem niscus

pear prominently in the posterior part of the section. The tracts that arise from these nuclei decussate in the medial lemniscus (see above). Tracts: The ascending and descending tracts correspond to those in the previous gures in this section. The rhomboid fossa, which is the oor of the fourth ventricle, has narrowed substantially at this level to become the central canal.

Nucleus gracilis

Fasciculus gracilis

Fasciculus cuneatus

Substantia gelatinosa

Solitary tract

Spinal nucleus of trigem inal nerve

Nucleus of accessory nerve

Reticular formation

Central canal

Central sym pathetic tract

Decussation of pyramids

Posterior spinocerebellar tract

Lateral pyram idal tract

Rubrospinal tract

Medial longitudinal fasciculus

Lateral spinothalam ic tract

Tectospinal tract

Fig. 4.41 Transve rse se ction through the low e r me dulla oblongata (D) The medulla oblongata is continuous with the spinal cord at this level, showing no distinct transition. Nuclei: The cranial nerve nuclei visible at this level are the spinal part of the trigeminal nerve and the nucleus of the accessory nerve. This section passes through the caudal ends of the nuclei in the relay station of the posterior funiculus—the nucleus cuneatus and nucleus gracilis.

Anterior pyramidal tract

Tracts: The ascending and descending tracts correspond to those in the previous gures in this section. The section passes through the decussation of the pyramids, and we can now distinguish the anterior pyramidal tract (uncrossed) from the lateral pyramidal tract (crossed). CSF space : This section passes through a portion of the central canal, which is markedly smaller at this level than in Fig 4.40. It may even be obliterated at some sites, but this has no clinical signi cance.

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Cerebrospinal Fluid (CSF) Spaces & Ventricles Arachnoid granulations

Choroid plexus (lateral ventricle)

Choroid plexus (3rd ventricle) Superior sagit tal sinus Am bient cistern Interhem ispheric cistern

Straight sinus

Interventricular foram en

Cerebral aqueduct

Confluence of the sinuses Cistern of lam ina term inalis

Basal cistern

Verm ian cistern Choroid plexus (4th ventricle)

Chiasm atic cistern

Cerebellom edullary cistern (cisterna m agna)

Interpeduncular cistern

Median aperture

Pontom edullary cistern

Central canal of the spinal cord

Spinal cord Vertebral venous plexus CSF flow

Subarachnoid space

Subarachnoid space

Endoneural space

Ventricle Vein or venous sinus

Spinal nerve

Choroid plexus

Fig. 4.42 CSF space s Schematic midsagit tal section. Medial view of right hemisphere. The brain and spinal cord are suspended in CSF. CSF is located in the subarachnoid space enclosed by the meningeal layers surrounding the brain and spinal cord. The cerebral ventricles and subarachnoid space have a combined capacit y of approximately 150 mL of CSF (80%in subarachnoid space, 20% in ventricles). This volume is completely replaced t wo to four times daily. CSF is produced in the choroid plexus (red) and is present in

each of the four cerebral ventricles. It ows from the ventricles through the median and lateral apertures (not shown) into the subarachnoid space. Most CSF drains from the subarachnoid space through the arachnoid granulations into the dural venous sinuses. Smaller amounts drain along the proximal portions of the spinal nerves into venous plexuses or lymphatic pathways. Obstruction of CSF drainage will cause a rapid rise in intracranial pressure due to the high rate of CSF turnover.

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Lateral ventricle Interthalam ic Fornix (central part) adhesion

Suprapineal recess Pineal recess

Interventricular foram en

Pineal body

3rd ventricle

Cerebral aqueduct

Corpus callosum Lateral ventricle (anterior horn)

Collateral trigone

Supraoptic recess Optic chiasm

Lateral ventricle (posterior horn)

Infundibular recess Pituitary gland Lateral ventricle (inferior horn) 4th ventricle Lateral recess, ends in lateral aperture of 4th ventricle Central canal

Fig. 4.43 Ve ntricular syste m w ith its ne ig hboring structure s Left lateral view. The ventricular system is a greatly expanded and convoluted tube that represents a continuation of the central spinal canal into the brain. There are four cerebral ventricles, or cavities, lled with cerebrospinal uid and lined by a specialized epithelium, the ependyma. The four ventricles are as follows: • The two lateral ventricles, each of which communicates through an interventricular foramen with the • third ventricle, which in turn communicates through the cerebral aqueduct with the • fourth ventricle. This ventricle communicates with the subarachnoid space (see Fig 4.42).

Median aperture of 4th ventricle

The largest ventricles are the lateral ventricles, each of which consists of an anterior, inferior, and posterior horn and a central part. Certain portions of the ventricular system can be assigned to speci c parts of the brain: the anterior (frontal) horn to the frontal lobe of the cerebrum, the inferior (temporal) horn to the temporal lobe, the posterior (occipital) horn to the occipital lobe, the third ventricle to the diencephalon, the aqueduct to the mesencephalon (midbrain), and the fourth ventricle to the rhombencephalon (hindbrain). Certain diseases (e.g., atrophy of brain tissue in Alzheimer‘s disease and internal hydrocephalus) are characterized by abnormal enlargement of the ventricular system and are diagnosed from the size of the ventricles in sectional images of the brain.

3rd ventricle Anterior horn Right lateral ventricle

Inferior horn

Cerebral aqueduct

Left lateral ventricle Collateral trigone

Lateral recess Anterior horn

Posterior horn

4th ventricle

Collateral trigone

A

Lateral ventricle

Posterior horn

Fig. 4.44 Cast of the ve ntricular syste m A Superior view. B Left lateral view. These cast specimens demonstrate the four ventricular cavities and their connections. Hydrocephalus is an excess of cerebrospinal uid (CSF) in the ventricles of the brain. It usually occurs due to partial obstruction of the ow of CSF bet ween the ventricles or bet ween the ventricles and other parts of the brain. Excess CSF in the ventricles causes them to dilate and exert pressure on the surrounding cortex. In infants, the bones of the calvaria separate giving the characteristic increase in head size.

Interventricular foram en

Inferior horn

3rd ventricle 4th ventricle

Cerebral aqueduct B

Lateral recess

Central canal

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Arteries of the Brain

Anterior cerebral artery, postcom m unicating part,

Anterior com m unicating artery Internal carotid artery

Anterior cerebral artery, precom municating part,

Middle cerebral artery, sphenoidal part,

Posterior cerebral artery, postcom m unicating part,

Middle cerebral artery, insular part,

Posterior com m unicating artery

Posterior cerebral artery, precom m unicating part,

Anterior choroidal artery Lateral occipital artery, Pontine arteries Superior cerebellar artery

Anterior inferior cerebellar artery

Basilar artery Posterior inferior cerebellar artery

Medial occipital artery,

Vertebral artery

Anterior spinal artery

Fig. 4.45 Arte ries at the base of the brain The cerebellum and temporal lobe have been removed on the left side to display the course of the posterior cerebral artery. This view was selected because most of the arteries that supply the brain enter the cerebrum from its basal aspect (also see Fig. 3.17 for the circle of Willis). Note: The three principal arteries of the cerebrum, the anterior, middle and posterior cerebral arteries, arise from di erent sources. The anterior

and middle cerebral arteries are branches of the internal carotid artery, while the posterior cerebral arteries are terminal branches of the basilar artery. The vertebral arteries, which fuse to form the basilar artery, distribute branches to the spinal cord, brainstem, and cerebellum (anterior spinal artery, posterior spinal arteries, superior cerebellar artery, and anterior and posterior inferior cerebellar arteries). Corpus Lateral callosum ventricle Thalam us

Caudate nucleus

Insula

Cortical m argin

Claustrum

Fig. 4.46 Ce rebral arte ries: Distribution are as Lateral view of the left hemisphere. The central gray and white mat ter have a complex blood supply (yellow) that includes the anterior choroidal artery.

Internal capsule

Hippocampus

Globus pallidus

Putam en

Anterior cerebral artery Middle cerebral artery Posterior cerebral artery

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Anterior comm unicating artery

Posterior com m unicating artery

Internal carotid artery

Middle cerebral artery Basilar artery

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Fig. 4.47 Sites of be rry ane urysms at the base of the brain (after Bähr and Frotscher) The rupture of congenital or acquired arterial aneurysms at the base of the brain is the most frequent cause of subarachnoid hemorrhage and accounts for approximately 5 % of all strokes. These are abnormal saccular dilations of the circle of Willis and are especially common at the site of branching. When one of these thin-walled aneurysms ruptures, arterial blood escapes into the subarachnoid space. The most common site is the junction bet ween the anterior cerebral and anterior communicating arteries (1); the second most likely site is the branching of the posterior communicating artery from the internal carotid artery (2).

Vertebral arteries

Corpus callosum

Thalam us

Caudate nucleus

Internal capsule Putam en Hypertensive hem orrhage in the region of the basal ganglia

Claustrum Lenticulostriate arteries Globus pallidus Middle cerebral artery

Fig. 4.48 Intrace rebral he morrhag e Coronal section at the level of the thalamus. Unlike the extracerebral hem orrhages described above, intracerebral hemorrhage occurs when dam aged arteries bleed directly into the substance of the brain. This distinction is of very great clinical importance because extracerebral hemorrhages can be controlled by surgical hemostasis of the bleeding vessel, whereas intracerebral hemorrhages cannot. The most frequent cause of intracerebral hemorrhage (hemorrhagic stroke) is hypertension (high blood pressure). Because the soft brain tissue o ers very lit tle resistance, a large hematoma may form within the brain. The most common sources of intracerebral bleeding are speci c branches of the middle cerebral artery—

the lenticulostriate arteries pictured here (known also as the “stroke arteries”). The hemorrhage causes a cerebral infarction (death of brain tissue) in the region of the internal capsule, one e ect of which is to disrupt the pyramidal tract, which passes through the capsule. The loss of pyramidal tract function below the lesion is manifested clinically by spastic paralysis of the limbs on the side of the body opposite to the injury (the pyramidal tracts cross below the level of the lesion). The hemorrhage is not always massive, and smaller bleeds may occur in the territories of the three main cerebral arteries, producing a t ypical clinical presentation (see Fig. 4.55).

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Veins of the Brain: Super cial & Deep Veins Because the veins of the brain do not run parallel to the arteries, marked di erences are noted bet ween the regions of arterial supply and venous drainage. While all of the cerebral arteries enter the brain at its base, venous blood is drained from the entire surface of the brain, including the base, and also from the interior of the brain by t wo groups of veins: the super cial cerebral veins and the deep cerebral veins. The super cial veins drain blood from the cerebral cortex (via cortical veins) and white mat ter

(via medullary veins) directly into the dural sinuses. The deep veins drain blood from the deeper portions of the white mat ter, basal ganglia, corpus callosum, and diencephalon into the great cerebral vein, which enters the straight sinus. The t wo venous regions (those of the super cial and deep veins) are interconnected by numerous intracerebral anastomoses (see Fig 4.52).

Superior cerebral veins Superior anastom otic vein (of Trolard) Superior sagittal sinus

Superficial middle cerebral vein

Inferior anastom otic vein (of Labbé) Confluence of sinuses Transverse sinus Inferior cerebral vein

A

Anterior vein of septum pellucidum

Thalam ostriate vein

Superior cerebral veins Inferior sagittal sinus Choroid plexus of fourth ventricle Superior sagittal sinus Great cerebral vein Internal occipital vein

Anterior cerebral vein

Straight sinus Transverse sinus (cut)

Internal cerebral vein Ba sila r ve in

Occip it a l sinus

B

Fig. 4.49   Supe r cial ve ins of the  brain (supe r cial ce rebral ve ins) A Left lateral view. B Medial view. A, B The super cial cerebral veins drain blood from the short cortical veins and long medullary veins in the white mat ter (see Fig 4.52) into the dural sinuses. Their course is extremely variable, and veins in the subarachnoid space do not follow arteries, gyri, or sulci. Consequently, only the most important of these vessels are named here.

Just before terminating in the dural sinuses, the veins leave the subarachnoid space and run a short subdural course bet ween the dura mater and arachnoid. These short subdural venous segments are called bridging veins. The bridging veins have great clinical importance because they may be ruptured by head trauma, resulting in a subdural hematoma (see p. 103

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Fig. 4.50 Re g ions draine d by the supe r cial ce rebral ve ins A Left lateral view, B view of the medial surface of the right hemisphere, C basal view. The veins on the lateral surface of the brain are classi ed by their direction of drainage as ascending (draining into the superior sagit tal sinus) or descending (draining into the transverse sinus). The super cial middle cerebral vein drains into both the cavernous and transverse sinuses.

B Superficial ascending cerebral veins

Superficial descending cerebral veins

Superficial m iddle cerebral vein

Basilar vein

C

Olfactory nerve Anterior com municating vein

Superficial m iddle cerebral vein Anterior cerebral vein

Optic tract Interpeduncular vein

Deep m iddle cerebral vein

Inferior choroidal vein

Cerebral peduncle

Basilar vein

Internal cerebral vein

Posterior venous confluence

Great cerebral vein

Superior sagittal sinus

Fig. 4.51 Basal ce rebral ve nous syste m The basal cerebral venous system drains blood from both super cial and deep cerebral veins. A venous circle formed by the basilar veins (of Rosenthal) exists at the base of the brain, analogous to the arterial circle of Willis. The basilar vein is formed in the anterior perforate substance by the union of the anterior cerebral and deep middle cerebral veins. Following the course of the optic tract, the basilar vein runs posteriorly around the cerebral peduncle and unites with the basilar vein from the opposite side on the dorsal aspect of the mesencephalon. The t wo internal cerebral veins also terminate at this venous junction, the posterior venous con uence. This junction gives rise to the midline great cerebral vein, which enters the straight sinus. The basilar vein receives tributaries from deep brain regions in its course (e.g., veins from the thalamus and hypothalamus, choroid plexus of the inferior horn, etc.). The t wo anterior cerebral veins are interconnected by the anterior communicating vein, creating a closed, ring-shaped drainage system.

Superficial cerebral veins Medullary anastom otic vein

Longitudinal vein of caudate nucleus

Superficial cerebral veins Medullary vein

Transverse veins of caudate nucleus

Vein of centrum sem iovale

Choroidal vein

Superficial m iddle cerebral vein

Internal cerebral vein Term inal vein

Lateral superior lenticular veins

Deep m iddle cerebral vein

Medial superior lenticular veins Inferior lenticular veins

Fig. 4.52 Anastomoses bet ween the superf cia l a nd deep cerebra l veins Basal ce rebral ve no us syste m Transverse section through the left hemisphere, anterior view. The super cial cerebral veins communicate with the deep cerebral veins through the anastomoses shown here. Flow reversal (double arrows) may occur in the boundary zones bet ween t wo territories.

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Blood Vessels of the Brain: Cerebrovascular Disease

Internal capsule Thalam us Basal ganglia

Intracranial vascular stenoses Anterior cerebral artery

Middle cerebral artery

Thrombi (arterioarterial em boli) Internal carotid artery

Carotid occlusion (hem odynam ic disturbance) Atheromatous lesion at the carotid bifurcation

Carotid bifurcation

Com m on carotid artery

Aortic arch Thrombotic material on the aortic arch Throm botic material in left atrium

Thrombi (cardiac em boli)

Fig. 4.53 Fre que nt causes of ce rebrovascular disease (after Mum enthaler) Disturbances of cerebral blood ow that deprive the brain of oxygen (cerebral ischemia) are the most frequent cause of central neurological de cits. The most serious complication is stroke: the vast majorit y of all strokes are caused by cerebral ischemic disease. Stroke has become the third leading cause of death in western industrialized countries (approximately 700,000 strokes occur in the United States each year). Cerebral ischemia is caused by a prolonged diminution or interruption of blood ow and involves the distribution area of the internal carotid artery in up to 90 % of cases. Much less commonly, cerebral ischemia is caused by an obstruction of venous out ow due to cerebral venous thrombosis

(see Fig. 4.54). A decrease of arterial blood ow in the carotid system most commonly results from an embolic or local thrombotic occlusion. Most emboli originate from atheromatous lesions at the carotid bifurcation (arterioarterial emboli) or from the expulsion of thrombotic material from the left ventricle (cardiac emboli). Blood clots (thrombi) may be dislodged from the heart as a result of valvular disease or atrial brillation. This produces emboli that may be carried by the bloodstream to the brain, where they may cause the functional occlusion of an artery supplying the brain. The most common example of this involves all of the distribution region of the middle cerebral artery, which is a direct continuation of the internal carotid artery.

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Le ft

A

B

Fig. 4.54 Ce rebral ve nous thrombosis Coronal section, anterior view. The cerebral veins, like the cerebral arteries, serve speci c territories (see pp. 258 and 260). Though much less common than decreased arterial ow, the obstruction of venous out ow is an important potential cause of ischemia and infarction. With a throm botic occlusion, for example, the quantit y of blood and thus the venous pressure are increased in the tributary region of the occluded vein. This causes a drop in the capillary pressure gradient, with an increased extravasation of uid from the capillary bed into the brain tissue (edema). There is a concomitant reduction of arterial in ow into the a ected region, depriving it of oxygen. The occlusion of speci c cerebral veins (e.g., due to cerebral venous thrombosis) leads to brain infarctions (stroke) at characteristic locations: A Superior cerebral veins: Thrombosis and infarction in the areas drained by the:

C

• Posterior superior cerebral veins (left, symptoms: contralateral hemiparesis). Motor aphasia occurs if the infarction involves the motor speech center in the dominant hemisphere. B Inferior cerebral veins: Thrombosis of the right inferior cerebral veins leads to infarction of the right temporal lobe (symptoms: sensory aphasia, contralateral hemianopia). C Internal cerebral veins: Bilateral thrombosis leads to a symmetrical infarction a ecting the thalamus and basal ganglia. This is characterized by a rapid deterioration of consciousness ranging to coma. Because the dural sinuses have extensive anastomoses, a limited occlusion a ecting part of a sinus often does not cause pronounced clinical symptoms, unlike the venous thromboses described here.

• Medial superior cerebral veins (right, symptoms: contralateral lower limb weakness);

Vascular territory Anterior cerebral artery

Middle cerebral artery

Posterior cerebral artery

Neurological symptoms Hem iparesis (with or without hem isensory deficit)

Hem iparesis (with or without hem isensory deficit) mainly affecting the arm and face (WernickeMann t ype)

Hem isensory losses

Bladder dysfunction

Fig. 4.55 Cardinal symptoms of occlusion of the thre e main ce rebral arte ries (after Masuhr and Neum ann) When the anterior, middle or posterior cerebral artery becomes occluded, characteristic functional de cits occur in the oxygen-deprived brain areas supplied by the occluded vessel. In many cases the a ected artery can be identi ed based on the associated neurological de cit: • Bladder weakness (cortical bladder center) and paralysis of the lower limb (hemiplegia with or without hemisensory de cit, predominantly a ecting the leg) on the side opposite the occlusion indicate an infarction in the territory of the anterior cerebral artery. • Contralateral hemiplegia a ecting the arm and face more than the leg indicates an infarction in the territory of the middle cerebral artery. If the dominant hemisphere is a ected, aphasia also occurs (the patient cannot name objects, for example). • Visual disturbances a ecting the contralateral visual eld (hemianopia) may signify an infarction in the territory of the posterior cerebral artery, because the structures supplied by this artery include the visual cortex in the calcarine sulcus of the occipital lobe. If branches to the thalamus are also a ected, the patient may also exhibit a contralateral hemisensory de cit because the a erent sensory bers have already crossed below the thalamus.

Aphasia

Hem ianopia

The extent of the infarction depends partly on whether the occlusion is proximal or distal. Generally a proximal occlusion will cause a much more extensive infarction than a distal occlusion. MCA infarctions are the most common because the middle cerebral artery is essentially a direct continuation of the internal carotid artery.

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Meninges The brain and spinal cord are covered by membranes called meninges. The meninges are composed of three layers: dura mater (dura), arachnoid (arachnoid membrane), and pia mater.

The subarachnoid space, located bet ween the arachnoid and pia, contains cerebrospinal uid (CSF, see p. 94). See p. 74 for the coverings of the spinal cord.

Dura m ater (cut)

Cranial bone

Outer table Diploë Inner table

Superior sagit tal sinus

Superior cerebral veins

Arachnoid m ater

Middle cerebral artery (branches)

Lateral lacuna (opened)

Pia mater (on cerebral surface)

Arachnoid granulations (arachnoid villi)

Bridging veins

Confluence of the sinuses

Fig. 4.56 Laye rs of the Me ning es Superior view of opened cranium. Left side: Dura mater (outer layer) cut to reveal arachnoid (middle layer). Right side: Dura mater and arachnoid removed to reveal pia mater (inner layer) lining the surface of the brain. Note: Arachnoid granulations, sites for loss of cerebrospinal uid into the venous blood, are protrusions of the arachnoid layer of the meninges into the venous sinus system. Migraines are caused by the dilation of blood vessels in the pia mater and dura mater surrounding the brain which triggers the release of neuropeptides, e.g., substance P, from parasympathetic nerve bers approx-

imating these vessels and excites nociceptive bers that travel in the trigeminal nerve (CN V) back to the brain. They are characterized by a severe, unilateral throbbing headache, which is often preceded by an aura (usually visual), and may be accompanied by nausea, vomiting, and photophobia (sensitivit y to light). Meningitis is in ammation of the meninges of the brain (pia mater and arachnoid), usually due to a viral infection. Symptoms include headache, sti neck, photophobia, irritabilit y, drowsiness, vomiting, fever, seizures, and rash (viral or meningococcal meningitis).

Tentorial notch Tentorium cerebelli Ostia of bridging veins Falx cerebri

Fig. 4.57 Dural se pta (folds) Left anterior oblique view. Two layers of meningeal dura come together, after separating from the periosteal dura during formation of a dural (venous) sinus, to form a dural fold or septa. These include the falx cerebri (separating right and left cerebral hemispheres); the tentorium cerebelli (supporting the cerebrum to keep it from crushing the underlying cerebellum); the falx cerebelli (not shown, that separates right and left cerebellar lobes under the tentorium); and the diaphragma sellae (forms the roof over the pituitary (hypophyseal) fossa and is invaginated by the pituitary gland).

Diaphragm a sellae Crista galli Optic nerve Internal carotid artery

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Bridging vein Ruptured m iddle m eningeal artery

Superior sagit tal sinus

Subarachnoid space

Falx cerebri

Dura m ater

Ruptured aneurysm

Inferior sagit tal sinus

Calvaria

B

A

C

Fig. 4.58   Extrace rebral he morrhag es Bleeding bet ween the bony calvarium and the soft tissues of the brain (extracerebral hemorrhage) exerts pressure on the brain. A rise of intracranial pressure may damage brain tissue both at the bleeding site and in more remote brain areas. Three t ypes of extracranial hemorrhage are distinguished based on the relationship to the dura mater: (A) epidural hematoma, (B) subdural hematoma, or (C) subarachnoid hemorrhage. A Epidural hematomas generally develop after a head injury involving a skull fracture, causing rupture of the middle meningeal artery. The hematoma forms bet ween the calvaria and the periosteal layer of the dura ma-

Sphenoid sinus

ter. B Subdural hematomas usually form when trauma to the head causes the rupture of bridging veins. Bleeding occurs bet ween the dura mater and the arachnoid mater. Because the source of the bleeding is venous, a subdural hematoma may develop over a period of weeks. C Subarachnoid hemorrhage is an arterial bleed caused by the rupture of an aneurysm of an artery at the base of the brain (see Fig 4.47). It is t ypically caused by a brief, sudden rise in blood pressure, like that produced by a sudden rise in intra-abdominal pressure, e.g. straining at stool. Because the hemorrhage is into the CSF- lled subarachnoid space, blood can be detected in the CSF by means of a lumbar puncture (see Fig 4.9).

Superior sagittal sinus

Falx cerebri

Telencephalon

Falx cerebri Inferior sagittal sinus

Temporal lobe

Mesencephalon

Herniation Cerebellum

Tentorium cerebelli

Foram en magnum A

Cerebellar tonsils

Fig. 4.59 Pote ntial sites of brain he rniation be neath the fre e e dg es of the me ning es Coronal section, anterior view. The tentorium cerebelli divides the cranial cavit y into a supratentorial and an infratentorial space. The telencephalon is supratentorial, and the cerebellum is infratentorial (A). Because the dura is composed of tough, collagenous connective tissue, it creates a rigid intracranial framework. As a result, a mass lesion within the cranium may displace the cerebral tissue and cause portions of the cerebrum to become entrapped (herniate) beneath the rigid dural septa (= duplication of the meningeal layer of the dura). A Axial herniation. This t ype of herniation is usually caused by generalized brain edema. It is a symmetrical herniation in which the middle and lower portions of both temporal lobes of the cerebrum herniate down through the tentorial notch, exerting pressure on the upper portion of

Epidural hematoma

Contralateral cerebral peduncle

Mesiobasal tem poral lobe

Com pression Tentorium cerebelli

Herniation Pons

Pyramidal tract

Medulla oblongata B

Decussation of pyram idal tract

the midbrain (bilateral uncal herniation). If the pressure persists, it will force the cerebellar tonsils through the foramen magnum and also com press the lower part of the brainstem (tonsillar herniation). Because respiratory and circulatory centers are located in the brainstem, this t ype of herniation is life-threatening. Concomitant vascular compression may cause brainstem infarction. B Lateral herniation. This t ype is caused by a unilateral mass e ect (e.g., from a brain tumor or intracranial hematoma), as illustrated here on the right side. Compression of the ipsilateral cerebral peduncle usually produces contralateral hemiparesis. Sometimes, the herniating mesiobasal portions of the temporal lobe press the opposite cerebral peduncle against the sharp edge of the tentorium. This damages the pyramidal tract above the level of its decussation, causing hemiparesis to develop on the side opposite the injury.

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Sensory Pathw ays (Excluding the Head)

Sensory cortex (postcentral gyrus)

3rd neurons

Thalam us Accessory nucleus cuneatus 2nd neuron

S

Cuneocerebellar fibers

Nucleus cuneatus Nucleus gracilis

Medial lem niscus

Anterolateral system

F D

S A G*

Unconscious proprioception Position sense, conscious proprioception, vibration, touch Pressure, touch Pain, temperature

Spinal ganglion (with 1st neurons) 2nd neurons

Fig. 4.60 Se nsory pathw ays (asce nding tracts) Spinal nerve sensory pathways involve a three neuron chain: rst-order, second-order, and third order. First-order sensory neurons, with cell bodies located outside the CNS, collect sensory data from the sensory organ and convey it to the CNS. The axons of rst-order neurons enter the CNS, through the posterior (sensory) root and posteior horn, to synapse on second-order sensory neurons. Second-order sensory neurons, located

α-m otor neuron

within the CNS, receive impulses from rst-order neurons in the PNS. The axons of second-order neurons ascend as tracts to synapse on third-order sensory neurons located in the thalamus; some second-order neurons project to the cerebellum via the spinocerebellar and cuneocerebellar tracts. Third-order sensory neurons project axons to the sensory cortex. See Table 4.7 for more details.

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H G F D S A Ta ble 4.7 Asce nding tracts of the spinal cord Tract

Locatio n

Functio n

Ne uro ns

Anterior spinothalam ic tract

Anterior funiculus

Pathway for crude touch and pressure sensation

Lateral spinothalam ic tract

Anterior and lateral funiculi

Pathway for pain, tem perature, tickle, itch, and sexual sensation

1st order a erent neurons located in spinal ganglia; cont ain 2nd order neurons and cross in the anterior com m issure

Anterior spinocerebellar tract

Lateral funiculus

Pathway for unconscious coordination of m otor activities (unconscious proprioception, autom atic processes, e.g., jogging, riding a bike) to the cerebellum

Projection (2nd order) neurons receive proprioceptive signals from 1st order a erent bers originating at the 1st order neurons of spinal ganglia

Posterior funiculus

Pathway for position sense (conscious proprioception) and ne cut aneous sensation (touch, vibration, ne pressure sense, t wo-point discrim ination)

Cell bodies of 1st order neurons located in spinal ganglion; pass uncrossed to the dorsal colum n nuclei

Posterior spinocerebellar tract Fasciculus cuneatus

Fasciculus gracilis*

Conveys inform ation from upper lim b (not present below T3)

Conveys inform ation from lower lim b

* The fasciculi cuneatus and gracilis convey inform ation from the upper and lower lim bs, respectively. At this spinal cord level, only the fasciculus cuneatus is present.

Postcentral gyrus

Thalam us Internal capsule Pallidum Putam en Head of caudate nucleus Pyram idal tract

Tail of caudate nucleus

Medial lem niscus Lateral spinothalam ic tract

Fig. 4.61 Arrang e me nt of se nsory pathw ays in the ce rebrum Anterior view of the right postcentral gyrus. The cell bodies of the third order neurons of the sensory pathways are located in the thalamus. Their axons project to the postcentral gyrus, where the primary somatosensory cortex is located. The postcentral gyrus has a somatotopic organization, meaning that each body region is represented in a particular cortical area. The body regions in the cortex are not represented in proportion to their actual size, but in proportion to the densit y of their sensory innervation. The ngers and head have abundant sensory receptors, and so their cortical representation is correspondingly large. Conversely, the less dense sensory innervation of the but tocks and legs results in smaller areas of representation. Based on these varying numbers of peripheral receptors, we can construct a “sensory homunculus” whose parts correspond to the cortical areas concerned with their perception. Note: The head of the homunculus is upright while the trunk is upside down. The axons of the sensory neurons ascending from the thalamus travel side by side with the axons forming the pyramidal tract (red) in the posterior part of the internal capsule. Because of this arrangement, a large cerebral hemorrhage involving the internal capsule produces sensory as well as motor de cits (see Kell et al.).

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Sensory Pathw ays: Pain Pathw ays in the Head & the Central Analgesic System

Primary somatosensory cortex

Thalam us, ventral posterom edial nucleus

Trigem inothalam ic tract Trigem inal ganglion Ophthalm ic nerve (CN V1 )

Sölder lines

Oral part (A) Spinal nucleus of trigeminal nerve

Maxillary nerve (CN V2 )

Interpolar part (B)

A

Caudal part (C)

B

Mandibular nerve (CN V3 )

C

Fig. 4.62 Pain pathw ays in the head (after Lorke) The pain bers in the head accompany the principal divisions of the trigeminal nerve (CN V1 –V3 ). The cell bodies of these rst order a erent neurons of the pain pathway are located in the trigeminal ganglion. Their axons terminate in the spinal nucleus of the trigeminal nerve. Note the somatotopic organization of this nuclear region: The perioral region (A) is cranial and the occipital regions (C) are caudal. Because of this arrangement, central lesions lead to de cits that are distributed along the Sölder lines. The axons of the second order neurons cross the midline and travel in the trigeminothalamic tract to the ventral posteromedial nucleus and to the intralaminar thalamic nuclei on the opposite side, where they terminate. The third order (thalamic) neuron of the pain pathway ends in the primary somatosensory cortex. Only the pain bers of the trigeminal nerve

are pictured in the diagram. In the trigeminal nerve itself, the other sensory bers run parallel to the pain bers but terminate in various trigeminal nuclei. Oral dysaesthesia, or burning mouth syndrome, is a debilitating, intractable, burning sensation of the oral mucosa that is present without evidence of clinical disease. The precise cause of oral dysaesthesia is unknown but derangements in central and peripheral pain pathways have been implicated and it is also thought to have a strong psycogenic component. It is many times more common in women and tends to a ect those in the 40– 50 years age range, many of whom are su ering from depression. Diagnosis is made by exclusion of all organic and prosthetic causes. Treatment is usually with antidepressant drugs, which treat both any precipitating or coexisting depression, and a ect central pain pathways.

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Prefrontal cortex

Thalamus

Hypothalamus Amygdala

Anterior pretectal nucleus

Central gray m at ter Mesencephalon

Fig. 4.63 Pathw ays of the ce ntral desce nding analg esic syste m (after Lorke) Besides the ascending pathways that carry pain sensation to the primary somatosensory cortex, there are also descending pathways that have the abilit y to suppress pain impulses. The central relay station for the descending analgesic (pain-relieving) system is the central gray mat ter of the mesencephalon. It is activated by a erent input from the hypothalamus, the prefrontal cortex, and the amygdaloid bodies (part of the limbic system, not shown). It also receives a erent input from the spinal cord. The axons from the excitatory glutaminergic neurons (red) of the central gray mat ter terminate on serotoninergic neurons in the raphe nuclei and on noradrenergic neurons in the locus ceruleus (both shown in blue). The axons from both t ypes of neuron descend in the posterolateral funiculus. They terminate directly or indirectly (via inhibitory neurons) on the analgesic projection neurons (second order afferent neuron of the pain pathway), thereby inhibiting the further conduction of pain im pulses.

Locus ceruleus Raphe nuclei

Descending noradrenergic and serotoninergic fibers

Posterolateral funiculus

Processing and conduction of nociceptive signals in the spinal cord

Processing of nociceptive signals in the brain

Pain perception

General anesthesia, psychotherapeutic techniques

Nociceptive signal conduction in the peripheral nerve

System ic or epidural opiates, stim ulation therapy, neurosurgery

Peripheral or epidural nerve block Inflamm ation, edema, form ation of pain m ediators

Im mobilization, cooling, analgesic medication, anti-inflam matory m edication

Tissue injury

Fig. 4.64 Pain pe rce ption and the rape utic inte rve ntions Peripheral pain may be caused by local tissue injury from a bee sting, for example. The information on this injury is transmit ted by several relay stations to the primary somatosensory cortex, where the signals are perceived as pain (translated from simple encoded impulses). Pain, then, is a complex experiential phenomenon that is processed and relayed at various levels in the nervous system, and so there are multiple levels at which pain may be alleviated by therapeutic measures (red arrows).

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Motor Pathw ays Pyramidal (corticospinal) tract

Extrapyramidal motor system Precentral gyrus (prim ary m otor cortex)

Leg Arm

Supplem entary m otor cortexes

Postcentral gyrus (prim ary som atosensory cortex)

Face

Corticospinal fibers

Corticonuclear fibers

Tegm ental nucleus

Corticospinal tract (with extrapyram idal fibers)

Red nucleus

From cerebellum

Substantia nigra Pyram idal tract

Ventral lateral nucleus

CN VII

Inferior olive CN XII

Pyram id Posterior root Decussation of pyram ids

S D J

S Anterior root

A

G α-m otor neuron (with interneurons)

H

A

F

S D F A

H

G

Ta ble 4.8 Desce nding tracts of the spinal cord Tract Pyram idal tract

Function Anterior corticospinal tract

Most im port ant pathway for volunt ary m otor funct ion is the cingulate gyrus (lim bic system )

Lateral corticospinal tract

Extrapyram idal m otor system

Rubrospinal tract

Originates in the m otor cortex Corticonuclear bers to m otor nuclei of cranial nerves Corticospinal bers to m otor cells in anterior horn of the spinal cord Corticoreticular bers to nuclei of the reticular form ation

Pathway for autom atic and learned m otor processes (e.g., walking, running, cycling)

Reticulospinal tract Vest ibulospinal tract Tectospinal tract Olivospinal tract

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Fig. 4.65 Motor pathw ays (desce nding tracts) The motor pathway for the innervation of skeletal muscle involves t wo neurons, an upper motor neuron and a lower motor neuron. The cell bodies of the upper motor neurons, which are associated with both cranial nerves and spinal nerves, are located in the gray mat ter of the precentral gyrus of the cerebral cortex. The axons of the upper motor neurons descend via white mat ter tracts to reach the lower motor neurons, which are located in motor nuclei of in the brainstem and in the anterior horn of the spinal cord. The majorit y of upper motor neurons descending in the corticospinal tract cross to the contralateral side at the pyramidal decus-

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

sation at the spinomeduallary junction. The anterior horn is the anterior portion of the gray mat ter of the spinal cord, containing exclusively motor neurons. The axons of these neurons leave the CNS as the anterior (motor) root of the spinal nerves to synapse on target cells. The anterior (motor) root combines with the posterior (sensory) root, in the intervertebral foramen, to form a mixed spinal nerve. Lower motor neurons in the motor nuclei of the brainstem (cranial nerves) project axons that emerge from the CNS as the motor roots of cranial nerves. See Table 4.8 for more details.

Fig. 4.66 Somatotopic re prese ntation of the skeletal muscle in the pre ce ntral gyrus (motor homunculus) Anterior view. Regions in which the muscles are very densely innervated (e.g., the hand) must be supplied by many neurons in the precentral gyrus. As a result, they require a larger representation area in the cortex than regions supplied by fewer neurons (e.g., the trunk). This cortical representation is analogous to that in sensory innervation, where areas of varying size are also represented in the cortex (postcentral gyrus; com pare with the sensory homunculus in Fig 4.61). One cortical area is devoted to the trunk and limbs and another to the head. The axons for the head area are the corticonuclear bers, and the axons for the trunk and limbs are the corticospinal bers. The lat ter bers split into t wo groups below the telencephalon, forming the lateral and anterior corticospinal tracts.

Anterior corticospinal tract

Corticonuclear fibers Lateral corticospinal tract

Cerebral cortex

Thalamus

Basal ganglia

Cerebellum

Brainstem

Fig. 4.67   Simpli e d diag ram of the  se nsorimotor syste m role  in  move me nt co ntro l Voluntary movements require constant feedback from the periphery (muscle spindles, Golgi tendon organs) in order to remain within the desired limits. Because the motor and sensory systems are so closely interrelated functionally, they are often described jointly as the sensorimotor system. The spinal cord, brainstem, cerebellum, and cerebral cortex are the three control levels of the sensorimotor system. All information from periphery, cerebellum, and the basal ganglia passes through the thalamus on its way to the cerebral cortex. The clinical importance of the sensory system in movement is seen in sensory ataxia (loss of coordination) which may occur when sensory input into the control of movement is lost. The oculomotor component of the sensorimotor system is not shown.

Spinal cord

Motor information

Skeletal m otor function

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Autonomic Nervous System (I): Overview Parasym pathetic ganglia (in the head)

Sympathetic nervous system

Eye

Superior cervical ganglion

Parasympathetic nervous system

CN VII

CN III

Lacrim al and salivary glands

Parasympathetic ganglia (close to organs)

Sympathetic trunk

Cranial part: brainstem with parasympathetic nuclei

CN IX

Cranial vessels

CN X

Stellate ganglion* Heart T1 T2 T3 T4 T5 T6

Lung

Greater splanchnic nerve

Stom ach Celiac ganglion

T7 T8

Liver Pancreas

T9 Kidney

T10 T11

Intestine

T12 L1

Superior m esenteric ganglion

L2

Inferior m esenteric ganglion

L3

Parts of the colon, rectum

L4 L5

Bladder

S1 S2 S3 S4 S5

Genitalia

A

Inferior hypogastric plexus

* Stellate ganglion = inferior cervical ganglion and T1 sympathetic ganglion

Fig. 4.68 Autonomic ne rvous syste m The autonomic nervous system is the part of the peripheral nervous system that innervates smooth muscle, cardiac muscle, and glands. It is subdivided into the sympathetic (red) and the parasympathetic (blue) nervous systems, which often act in antagonistic fashion to regulate blood ow, secretions, and organ function. Both the sympathetic and parasympathetic nervous systems have a t woneuron pathway, which is under central nervous system control via an upper motor neuron with its cell body in the hypothalamus. In the sympathetic system, the preganglionic neuron synapses within the ganglia of the sympathetic trunk (paired, one on each side of vertebral column) or on one of the unpaired prevertebral ganglia located at the base of the artery for which the ganglion was named (celiac, superior and inferior mesenteric). Sympathetic postganglionic neurons then either reenter spinal nerves via grey rami communicantes and are distributed to their target structure or they reach their target structure by travelling

Pelvic splanchnic nerves

Sacral part: sacral cord with parasympathetic nuclei B

with arteries. Except in the head, parasympathetic preganglionic neurons synapse in ganglia in the wall of the target organ. Short postganglioinc parasympathetic neurons then innervate the organ. In the head there are four parasympathetic ganglia: ciliary ganglion, pterygopalatine ganglion, submandibular ganglion, otic ganglion, which are associated with cranial nerves III, VII, and IX, respectively. These four ganglia are responsible to distributing bers to smooth muscle within the eye and to the salivary glands and glands of the nasal cavit y, paranasal sinuses, hard and soft palate, and pharynx. Both sympathetic and parasympathetic preganglionic neurons secrete acet ylcholine, which acts upon nicotinic receptors in the ganglia. Sympathetic postganglionic neurons secrete norepinephrine, which acts upon adrenoceptors (α or β) in target tissues. Parasympathetic postganglionic neurons secrete acet ylcholine, which acts upon muscarinic receptors in target tissues.

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Ta ble 4.9 Parasympathe tic pathw ays Ne uro n

Location o f cell body (soma)

Upper m otor neuron

Hypothalamus: The cell bodies of parasym pathetic upper m otor neurons are located in the hypothalam us. Their axons descend via white m at ter tract s to synapse with the lower m otor neuron in the brainstem and sacral spinal cord (S2–S4).

Preganglionic neuron (lower m otor neuron)

The parasym pathetic nervous system is divided into t wo part s (cranial and sacral), based on the location of the preganglionic parasym pathetic neurons. Brainste m cranial ne rve nucle i: The axons of these secondary neurons leave the CNS as the m otor root of cranial nerves III, VII, IX, and X.

Spinal cord (S2–S4): The axons of these secondary neurons leave the CNS (S2–S4) as the pelvic splanchnic nerves. These nerves travel in the posterior ram i of the S2–S4 spinal nerves and are distributed via the sym pathetic plexuses to the pelvic viscera.

Postganglionic neuron

Cranial ne rve parasympathetic gang lia: The parasym pathetic cranial nerves of the head each have at least one ganglion: • CN III: Ciliary ganglion • CN VII: Pterygopalatine ganglion and subm andibular ganglion • CN IX: Otic ganglion • CN X: Sm all unnam ed ganglia close to t arget structures

Distribution of postganglionic bers

Parasym pathetic bers course with other ber t ypes to their t arget s. In the head, the postganglionic bers from the pterygopalatine ganglion (CN VII) and otic ganglion (CN IX) are distributed via branches of the trigem inal nerve (CN V). Postganglionic bers from the ciliary ganglion (CN III) course with sym pathetic and sensory bers in the short ciliary nerves (preganglionic bers travel with the som atom otor bers of CN III). In the thorax, abdom en, and pelvis, preganglionic parasym pathetic bers from CN X and the pelvic splanchnic nerves com bine with postganglionic sym pathetic bers to form plexuses (e.g., cardiac, pulm onary, esophageal).

Ta ble 4.10 Sympathe tic pathw ays Ne uro n

Location o f cell body (soma)

Upper m otor neuron

Hypothalamus: The cell bodies of parasym pathetic upper m otor neurons are located in the hypothalam us. Their axons descend via white m at ter tract s to synapse with the lower m otor neuron in the lateral horn of the spinal cord (T1–L2).

Preganglionic neuron (lower m otor neuron)

Lateral horn of spinal cord (T1–L2): The lateral horn is the middle portion of the gray mat ter of the spinal cord, situated bet ween the anterior and posterior horns. It contains exclusively autonomic (sympathetic) neurons. The axons of these neurons leave the CNS as the motor root of the spinal nerves and enter the paravertebral ganglia via the white rami communicantes (myelinated).

Preganglionic neurons in paravertebral ganglia

All preganglionic sympathetic neurons enter the sympathetic chain. There they may synapse in a chain ganglion or ascend or descend to synapse. Preganglionic sympathetic neurons synapse in one of t wo places, yielding t wo t ypes of sympathetic ganglia. Synapse in the paravertebral ganglia

Pass without synapsing through the parasym pathetic ganglia. These bers travel in the thoracic, lum bar, and sacral splanchnic nerves to synapse in the prevertebral ganglia.

Postganglionic neuron

Parave rtebral gang lia: These ganglia form the sym pathetic nerve trunks that ank the spinal cord. Postganglionic axons leave the sym pathetic trunk via the gray ram i com m unicantes (unmyelinated).

Preve rtebral g ang lia: Associated with peripheral plexuses, which spread along the abdom inal aort a. There are three prim ary prevertebral ganglia: • Celiac ganglion • Superior m esenteric ganglion • Inferior m esenteric ganglion

Distribution of postganglionic bers

Postganglionic bers are distributed in t wo ways: 1. Spinal nerves: Postganglionic neurons m ay re-enter the spinal nerves via the gray ram i com m unicantes. These sym pathetic neurons induce constriction of blood vessels, sweat glands, and arrector pili (m uscle bers at t ached to hair follicles, “goose bum ps”). 2. Arteries and ducts: Nerve plexuses may form along existing structures. Postganglionic sympathetic bers may travel with arteries to target structures. Viscera are innervated by this method (e.g., sympathetic innervation concerning vasoconstriction, bronchial dilatation, glandular secretions, pupillary dilatation, smooth muscle contraction).

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Autonomic Nervous System (II): Connections Fig. 4.69 Parasympathetic ne rvous syste m (cranial part): Ove rview There are four parasympathetic nuclei in the brainstem. The visceral e erent bers of these nuclei travel along particular cranial nerves, listed below. • Visceral oculomotor (Edinger– Westphal) nucleus: oculomotor nerve (CN III) • Superior salivatory nucleus: facial nerve (CN VII) • Inferior salivatory nucleus: glossopharyngeal nerve (CN IX) • Dorsal motor nucleus: vagus nerve (CN X)

Ciliary ganglion

Visceral oculom otor (Edinger– Westphal) nucleus

The presynaptic parasympathetic bers often travel with multiple cranial nerves to reach their target organs. The vagus nerve supplies all of the thoracic and abdominal organs as far as a point near the left colic exure. Note: The sympathetic bers to the head travel along the arteries to their target organs.

III

Pterygopalatine ganglion

Submandibular ganglion

Superior salivatory nucleus

VII

Inferior salivatory nucleus

IX X

Thoracic ganglia

Otic ganglion

Dorsal motor nucleus Abdom inal ganglia

Ta ble 4.11 Parasympathetic gang lia in the he ad Nucle us

Path of pre synaptic  be rs

Gang lion

Po stsynaptic  be rs

Targ e t o rg ans

Edinger-Westphal nucleus

Oculom otor nerve (CN III)

Ciliary ganglion

Short ciliary nerves (CN V1 )

Ciliary m uscle (accom m odation) Pupillary sphincter (m iosis)

Superior salivary nucleus

Nervus interm edius (CN VII root) →greater petrosal nerve→nerve of pterygoid canal

Pterygopalatine ganglion

• Maxillary nerve (CN V2 ) →zygom atic nerve→anostom osis→lacrim al nerve (CN V1 ) • Orbital branches • Posterior superior nasal branches • Nasopalatine nerves • Greater and lesser palatine nerves

• Lacrim al gland • Glands of nasal cavit y and paranasal sinuses • Glands of gingiva • Glands of hard and soft palate • Glands of pharynx

Nervus interm edius (CN VII root) →chorda t ym pani→lingual nerve (CN V3 )

Subm andibular ganglion

Glandular branches

Subm andibular gland Sublingual gland

Inferior salivatory nucleus

Glossopharyngeal nerve (CN IX) →t ym panic nerve→lesser petrosal nerve

Otic ganglion

Auriculotem poral nerve (CN V3 )

Parotid gland

Dorsal m otor (vagal) nucleus

Vagus nerve (X)

Ganglia near organs

Fine bers in organs, not individually nam ed

Thoracic and abdom inal viscera

→ = is continuous with

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Long ciliary nerve (CN V1 )

Postganglionic fibers

Ciliary ganglion Pupillary dilation Accommodation

Nasociliary nerve (CN V1 ) Pterygoid canal

Nerve of pterygoid canal Blood vessels Sweat glands

Deep petrosal nerve (CN VII)

Pterygopalatine ganglion Vasomotor innervation

Internal carotid artery plexus

Facial artery plexus

Superior cervical ganglion

Vasomotor innervation External carotid artery plexus

Fig. 4.70 Sympathetic inne rvation of the head Sympathetic preganglionic neurons of the head originate in the lateral horn of the spinal cord (TI–L2). They exit into the sympathetic chain ganglia and ascend to synapse in the superior cervical ganglion. Postganglionic neurons then travel with arterial plexuses. Postganglionic bers that travel with the carotid plexus (on the internal carotid artery) join with the nasociliary nerves (of CN V1 ) and then the long ciliary nerves to reach the dilator pupillae muscle (pupillary dilation); other postganglionic bers travel through the ciliary ganglion (without synapsing) to reach the ciliary muscle (accommodation). Still other postganglionic bers from the carotid plexus leave with the deep petrosal nerve, which joins with the

greater petrosal nerve (CN VII), to form the nerve of the pterygoid canal (vidian nerve). This nerve travels to the pterygopalatine ganglion where it distributes bers via branches of the maxillary nerve to the glands of the nasal cavit y, maxillary sinus, hard and soft palate, gingiva, and pharynx, and to sweat glands and blood vessels in the head. Postganglionic bers from the superior cervical ganglion that travel with the facial artery plexus pass through the submandibular ganglion (without synapsing) to the submandibular and sublingual glands. Other postganglionic bers travel with the middle meningeal plexus, through the otic ganglion (without synapsing), to the parotid gland.

Ta ble 4.12 Sympathetic  be rs in the  head Nucle us

Path o f presynaptic  be rs

Gang lio n

Po stsynaptic  be rs

Targ e t o rg ans

Lateral horn of spinal cord (TI–L2)

Enter sym pathetic chain ganglia and ascend to superior cervical ganglion

Superior cervical ganglion

ICA plexus→nasociliary nn. (CN V1 )→long ciliary nn. (CN V1 )

Dilator pupillae m uscle (mydriasis)

Postganglionic bers→ciliary ganglion*→short ciliary nerves

Ciliary m uscle (accom m odation)

ICA plexus→deep petrosal n.→n. of pterygoid canal→pterygopalatine ganglion*→branches of m axillary n. (CN V2 )

Glands of nasal cavit y Sweat glands Blood vessels

Facial artery plexus→subm andibular ganglion*

Subm andibular gland Sublingual gland

External carotid artery plexus

Parotid gland

*passes through without synpasing ; → = is continuous with ICA, internal carotid artery

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Cranial Nerves: Overview Ta ble 4.13 Cranial ne rves Cranial ne rve

CN I

Attachme nt to brain

Fibe r type (Table 4.11) A e re nt

CN II

E e re nt

CN I: Olfactory n.

Telencephalon

CN II: Optic n.

Diencephalon

CN IV

CN III: Oculom otor n.

Mesencephalon

CN VI

CN III

CN V

CN IV: Trochlear n.

CN VII

CN V: Trigem inal n.

Pons

CN VIII

CN VI: Abducent n.

Pontom edullary junction

CN IX CN X

CN VII: Facial n.

CN XI

CN VIII: Vestibulocochlear n. CN XII

CN IX: Glossopharyngeal n.

Medulla oblongat a

Fig. 4.71 Cranial ne rves Whereas the 31 spinal nerve pairs em erge from the spinal cord, the 12 pairs of cranial nerves em erge from the brain at various levels (Table 4.13). They are num bered according to the order of their em ergence. (Note: Cranial nerves I and II are not true peripheral nerves but are instead extensions of the telencephalon [CN I] and diencephalon [CN II].) Unlike the spinal nerves, which each have a posterior sensory and an anterior m otor root, the cranial nerves m ay contain a erent (sensory) and/or e erent (m otor) bers. The t ypes of bers (Table 4.14) correspond to the function of the nerve (Table 4.15).

CN X: Vagus n. CN XI: Accessory n. CN XII: Hypoglossal n.

Ta ble 4.14 Cranial ne rve   be r types The seven t ypes of cranial nerve bers are classi ed according to three criteria (re ected in the three-let ter codes): 1. General (G) vs. Special (S), 2. Som atic (S) vs. Visceral (V), 3. A erent (A) vs. E erent (E). Each ber t ype has an associated color used throughout this chapter. A e re nt (se nso ry)  be rs

General bers

Special bers

E e re nt (moto r)  be rs

GSA

General som atosensory

General sensation (touch, pain, and tem perature) from som ite derivatives (skin, skelet al m uscle, and m ucosa)

GSE

Som atom otor

Motor innervation to striated (skelet al) m uscle derived from som ites

GVA

General viscerosensory

General sensation from viscera (sm ooth m uscle, cardiac m uscle, and glands)

GVE

Parasym pathetic

Motor innervation to viscera (sm ooth m uscle, cardiac m uscle, glands, etc.)

SSA

Special som atosensory

Sight, hearing, and balance

SVA

Special viscerosensory

Taste and sm ell

SVE

Branchiom otor

Fibers to striated (skelet al) m uscle derived from the branchial arches

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Ta ble 4.15 Cranial ne rve function Cranial ne rve

Passag e thro ug h skull

Fibe r A

Se nsory te rritory (a e re nt) / Targ et o rg an (e e re nt)

E

CN I: Olfactory n. (p. 118)

Ethm oid bone (cribriform plate)

Sm ell: special viscerosensory bers from olfactory m ucosa of nasal cavit y

CN II: Optic n. (p. 119)

Optic canal

Sight : special som atosensory bers from retina

CN III: Oculom otor n. (pp. 120–121)

Superior orbit al ssure

Som atom otor innervation: to levator palpebrae superioris and four extraocular m m . (superior, m edial, and inferior rectus, and inferior oblique) Parasym pathetic innervation: preganglionic bers to ciliary ganglion; postganglionic bers to intraocular m m . (ciliary m m . and pupillary sphincter)

CN IV: Trochlear n. (pp. 120–121)

Superior orbit al ssure

Som atom otor innervation: to one extraocular m . (superior oblique)

CN V: Trigem inal n. (pp. 122–129)

CN V1 (pp. 124–125)

Superior orbit al ssure

General som atic sensation: from orbit, nasal cavit y, paranasal sinuses, and face

CN V2 (pp. 126–127)

Foram en rotundum

General som atic sensation: from nasal cavit y, paranasal sinuses, superior nasopharynx, upper oral cavit y, internal skull, and face

CN V3 (pp. 128–129)

Foram en ovale

General som atic sensation: from lower oral cavit y, ear, internal skull, and face Branchiom otor innervation: to the eight m m . derived from the 1st pharyngeal (branchial) arch (including m m . of m astication)

CN VI: Abducent n. (pp. 120–121)

Superior orbit al ssure

Som atom otor innervation: to one extraocular m . (lateral rectus)

CN VII: Facial n. (pp. 130–133)

Internal acoustic m eatus

General som atic sensation: from external ear Taste: special viscerosensory bers from tongue (anterior ⅔) and soft palate Parasympathetic innervation: preganglionic bers to submandibular and pterygo palatine ganglia; postganglionic bers to glands (e.g., lacrimal, submandibular, sublingual, palatine) and mucosa of nasal cavit y, palate, and paranasal sinuses Branchiom otor innervation: to m m . derived from the 2nd pharyngeal arch (including m m . of facial expression, st ylohyoid, and st apedius)

CN VIII: Vestibulocochlear n. (pp. 134–135)

Internal acoustic m eatus

Hearing and balance: special som atosensory bers from cochlea (hearing) and vestibular apparatus (balance)

CN IX: Glossopharyngeal n. (pp. 136–137)

Jugular foram en

General som atic sensation: from oral cavit y, pharynx, tongue (posterior ⅓), and m iddle ear Taste: special visceral sensation from tongue (posterior ⅓) General visceral sensation: from carotid body and sinus Parasym pathetic innervation: preganglionic bers to otic ganglion; postganglionic bers to parotid gland and inferior labial glands Branchiom otor innervation: to the one m . derived from the 3rd pharyngeal arch (st ylopharyngeus)

CN X: Vagus n. (pp. 138–139)

Jugular foram en

General som atic sensation: from ear and internal skull Taste: special visceral sensation from epiglot tis and root of tongue General visceral sensation: from aortic body, laryngopharynx and larynx, respiratory tract, and thoracoabdom inal viscera Parasympathetic innervation: preganglionic bers to sm all, unnamed ganglia near target organs or em bedded in sm ooth m uscle walls; postganglionic bers to glands, m ucosa, and sm ooth m uscle of pharynx, larynx, and thoracic and abdom inal viscera Branchiom otor innervation: to pharyngeal and laryngeal m m . derived from the 4th and 6th pharyngeal arches; also distributes branchiom otor bers from CN XI

CN XI: Accessory n. (p. 140)

Jugular foram en

CN XII: Hypoglossal n. (p. 141)

Hypoglossal canal

Som atom otor innervation: to trapezius and sternocleidom astoid Branchiom otor innervation: to laryngeal m m . (except cricothyroid) via pharyngeal plexus and CN X (Note: The branchiom otor bers from the cranial root of CN XI are distributed by CN X [vagus n.].) Som atom otor innervation: to all intrinsic and extrinsic lingual m m . (except palatoglossus)

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Cranial Nerve Nuclei Fig. 4.72 Cranial ne rve nucle i: topog raphic arrang e me nt Cross sections through the spinal cord and brainstem , superior view. Yellow = Som atic sensation. Green = Visceral sensation. Blue = Viscerom otor function. Red = Som atom otor function. The nuclei of the spinal and cranial nerves have a topographic arrangem ent based on em bryonic m igration of neuron populations. A Em bryonic spinal cord: Initially, the developing spinal cord dem onstrates a posteroanterior arrangem ent in which the sensory (afferent) neurons are posterior and the m otor (e erent) neurons are anterior. This pat tern is continued into the adult spinal cord: the cell bodies of a erent neurons (generally secondary neurons) are located in the posterior horn, and the cell bodies of e erent neurons (lower m otor neurons and preganglionic autonom ic neurons) are located in the anterior and lateral horns, respectively. B Early em bryonic brainstem : Sensory neurons (in the alar plate) m igrate laterally, whereas m otor nuclei (in the basal plate) m igrate m edially. This produces a m ediolateral arrangem ent of nuclear colum ns (functionally sim ilar nuclei st acked longitudinally). C Adult brainstem: The four longitudinal nuclear colum ns have a mediolateral arrangement (from medial to lateral): somatic e erent, visceral e erent, visceral a erent, and som atic a erent.

Posterior

Roof plate

There is not a 1-to-1 relationship bet ween cranial nerve ber t ypes and cranial nerve nuclei. Som e nerves derive sim ilar bers from m ultiple nuclei (e.g., CN V and CN VIII). Other nuclei are associated with m ultiple nerves. Note: The ve sensory cranial nerves have eight associated sensory ganglia (cell bodies of rst-order sensory neurons). The three parasym pathetic cranial nerves have four associated autonom ic ganglia (cell bodies of postganglionic neurons). Nucle i

Cranial ne rve

So matic a e re nt nucle ar column (yellow) General somatosensory: Three nuclei that are primarily associated with CN V but receive bers from other nerves.

• Mesencephalic nucleus • Principal (pontine) sensory nucleus • Spinal nucleus

CN V (via trigem inal ganglion) CN IX (via superior ganglion) CN X (via superior ganglion) Possibly CN VII (via geniculate ganglion)

Spe cial somatose nsory: Six nuclei that are associated with CN VIII.* The nerve and nuclei are divided into a vestibular part (balance) and a cochlear part (hearing).

• Medial, lateral, superior, and inferior vestibular nuclei

CN VIII, vestibular root (via vestibular ganglion)

• Anterior and posterior cochlear nuclei

CN VIII, cochlear root (via spiral ganglia)

Visce ral a e re nt nuclear column (green)

Alar plate Central canal Basal plate A

Ta ble 4.16 Cranial ne rve nucle i

Floor plate

Anterior

Ge ne ral and spe cial visce rose nsory: One nuclear com plex in the brainstem that consist s of a superior (t aste) and inferior (general visceral sensation) part and is associated with three cranial nerves.**

• Nucleus of the solit ary tract, inferior part

CN IX (via inferior ganglion)

• Nucleus of the solit ary tract, superior part

CN VII (via geniculate ganglion)

CN X (via inferior ganglion) CN IX (via inferior ganglion) CN X (via inferior ganglion)

Floor of the fourth ventricle (rhom boid fossa)

Visce ral motor nucle ar co lumn (blue) Parasympathetic (general visceromotor): Four nuclei that each have an associated cranial nerve and one or more ganglia.

Medial

B

Nucleus of solitary tract, upper part

Posterior vagal nucleus

Lateral

Nucleus of solitary tract, lower part Nuclei of vestibulocochlear nerve

Nucleus of hypoglossal nerve

Spinal nucleus of trigem inal nerve

Nucleus am biguus

Vagus nerve C

Olive

Hypoglossal nerve

• Edinger-Westphal nucleus

CN III (via ciliary ganglion)

• Superior salivatory nucleus

CN VII (via subm andibular and pterygopalatine ganglia)

• Inferior salivatory nucleus

CN IX (via otic ganglion)

• Dorsal m otor (vagal) nucleus

CN X (via myriad unnam ed ganglia near t arget organs)

Branchiomotor (special viscerom otor): Three nuclei that innervate the muscles of the pharyngeal arches via four cranial nerves.

• Trigem inal m otor nucleus

CN V

• Facial nucleus

CN VII

• Nucleus am biguus

CN IX CN X (with bers from CN XI)

So mato moto r nucle ar column (red)

Five nuclei, each associated with a separate nerve. • Nucleus of the oculom otor n.

CN III

• Nucleus of the trochlear n.

CN IV

• Nucleus of the abducent n.

CN VI

• Nucleus of the accessory n.

CN XI

• Nucleus of the hypoglossal n.

CN XII

*There are no brainstem nuclei associated with CN II because it em erges from the diencephalon. **The special visceral a erent bers in the olfactory nerve (CN I) project to the telencephalon.

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Afferent

Edinger-Westphal nucleus (CN III)

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Efferent

Nucleus of oculomotor nerve (CN III) Mesencephalic nucleus of trigem inal nerve (CN V)

Nucleus of trochlear nerve (CN IV) Trigem inal m otor nucleus (CN V)

CN V Principal (pontine) sensory nucleus of trigem inal nerve (CN V)

Nucleus of abducent nerve (CN VI)

Cochlear nucleus of vestibulocochlear nerve (CN VIII)

Facial m otor nucleus (CN VII)

Vestibular nuclei of vestibulocochlear nerve (CN VIII) Nucleus of hypoglossal nerve (CN XII)

Superior salivatory nucleus (CN VII) Inferior salivatory nucleus (CN IX)

CN VII CN VIII

CN VI

CN IX CN X

CN XI

Nucleus am biguus (CN IX, X, XI)

Nucleus of the solitary tract (CN VII, IX, X)

Dorsal m otor (vagal) nucleus (CN X)

Spinal nucleus of trigem inal nerve (CN V)

Nucleus of accessory nerve (CN XI)

A

CN IV

B

Nucleus of oculom otor nerve Visceral oculom otor nucleus

Olfactory tract

Nucleus of trochlear nerve Optic chiasm

Mesencephalic nucleus of trigem inal nerve

Principal (pontine) sensory nucleus of trigem inal nerve

Motor nucleus of trigem inal nerve Nucleus of abducent nerve

Superior salivatory nucleus

Dorsal m otor (vagal) nucleus

Inferior salivatory nucleus Vestibulocochlear nerve

Nucleus of hypoglossal nerve

Nucleus am biguus

Nucleus of solitary tract

Spinal nucleus of trigem inal nerve

General som atic efferent nuclei General visceral efferent nuclei Special visceral efferent nuclei General som atic afferent nuclei Special somatic afferent nuclei

Spinal nucleus of accessory nerve

General visceral afferent nuclei Special visceral afferent nuclei C

Fig. 4.73 Cranial ne rve nucle i: location A, B Posterior view of brainstem (cerebellum rem oved). C Left lateral view of m idsagit t al section. Note: The cranial nerves are num bered and described according to the level of their emergence from the brainstem . This does not necessarily correspond to the level of the cranial nerve nuclei associated with the nerve.

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CN I & II: Olfactory & Optic Nerves Neither the olfactory nerve nor the optic nerve is a true peripheral nerve. They are extensions of the brain (telencephalon and diencephalon, respectively). They are therefore both sheathed in m eninges (rem oved here) and cont ain CNS-speci c cells (oligodendrocytes and m icroglia).

Fig. 4.74 Olfactory ne rve (CN I) A Left lateral view of left nasal septum and right lateral nasal wall (the posterior part of the nasal septum is cut). B Inferior view of brain. (*Shaded structures are deep to the basal surface.) The olfactory nerve relays sm ell inform ation (special visceral a erent) to the cortex via a classical three-neuron pathway. 1. First-order sensory neurons are located in the m ucosa of the upper nasal septum and superior nasal concha (A). These bipolar neurons form 20 or so ber bundles collectively called the olfactory nerves (CN I). As the “olfactory region” is lim ited by the extent of these bers (2–4 cm 2 ), the nasal conchae create turbulence, which ensures that air (and olfactory stim uli) passes over this area. The thin, unmyelinated olfactory bers enter the anterior cranial fossa via the cribriform plate of the ethm oid bone. 2. Second-order sensory neurons are located in the olfactory bulb (B). Their axons course in the olfactory tract to the m edial or lateral olfactory striae. These axons synapse in the amygdala, the prepiriform area, or neighboring areas. 3. Third-order neurons relay the inform ation to the cerebral cortex.

Olfactory bulb (second-order sensory neurons)

Olfactory tract

Frontal sinus

Cribriform plate, ethm oid bone

Olfactory fibers (CN I, first-order sensory neurons)

Superior concha Nasal septum (cut)

Nasal septum

Middle concha

A

The rst-order neurons have a lim ited lifespan (several m onths) and are continuously replenished from a pool of precursor cells in the olfactory m ucosa. The regenerative capacit y of the olfactory m ucosa dim inishes with age. Injuries to the cribriform plate m ay dam age the m eningeal covering of the olfactory bers, causing olfactory disturbances and cere brospinal uid leakage (“runny nose” after head traum a). See p. 156 for the m echanism s of sm ell.

Medial olfactory stria

Olfactory bulb (secondorder sensory neurons)

Lateral olfactory stria

Olfactory tract Anterior perforated substance

Prepiriform area*

Semilunar gyrus

Amygdala*

Am bient gyrus

B

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Fig. 4.75 Optic ne rve (CN II) A Inferior view of brain. B Left lateral view of opened orbit. C Left posterolateral view of brainstem . The optic nerve (special som atic a erent) relays sight inform ation from the retina to the visual cortex (striate area) via a four-neuron pathway (see p. 254). First-order neurons (rods and cones) in the retina translate incom ing photons into im pulses, which are relayed to second-order bipolar neurons and third-order ganglion cells. These retinal ganglion cells com bine to form the op tic nerve (CN II). The optic nerve passes from the orbit into the m iddle cranial fossa via the optic canal (the optic canal is m edial to the superior orbit al ssure by which the other cranial nerves enter the orbit, B). Ninet y percent of the third-order neurons in the optic nerve synapse in the lateral geniculate body (C), which then project s to the striate area. Ten percent of the third-order neurons synapse in the m esencephalon. This nongeniculate part of the visual pathway functions in unconscious and re ex action. See p. 254 for the m echanism s of sight. Lesion of the optic nerve m ay cause partial or com plete loss of vision, depending on the point at which the nerve is disrupted (see p. 256).

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Optic nerve (CN II)

Optic chiasm Optic tract

Lateral geniculate body Medial geniculate body Optic radiation

Occipital pole

A

Optic nerve (CN II) passing through optic canal

Optic tract

Lateral geniculate body

Thalam us

Optic chiasm

Optic tract Optic nerve (CN II)

B

Ophthalm ic nerve (CN V1 ) passing through superior orbital fissure

Superior colliculus Optic chiasm

C

Mesencephalon

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CN III, IV & VI: Oculomotor, Trochlear, & Abducent Nerves Cerebral peduncles of m esencephalon

Cerebral aqueduct

Oculom otor nerve (CN III)

Trochlear nerve (CN IV)

Edinger-Westphal nucleus

Nucleus of trochlear nerve

Nucleus of oculom otor nerve

Pons

Tectum Edinger-Westphal nucleus

Central gray substance Red nucleus

Nucleus of oculom otor nerve

Substantia nigra

Cerebral peduncle

B

Abducent nerve (CN VI) Nucleus of abducent nerve

Medulla oblongata

Ta ble 4.18 Trochlear ne rve (CN IV) Nucle us and  be r distribution So matomoto r (red)

A

Fig. 4.76   Cranial ne rves of the  e xtraocular muscles A Anterior view of brainstem . B Superior view of cross section through the m esencephalon. CN III, IV, and VI are the three cranial nerves that collectively innervate the six extraocular m uscles. (Note: CN III is also involved with the parasym pathetic supply to the intraocular m uscles.) CN III and IV arise from nuclei in the m esencephalon (m idbrain, the highest level of the brainstem ) and em erge at roughly the sam e level. CN VI arises from nuclei in the pons and em erges from the brainstem at the pontom edullary junction. Ta ble 4.17 Oculomotor ne rve (CN III) Nucle i, gang lion, and  be r distributio n Somato motor (red)

Nucleus of the oculom otor nerve (m esencephalon)

Lower m otor neurons innervate: • Levator palpebrae superioris • Superior, m edial, and inferior rectus m uscles • Inferior oblique

Parasympathe tic (blue)

Edinger-Westphal nucleus (m esencephalon)

Nucleus of the trochlear nerve (m esencephalon)

Lower m otor neurons innervate: • Superior oblique

Co urse

CN IV is the only cranial nerve to em erge from the posterior surface of the brainstem . After em erging from the m esencephalon, it courses anteriorly around the cerebral peduncle. CN IV then enters the orbit through the supe rio r o rbital  ssure , passing lateral to the com m on tendinous ring. It has the longest intradural course of the three extraocular m otor nerves. Lesions

Lesions cause trochlear nerve palsy: • Superom edial deviation of the a ected eye, causing diplopia (double vision) = disabled superior oblique Note: Because CN IV crosses to the opposite side, lesions close to the nucleus result in trochlear nerve palsy on the opposite side (contralateral palsy). Lesions past the site where the nerve crosses the m idline cause palsy on the sam e side (ipsilateral palsy).

Ta ble 4.19 Abduce nt ne rve (CN VI)

Preganglionic neurons travel in the inferior division of CN III Postganglionic neurons in the ciliary g ang lio n innervate: Intraocular m uscles (pupillary sphincter and ciliary m uscle)

Co urse

CN III em erges from the m esencephalon, the highest level of the brainstem . It runs anteriorly through the lateral wall of the cavernous sinus to enter the orbit through the supe rior orbital  ssure . After passing through the com m on tendinous ring, CN III divides into a superior and an inferior division. Le sio ns

Lesions cause oculomotor palsy of various extents. Complete oculomotor palsy is marked by paralysis of all the innervated muscles, causing: • Ptosis (drooping of eyelid) = disabled levator palpebrae superioris • Inferolateral deviation of a ected eye, causing diplopia (double vision) = disabled extraocular m uscles • Mydriasis (pupil dilation) = disabled pupillary sphincter • Accom m odation di culties (di cult y focusing) = disabled ciliary m uscle

Nucle us and  be r distribution So mato moto r (red)

Nucleus of the abducent nerve (pons)

Lower m otor neurons innervate: • Lateral rectus

Co urse

CN VI follows a long extradural path. It em erges from the pontom edullary junction (inferior border of pons) and runs through the cavernous sinus in close proxim it y to the internal carotid artery. CN VI enters the orbit through the supe rior orbital  ssure and courses through the com m on tendinous ring. Lesions

Lesions cause abducent nerve palsy: • Medial deviation of the a ected eye, causing diplopia = disabled lateral rectus Note: The path of CN VI through the cavernous sinus exposes it to injury. Cavernous sinus throm bosis, aneurysm s of the internal carotid artery, m eningitis, and subdural hem orrhage m ay all com press the nerve, resulting in nerve palsy. Excessive fall in CSF pressure (e.g., due to lum bar puncture) m ay cause the brainstem to descend, exerting traction on the nerve.

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Short ciliary nerves

Levator palpebrae superioris

Superior rectus

Trochlea

Ciliary ganglion Com m on tendinous ring

CN III

Superior oblique

Mesencephalon Lateral rectus (cut) Pons

CN IV

Pontom edullary junction CN VI

A

Inferior oblique

Internal carotid artery and plexus Lateral rectus (cut)

Supraorbital nerve (cut)

CN III, inferior division

Sympathetic root (postganglionic fibers from superior cervical ganglion via internal carotid plexus)

Parasym pathetic root (preganglionic fibers from CN III)

Trochlea

Levator palpebrae superioris

Superior oblique

Superior rectus

Medial rectus

Lacrim al gland

Inferior rectus

Lateral rectus

Frontal nerve (CN V1 )

CN VI

CN IV

CN IV

Superior ophthalm ic vein

Levator palpebrae superioris

Superior rectus Lacrimal nerve (CN V1 )

Superior oblique

CN III

Optic nerve (CN II) Optic nerve (CN II)

Medial rectus CN III Inferior rectus

B

C

Fig. 4.77 Ne rves supplying the ocular muscles Right orbit. A Lateral view with tem poral wall rem oved. B Superior view of opened orbit. C Anterior view. Cranial nerves III, IV, and VI enter the orbit through the superior orbital ssure, lateral to the optic canal (CN IV then passes lateral to the com m on tendinous ring, and CN III and VI pass through it). All three nerves supply som atom otor innervation to the extra ocular m uscles. The ciliary ganglion com m unicates three t ypes of bers (parasym pathetic, sym pathetic, and sensory) to and from the intraocular m uscles via the short ciliary nerves. (Only parasym pathetics synapse in the ciliary ganglion. All other bers pass through without synapsing.) The ciliary ganglion therefore has three root s: • Parasym pathetic (m otor) root : Preganglionic parasym pathetic bers travel with the inferior division of CN III to the ciliary ganglion. Only

Lateral rectus

CN VI

Inferior oblique

the parasym pathetic bers synapse in the ciliary ganglion (the other t wo ber t ypes pass through the ganglion without synapsing). • Sympathetic root: Postganglionic sympathetic bers from the superior cervical ganglion travel on the internal carotid artery to enter the superior orbital ssure, where they may course along the ophthalmic artery to enter the short ciliary nerves via the ciliary ganglion. • Sensory root: Sensory bers (from the eyeball) travel to the nasociliary nerve (CN V1 ) via the ciliary ganglion. The short ciliary nerves therefore cont ain sensory bers from the eyeball and postganglionic sym pathetic and parasym pathetic bers from the superior cervical and ciliary ganglion, respectively. Note: Sym pathetic bers from the superior cervical ganglion m ay also travel with the nasociliary nerve (CN V1 ) and reach the intraocular m uscles via the long ciliary nerves.

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CN V: Trigeminal Nerve, Nuclei, & Divisions Ophthalm ic division (CN V1 )

Mesencephalic nucleus

Ta ble 4.20 Trig e minal ne rve nucle i and lesions Nucle i

Trigem inal ganglion

So mato se nso ry (yellow)

Maxillary division (CN V2 )

A erent neurons from the sensory territories of all three trigem inal divisions synapse in three brainstem nuclei nam ed for their location.

Mandibular division (CN V3 )

Nucle us

Locatio n

Se nsation

Mesencephalic nucleus

Mesencephalon

Proprioception (Note: The rst-order sensory cell bodies of proprioceptive bers associated with CN V have their cell bodies located in the m esencephalic nucleus.)

Principal (pontine) sensory nucleus

Pons

Touch

Spinal nucleus

Medulla oblongat a

Pain and tem perature

Trigem inal nerve (CN V) Motor nucleus Principal (pontine) sensory nucleus

Spinal nucleus

Note: These sensory nuclei contain the cell bodies of second-order neurons. The m esencephalic nucleus is an exception —it contains the cell bodies of rst-order pseudounipolar neurons, which have m igrated into the brain.

A

Mesencephalic nucleus

Fourth ventricle

Pons

Branchio motor (purple)

Lower m otor neurons are located in the m otor nucleus of the trigem inal nerve. They innervate the eight m uscles derived from the 1st branchial arch:

Principal nucleus

• • • •

Motor nucleus

Masseter Tem poralis Lateral pterygoid Medial pterygoid

• • • •

Tensor veli palatini Tensor t ym pani Mylohyoid Digastric, anterior belly

Lesions

Trigem inal nerve (CN V) B

Fig. 4.78 Trig e minal ne rve nucle i A Anterior view of brainstem . B Superior view of cross section through the pons. A erent neurons in the trigem inal nerve divisions convey general somatic sensation (touch, pain, and temperature) to the CNS. The neurons from all three divisions synapse in three brainstem nuclei named for their locations (see Table 4.20):

Traum atic lesions of the trigem inal nerve m ay cause sensory loss in corresponding territories or paralysis to the t arget m uscles. Note: The a erent bers of the trigem inal nerve com pose the a erent lim b of the corneal re ex (re ex eyelid closure). • Trigem inal neuralgia is a disorder of CN V causing intense, crippling pain in the sensory territories.

• Mese nce phalic nucle us • Principal (po ntine ) se nso ry nucle us • Spinal nucle us

Mesencephalic nucleus

E erent bers arise from lower m otor neurons in the motor nucle us. These bers exit at the m otor root of the trigem inal nerve and unite with the m andibular division (CN V3 ) in the foram en ovale. The branchio m otor bers innervate the m uscles of the rst pharyngeal (brachial) arch.

Principal (pontine) sensory nucleus

Fig. 4.79 Trige minal ne rve lesions Lesions of the trigem inal nerve divisions (peripheral nerves) will produce sensory loss following the pat tern in Fig. 4.80B and potentially m otor paralysis. Lesions of the spinal nucleus of the trigem inal cord will produce sensory loss (pain and tem perature) in the pat tern shown here (Sölder lines). These concentric circles correspond to the som atotopic organization of the spinal cord nucleus: m ore cranial portions receive axons from the center of the face, and m ore caudal portions receive axons from the periphery.

Oralis

Interpolaris Spinal nucleus Caudalis A

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Sölder lines

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CN V1 (ophthalm ic division)

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Trigem inal ganglion (sensory)

B

CN V2 (m axillary division)

D

C

CN V3 (m andibular division)

A

E

Fig. 4.80 Trig e minal ne rve divisions and distribution A Left lateral view of trigem inal divisions. B–D Som atosensory nerve territories. E Branchiom otor nerve territories. The trigem inal nerve is the m ajor sensory nerve of the face. It has three

m ajor divisions (A) that convey general som atic sensation (touch, pain, and proprioception) from the face (B) and select m ucosa (C and D). The trigem inal nerve also cont ains branchiom otor bers that innervate the eight m uscles derived from the rst branchial arch (E).

Ta ble 4.21 Trig e minal ne rve (CN V) divisions and distribution CN V consists of a large sensory root and a small motor root, which emerge from the brainstem separately in the middle cranial fossa at the level of the pons. Se nsory root Fibe rs

Ge ne ral so matose nso ry (yellow): Convey general sensation (touch, pain, and tem perature) from the sensory territories of CN V (see Fig . 4.80 ). The cell bodies of these rst-order pseudounipolar neurons are prim arily located in the trigem inal ganglion.

Co urse

The sensory root is form ed by three divisions that unite as the trig e minal gang lion in the m iddle cranial fossa.

Divisio n

Distributio n

CN V1 (ophthalm ic division)

From orbit via superior orbit al ssure (see p. 124)

CN V2 (m axillary division)

From pterygopalatine fossa via foram en rotundum (see pp. 126, 144)

CN V3 (m andibular division)

From inferior skull base via foram en ovale (see pp. 144, 128)

A erent axons from all three divisions synapse on three brainstem nuclei located in the m esencephalon, pons, and m edulla oblongat a of the spinal cord.

Nucle i

Se nsatio n

Mesencephalic nucleus

Proprioception (see Table 4.20 )

Principal (pontine) sensory nucleus

Touch

Spinal nucleus

Pain and tem perature

Fibe rs

Branchiomotor (purple): Conveys m otor bers to the eight m uscles derived from the 1st branchial (pharyngeal) arch:

• • • •

• • • •

Co urse

The m otor root em erges separately from the pons and unites with CN V3 in the foram en ovale.

Nucle us

Motor nucleus (located in pons)

Nucle i

Motor ro ot

Masseter Tem poralis Lateral pterygoid Medial pterygoid

Tensor veli palatini Tensor t ym pani Mylohyoid Digastric, anterior belly

“Sca o lding”: CN V is used as sca olding for the distribution of autonomic (sympathetic and parasympathetic) and taste bers from other cranial nerves. Parasympathe tic

All three branches of CN V are used to convey postganglionic parasym pathetic bers from parasym pathetic ganglia. • CN VII: Preganglionic bers from CN VII synapse in the pterygopalatine or the subm andibular ganglion, associated with CN V2 and CN V3 , respectively. Postganglionic parasym pathetic bers then travel with the sensory branches of CN V to reach their t arget s. • CN IX: Preganglionic bers synapse in the otic ganglion; postganglionic bers are distributed along branches of CN V3 .

Sympathe tic

Postganglionic sym pathetic bers from the superior cervical ganglion m ay also be distributed by the sensory branches of CN V.

Taste

Taste bers from the presulcal tongue (anterior t wo thirds) travel via the lingual nerve (CN V3 ) to the chorda t ym pani (CN VII) and nuclei of CN VII.

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CN V1: Trigeminal Nerve, Ophthalmic Division Fig. 4.81 Ophthalmic division (CN V1 ) of the trig e minal ne rve Lateral view of the partially opened right orbit. The ophthalm ic nerve divides into three m ajor branches before reaching the superior orbit al ssure: the lacrim al (L), front al (F), and nasociliary (N) nerves. These nerves run roughly in the lateral, m iddle, and m edial portions of the upper orbit, respectively. The lacrim al and front al nerves enter the orbit superior to the com m on tendinous ring, and the nasociliary nerve enters through it. See Table 4.22 for labels.

Superior orbital fissure (opened)

with trochlea Supratrochlear artery Cribriform plate with anterior ethm oidal artery N4

with posterior ethm oidal artery N3

N

CN IV A

Superior ophtham ic vein

N2 N3

F

CN II in optic canal

F2

M N5

CN V1

Trigem inal ganglion CN V2

N5

F1

N4

CN V3

N

N1

Ciliary ganglion

Short ciliary nerves

F2 F2

, m edial and lateral branches with supraorbital artery

F1

Superior rectus

N3

Short ciliary nerves with short posterior ciliary arteries

L

N2

CN VI

F

Fig. 4.82 Ophthalmic ne rve divisions in the orbit Superior view of orbit. (Removed: Bony roof, periorbit a, and periorbit al fat.) See Table 4.22 for labels. A Lacrim al, front al, and nasociliary divisions. B Nasociliary nerve and ciliary ganglion. (Cut: Superior rectus and levator palpebrae superioris.) The extraocular m uscles receive som atom otor innervation from the oculom otor (CN III), trochlear (CN IV), and abducent (CN VI) nerves. The intraocular m uscles receive autonom ic (sym pathetic and parasym pathetic) innervation via the short and long ciliary nerves. Sym pa-

F1

N5 N4

Ophthalm ic vein

with lacrim al gland L

Levator palpebrae superioris and superior rectus (cut)

Levator palpebrae superioris

Lacrim al gland and artery

Com m unicating branch with CN V2

CN II N F

(cut)

Lacrim al gland and artery L

Inferior ophthalm ic vein CN VI Ciliary ganglion N1

CN III

B

thetic bers from the superior cervical ganglion ascend on the internal caro tid artery and travel in t wo m anners: they m ay join the nasociliary nerve (CN V1 ), which distributes them as the long ciliary nerves, or they m ay course along the ophthalm ic artery to enter the ciliary ganglion as the sympathetic root. The ciliary ganglion also receives parasym pathetic bers from CN III (via the parasympathetic root). The ganglion distrib utes these sym pathetic and parasym pathetic bers via the short ciliary nerves. The short ciliary nerves contain sensory bers, which enter the nasociliary nerve via the sensory root of the ciliary ganglion.

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Ta ble 4.22 Ophthalmic ne rve (CN V1 ) The ophthalm ic nerve (CN V1 ) is a sensory nerve* that conveys bers from structures of the superior facial skeleton to the trigem inal ganglion. CN V1 gives o one branch in the m iddle cranial fossa before dividing into three m ajor branches, which pass through the superior orbit al ssure into the orbit. The lacrim al, front al, and nasociliary nerves travel in the lateral, m iddle, and m edial portions of the upper orbit, respectively. M

Me ning e al n.

Sensory: Dura m ater of the m iddle cranial fossa.

L

Lacrimal n.

The sm allest of the three m ajor branches, the lacrim al nerve runs in the superolateral orbit.

Opening

Superior orbit al ssure (above the com m on tendinous ring).

Course

Runs (with the lacrim al artery) along the superior surface of the lateral rectus, through the lacrim al gland and orbit al septum to the skin of the upper eyelid.

Innervation

Sensory: Upper eyelid (skin and conjunctiva) and lacrim al gland. Sensory and parasym pathetic: Lacrim al gland. Postganglionic parasym pathetic secretom otor bers from the pterygopalatine ganglion of the facial nerve (CN VII) travel with the zygom atic and zygom aticotem poral nerves (CN V2 ). They enter the sensory lacrim al nerve (CN V1 ) via a com m unicating branch and are distributed to the gland. Postganglionic sym pathetic bers follow a sim ilar path.

F

Frontal n.

The largest of the three m ajor branches, the front al nerve runs in the m iddle of the upper orbit.

Opening

Superior orbit al ssure (above the com m on tendinous ring).

Course and branches

Runs along the superior surface of the levator palpebrae superioris, below the periosteum . At roughly the level of the posterior eyeball, the front al nerve divides into t wo term inal branches:

Innervation

N

Nasociliary n.

F1

Suprao rbital n.

Continues on the superior surface of the levator palpebrae superioris and passes through the supraorbit al foram en (notch).

F2

Supratrochle ar n.

Courses anterom edially with the supratrochlear artery toward the trochlea (tendon of superior oblique) and passes through the front al notch.

Sensory: Upper eyelid (skin and conjunctiva) and the skin of the forehead (both branches). The supraorbit al n. also receives bers from front al sinus m ucosa; the supratrochlear n. com m unicates with the infratrochlear nerve. The nasociliary nerve runs in the m iddle and m edial part s of the upper orbit.

Opening

Superior orbit al ssure (via the com m on tendinous ring).

Course and branches

Runs medially (across the optic nerve [CN II]) and then anteriorly bet ween the superior oblique and medial rectus. Gives o three branches (t wo sensory and one sympathetic) before dividing into t wo terminal branches (anterior ethmoid and infratrochlear nerves). Se nsory root o f the ciliary gang lion N1

Innervation

Sensory: Fibers from the sho rt ciliary ne rve s pass without synapsing through the ciliary ganglion and enter the nasociliary nerve via the sensory root.

N2

Lo ng ciliary nn.

Sensory: Eye (e.g., cornea and sclera).

N3

Po ste rior ethmo id n.

Sensory: Ethm oid air cells and sphenoid sinus. Fibers run in the ethm oid bone (posterior ethm oid canal) to the nasociliary nerve.

N4

Ante rio r e thmoid n.

Sensory: Super cial nose and anterior nasal cavit y. • Inte rnal nasal n.: Mucosa of the anterior portions of the nasal septum (m edial internal nasal n.) and lateral nasal wall (lateral internal nasal n.). •  Exte rnal nasal n.: Skin of the nose (courses under the nasalis m uscle). Fibers from these t wo term inal branches ascend via the nasal bone, course posteriorly in the cranial cavit y over the cribriform plate, and enter the orbit via the anterior ethm oid canal.

N5

Infratrochlear n.

Sensory: Medial aspect of the upper eyelid (skin and conjunctiva) and the lacrimal sac. Fibers enter the orbit near the trochlea (tendon of superior oblique) and course posteriorly to the nasociliary nerve.

Sensory: Ethm oid air cells, sphenoid sinus, anterior nasal cavit y, super cial nose, upper eyelid, lacrim al sac, and eye.

*Note: Nerve courses are traditionally described proxim al to dist al (CNS to periphery). However, for sensory nerves, the sensory relay is in the opposite direction. It is m ore appropriate to t alk of sensory nerves collecting bers than to t alk of them branching to supply a region.

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CN V2 : Trigeminal Nerve, Maxillary Division Trigem inal ganglion

I

CN V1

Com m unicating branch with lacrim al nerve (from V1 )

Z

CN V2

CN V3

I

, anterior superior alveolar nerve I

, m iddle superior alveolar nerve I

M

Superior alveolar plexus

G

Pterygopalatine ganglion P

A

Cribriform plate

Frontal sinus

Anterior ethm oidal nerve (CN V1 )

G1 G

Olfactory fibers (CN I)

CN V2

Medial nasal branches Medial posterior superior nasal nerves M

entering incisive canal G2

B

Sphenoid sinus

Olfactory bulb

Pterygopalatine ganglion

Sphenopalatine foram en (opened)

G3

Cribriform plate

Olfactory fibers (CN I) G3 ,

lateral posterior superior nasal nerves

External nasal branch Internal nasal branch

Anterior ethm oidal nerve (CN V1 )

Lateral nasal branches

G5

Pterygopalatine ganglion G4

G4 ,

lesser palatine nerve G4 ,

C

greater palatine nerve

, greater palatine nerve, posterior inferior lateral nasal branches G4

Fig. 4.83   Maxillary division (CN V2 ) of the trig e minal ne rve Right lateral view. See Table 4.23 for labels. A Opened right m axillary sinus. B Nasal septum in right nasal cavit y. C Left lateral nasal wall.

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Ta ble 4.23 Maxillary ne rve  (CN V2 ) Like the ophthalm ic nerve (CN V1 ), the m axillary nerve (CN V2 ) is a sensory nerve* that conveys bers from structures of the facial skeleton to the trigem inal ganglion. CN V2 gives o one branch in the m iddle cranial fossa before entering the foram en rotundum to the pterygopalatine fossa. In the pterygopalatine fossa, the m axillary nerve divides into branches (e.g., zygom atic, posterior superior alveolar, and infraorbit al nerves) and receives ganglionic branches from the pterygopalatine ganglion. This ganglion has ve m ajor branches, which distribute CN V2 bers. These sensory CN V2 bers convey autonom ic bers from the pterygopalatine ganglion. Dire ct branche s of the  maxillary n. (CN V2 ) M

Middle me ning eal n.

Sensory: Meninges of the m iddle cranial fossa.

G

Gang lionic branches

Generally, t wo ganglionic branches suspend (pass through) the pte ryg o palatine g ang lion from CN V2 (see below).

Z

Zyg omatic n.

Sensory: Skin of the tem ple (zyg o maticote mporal ne rve ) and cheek (zyg omatico facial ne rve ). Fibers enter the orbit via canals in the zygom atic bone and course in the lateral orbit wall to CN V2 via the inferior orbit al ssure.

Po ste rior supe rio r alve o lar n. P

I

Infrao rbital n.

Sensory: Maxillary m olars (with associated gingivae and buccal m ucosa) and m axillary sinus. Fibers course on the infratem poral surface of the m axilla. The posterior superior alveolar nerve contributes to the supe rior alve olar ple xus (anterior, m iddle, and superior alveolar nn.). Sensory: Lower eyelid (skin and conjunctiva), m axillary sinus, and m axillary teeth (via anterior and m iddle superior alveolar branches). • Middle superior alveolar nerve : Sensory bers from the maxillary premolars (with associated gingivae, buccal mucosa, and maxillary sinus). (The occurance is variable). • Ante rio r supe rior alve o lar ne rve : Sensory bers from the m axillary incisors and canines (with associated gingivae, lingual m ucosa, and m axillary sinus). Nasal branch: Sensory bers from anterior portions of the nasal wall, oor, and septum . These bers enter the infraorbit al canal and em erge from the infraorbit al groove.

Branches passing thro ug h the pte ryg opalatine g ang lio n: The pterygopalatine ganglion is a parasym pathetic ganglion of the facial nerve (CN VII). It conveys rst-order sensory bers to CN V2 from ve m ajor branches supplying the orbit, nasal cavit y, hard and soft palates, and nasopharynx. G1

Orbital branches

Sensory: Orbit al periosteum (via inferior orbit al ssure) and paranasal sinuses (ethm oid air cells and sphenoid sinus, via the posterior ethm oid canal).

G2

Nasopalatine n.

Sensory: Anterior hard palate and the inferior nasal septum . The left and right nasopalatine nerves ascend (in the anterior and posterior incisive foram ina, respectively) and converge in the incisive fossa. They travel posterosuperiorly on the nasal septum (vom er) through the sphenopalatine foram en.

Po ste rior supe rio r nasal nn.

Sensory: Posterosuperior nasal cavit y. (Note: The anterior ethmoid nerve [CN V1 ] conveys bers from the anterosuperior portion.) • Late ral po ste rio r supe rior nasal nn.: Posterior ethm oid air cells and m ucosa in the posterior of the superior and m iddle nasal conchae. • Me dial poste rio r supe rior nasal nn.: Mucosa of the posterior nasal roof and septum .

G3

G4

Palatine nn.

Sensory: Hard and soft palates. • Gre ate r palatine n.: Hard palate (gingivae, m ucosa, and glands) and soft palate via greater palatine canal. Receives bers from the inferior nasal concha and walls of the m iddle and inferior nasal m eatuses through the perpendicular plate of the ethm oid bone (posterior inferior nasal branches). • Lesse r palatine n.: Soft palate, palatine tonsils, and uvula via lesser palatine canal. The greater and lesser palatine nerves converge in the greater palatine canal.

G5

Pharyng eal n.

Sensory: Mucosa of the superior nasopharynx via palatovaginal (pharyngeal) canal.

Autonomic sca o lding : The pterygopalatine ganglion is a liated with the sensory CN V2 . Postganglionic autonom ic bers are distributed by sensory bers of CN V2 . Pte ryg o palatine g ang lio n (CN VII)

Moto r root: Preganglionic parasym pathetic bers from the facial nerve (CN VII) travel in the g reate r pe tro sal ne rve (joins with deep petrosal nerve to form nerve of pterygoid canal). Sympathetic ro ot: Postganglionic sym pathetic bers from the superior cervical ganglion ascend (via the internal carotid plexus) and travel in the de e p pe tro sal ne rve (joins with greater petrosal nerve to form nerve of pterygoid canal). Se nsory root: Sensory bers pass through the ganglion from ve sensory branches (see above).

• Lacrimal g land: Postganglionic parasym pathetic secretom otor bers to the lacrim al gland leave the pterygopalatine ganglion on the zygom atic nerve (CN V2 ). They travel with the zygom aticotem poral nerve to the lacrim al nerve (CN V1 ) via a com m unicating branch. • Glands o f the oral cavity: Postganglionic parasym pathetic bers to the glands of the palatine, pharyngeal, and nasal m ucosa reach their t arget s via corresponding sensory branches of CN V2 . • Bloo d ve ssels: Postganglionic sym pathetic bers are distributed by CN V2 . • Taste (CN VII): Taste bers (special visceral a erent) associated with CN VII ascend from the palate to the greater petrosal nerve and geniculate ganglion of CN VII via the palatine nerves. *Note: Nerve courses are traditionally described proxim al to dist al (CNS to periphery). However, for sensory nerves, the sensory relay is in the opposite direction. It is m ore appropriate to t alk of sensory nerves collecting bers than to t alk of them branching to supply a region.

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CN V3 : Trigeminal Nerve, Mandibular Division

Maxillary division (CN V2 , via foram en rotundum )

Trigem inal nerve (CN V)

Pterygopalatine ganglion

Posterior Middle Anterior

Superior alveolar nerves

Zygom atic nerve Infraorbital nerve (and foram en)

Mandibular division (CN V3 , via foram en ovale)

Long buccal nerve Medial and lateral pterygoid nerves

Auriculotemporal nerve

Masseteric nerve Mylohyoid nerve Lingual nerve

Inferior alveolar nerve (in m andibular canal) Inferior dental branches Mental nerve (and foram en) CN V3 (m andibular nerve)

Nerve of tensor t ym pani Foram en ovale Nerve of tensor veli palatini

Facial nerve Lesser petrosal nerve

Nerve of m edial pterygoid

St ylom astoid foram en Auriculotemporal nerve

Chorda t ympani

Com m unicating branch to auriculotemporal nerve

Otic ganglion

Medial pterygoid m uscle Lingual nerve

Nerve to mylohyoid Inferior alveolar nerve B

Subm andibular ganglion Nerve to mylohyoid

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Fig. 4.84 Mandibular division (CN V3 ) o f the trig e minal ne rve Right lateral view. A Partially opened mandible with m iddle cranial fossa windowed. B Opened oral cavit y (right half of mandible removed). The trunk of CN V3 gives o t wo branches (recurrent m eningeal and m edial pterygoid nerves) before split ting into an anterior and a posterior division (see Table 4.24). The nerve to the m edial pterygoid conveys branchiom otor bers to the otic ganglion; these bers pass without synapsing to innervate the tensors t ym pani and veli palatini. The otic ganglion is the parasym pathetic ganglion of the glossopharyngeal nerve (CN IX). Preganglionic bers enter via the lesser petrosal nerve (reconstituted from the t ym panic plexus; see p. 137). Postganglionic bers leave with the auriculotem poral nerve (CN V3 ) to innervate the buccal gland. Taste bers of CN VII travel in the lingual nerve (CN V3 ) to the chorda t ym pani (which they enter either directly or indirectly via the otic ganglion). These bers ascend in the chorda t ym pani via the t ym panic cavit y to the facial nerve (CN VII; see p. 131).

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Ta ble 4.24 Mandibular ne rve (CN V3 ) The m andibular nerve (CN V3 ) is the m ixed a erent-e erent branch of CN V, cont aining general sensory bers and branchiom otor bers to the eight m uscles derived from the 1st pharyngeal arch. The large sensory and sm all m otor root s of CN V leave the m iddle cranial fossa via the foram en ovale. In the infratem poral fossa, they unite to form the CN V3 trunk. The trunk gives o t wo branches before split ting into an anterior and a posterior division. Of the eight branchial arch m uscles, three are supplied by the trunk, three by the anterior division, and t wo by the posterior division. Trunk: The trunk of CN V3 gives o one sensory and one m otor branch. The m otor branch conveys branchiom otor bers to three of the eight m uscles of the 1st pharyngeal arch. Re curre nt me ning e al branch (nervus spinosum ) R

MP

Me dial pte ryg o id n.

Sensory: Dura of the m iddle cranial fossa (also anterior cranial fossa and calvarium ). The nervus spinosum arises in the infratem poral fossa and re-enters the m iddle cranial fossa via the foram en spinosum . Branchiom otor: Directly to the me dial pte ryg o id . Cert ain bers enter the otic ganglion via the m otor root and pass without synapsing to: • N. to tensor veli palatini: Te nsor veli palatini. • N. to tensor t ym pani: Te nsor tympani.

Ante rior divisio n: The anterior division of CN V3 cont ains predom inantly e erent bers (with one sensory branch, the buccal nerve.) The branchio m otor bers innervate three of the eight m uscles of the 1st pharyngeal arch. M

Massete r n.

Branchiom otor: Massete r. Sensory: Tem porom andibular joint (articular branches).

T

De e p te mporal nn.

Branchiom otor: Te mporalis via t wo branches: • Anterior deep tem poral n. • Posterior deep tem poral n.

LP

Late ral pte ryg oid n.

Branchiom otor: Late ral pte ryg oid .

B

Lo ng buccal n.

Sensory: Cheek (skin and m ucosa) and buccal gingivae of the m olars.

Poste rior division: The larger posterior division of CN V3 cont ains predom inantly a erent bers (with one m otor branch, the mylohyoid nerve). The mylohyoid nerve arises from the inferior alveolar nerve and supplies the rem aining t wo m uscles of the 1st pharyngeal arch. A

Auriculote mpo ral n.

Sensory: Skin of the ear and tem ple. Fibers pass through the parotid gland, behind the tem porom andibular joint, and into the infratem poral fossa. The nerve t ypically split s around the m iddle m eningeal artery (a branch of the m axillary artery) before joining the posterior division. Distributes postganglionic parasym pathetic bers from the otic ganglion.

L

Ling ual n.

Sensory: Mucosa of the oral cavit y (presulcal tongue, oral oor, and gingival covering of lingual surface of m andibular teeth). In the infratem poral fossa, the lingual nerve com bines with the chorda t ym pani (CN VII).

I

Infe rior alve o lar n.

Sensory: Mandibular teeth and chin: • Incisive branch: Incisors, canines, and 1st prem olars (with associated labial gingivae). • Me ntal n.: Labial gingivae of the incisors and the skin of the lower lip and chin. The m ental nerve enters the m ental foram en and com bines with the incisive branch in the m andibular canal. The inferior alveolar nerve exits the mandible via the mandibular foram en and com bines to form the posterior division of CN V3 . Note: 2nd prem olars and m andibular molars are supplied by the inferior alveolar nerve before it splits into its term inal branches. Branchiom otor: Fibers branch just proxim al to the m andibular foram en: • Mylohyo id n.: Mylohyo id and anterior belly of the digastric .

Autonomic sca o lding : The parasym pathetic ganglia of CN VII (subm andibular ganglion) and CN IX (otic ganglion) are functionally associated with CN V3 . Submandibular gang lion (CN VII)

Otic g ang lio n (CN IX)

Parasym pathetic root

Preganglionic parasym pathetic bers from the facial nerve (CN VII) travel to the ganglion in the cho rda tympani, facial nerve, and lingual nerve (CN V3 ).

Sym pathetic root

Sym pathetic bers from the supe rior ce rvical gang lion ascend (via the internal carotid plexus) and travel in a plexus on the facial artery.

Parasym pathetic root

Preganglionic parasympathetic bers enter from CN IX via the lesser petrosal nerve .

Sym pathetic root

Postganglionic sym pathetic bers from the supe rior ce rvical g ang lio n enter via a plexus on the m iddle m eningeal artery.

• Parotid gland: Postganglionic parasympathetic bers from the otic ganglion travel to the parotid gland via the auriculotemporal n. (CN V3 ). • Submandibular and subling ual g lands: Postganglionic autonom ic bers to the subm andibular and sublingual glands travel from the subm andibular ganglion via glandular branches. • Taste (CN VII): Taste bers (special viscerosensory bers) to CN VII may travel via the lingual nerve (CN V3 ) to the chorda t ympani (CN VII). Note: Nerve courses are traditionally described proxim al to dist al (CNS to periphery). However, for sensory nerves, the sensory relay is in the opposite direction. It is m ore appropriate to t alk of sensory nerves collecting bers than to t alk of them branching to supply a region.

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CN VII: Facial Nerve, Nuclei & Internal Branches

Nucleus of the abducent nerve (CN VI)

Ta ble 4.25 Facial ne rve (CN VII)

Pons

Nucle i, g ang lia, and  be r distributio n Branchio motor (purple)

Superior salivatory nucleus

Facial m otor nucleus

Facial m otor nucleus Nervus intermedius Geniculate ganglion St ylomastoid foram en Branches of the parotid plexus A

Lower m otor neurons innervate all m uscles of the 2nd pharyngeal (branchial) arch: • Muscles of facial expression • St ylohyoid • Digastric, posterior belly • St apedius

Parasympathe tic (blue)

Superior salivatory nucleus

Nucleus of solitary tract

Nucleus of the abducent nerve (CN VI)

Internal genu of facial nerve

Nucleus of solitary tract, superior part

Postganglionic neurons innervate: • Lacrim al gland • Subm andibular and sublingual glands • Sm all glands of the oral and nasal cavities Spe cial visce ral a e re nt (light green)

Nucleus of the solit ary tract, superior part

Superior salivatory nucleus Facial m otor nucleus

Preganglionic neurons synapse in the pte ryg o palatine or submandibular g ang lio n .

First-order pseudounipolar cells in the g e niculate gang lion relay t aste sensation from the presulcal tongue (anterior t wo thirds) and soft palate (via the chorda t ym pani and greater petrosal nerve).

Ge ne ral so matic a e re nt (yellow)

Facial nerve

First-order pseudounipolar cells in the g e niculate g ang lion relay general sensation from the external ear (auricle and skin of the auditory canal) and lateral t ym panic m em brane.

B

Fig. 4.85 Facial ne rve (CN VII) A Anterior view of brainstem . B Superior view of cross section through pons. Fibe rs: The facial nerve provides branchiom otor innervation to the m uscles of the second pharyngeal arch and parasym pathetic m otor innervation to m ost salivary glands (via the pterygopalatine and subm andibular ganglia). Taste bers are conveyed via pseudounipolar sensory neurons with cell bodies in the geniculate ganglion. The facial nerve also receives general sensation from the external ear. Branches: The super cial branches of CN VII are primarily branchiom otor (only the posterior auricular nerve may contain sensory bers as well as m otor). Taste and preganglionic parasympathetic bers travel in both the chorda t ympani and greater petrosal nerves. These bers converge in the external genu and enter the brainstem together as the nervus interm edius.

Co urse Eme rg e nce : Axons from the superior salivatory nucleus and the nucleus of the solit ary tract form the ne rvus inte rme dius. These com bine with the branchiom otor and som atosensory bers to em erge from the brainstem as CN VII. Inte rnal branches: CN VII enters the petrous bone via the internal acoustic m eatus. Within the facial canal, it gives o one branchiom otor branch (nerve to the st apedius) and t wo nerves (greater petrosal nerve and chorda t ym pani) cont aining both parasym pathetic and t aste bers. Exte rnal branche s: The rem aining bers em erge via the st ylom astoid foram en. Three direct branches arise before the bers enter the parot id gland (nerve to posterior belly of digast ric, nerve to st ylohyoid, and posterior auricular nerve). In t he gland, the branchiom otor bers branch to form the parotid plexus, which innervates t he m uscles of the 2nd pharyngeal arch. Lesions

CN VII is m ost easily injured in it s dist al portions (after em erging from the parotid gland). Nerve lesions of the parotid plexus cause m uscle paralysis. Tem poral bone fractures m ay injure the nerve within the facial canal, causing disturbances of t aste, lacrim ation, salivation, etc. (see Fig . 4.86 ).

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Fig. 4.86 Branches of the facial ne rve The facial nerve enters the facial canal of the petrous bone via the internal acoustic m eatus. Most branchiom otor bers and all som ato sensory bers em erge via the st ylom astoid foram en. Within the facial canal, CN VII gives o one branchiom otor branch and t wo nerves containing both parasym pathetic and t aste bers (greater petrosal nerve and chorda t ym pani). Tem poral bone fractures m ay injure the facial nerve at various levels:

1 Internal acoustic m eatus CN VIII

2

Greater petrosal nerve 3 Nerve to the stapedius Chorda t ympani

St ylom astoid foram en

4. Neuroa na tomy & Innerva tion of the Hea d & Neck

1 Internal acoustic m eatus: Lesions a ect CN VII and the vestibulocochlear nerve (CN VIII). Peripheral m otor facial paralysis is accom panied by hearing loss and dizziness. 2 External genu of facial nerve: Peripheral m otor facial paralysis is accom panied by disturbances of t aste sensation, lacrim ation, and salivation (greater petrosal nerve). 3 Motor paralysis is accom panied by disturbances of salivation and t aste (chorda t ym pani). Paralysis of the st apedius causes hyperacusis (hypersensitivit y to norm al sounds). 4 Facial paralysis is accom panied by disturbances of t aste and salivation (chorda t ym pani). 5 Facial paralysis is the only m anifestation of a lesion at this level.

4

5

Posterior auricular nerve Nerves to the st ylohyoid and posterior digastric

Parotid plexus

Fig. 4.87 Course of the facial ne rve Right lateral view of right temporal bone (petrous part). Both the facial nerve and vestibulocochlear nerve (CN VIII, not shown) pass through the internal acoustic meatus on the posterior surface of the petrous bone. The facial nerve courses laterally in the bone to the external genu, which contains the geniculate ganglion (cell bodies of rst-order pseudounipolar sensory neurons). At the genu (L. genu = knee), CN VII bends and descends in the facial canal. It gives o three branches bet ween the geniculate ganglion and the st ylomastoid foramen: • Greater petrosal nerve : Parasympathetic and taste (special visceral a erent) bers branch from the geniculate ganglion in the greater petrosal canal. They emerge on the anterior surface of the petrous pyramid and continue across the surface of the foramen lacerum. The greater petrosal nerve combines with the deep petrosal nerve in the pterygoid canal (nerve of the pterygoid canal, vidian nerve). The greater petrosal nerve contains the bers that form the motor root of the pterygopalatine ganglion (the parasympathetic ganglion of CN VII). The pterygopalatine ganglion distributes autonomic bers via the trigeminal nerve (primarily the maxillary division, CN V2 ). • Stape dial ne rve : Branchiom otor bers innervate the stapedius m uscle. • Chorda tympani: The remaining parasympathetic and taste bers leave the facial nerve as the chorda t ympani. This nerve runs through the t ympanic cavit y and petrot ympanic ssure to the infratemporal fossa, where it unites with the lingual nerve (CN V3 ).

Facial nerve (CN VII) in facial canal

Geniculate ganglion

Trigem inal nerve (CN V)

Hiatus of greater petrosal canal

Stapedial nerve and m uscle

Trigem inal ganglion CN V1 CN V3

Greater petrosal nerve

CN V2

Tympanic cavit y

Chorda t ympani

Posterior auricular nerve

St ylom astoid foram en

Petrot ympanic fissure

Pterygopalatine ganglion

Lingual nerve (CN V3 )

St ylohyoid m uscle with nerve Branchiom otor fibers to m uscles of facial expression

Digastric m uscle, posterior belly with nerve

The remaining bers (branchiom otor with some general sensory) exit via the st ylom astoid foram en.

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CN VII: Facial Nerve, External Branches & Ganglia Fig. 4.88 Inne rvation of the se cond branchial arch muscles Left lateral view. The branchiom otor bers of CN VII innervate all the m uscles derived from the second pharyngeal arch. With the excep tion of the st apedial nerve (to the st apedius), all branchiom otor bers in the facial nerve em erge from the facial canal via the st ylom astoid foram en. Three branches arise before the parotid plexus: • Posterior auricular nerve (Note: This may also contain general somatosensory bers.) • Nerve to the digastric (posterior belly) • Nerve to the st ylohyoid The rem aining branchiom otor bers then enter the parotid gland where they divide into t wo trunks (tem porofacial and cervicofacial) and ve m ajor branches, which innervate the m uscles of facial expression: • • • • •

Tem poral branches

Parotid plexus Zygom atic branches

Posterior auricular nerve

Buccal branches Marginal m andibular branch

Facial nerve Nerve to digastric (posterior belly) Cervical branch

Nerve to st ylohyoid

Tem poral Zygom atic Buccal Mandibular (m arginal m andibular) Cervical

The branching of the plexus is variable.

Fig. 4.89 Facial paralysis A Upper m otor neurons in the prim ary som atom otor cortex (precentral gyrus) descend to the cell bodies of lower m otor neurons in the facial m otor nucleus. The axons of these lower m otor neurons innervate the m uscles derived from the second branchial arch. The facial m otor nucleus has a “bipartite” structure: it s cranial (upper) part supplies the m uscles of the calvaria and palpebral ssure, and it s caudal (lower) part supplies the m uscles of the lower face. The cranial part of the nucleus receives bilateral innervation (from upper m otor neurons in both hem ispheres). The caudal part receives contralateral innervation (from cortical neurons on the other side). B Central (supranuclear) paralysis: Loss of upper m otor neurons (shown here for the left hem isphere) causes contralateral paralysis in the lower half of the face but no paralysis in the upper half. For example, the patient’s m outh will sag on the right (contralateral paralysis of lower muscles), but the abilit y to wrinkle the forehead and close the eyes is intact. C Peripheral (infranuclear) paralysis: Loss of lower m otor neurons (shown here for right brainstem ) causes com plete ipsilateral paralysis. For exam ple, the whole right side of the face is paralyzed. Depending on the site of the lesion, additional de cit s m ay be present (decreased lacrim ation or salivation, loss of t aste sensation in the presulcal (anterior t wo thirds) tongue).

Precentral gyrus

Corticonuclear fibers

B

A

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Facial nerve (CN VII)

Facial m otor nucleus

C

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Maxillary division

Internal carotid artery with internal carotid plexus

Lacrim al gland Via com m unicating branch to lacrim al nerve

Trigem inal Deep ganglion petrosal nerve

Postganglionic sym pathetic fibers

Geniculate ganglion

Nasal glands Superior salivatory nucleus Facial nerve Nucleus of the solitary tract Pterygopalatine ganglion

Mandibular division Greater petrosal nerve

Taste buds of soft palate Subm andibular ganglion

St ylom astoid foram en Parotid gland

Glandular branches

Pterygoid canal with nerve of pterygoid canal

Sublingual gland

Lingual nerve Chorda t ympani

Submandibular gland

Fig. 4.90 Facial ne rve gang lia Autonom ic and taste bers often travel with sensory bers from other nerves to reach their t arget s. Parasym pathetic and t aste bers leave the facial nerve via t wo branches: the greater petrosal nerve and the chorda t ym pani. • Greate r pe trosal ne rve : Preganglionic parasym pathetic and t aste bers from the geniculate ganglion course in the greater petrosal canal. They are joined by the deep petrosal nerve, which conveys postganglionic sym pathetic bers from the superior cervical ganglion (via the internal carotid plexus). The greater and deep petrosal nerves com bine to form the nerve of the pterygoid canal (vidian nerve), which conveys sym pathetic, parasym pathetic, and t aste bers to the pterygopalatine ganglion (only parasym pathetics will synapse at the ganglion; all other ber t ypes pass through without synapsing). Branches of CN V2 then distribute the bers to their t arget s: ◦ Lacrimal g land: Autonom ic bers (sym pathetic and parasym pathetic) run with branches of CN V2 (zygom atic and zygom atico tem poral nerves) to a com m unicating branch, which conveys them to the lacrim al nerve (CN V1 ) and thus to the lacrim al gland. ◦ Small g lands o f the nasal and oral cavities: Autonom ic bers run with branches of CN V2 to the sm all glands in the m ucosa of the nasal cavit y, m axillary sinuses, and palatine tonsils.

◦ Taste : Taste bers run with branches of CN V2 to the soft palate. • Chorda tympani: Preganglionic parasym pathetic and taste bers course through the chorda t ym pani. They em erge from the petrot ym panic ssure and com bine with the lingual nerve (CN V3 ) in the infratem poral fossa. They are conveyed to the subm andibular ganglion by the lingual nerve, and from there, postganglionic branches travel to their t arget s via branches of CN V3 . ◦ Submandibular and subling ual g lands: Postganglionic parasym pathetic bers run with branches of CN V3 to the glands. ◦ Taste buds of to ng ue : The t aste buds on the presulcal portion (anterior t wo thirds) of the tongue receive t aste bers from the chorda t ym pani via the lingual nerve (CN V3 ). Note: The post sulcal portion (posterior one third) of the tongue and the oropharynx receive taste bers from CN IX. The root of the tongue and epiglot tis receive taste bers from CN X. Note: The lesse r petrosal ne rve runs in the lesser petrosal canal roughly parallel to the greater petrosal nerve. The lesser petrosal nerve conveys preganglionic parasym pathetic bers from the t ym panic plexus (CN IX) to the otic ganglion. These bers innervate the parotid, buccal, and inferior labial glands, with postganglionic bers distributed via branches of CN V3 .

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CN VIII: Vestibulocochlear Nerve

Superior vestibular nucleus

Flocculus of cerebellum

Medial vestibular nucleus

Lateral vestibular nucleus

Direct fibers to cerebellum Superior vestibular nucleus

Vestibulocochlear nerve (CN VIII) Vestibular root

Medial vestibular nucleus

Vestibular ganglion, superior and inferior part s

B

Lateral vestibular nucleus

Sem icircular canals

Fig. 4.91 Vestibular root and nucle i A Anterior view of the m edulla oblongat a and pons. B Cross section through the upper m edulla oblongata.

Inferior vestibular nucleus A Posterior cochlear nucleus Anterior cochlear nucleus

Anterior cochlear nucleus

Posterior cochlear nucleus

B

Cochlear root A

Cochlea with spiral ganglia

Vestibulocochlear nerve (CN VIII)

Fig. 4.93 Acoustic ne uroma in the ce rebellopontine ang le Acoustic neurom as (m ore accurately, vestibular schwannom as) are benign tum ors of the cerebellopontine angle arising from the Schwann cells of the vestibular root of CN VIII. As they grow, they com press and displace the adjacent structures and cause slowly progressive hearing loss and gait at axia. Large tum ors can im pair the egress of CSF from the 4th ventricle, causing hydrocephalus and sym ptom atic intracranial hyper tension (vom iting, im pairm ent of consciousness).

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Fig. 4.92 Cochlear root and nucle i A Anterior view of the m edulla oblongat a and pons. B Cross section through the upper m edulla oblongat a.

Cerebellopontine angle Acoustic neurom a (vestibular schwannom a)

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Vestibular ganglion, superior part

Vestibulocochlear nerve (CN VIII) Vestibular root

Anterior ampullary nerve

Utricular nerve

Cochlear root

Vestibular ganglion, inferior part

Lateral ampullary nerve

Spiral ganglia Posterior ampullary nerve Saccular nerve

Fig. 4.94 Vestibulocochlear ne rve (CN VIII) The vestibulocochlear nerve consist s of t wo part s. The vestibular root conveys a erent im pulses from the vestibular apparatus (balance). The cochlear root conveys a erent im pulses from the auditory apparatus (hearing).

Ta ble 4.26 Vestibulocochle ar ne rve (CN VIII) Nucle i, g ang lia, and  be r distribution Spe cial somatic a e re nt (orange): Special som atic sensory neurons convey sensory bers from the vestibular apparatus (balance) and auditory apparatus (hearing). Both part s of the nerve cont ain rst-order bipolar sensory neurons. Ne uro ns

Ve stibular ro ot

Cochle ar root

Peripheral processes

In the sensory cells of the sem icircular canals, the saccule, and the utricle.

In the hair cells of the organ of Corti.

Cell bodies

Ve stibular g ang lion • Inferior part : Peripheral processes from saccule and posterior sem icircular canal. • Superior part : Peripheral processes from anterior and lateral sem icircular canals and utricle.

Spiral g ang lia. The peripheral processes from the neurons in these myriad ganglia radiate out ward to receive sensory input from the spiral m odiolus.

Central processes (axons)

To four ve stibular nucle i in the m edulla oblongat a ( oor of the rhom boid fossa). A few pass directly to the cerebellum via the inferior cerebellar peduncle.

To t wo co chle ar nucle i lateral to the vestibular nuclei.

Nuclei

Superior, lateral, m edial, and inferior vestibular nuclei.

Anterior and posterior cochlear nuclei.

Lesions

Dizziness and vertigo.

Hearing loss (ranging to deafness).

Course

The vestibular and cochlear root s unite in the internal acoustic m eatus to form the vestibulocochlear nerve, which is covered by a com m on connective tissue sheath. The nerve em erges from the internal acoustic m eatus on the m edial surface of the petrous tem poral bone and enters the brainstem at the level of the pontom edullary junction, in particular at the cerebellopontine angle.

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

CN IX: Glossopharyngeal Nerve

Inferior salivatory nucleus

Nucleus of the solitary tract, superior part

Inferior salivatory nucleus

Nucleus of the solitary tract, inferior part

Nucleus am biguus

Nucleus am biguus

B

Nucleus of the solitary tract, superior part

Fig. 4.95 Glossopharyng eal ne rve nucle i A Anterior view of brainstem . B Cross section through the m edulla oblongat a.

Nucleus of the solitary tract, inferior part

Ta ble 4.27 Glossopharyng eal ne rve (CN IX)

Jugular foram en Tympanic nerve Inferior ganglion

Muscular branch

A

Glossopharyngeal nerve

Nucle i, g ang lia, and  be r distributio n Superior ganglion

Branchio motor (purple)

Nucleus am biguus

Carotid branch Pharyngeal branches

Spinal nucleus of trigem inal nerve

Lower m otor neurons innervate the m uscles derived from the 3rd, 4th, and 6th pharyngeal (branchial) arches via CN IX, X, and XI. • CN IX innervates the derivative of the 3rd branchial arch (st ylopharyngeus)

Parasympathe tic (blue)

Inferior salivatory nucleus

Preganglionic neurons synapse in the otic ganglion . Postganglionic neurons innervate: • Parotid gland (Fig . 4.96A) • Buccal glands • Inferior labial glands

Ge ne ral so matic a e re nt (yellow)

Spinal nucleus of CN V

B

A

First-order pseudounipolar cells in the supe rior gang lion of CN IX innervate: • Nasopharynx (inferior torus tubarius), oropharynx, post sulcal tongue, palatine tonsils, and uvula (Fig . 4.96C). These bers include the a erent lim b of the gag re ex. • Tym panic cavit y and pharyngot ym panic tube (Fig . 4.96D).

Visce ro se nso ry (green)

First-order pseudounipolar cells in the infe rior gang lion relay t aste and visceral sensation to the nucle us of the so litary tract . This nuclear com plex consist s of a superior part (t aste) and inferior part (general visceral sensation). Nucleus of the solit ary tract

Visceral sensation (Fig . 4.96F): General viscero sensory bers from the carotid body (chem oreceptors) and carotid sinus (pressure receptors) synapse in the infe rior part .

D

C

Taste (Fig. 4.96E): Special viscerosensory bers from the postsulcal tongue synapse in the superior part .

Co urse

The glossopharyngeal nerve arises from the m edulla oblongata and exit s the skull by passing through the jugular foramen. It has t wo sensory ganglia with rst-order pseudounipolar sensory cells: the superior ganglion (som atosensory) is within the cranial cavit y, and the inferior ganglion (viscerosensory) is distal to the jugular foram en. E

Fig. 4.96   Distribution of CN IX  be rs

F

Lesions

Isolated CN IX lesions are rare. Lesions tend to occur during basal skull fractures, which disrupt the jugular foram en. Such injuries would a ect CN IX, X, and XI.

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Greater petrosal nerve Tubarian branch

Ta ble 4.28 Glossopharyng eal ne rve branches

Caroticot ympanic nerve

Lesser petrosal nerve

Ty

Lesser petrosal nerve

Som atosensory and preganglionic parasym pathetic bers branch at the inferior ganglion and travel through the t ym panic canaliculus as the t ym panic nerve. • Tympanic ple xus: The t ym panic nerve com bines with postganglionic sym pathetic bers from the superior cervical ganglion (via carotid plexus and caroticot ym panic nerve) and branches to form the t ym panic plexus. This plexus provides general som ato sensory innervation to the t ym panic cavit y, pharyngot ym panic tube, and m astoid air cells. • Lesse r pe trosal n.: The preganglionic parasym pathetic bers in the t ym panic plexus are reconstituted as the lesser petrosal nerve, which runs in the lesser petrosal canal to synapse in the otic ganglion. • Otic gang lion: The postganglionic parasym pathetic bers innervate the parotid, buccal, and inferior labial glands by traveling with branches of CN V3 .

Carotid plexus on internal carotid artery Tympanic canaliculus with t ympanic nerve Ty Superior and inferior ganglia CN IX

Tympanic plexus

A

CN IX

CN X Superior ganglion

Ty

L

Tympanic n.

Inferior ganglion

To

C

General viscerosensory bers from the carotid sinus (pressure receptors) and carotid body (chem oreceptors) ascend on the internal carotid artery to join CN IX or X on their way to the inferior part of the nucleus of the solit ary tract. P

Pharyng e al branches

The pharyng eal ple xus consist s of general som atosensory bers (from CN IX), sym pathetic bers (from the sym pathetic trunk), and m otor bers (from CN X). • CN IX receives sensory bers from the m ucosa of the naso- and oropharynx via the pharyngeal plexus.

M

C

P

CN X, branch to carotid sinus CN X, pharyngeal branches

Pharyngeal plexus

Carotid branch

Carotid body Carotid sinus

B

M

The branchiom otor bers in CN IX innervate the derivative of the 3rd pharyngeal (branchial) arch, the stylopharyng e us . To

Tonsillar branches

General som atosensory bers from the palatine tonsils and m ucosa of the oropharynx. L

Fig. 4.97 Glossopharyng eal ne rve branches A Left anterolateral view of opened t ym panic cavit y. B Left lateral view.

Muscular branch

Ling ual branche s

General som atosensory and special viscerosensory (t aste) bers from the post sulcal tongue (posterior one third).

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

CN X: Vagus Nerve Ta ble 4.29 Vag us ne rve (CN X) Nucle i, g ang lia, and  be r distributio n Dorsal m otor nucleus

Branchio motor (purple)

Nucleus am biguus

Nucleus am biguus

Nucleus of the solitary tract, superior part Nucleus of the solitary tract, inferior part Superior ganglion

Parasympathe tic (blue)

Inferior ganglion Pharyngeal branch

Dorsal m otor nucleus

Jugular foram en

Spinal nucleus of trigem inal nerve

A

Ge ne ral so matic a e re nt (yellow)

Spinal nucleus of CN X

Dorsal m otor nucleus

Nucleus of the solitary tract, superior part

Preganglionic neurons synapse in sm all, unnam ed ganglia close to t arget structures. Postganglionic neurons innervate: • Sm ooth m uscles and glands of thoracic and abdom inal viscera (Fig . 4.100G)

Superior laryngeal nerve

Nucleus of the solitary tract, inferior part

First-order pseudounipolar cells in the supe rior (jug ular) gang lion innervate: • Dura of the posterior cranial fossa (Fig . 4.100F) • External auditory canal, and lateral t ym panic m em brane (Fig . 4.100C) • Mucosa of the oropharynx and laryngopharynx

Visce ro se nso ry (green)

Spinal nucleus of trigem inal nerve

First-order pseudounipolar cells in the infe rior (no do se ) g ang lio n relay t aste and visceral sensation to the nucle us o f the solitary tract . This nuclear com plex consist s of a superior part (t aste) and inferior part (general visceral sensation).

Nucleus am biguus B

Lower m otor neurons innervate the m uscles derived from the 3rd, 4th, and 6th Phyryngeal (branchial) arches via CN IX, X, and XI. CN X innervates the derivatives of the 4th and 6th branchial arches: • Pharyngeal m uscles (pharyngeal constrictors) • Muscles of the soft palate (levator veli palatini, m usculus uvulae, palatoglossus, palatopharyngeus) • Intrinsic laryngeal m uscles

Olive

Fig. 4.98 Vagus ne rve nucle i A Anterior view of m edulla oblongat a. B Cross section through the m edulla oblongat a. The vagus nerve has the m ost extensive distribution of all the cranial nerves (L. vagus = vagabond). Parasym pathetic bers descend into the thorax and abdom en. These bers form autonom ic plexuses with postganglionic sym pathetic bers (from the sym pathetic trunk and abdom inal ganglia). The plexuses extend along organs and blood vessels and provide m otor innervation to the thoracic and abdom inal viscera. General viscerosensory bers ascend via CN X to the inferior part of the nucleus of the solit ary tract.

Nucleus of the solit ary tract

Taste (Fig . 4.100D): Fibers from the epiglot tis and the root of the tongue are conveyed to the supe rior part of the nucleus of the solit ary tract. Visceral sensation (Fig . 4.100G): Fibers are relayed to the infe rior part of the nucleus of the solit ary tract from : • Mucosa of the laryngopharynx and larynx (Fig . 4.100A) • Aortic arch (pressure receptors) and para-aortic body (chem oreceptors) (Fig . 4.100E) • Thoracic and abdom inal viscera (Fig . 4.100G)

Co urse

The vagus nerve arises from the m edulla oblongat a and em erges from the skull via the jugular foram en. It has t wo sensory ganglia with rst-order pseudounipolar cells: the superior (jugular) ganglion (som atosensory) is within the cranial cavit y, and the inferior (nodose) ganglion (viscerosensory) is dist al to the jugular foram en. Lesions

The recurrent laryngeal nerve supplies parasym pathetic innervation to the intrinsic laryngeal m uscles (except the cricothyroid). This includes the posterior cricoarytenoid, the only m uscle that abduct s the vocal cords. Unilateral lesions of this nerve cause hoarseness; bilateral destruction leads to respiratory distress (dyspnea).

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Ta ble 4.30 Vagus ne rve branches

CN X Thyrohyoid m em brane

Me ning e al branche s Pharyngeal branches

General somatosensory bers from the dura of the posterior cranial fossa.

Superior laryngeal nerve

Auricular branch Internal laryngeal nerve

External laryngeal nerve

General som atosensory bers from external ear (auricle, external acoustic canal, and part of lateral side of t ym panic m em brane). Pharyng e al branche s

Cricothyroid m uscle Right recurrent laryngeal nerve

The pharyng e al ple xus consist s of general som atosensory bers (from CN IX), sym pathetic bers (from the sym pathetic trunk), and m otor bers (from CN X). • CN X conveys branchiom otor bers to the pharyngeal m uscles.

Left recurrent laryngeal nerve

Carotid branch

General viscerosensory bers from the carotid body (chem oreceptors) ascend on the internal carotid artery to join CN IX or X on their way to the inferior part of the nucleus of the solitary tract.

Subclavian artery Brachiocephalic trunk

Supe rior laryng e al n. Aortic arch

Com bines with a sym pathetic branch from the superior cervical ganglion and divides into: • Inte rnal laryng e al n.: Sensory bers from the m ucosa of the laryngopharynx,larynx, and root of the tongue • Exte rnal laryng eal n.: Parasym pathetic m otor innervation to the cricothyroid.

Left recurrent laryngeal nerve Cervical cardiac branches

Re curre nt laryng eal n.

The recurrent laryngeal nerve is asym m etrical: • Right recurrent laryngeal n.: Recurs behind the right subclavian artery. • Left recurrent laryngeal n.: Recurs behind the aortic arch. Ascends bet ween the trachea and esophagus. The recurrent laryngeal nerves supply: • Motor innervation to the laryngeal muscles (except the cricothyroid). • Viscerosensory innervation to the laryngeal m ucosa.

Anterior esophageal plexus

Branche s to the  tho rax and abdo me n

The vagus nerve also conveys parasym pathetic and general viscerosensory bers from the cardiac, pulm onary, esophageal, celiac, renal, hepatic, and gastric plexuses (Fig . 4.100G)

Fig. 4.99 Vag us ne rve branche s in the ne ck Anterior view.

B

C

A

D

E

F

G

Fig. 4.100 Distribution of the vag us ne rve (CN X)

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

CN XI & XII: Accessory Spinal & Hypoglossal Nerves Ta ble 4.31 Accessory ne rve (CN XI) Nucle i, gang lia, and  be r distribution Branchiomoto r (purple)

Nucleus am biguus

Jugular foram en Vagus nerve (CN X) Corticobulbar fibers

To laryngeal m uscles via pharyngeal plexus and recurrent laryngeal nerve

Nucleus am biguus Foram en m agnum

Cranial root

Accessory nerve (CN XI), external branch

Spinal root

Trapezius

A

Fig. 4.101 Accessory ne rve A Posterior view of brainstem . B Right lateral view of sternocleidom astoid and trapezius.

Ge ne ral somato motor (red)

Spinal nucleus of CN XI

Sternocleidom astoid

Spinal nucleus of accessory nerve

Lower motor neurons innervate the muscles derived from the 3rd, 4th, and 6th branchial arches via CN IX, X, and XI. • CN XI innervates the laryngeal m uscles (except cricoarytenoid) with m otor bers being distributed by branches of CN X.

Lower m otor neurons in the lateral part of the anterior horn of C2–C6 spinal cord segm ent s innervate: • Trapezius (upper part). • Sternocleidom astoid.

Course

CN XI arises and courses in t wo part s that unite brie y dist al to the jugular foram en:

B

(Note: For didactic reasons, the right m uscles are displayed though they are innervated by the right cranial nerve nuclei.)

Cranial root: Branchiomotor bers emerge from the medulla oblongata and pass through the jugular foramen. They brie y unite with the spinal root before joining CN X at the inferior ganglion. CN X distributes the branchiomotor bers via the pharyngeal plexus and the external and recurrent laryngeal nerves. Spinal ro ot : General som atom otor bers em erge as rootlet s from the spinal m edulla. They unite and ascend through the foram en m agnum . The spinal root then passes through the jugular foram en, courses brie y with the cranial root, and then descends to innervate the sternocleidom astoid and trapezius. Le sio ns

B

Trapezius paralysis: Unilateral lesions m ay occur during operations in the neck (e.g., lym ph node biopsies), causing : • Drooping of the shoulder on the a ected side. • Di cult y raising the arm above the horizontal.

A

Fig. 4.102 Accessory ne rve lesions Accessory nerve lesions cause partial paralysis of the trapezius and com plete ( accid) paralysis of the sternocleidom astoid (see Table 4.28). Both lesions shown here are unilateral

The sternocleidomastoid is exclusively innervated by CN XI, and the lower portions of the trapezius may be innervated by C3– C5. Accessory nerve lesions therefore cause complete ( accid) sternocleidomastoid paralysis but only partial trapezius paralysis.

(right side). A Posterior view. Partial paralysis of the trapezius causes drooping of the shoulder on the a ected side. B Right anterolateral view. Flaccid paralysis of the sternocleidom astoid causes torticollis (wry neck).

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Ste rno cle idomasto id paralysis: • Unilateral lesions: Flaccid paralysis causes torticollis (wry neck, i.e., di cult y turning the head to the opposite side). • Bilateral lesions: Di cult y holding the head upright.

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4. Neuroa na tomy & Innerva tion of the Hea d & Neck

Hypoglossal trigone (in rhom boid fossa)

Ta ble 4.32 Hypog lossal ne rve (CN XII) Nucleus of the hypoglossal nerve (CN XII)

Pyram id

Olive

Nucle i, g ang lia, and  be r distributio n Ge ne ral so matomoto r (red)

Nucleus of the hypoglossal nerve

CN XII

Nucleus of CN XII

Foram en m agnum

Lower m otor neurons innervate: • Extrinsic lingual m uscles (except palatoglossus). • Intrinsic lingual m uscles.

Course Pyram id

Olive

Anterior condylar canal

A

Fig. 4.103 Hypoglossal ne rve nucle i The nucleus of the hypoglossal nerve is located in the oor of the rhom boid fossa. Rootlet s em erge bet ween the pyram id and the olive. A Cross section through the m edulla oblon-

B

C1 spinal nerve

gata. The proxim it y of the nuclei to the m idline causes extensive lesions to involve both nuclei. B Anterior view of m edulla oblongata.

The hypoglossal nerve em erges from the m edulla oblongat a as rootlet s bet ween the olive and pyram id. These rootlet s com bine into CN XII, which courses through the hypoglossal (anterior condylar) canal. CN XII enters the root of the tongue superior to the hyoid bone and lateral to the hyoglossus. • C1 m otor bers from the cervical plexus travel with the hypoglossal nerve: som e branch to form the superior root of the ansa cervicalis (not shown), whereas others continue with CN XII to supply the geniohyoid and thyrohyoid m uscles. Le sions

Precentral gyrus

Left and right genioglossus m uscles

B Corticobulbar fibers

Paralyzed genioglossus

C Tongue St yloglossus m uscle

Fig. 4.104 Hypog lossal ne rve A Course of the hypoglossal nerve. Upper m otor neurons synapse on lower m otor neurons on the contralateral nucleus of the hypoglossal nerve. Supranuclear lesions will therefore cause contralateral paralysis; peripheral lesions will cause ipsilateral paralysis (sam e side). B The functional genioglossus extends the tongue anteriorly. C Unilateral paralysis due to a peripheral lesion causes the tongue to deviate toward the a ected side (dom inance of the intact genioglossus).

CN X

C1

Nucleus of the hypoglossal nerve

Anterior condylar canal

Upper m otor neurons innervate the lower m otor neurons in the contralateral nucleus of the hypoglossal nerve. Supranuclear lesions (central hypoglossal paralysis) will therefore cause the tongue to deviate away from the a ected side. Nuclear or peripheral lesions will cause the tongue to deviate toward the a ected side (Fig. 4.104C).

CN XII

Genioglossus m uscle Hyoglossus m uscle

A

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Regions of the Head 5

Face & Scalp Muscles of the Face Muscles of Facial Expression: Calvaria, Ear, & Eye Muscles of Facial Expression: Mouth Neurovascular Topography of the Anterior Face & Scalp: Super cial Layer Neurovascular Topography of the Lateral Head: Super cial Layer Neurovascular Topography of the Lateral Head: Interm ediate & Deep Layers

6

7

150 152 154

9

156 158 160 162 164 166 168 170

172 174 176 178 180 182

Oral Cavity & Pharynx Oral Cavit y: Overview Vasculature of the Oral Cavit y Innervation of the Oral Cavit y Teeth in situ & Term inology Structure of the Teeth & Periodontium Maxillary Perm anent Teeth Mandibular Perm anent Teeth Deciduous Teeth Radiographs of Teeth Lingual Mucosa Glossal Muscles Neurovasculature of the Tongue

10 184 186 188 190 192 194 196 198 200 202 204 206

208 210 212 214 216 218 220 222 224 226

Orbit & Eye Bones of the Orbit Com m unications of the Orbit Extraocular Muscles Innervation of the Extraocular Muscles (CN III, IV, & VI) Neurovasculature of the Orbit Topography of the Orbit (I) Topography of the Orbit (II) Lacrim al Apparatus Eyeball Eye: Blood Supply Eye: Lens & Cornea Eye: Iris & Ocular Cham bers Eye: Retina Visual System (I): Overview & Geniculate Part Visual System (II): Lesions & Nongeniculate Part Visual System (III): Re exes Visual System (IV): Coordination of Eye Movem ent

Nose & Nasal Cavity Nose: Nasal Skeleton Overview of the Nasal Cavit y & Paranasal Sinuses Nasal Cavit y Mucosa of the Nasal Cavit y Nose & Paranasal Sinuses: Histology & Clinical Anatomy Olfactory System (Sm ell)

8

144 146 148

Te mporal, Infrate mporal, & Pte ryg opalatine Fossae Tem poral & Infratem poral Fossae: Content s Infratem poral Fossa: Content s Muscles of Mastication: Overview Muscles of Mastication: Deep Muscles Tem porom andibular Joint (TMJ) Tem porom andibular Joint (TMJ): Biom echanics Pterygopalatine Fossa: Overview Topography of the Pterygopalatine Fossa

Gustatory Pathway Floor of the Oral Cavit y Salivary Glands Hard & Soft Palates Pharynx: Divisions & Content s Muscles of the Pharynx (I) Muscles of the Pharynx (II) Muscles of the Pharynx (III) & Innervation Neurovascular Topography of the Pharynx Potential Tissue Spaces in the Head & Spread of Dent al Infections

228 230 232 234 236 238 240 242 244 246 248 250 252 254 256 258 260

Ear Overview & External Ear (I) External Ear (II): Auricle Middle Ear (I): Tym panic Cavit y & Pharyngot ym panic Tube Middle Ear (II): Auditory Ossicles & Tym panic Cavit y Inner Ear (I): Overview & Innervation (CN VIII) Arteries & Veins of the Middle & Inner Ear Inner Ear (II): Auditory Apparatus Auditory Pathway Inner Ear (III): Vestibular Apparatus Vestibular Pathway

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262 264 266 268 270 272 274 276 278 280

Regions of the Hea d

5. Fa ce & Sca lp

Muscles of the Face

Epicranial aponeurosis (galea aponeurotica)

Occipitofrontalis, frontal belly

Corrugator supercilii

Procerus

Levator labii superioris alaeque nasi

Levator labii superioris alaeque nasi Orbicularis oculi

Palpebral fissure (closed)

Levator labii superioris

Nasalis

Zygom aticus m inor

Levator labii superioris

Zygom aticus m ajor

Zygom aticus m inor

Levator anguli oris

Zygom aticus m ajor

Parotid duct and gland Buccinator Buccal fat pad

Levator anguli oris

Masseter (m uscle of m astication)

Risorius

Orbicularis oris

Labial fissure (closed) Depressor anguli oris

Depressor anguli oris

Plat ysm a

Depressor labii inferioris

Depressor labii inferioris

Mentalis

Fig. 5.1 Supe r cial facial muscles Anterior view. The super cial layer of m uscles is shown on the right side of the face. Cert ain m uscles have been cut on the left to expose deeper m uscles. The m uscles of facial expression are the super cial layer of m uscles that arise either directly from the periosteum or from adjacent m uscles and insert onto other facial m uscles or directly into the connective tissue of the skin. Because of their cutaneous at t achm ent s, the m uscles of facial expression are able to m ove the facial skin (an action that m ay be tem porarily abolished by botulinum toxin injection). They also serve a protective function (especially for the eyes) and are active during food ingestion (closing the labial ssure). The m uscles of facial expression are innervated by branches of the facial nerve (CN VII). As these m uscles are located in the subcut aneous fat, and because

the super cial body fascia is absent in the face, surgeons m ust be particularly careful when dissecting this region. The lack of fascia on the face and the loose connective tissue bet ween the cutaneous at t achm ent s of the facial m uscles also m eans that facial lacerations, following a blow to the face for exam ple, tend to gape widely. This necessit ates careful suturing of these lacerations to approxim ate the edges of the wound and to prevent scarring. The loose nature of the connective tissue also provides a place for blood and uid to accum ulate, leading to swelling and bruising of the face. Such swelling m ay also be apparent following an in am m atory insult, such as a bee sting. The m uscles of m astication lie deep to the m uscles of facial expression. They control the m ovem ent of the m andible and are innervated by branches of the trigem inal nerve (CN V).

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Regions of the Hea d

5. Fa ce & Sca lp

Epicranial aponeurosis Superior auricular m uscle Occipitofrontalis, frontal belly (frontalis)

Temporoparietalis (variable) Orbicularis oculi Procerus Anterior auricular m uscle Nasalis Levator labii superioris alaeque nasi

Levator labii superioris

Occipitofrontalis, occipital belly (occipitalis)

Zygom aticus m inor

Posterior auricular m uscle

Orbicularis oris Zygom aticus m ajor

Trapezius

Risorius

Sternocleidom astoid

Depressor labii inferioris Mentalis

Depressor anguli oris Plat ysm a

Fig. 5.2 Supe r cial facial muscle s Lateral view. The epicranial aponeurosis (galea aponeurotica) is a tough tendinous sheet stretching over the calvaria; it is loosely at t ached to the periosteum . The m uscles of the calvaria that arise from the epicranial aponeurosis (tem poropariet alis and occipitofront alis) are collectively known as the “epicranial m uscles.” The occipitofront alis has t wo bellies: front al (front alis) and occipit al (occipit alis). The trapezius and sternocleidom astoid m uscles are super cial neck m uscles.

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Regions of the Hea d

5. Fa ce & Sca lp

Muscles of Facial Expression: Calvaria, Ear, & Eye

Epicranial aponeurosis

Epicranial aponeurosis

Orbicularis oculi

Procerus

A

Corrugator supercilii

B

Parotid gland

Fig. 5.3 Muscles of facial e xpre ssion: calvaria and e ar A Anterior view of calvaria. B Left lateral view of auricular m uscles.

Orbicularis oculi, orbital part Orbicularis oculi, orbital part s

Orbicularis oculi, palpebral parts

Orbicularis oculi, lacrim al part Posterior lacrim al crest

Zygom aticus m ajor and m inor

Alar cartilage

Levator labii superioris

Anterior lacrim al crest B

A

Fig. 5.4 Muscles of facial e xpression: palpebral  ssure  and nose A Anterior view. The m ost functionally im port ant m uscle of this region is the orbicularis oculi, which closes the palpebral ssure (a protective re ex against foreign m at ter). As the orbicularis oculi closes the palpebral ssure, it does so by closing from lateral to m edial, thus spreading lacrim al secretions across the cornea (p. 243). If the action of the orbicularis oculi is lost because of facial nerve paralysis, the loss of this protective re ex will be accom panied by drying of the cornea from prolonged exposure to the air. The function of the orbicularis oculi is tested by asking the patient to squeeze the eyelids tightly shut. Other sym ptom s of facial nerve paralysis (Bell palsy) in-

clude ipsilateral drooping of the corner of the m outh, eyebrow, and lower eyelid, and the inabilit y to sm ile, whistle, blow out cheeks, or wrinkle the forehead (due to paralysis of the other m uscles of facial expression). B The orbicularis oculi has been dissected from the left orbit to the m edial canthus of the eye and re ected anteriorly to dem onstrate it s lacrim al part (called the Horner m uscle). This part of the orbicularis oculi arises m ainly from the posterior lacrim al crest, and it s action is a subject of debate (it m ay have a functional role in drainage of the lacrim al sac).

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A

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D

C

Fig. 5.5 Chang es of facial e xpression: palpebral  ssure  and nose Anterior view. A Corrugator supercilii. B Orbicularis oculi. C Nasalis. D Levator labii superioris alaeque nasi.

Ta ble 5.1 Muscle s of facial e xpression: calvaria and ear, palbebral  ssure  and nose Muscle  and parts

Orig in

Inse rtion

I*

Main action(s)

Epicranial aponeurosis near coronal suture

Skin and subcut aneous tissue of eyebrows and forehead

T

Elevates eyebrows; wrinkles skin of forehead

T

Elevate ear

Calvaria and e ar

Occipitofront alis, frontal belly Auricular m uscles Anterior

Tem poral fascia (anterior portion)

Helix of the ear

• Pull ear superiorly and anteriorly

Posterior

Epicranial aponeurosis on side of head

Upper portion of auricle

• Elevate ear

Superior

Tem poral fascia

Helix of the ear

Occipital bone (highest nuchal line) and temporal bone (mastoid part)

Epicranial aponeurosis near coronal suture

Occipitofront alis, occipit al belly

PA

• Pull ear superiorly and posteriorly Pulls scalp backward

Palpebral  ssure  and nose

Orbicularis oculi

Whole m uscle act s as orbit al sphincter (closes eyelids)

• Orbit al part

Medial orbit al m argin (front al bone and m axilla) and m edial palpebral ligam ent

Adjacent m uscles (occipitofront alis, corrugator supercilii, levator labii, etc.)

T/Z

• Volunt ary closure of eyelids, furrowing of nose and eyebrows during squinting

• Palpebral part

Medial palpebral ligam ent

Eyelids (as lateral palpebral raphe)

• Voluntary (sleeping) and involuntary closure (blinking) of eyelids

• Lacrim al part

Lacrim al crest

Tarsi of eyelids, lateral palpebral raphe

• Pulls eyelids m edially

Procerus

Fascial aponeurosis of lower nasal bone

Skin bet ween eyebrows

T/Z

Pulls eyebrows m edially and inferiorly (frowning)

Corrugator supercilii

Bone of superciliary arch (m edial end)

Skin above supraorbit al m argin

T

Act s with orbicularis oculi to pull eyebrows m edially and inferiorly (during squinting)

Maxilla

Aponeurosis at bridge of nose

B/Z

• Com presses nasal aperture (com pressor naris)

Nasalis • Transverse part • Alar part

Levator labii superioris alaeque nasi

Ala nasi

Front al process of m axilla

Greater alar cartilage and orbit al m uscles (levator labii superioris and orbicularis oris)

• Widens nasal aperture ( ares nostril) by drawing ala toward nasal septum B/Z

Elevates upper lip, increases the curvature of the nasolabial furrow, dilates nostril

* Innervation: The m uscles of facial expression are innervated by six branches of the facial nerve (CN VII). The posterior m uscles are innervated by the posterior auricular (PA) nerve, which arises before the facial nerve enters the parotid gland (see p. 131). The anterior m uscles are innervated by ve branches o the parotid plexus of the facial nerve: tem poral (T), zygom atic (Z), buccal (B), m arginal m andibular (M), and cervical (C).

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Muscles of Facial Expression: Mouth Orbicularis oculi

Levator anguli oris

Lateral pterygoid (m uscle of m astication)

Orbicularis oris Risorius

Masseter (cut) (m uscle of m astication)

Masseter (m uscle of m astication) B

A

Mentalis

Temporalis (cut) (m uscle of m astication)

Levator labii superioris

Lateral pterygoid (m uscle of m astication) Orbicularis oris

Medial pterygoid (m uscle of m astication) Mandibular ram us (cut)

Depressor labii inferioris Mentalis

C

Depressor labii inferioris

Buccinator

Depressor anguli oris

D

Masseter (cut)

Zygom aticus m inor (cut)

Zygom aticus m inor Zygom aticus m ajor

Levator labii superioris

Zygom aticus m ajor (cut)

Levator anguli oris (cut)

Levator anguli oris

Parotid duct Buccinator

Fig. 5.6   Muscles of facial expression: mouth A–D Left lateral view. E Anterior view. A Zygom aticus m ajor and m inor. B Levator labii superioris and depressor labii inferioris (exposed by rem oval of the depressor anguli oris). C Levator anguli oris and depressor anguli oris. D Buccinator. E Muscles of facial expression of the m outh.

Masseter

Plat ysma Depressor anguli oris

E

Depressor anguli oris (cut) Depressor labii inferioris

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A

B

C

D

F

G

H

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Fig. 5.7 Changes of facial expression: mouth Anterior view. A Orbicularis oris. B Buccinator. C Zygom aticus m ajor. D Risorius. E Levator anguli oris. F Depressor anguli oris. G Depressor labii inferioris. H Mentalis.

Ta ble 5.2 Muscle s of facial e xpression: mouth Muscle

Zygom aticus m ajor

Orig in

Inse rtion

I*

Main action(s)

Zygom atic bone (lateral surface, posterior part)

Muscles at the angle of the m outh

Z

Pulls corner of m outh superiorly and laterally

Zygom aticus m inor Levator labii superioris alaeque nasi

Upper lip just m edial to corner of the m outh

Pulls upper lip superiorly

Maxilla (front al process)

Upper lip and alar cartilage of nose

Maxilla (front al process) and infraorbit al m argin

Skin of upper lip

Mandible (anterior portion of oblique line)

Lower lip at m idline; blends with m uscle from opposite side

M

Pulls lower lip inferiorly and laterally, also contributes to eversion (pouting)

Levator anguli oris

Maxilla (canine fossa, below infraorbit al foram en)

Muscles at the angle of m outh

B/Z

Raises angle of m outh; helps form nasolabial furrow

Depressor anguli oris

Mandible (oblique line below canine, prem olar, and 1st m olar teeth)

Skin at corner of m outh; blends with orbicularis oris

B/ M

Pulls angle of m outh inferiorly and laterally

Buccinator

Alveolar processes of m axilla and m andible (by m olars); pterygo m andibular raphe

Lips, orbicularis oris, subm ucosa of lips and cheek

B

• Suckling in nursing infant • Presses cheek against m olar teeth, working with tongue to keep food bet ween occlusal surfaces and out of oral vestibule; expels air from oral cavit y/resist s distention when blowing Unilateral: draws m outh to one side

Orbicularis oris

Deep surface of skin Superiorly: Maxilla (m edian plane) Inferiorly: Mandible

Mucous m em brane of lips

B/ M

Act s as oral sphincter • Com presses and protrudes lip (e.g., whistling, sucking, kissing) • Resist s distention (when blowing)

Risorius

Fascia and super cial m uscles over m asseter

Skin of corner of m outh

B

Retract s corner of m outh as in sm iling, laughing, grim acing

Ment alis

Frenulum of lower lip

Skin of chin

M

Elevates and protrudes lower lip (drinking)

Skin over lower neck and upper lateral thorax

Mandible (inferior border); skin over lower face; angle of m outh

C

Depresses and wrinkles skin of lower face and m outh; tenses skin of neck; aids in forced depression of the m andible

Levator labii superioris Depressor labii inferioris

Plat ysm a

B/Z

Elevates upper lip; ares nostril Elevates upper lip

* Innervation: The m uscles of facial expression are innervated by six branches of the facial nerve (CN VII). The posterior m uscles are innervated by the posterior auricular (PA) nerve, which arises before the facial nerve enters the parotid gland. The anterior m uscles are innervated by ve branches o the parotid plexus of the facial nerve: tem poral (T), zygom atic (Z), buccal (B), m arginal m andibular (M), and cervical (C).

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Neurovascular Topography of the Anterior Face & Scalp: Super cial Layer Epicranial aponeurosis (galea aponeurotica)

Infratrochlear nerve (CN V1) Supratrochlear nerve (CN V1 )

Superior palpebral nerve (CN V1 )

Supraorbital nerve, lateral branch (CN V1 )

Lacrim al nerve (CN V1 )

Supraorbital nerve, m edial branch (CN V1 ) Dorsal nasal artery

Facial nerve, temporal branches

Lateral nasal artery Auriculotemporal nerve (CN V3 )

Angular artery and vein

Superficial temporal artery and vein

Facial nerve, zygom atic branches

Infraorbital artery and nerve (via infraorbital foram en)

Facial nerve, buccal branches

Transverse facial artery (branch of superficial temporal artery) Parotid duct

Parotid gland

Superior labial nerve (CN V2 ) and artery Masseter

Facial nerve, m arginal m andibular branch

Facial artery and vein

External nasal nerve (CN V1 )

Mental artery, vein, and nerve (via m ental foram en)

Inferior labial nerve (CN V3 ) and artery

Fig. 5.8 Ne urovasculature  of the  supe r cial laye r of the  ante rior  face Anterior view. Removed: Skin and fat t y tissue. The m uscles of facial expression have been partially rem oved on the left side to display underlying m usculature and neurovascular structures. The m uscles of facial expression receive m otor innervation from the facial nerve (CN VII), which em erges laterally from the parotid gland. The m uscles of m astication receive m otor innervation from the m andibular division of the

trigem inal nerve (CN V3 ). The face receives sensory innervation prim arily from the term inal branches of the three divisions of the trigem inal nerve (CN V), but also from the great auricular nerve, which arises from the cervical plexus (see pp. 316 and 317). The face receives blood supply prim arily from branches of the external carotid artery, though these do anastom ose on the face with facial branches of the internal carotid artery (see Fig . 3.12).

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Scalp veins

Dura m ater, periosteal layer

Em issary vein

Skin

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Connective tissue

Loose areolar tissue

Scalp

Pericranium Outer table Diploe Inner table

Arachnoid granulations

Dura m ater, m eningeal layer

Falx cerebri

Fig. 5.9   Scalp The scalp consist s of ve layers. From super cial to deep, these are Skin, Connective tissue, epicranical Aponeurosis (galea aponeurotica), Loose areolar tissue, and Pericranium . Scalp infections are able to spread easily through the loose connective tissue layer. They m ay spread intracranially to the dural venous sinuses through em issary veins, causing m eningitis, or to the eyelids or nose because the frontalis m uscle insert s into the skin and subcut aneous tissue but does not at t ach to bone. Infections that spread to the eyelid cause rapid swelling because the skin of the eyelid is very thin and it covers a loose connective tissue layer. Scalp infections are unable to spread into the neck because the occipital bellies of the occipitofront alis m uscles at t ach to the occipit al bone and the m astoid process of

Epicranial aponeurosis (galea aponeurotica)

the tem poral bone. Likewise they are prevented from spreading laterally beyond the zygom atic arches because the epicranial aponeurosis is continuous with the tem poral fascia, which at t aches to the zygom atic arches. Scalp lacerations bleed profusely because the arteries entering the periphery of the scalp bleed from both ends owing to extensive anastom oses. Furtherm ore, the arteries do not contract to arrest bleeding because they are held open by the dense connective tissue layer of the scalp.The occipitofrontalis m ay go into spasm following scalp laceration causing the wound to gape. Scalp lacerations should be sutured or otherwise controlled as soon as possible after injury to prevent serious, som etim es fat al, loss of blood.

Fig. 5.10  Ve nous “dang e r zone ” in the  face The super cial veins of the face have extensive connections with the deep veins of the head (e.g., the pterygoid plexus) and dural sinuses (e.g., the cavernous sinus) (see p. 66). Veins in the triangular danger zone are, in general, valveless. There is therefore a particularly high risk of bacterial dissem ination into the cranial cavit y. For exam ple, bacteria from a boil on the lip m ay enter the facial vein and cause m eningitis by passing through venous com m unications with the cavernous sinus.

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Neurovascular Topography of the Lateral Head: Super cial Layer Superficial temporal artery, frontal branch

Superficial tem poral artery and vein

Superficial tem poral artery, parietal branch

Supraorbital nerve (CN V1 )

Supratrochlear nerve (CN V1 ) Zygom aticoorbital artery Auriculotemporal nerve (CN V3 ) Infratrochlear nerve (CN V1 ) Angular vein External nasal nerve (CN V1 ) Transverse facial artery Infraorbital nerve (CN V2 )

Occipital artery

Parotid duct

Greater occipital nerve (C2)

Buccinator

Lesser occipital nerve (from cervical plexus [C2]) Sternocleidom astoid

Mental nerve (CN V3 )

Posterior auricular vein

Parotid gland Facial vein Masseter

Branches of parotid plexus of facial nerve

Fig. 5.11 Ne urovasculature  of the  supe r cial laye r of the  late ral  he ad Left lateral view. The arteries supplying the lateral head arise from branches of the external carotid artery (see Fig. 5.12). Blood drains prim arily into the internal, external, and anterior jugular veins (see p. 62). The m uscles of facial expression receive m otor innervation from

Retrom andibular vein, posterior division

External jugular vein

Great auricular nerve (from cervical plexus [C2–C3])

the facial nerve (CN VII), which em erges laterally from the parotid gland (see p. 133). The m uscles of m astication receive m otor innervation from the m andibular division of the trigem inal nerve (CN V3 , see p. 128). The sensory innervation of the face is shown in Fig. 5.13.

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Zygomatico-orbital artery

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Middle temporal artery

Supraorbital artery Transverse facial artery

Dorsal nasal artery

Superficial temporal artery

Angular artery Inferior alveolar artery

Maxillary artery

Superior labial artery

Occipital artery

Inferior labial artery

Facial artery External carotid artery

Mental artery Subm ental artery

Fig. 5.12   Supe r cial arte ries of the  he ad Left lateral view. The super cial face is supplied prim arily by branches of the external carotid artery (e.g., facial, super cial tem poral, and m axillary arteries). However, there is a lim ited contribution from branches

Internal carotid artery

derived from the internal carotid artery in the region of the orbital rim . Note: The internal carotid artery is colored purple and the anterior, m edial, posterior, and term inal branches of the external carotid artery are colored red, blue, green, and yellow, respectively.

Ophthalm ic division (CN V1 )

Trigem inal nerve (CN V)

Greater occipital nerve (posterior ram us of C2)

Maxillary division (CN V2 )

Mandibular division (CN V3 )

Spinal nerves (posterior ram i) Lesser occipital nerve (cervical plexus [C2])

Transverse cervical nerve (cervical plexus [C2–C3])

Supraclavicular nerves (cervical plexus [C3–C4])

Greater auricular nerve (cervical plexus [C2–C3])

Fig. 5.13   Se nsory inne rvation of the  late ral head and ne ck Left lateral view. The head receives sensory innervation prim arily from the trigem inal nerve (orange), the cervical plexus (green and gray), and the posterior ram i of the spinal nerves (blue). Sensory supply to the face is prim arily from the term inal branches of the three trigem inal nerve divisions. The occiput and nuchal region are supplied prim arily by posterior ram i of the spinal nerves. The anterior ram i of the rst four

spinal nerves com bine to form the cervical plexus. The cervical plexus gives o four cut aneous branches that supply the lateral head and neck (nerves listed with their associated spinal nerve bers): lesser occipit al (C2, occasionally C3), greater auricular (C2–C3), transverse cervical (C2–C3), and supraclavicular (C3–C4) nerves (see Fig . 12.3).

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Neurovascular Topography of the Lateral Head: Intermediate & Deep Layers Superficial tem poral artery, parietal and occipital branches

Tem porofacial trunk Supraorbital nerve (CN V1 )

Supratrochlear nerve (CN V1 ) Auriculotemporal nerve (CN V3 ) Infratrochlear nerve (CN V1 ) Tem poral branches of parotid plexus (CN VII) External nasal nerve (CN V1 )

Infraorbital nerve (CN V2 )

Occipital artery Greater occipital nerve (posterior ram us of C2)

Zygom atic branches of parotid plexus (CN VII)

Posterior auricular nerve (CN VII)

Parotid duct Buccal branches of parotid plexus (CN VII)

Lesser occipital nerve (cervical plexus [C2]) Sternocleidom astoid

Mental nerve (CN V3 )

Nerve to digastric, posterior belly (CN VII) Nerve to stylohyoid (CN VII) Masseter Marginal m andibular Cervical Cervicofacial branch of branch of trunk parotid plexus parotid plexus (CN VII) (CN VII)

Fig. 5.14   Ne rves of the  inte rme diate  laye r of the  late ral head Left lateral view. The parotid gland has been rem oved to dem onstrate the structure of the parotid plexus of the facial nerve (see Fig . 4.88). The occiput receives sensory innervation from the greater occipit al

Intraparotid plexus of the facial nerve (CN VII)

External jugular vein

Great auricular nerve (cervical plexus [C2–C3])

nerve, which arises from the posterior prim ary ram us of C2, and the lesser occipital nerve, which arises from the cervical plexus (anterior ram i of C2).

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Supraorbital nerve (CN V1 )

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Lacrim al nerve (CN V1 )

Supratrochlear nerve (CN V1 ) Deep temporal nerves (CN V3 )

Temporalis

Zygomatic arch

Deep temporal arteries

Infratrochlear nerve (CN V1 )

Auriculotemporal nerve (CN V3 )

External nasal nerve (CN V1 )

Superficial temporal artery and vein

Zygom aticofacial nerve (CN V1 )

Lateral pterygoid

Infraorbital nerve (CN V1 )

Posterior superior alveolar nerve

Long buccal nerve (CN V3 )

Facial nerve (CN V1 )

Buccinator

Medial pterygoid

Lingual nerve (CN V3 )

Ram us of m andible

Mental nerve (CN V3 )

Inferior alveolar nerve (CN V3 )

Inferior alveolar artery

Fig. 5.15   Ne urovasculature  of the  late ral face Left lateral view. The m asseter and zygom atic arch have been windowed to reveal the deep structures. Also, the ram us and body of the

Masseter

m andible have been opened to dem onstrate neurovascular structures that traverse it.

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6. Tempora l, Infra tempora l, & Pterygopa la tine Fossa e

Temporal & Infratemporal Fossae: Contents Pterygopalatine fossa

Superior temporal line Inferior temporal line Frontal bone, zygom atic process

Fig. 6.1 Te mporal fossa Left lateral view. The tem poral fossa is located on the lateral aspect of the skull. It s boundaries are listed in Table 6.1. The tem poral fossa com m unicates with the infratem poral fossa inferiorly (m edial to the zygom atic arch). The pterygopalatine fossa can also be seen here m edial to the infratem poral fossa due to the rem oval of the zygom atic arch and som e of the zygom atic bone.

Zygom atic bone, frontal process Supram astoid crest

Zygom atic bone (cut)

Zygom atic arch (cut)

Infratemporal fossa Coronoid process

Inferior orbital fissure Sphenopalatine foram en

Temporal bone, zygom atic process

Temporal bone, squam ous part

Mandibular fossa Articular em inence External acoustic m eatus Foram en spinosum Foram en ovale Lateral pterygoid plate

Infratemporal surface of m axilla Maxillary tuberosit y

Medial pterygoid plate

Palatine bone, pyram idal process

Occipital condyle

Pterygoid ham ulus

Foram en m agnum

Maxilla, palatine process

Palatine bar, m axillary process

Pterygom axillary fissure

Fig. 6.2 Infrate mporal fossa Oblique external view of the base of the skull. The infratem poral fossa’s bony boundaries are listed in Table 6.3. The infratem poral fossa com m unicates medially with the pterygopalatine fossa via the pterygom axillary ssure; anteriorly with the orbit via the inferior orbit al ssure; superiorly with the m iddle cranial fossa via foram en ovale and foram en spinosum , and with the tem poral fossa passing m edial to the zygom atic arch.

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6. Tempora l, Infra tempora l, & Pterygopa la tine Fossa e

Occipitofrontalis, frontal belly (frontalis)

Temporal branches (CN VII)

Auriculotemporal nerve (CN V3 )

Zygom atic branch (CN VII)

Deep temporal artery

Zygom atic arch

Lateral pterygoid

Temporalis tendon

Lateral (temporom andibular) ligam ent

Coronoid process

Facial nerve

Parotid duct

Masseter (cut)

Fig. 6.3 Ne urovascular topog raphy of the te mporal fossa Left lateral view. Cut: Masseter. Revealed: Tem poral fossa and tem porom andibular joint. The m uscles and neurovasculature of the tem poral fossa are listed in Table 6.2.

Ta ble 6.1 Borde rs of the te mporal fossa

Ta ble 6.2 Muscles and ne urovasculature of the te mporal fossa

Superior

Superior and inferior tem poral lines

Muscle

Vasculature

Ne rve s

Inferior

Zygom atic arch (laterally); infratem poral crest of the greater wing of sphenoid bone (m edially)

Tem poralis

Super cial tem poral a. and v.

Auriculotem poral n. (CN V3 )

Anterior

Front al process of zygom atic bone; zygom atic process of frontal bone

Deep tem poral aa. and vv.

Deep tem poral nn. (CN V3 )

Posterior

Supram astoid crest

Medial

Sphenoid, tem poral, pariet al, and front al bones

Lateral

Tem poral fascia

Tem poral branches (CN VII)

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Infratemporal Fossa: Contents The infratem poral fossa is located lateral to the lateral pterygoid plate of the sphenoid, m edial to the ram us of the m andible, posterior to the m axilla, anterior to the st yloid process (and the carotid sheath and it s content s), and inferior to the greater wing of the sphenoid and a sm all part of the tem poral bone. It is continuous with the pterygopalatine

fossa (through the pterygom axillary ssure). The m axillary artery gives rise to it s m andibular (bony, rst part) and pterygoid (m uscular, second part) branches in the infratem poral fossa. The m andibular division of the trigem inal nerve (CN V3 ) divides into it s term inal branches in the infratem poral fossa.

Temporalis (cut)

Superficial tem poral artery and vein

Deep temporal nerves (CN V3 ) Deep temporal arteries

Superior alveolar nerves, posterior superior alveolar branches (CN V2 )

Auriculotemporal nerve (CN V3 )

Maxillary artery

Lateral pterygoid, superior and inferior heads

Buccal artery and long buccal nerve (CN V3 ) Medial pterygoid, superficial and deep heads

Facial nerve (CN VII)

Lingual nerve (CN V3 )

Ram us of m andible (cut)

Facial artery and vein

Inferior alveolar artery and nerve (CN V3 )

Masseter (cut)

Sternocleidom astoid Retrom andibular vein, posterior division

Fig. 6.4   Infrate mporal fossa, supe r cial disse ction Left lateral view. Removed: Masseter, anterior portion of the m andibular ram us, and zygom atic arch. The pterygoid plexus norm ally is em bedded bet ween the m edial and lateral pterygoids. It drains to the

Ta ble 6.3 Borde rs of the infrate mporal fossa Superior*

Inferior

m axillary vein, a tribut ary of the retrom andibular vein. The inferior alveolar artery and nerve can be seen entering the m andibular canal (the accom panying vein has been rem oved).

Ta ble 6.4 Muscles and ve ssels of the infrate mporal fossa

Inferior surface of the greater wing of the sphenoid bone Squam ous part of the tem poral bone (sm all contribution)

Muscles

Arte rie s

Ve ins

Lateral and m edial pterygoids

Pterygoid plexus and it s tribut aries

Dem arked by an im aginary line that is an inward extension of the m andibular plane

Tem poralis tendon

Maxillary a. • Mandibular branches • Pterygoid branches

Maxillary v.

Anterior

Infratem poral surface of the m axilla

Deep facial v. (deep portion)

Posterior

St yloid process and content s of carotid sheath

Em issary vv.

Medial

Lateral surface of the lateral pterygoid plate and pyram idal process of the palatine bone

Lateral

Medial surface of the ram us of the m andible

* The infratem poral crest separates the roof from the tem poral fossa above.

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Superficial temporal artery and vein

Temporalis (cut) Deep tem poral nerves (CN V3 )

Lateral pterygoid (cut)

Infraorbital artery

Auriculotemporal nerve

Sphenopalatine artery Posterior superior alveolar artery

Trigem inal nerve, m andibular division (CN V3 )

Buccal artery and long buccal nerve (CN V3 )

Middle m eningeal artery

Buccinator Medial pterygoid, superficial head

Maxillary artery

Lingual nerve (CN V3 )

Medial pterygoid, deep head

Facial artery and vein

Facial nerve (CN VII)

Masseter (cut)

Inferior alveolar artery and nerve (CN V3 )

Fig. 6.5 Infrate mporal fossa, de e p disse ction Left lateral view. Removed: Both heads of the lateral pterygoid m uscle. The branches of the m axillary artery and m andibular division of the trigem inal nerve (CN V3 ) can be identi ed. Note: By careful observation, it is possible to de ne the site where the auriculotem poral nerve (branch

of the m andibular division) split s around the m iddle m eningeal artery before the artery enters the m iddle cranial fossa through the foram en spinosum . Branches of the third part of the m axillary artery can be observed in the pterygopalatine fossa, which is m edial to the infratem poral fossa.

Ta ble 6.5 Ne rves in the infrate mporal fossa CN V3

Trunk of CN V3 and direct branches: • Recurrent m eningeal branch (nervus spinosus) • Medial pterygoid n. • Tensor veli palatini • Tensor t ympani

CN V2

Posterior superior alveolar n.

Othe r

Otic ganglion

Anterior division: • Masseteric n. • Deep tem poral nn. • Long buccal n. • Lateral pterygoid n.

Posterior division: • Auriculotem poral n. • Lingual n. • Inferior alveolar n. • Mylohyoid n.

Lesser petrosal n. (CN IX)

Chorda t ym pani (CN VII)

The anterior aspect of t he infratem poral fossa is the site of needle placem ent for a posterior superior alveolar nerve block (p. 477).

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Muscles of Mastication: Overview The m uscles of m astication are located at various depths in the parotid and infratem poral regions of the face. They at t ach to the m andible and

receive their m otor innervation from the m andibular division of the trigem inal nerve (CN V3 ).

Ta ble 6.6 Massete r and te mporalis muscles Muscle

Masseter

Orig in

Inse rtio n

Inne rvation*

Actio n

Super cial head

Zygom atic bone (m axillary process) and zygom atic arch (lateral aspect of anterior ⅔)

Mandibular angle and ram us (inferior lateral surface)

Masseteric n. (anterior division of CN V3 )

Elevates m andible; also assist s in protraction, retraction, and side-to-side m otion

Middle head

Zygom atic arch (m edial aspect of anterior ⅔)

Mandibular ram us (central part of occlusal surface)

Zygom atic arch (deep surface of posterior ⅓)

Mandibular ramus (superior lateral surface) and inferior coronoid process

Tem poral fascia

Coronoid process of m andible (apex, m edial surface, and anterior surface of m andibular ram us)

Deep temporal nn. (anterior division of CN V3 )

Vertical (anterior) f bers: Elevate m andible Horizontal (posterior) f bers: Retract (retrude) m andible Unilateral: Lateral m ovem ent of m andible (chewing)

Deep head

Tem poralis

Super cial head Deep head

Tem poral fossa (inferior tem poral line)

* The m uscles of m astication are innervated by m otor branches of the m andibular nerve (CN V3 ), the 3rd division of the trigem inal nerve (CN V).

Fig. 6.6 Massete r

Fig. 6.7 Te mporalis

Fig. 6.8 Pte ryg oids

Ta ble 6.7 Late ral and me dial pte ryg oid muscles Muscle

Lateral pterygoid

Medial pterygoid

Orig in

Inse rtion

Inne rvation

Actio n

Superior (upper) head

Greater wing of sphenoid bone (infratemporal crest)

Mandible (pterygoid fovea) and temporomandibular joint (articular disk)

Lateral pterygoid nerve (anterior division of CN V3 )

Inferior (lower) head

Lateral pterygoid plate (lateral surface)

Mandible (pterygoid fovea and condylar process)

Bilateral: Protrudes m andible (pulls articular disk forward) and opens m outh. Unilateral: Alternating actions, along with ipsilateral m edial pterygoid, result in side-to -side m ovem ent s necessary for grinding.

Super cial (external) head

Maxilla (m axillary tuberosit y) and palatine bone (pyram idal process)

Pterygoid rugosit y on m edial surface of the m andibular angle

Medial pterygoid nerve (anterior division of CN V3 )

Deep (internal) head

Medial surface of lateral pterygoid plate and pterygoid fossa

Bilateral: Elevation of m andible; also act s with lateral pterygoid to assist in protrusion of m andible. Unilateral: Act s with ipsilateral lateral pterygoid to protrude m andible and produce m edial m ovem ent toward the opposite side. Alternating actions bet ween right and left sides result s in side-to -side chewing m ovem ent s.

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Zygom atic arch

Frontal bone

6. Tempora l, Infra tempora l, & Pterygopa la tine Fossa e

Parietal bone Inferior tem poral line Superior temporal line

Masseter, deep part

Temporalis

Temporal bone External acoustic m eatus Mastoid process Zygom atic arch (cut)

Joint capsule of temporom andibular joint

Temporalis

St yloid process A

Masseter, superficial part

Lateral ligam ent

Fig. 6.9 Te mporalis and massete r Left lateral view. A Super cial dissection. B Deep dissection. The m asseter and zygom atic arch have been partially rem oved to show the full extent of the tem poralis. The tem poralis is the m ost powerful m uscle of m astication, doing approxim ately half the work. It works with the m asseter (consisting of a super cial, an interm ediate, and a deep part) to elevate the m andible and close the m outh. Note: A sm all portion of the lateral pterygoid is visible in B. These m uscles, along with the other m uscles of m astication, m ay becom e hypertrophied in bruxism, a condition in which an individual clenches or grinds their teeth. The m uscles m ay be tender and painful, especially during chewing. Spasm of the m uscles causes trismus (restricted m outh opening) and it m ay be difcult for the dentist to retract the cheek (due to m asseter hypertrophy and spasm ). Other sym ptom s of bruxism include tem porom andibular joint pain, excessive tooth wear, and tooth fracture.

Joint capsule of temporom andibular joint Lateral (temporom andibular) ligam ent Lateral pterygoid

B

Coronoid process

Masseter (cut)

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Muscles of Mastication: Deep Muscles

Temporalis (cut)

Lateral pterygoid, superior head (cut)

Lateral pterygoid, superior head

Articular disk

Temporom andibular joint capsule

Lateral pterygoid, inferior head (cut)

Lateral pterygoid, inferior head

Medial pterygoid, deep (internal) head

Medial pterygoid (superficial and deep heads)

Pterygoid process, lateral plate

Masseter (cut) A

B

Fig. 6.10 Late ral and me dial pte rygoid muscles Left lateral views. A The coronoid process of the m andible has been rem oved here along with the lower part of the tem poralis so that both pterygoid m uscles are observed (see Fig . 6.9B). B Here the tem poralis has been com pletely rem oved, and the inferior head of the lateral pterygoid has been windowed. The lateral pterygoid initiates depression of the m andible, which is then continued by the supra hyoid and infrahyoid m uscles and gravit y. With

Medial pterygoid, superficial (external) head

the tem porom andibular joint opened, we can see that bers from the superior head of the lateral pterygoid blend with the articular disk. The lateral pterygoid functions as the guide m uscle of the tem porom andibular joint. The medial pterygoid runs alm ost perpendicular to the lateral pterygoid and contributes to the for m ation of a m uscular sling that partially encom passes the m andible (see Fig . 6.11). Note how the inferior head of the lateral pterygoid originates bet ween the t wo heads of the m edial pterygoid.

Lateral pterygoid plate Tem poralis

Temporalis Upper and lower compartm ent s Lateral pterygoid, superior head

Articular disk Head (condyle) of m andible, articular surface

Lateral pterygoid, inferior head

Coronoid process (with temporalis)

Fig. 6.11 Masticatory muscular sling Oblique posterior view. The m asseter and medial pterygoid form a m uscular sling in which the m andible is suspended. By com bining the actions of both m uscles into a functional unit, this sling enables powerful closure of the jaws and side-to-side m ovem ent s when acting unilaterally. Note: The space bet ween the m edial border of the m andible and the m edial pterygoid is referred to as the pterygom andibular space. It is im port ant as it is the t arget area for adm inistering local anesthesia to the inferior alveolar nerve.

Masseter, deep head Medial pterygoid, deep (internal) head Masseter, superficial head Angle of m andible Pterygom andibular space

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Superior sagit tal sinus

Falx cerebri

Frontal lobe

Inferior sagit tal sinus

Superficial and deep temporal fascia

Dura m ater

Temporal lobe Optic nerve (CN II)

Ethm oid air cells

Tem poralis (deep and superfical heads)

Sphenoid sinus

Lateral pterygoid, superior head

Zygom atic arch

Masseter, deep head

Coronoid process Nasopharynx

Lateral pterygoid, inferior head Lateral pterygoid plate

Parotid gland

Medial pterygoid (deep and superficial heads)

Oropharynx

Masseter, superficial head

Tongue

Inferior alveolar nerve (from posterior division of CN V3 ) in m andibular canal

Mandible

Lingual septum

Subm andibular gland (extraoral lobe)

Plat ysm a

Geniohyoid

Fig. 6.12 Muscles of mastication, coronal se ction at the level of the sphe noid sinus Posterior view. The topography of the m uscles of m astication and neighboring structures is particularly well displayed in this section. The m uscles of m astication can be bim anually palpated to assess for hypertrophy or tenderness. To palpate the tem poralis, the clinician places his ngers over the tem poral region and works his way down the length of this m uscle from superior to inferior; to palpate the m asseter

Hyoglossus

Digastric, anterior belly

Mylohyoid

the patient is asked to put their teeth together without clenching while the clinician palpates over the lateral cheek from superior to inferior; the lateral pterygoid is palpated by the clinician placing his index or little nger in the buccal sulcus as far posteriorly as possible and palpating in a posterior, superior, and m edial direction (it is a source of som e debate whether this actually allows for palpation of the lateral pterygoid); the m edial pterygoid is palpated along the m edial border of the body and angle of the m andible.

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Temporomandibular Joint (TMJ)

Foram en spinosum

Temporal process, zygom atic bone Medial and lateral pterygoid plates Foram en ovale (conducts CN V3 )

Zygom atic process, temporal bone

Articular tubercle (em inence)

Spine of sphenoid bone Petrot ympanic fissure Tympanosquam osal fissure St yloid process

Mandibular (glenoid) fossa External acoustic m eatus (auditory canal)

Mastoid process

St ylom astoid foram en Jugular foram en

Fig. 6.13 Mandibular (gle noid) fossa of the TMJ Inferior view. The head of the m andible articulates with the articular disk in the m andibular (glenoid) fossa of the tem poral bone. The m andibular fossa is a depression in the squam ous part of the tem po ral bone. The articular tubercle is located on the anterior side of the m andibular fossa. The head of the m andible is m arkedly sm aller than the m andibular fossa, allowing it to have an adequate range of m ovem ent. Unlike other articular surfaces, the m andibular fossa is covered by bro cartilage rather than hyaline cartilage. As a result, it is not as

Carotid canal

clearly delineated on the skull as other articular surfaces. The external auditory canal lies just posterior to the m andibular fossa. Traum a to the m andible m ay dam age the auditory canal. Note: The m andibular fossa is divided into t wo com partm ent s (anterior and posterior), separated by the t ym panosquam osal and petrot ym panic ssures. The posterior com partm ent is nonarticulatory, and the chorda t ym pani nerve and anterior t ym panic artery are able to pass through this space without being com pressed. The glenoid lobe of the parotid gland m ay also project into the posterior com partm ent.

Head of m andible

Joint capsule

Pterygoid fovea

Neck of m andible

Coronoid process Neck of m andible

Lateral (tem porom andibular) ligam ent

Lingula St ylom andibular ligam ent

Mandibular foram en

A

B

Mylohyoid groove

Fig. 6.14 Processes of the mandible A Anterior view. B Posterior view. The head of the m andible not only is m arkedly sm aller than the articular fossa but also has a cylindrical shape. This shape increases the m obilit y of the m andibular head, as it allows rotational m ovem ent s about a vertical axis (condular–hinge axis).

Fig. 6.15 Ligame nts of the left TMJ Lateral view. The TMJ is surrounded by a relatively lax capsule, which perm it s physiological dislocation during jaw opening. The joint is st abilized by three ligam ent s: lateral (tem porom andibular), st ylo m andibular, and sphenom andibular (see Fig. 6.16). This lateral view dem onstrates the strongest of these ligam ent s, the lateral ligam ent, which stretches over the capsule and is blended with it.

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Lateral pterygoid plate

Articular tubercle (em inence)

Pterygospinous ligam ent (variable)

Articular disk

Mandibular notch

Joint capsule

Sphenom andibular ligam ent

Head (condyle) of m andible

St ylom andibular ligam ent

St ylom andibular ligam ent

Mandibular foram en Medial pterygoid plate

Fig. 6.16 Ligame nts of the rig ht TMJ Medial view. The sphenom andibular ligam ent can be identi ed in this view.

Fig. 6.17 Ope ne d left TMJ Lateral view. The capsule extends posteriorly to the petrot ym panic ssure (not shown here). Interposed bet ween the m andibular head and fossa is the articular disk, which is at t ached to the joint capsule on all sides. Note: The articular disk (m eniscus) divides the TMJ into upper and lower com partm ent s. Gliding (translational) m ovem ent occcurs in the upper com partm ent, hinge (rot ational) m ovem ent in the lower com partm ent.

Articular tubercle (em inence) Auriculotemporal nerve

Posterior division

Mandibular nerve (CN V3 ) Anterior division Posterior deep temporal nerve

Mandibular fossa

Masseteric nerve

Fig. 6.18 Dislocation of the TMJ The head of the m andible m ay slide past the articular tubercle when the m outh is opened, dislocating the TMJ. This m ay result from heavy yawning or a blow to the opened m andible. When the joint dislocates, the m andible becom es locked in a protruded position and can no longer be closed. This condition is easily diagnosed clinically and is reduced by pressing on the m andibular row of teeth.

Fig. 6.19 Se nsory inne rvation of the TMJ capsule (after Schm idt) Superior view. The TMJ capsule is supplied by articular branches arising from three branches of the m andibular division of the trigem inal nerve (CN V3 ): • Auriculotem poral nerve (posterior division of CN V3 ) • Posterior deep temporal nerve (anterior division of CN V3 ) • Masseteric nerve (anterior division of CN V3 ) Note: While the m asseteric and posterior deep tem poral nerves are generally considered to be m otor nerves, they also innervate the TMJ.

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Temporomandibular Joint (TMJ): Biomechanics

Retrusion

Transverse axis through head of m andible (axis of rotation)

150°

A

Head (condyle) of m andible

B

Median plane

Protrusion

Axis of rotation

Axis of rotation

Resting condyle Swinging condyle

Balance side (m ediotrusion)

Working side (laterotrusion) Working side

C

Bennet t angle

Fig. 6.20 Move me nts of the mandible in the TMJ Superior view. Most of the m ovem ent s in the TMJ are com plex m otions that have three m ain com ponent s: • Rot ation (opening and closing the m outh) • Translation (protrusion and retrusion of the m andible) • Grinding m ovem ent s during m astication A Ro tatio n. The axis for joint rot at ion runs t ransversely t hrough bot h heads of t he m andible. The t wo axes intersect at an angle of approxim ately 150 degrees (range of 110–180 degrees bet ween individuals). During t his m ovem ent t he TMJ act s as a hinge joint (abduct ion/depression and adduct ion/elevat ion of t he m andible). In hum ans, pure rot at ion in t he TMJ usually occurs only during sleep wit h t he m out h slight ly open (apert ure angle up to approxim ately 15 degrees, see Fig . 6.21B). When t he m out h is opened past 15 degrees, rot at ion is com bined with t ranslat ion (gliding) of t he m andibular head.

Balance side

D

B Translatio n. In this m ovem ent the m andible is advanced (protruded) and retracted (retruded). The axes (condylar–hinge axes) for this m ovem ent are parallel to the m edian axes through the center of the m andibular heads. C Grinding movements in the left TMJ. In describing these lateral movements, a distinction is made bet ween the “resting condyle” and the “swinging condyle.” The resting condyle on the left working side rotates about an almost vertical axis through the head of the mandible (also a rotational axis), whereas the swinging condyle on the right balance side swings forward and inward in a translational movement. The lateral excursion of the mandible is measured in degrees and is called the Bennett angle. During this movement the mandible moves in laterotrusion on the working side and in mediotrusion on the balance side. D Grinding move me nts in the rig ht TMJ. Here, the right TMJ is the working side. The right resting condyle rotates about an alm ost vertical axis, and the left condyle on the balance side swings forward and inward.

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Lateral pterygoid, superior head

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Articular tubercle (em inence) Mandibular (glenoid) fossa Articular disk Head of m andible Joint capsule Lateral pterygoid, inferior head

A Lateral pterygoid, superior head Articular disk Head of m andible Joint capsule Lateral pterygoid, inferior head

15°

Axis of rotation

B Lateral pterygoid, superior head

Mandibular (glenoid) fossa Articular disk Joint capsule Lateral pterygoid, inferior head

>15°

C

Fig. 6.21 Move me nts of the TMJ Left lateral view. Each drawing shows the left TMJ (including the articular disk and capsule) and the lateral pterygoid m uscle. Note: The gap bet ween the heads of the lateral pterygoid is exaggerated. Each schem atic diagram at right shows the corresponding axis of joint m ovem ent. The m uscle, capsule, and disk form a functionally coordinated m usculo -disco -capsular system and work closely together when the m outh is opened and closed. A Mouth close d, te e th in occlusion. When the m outh is in the closed position with teeth in occlusion, the head (condyle) of the m andible m aint ains it s cont act with the articular disk, and the space of the up -

per com partm ent is m aint ained bet ween the articular disk and the m andibular (glenoid) fossa of the tem poral bone. B Mouth ope ne d to 15 de g re es. Up to 15 degrees of abduction, the head of the m andible rem ains in the m andibular fossa. C Mouth ope ne d past 15 de g re es. At this point the head of the m andible glides (translates) forward onto the articular tubercle (em inence). The joint axis that runs transversely through the m andibular head is shifted forward. The articular disk is pulled forward by the superior part of the lateral pterygoid m uscle, and the head (condyle) of the m andible is drawn forward by the inferior part of that m uscle.

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Pterygopalatine Fossa: Overview

Frontal bone, zygom atic process

Greater wing of sphenoid bone, temporal surface

Temporal bone, squam ous part

Ethm oid bone Sphenosquam ous suture

Sphenopalatine foram en

Pterygopalatine fossa

Zygom atic bone Maxillary tuberosit y

A

Pterygoid ham ulus, m edial pterygoid plate

Lateral pterygoid plate Inferior orbital fissure

Fig. 6.22 Pte ryg opalatine fossa A Left lateral view of left infratem poral fossa and pterygopalatine fossa. B Inferior view of right infratem poral fossa and lateral approach to pterygopalatine fossa. The pterygopalatine fossa is a crossroads bet ween the orbit, nasal cavit y, oral cavit y, nasopharynx, and m iddle cranial fossa. It is traversed by m any nerves and vessels supplying these structures. The pterygopalatine fossa is continuous laterally with the infratem poral fossa through the pterygopalatine ssure. The lateral approach through the infratem poral fossa is used in surgical operations on tum ors of the pterygopalatine fossa (e.g., nasopharyngeal brom a).

Lateral approach to pterygopalatine fossa

Greater wing of sphenoid bone, infratemporal surface

Choana Palatine bone, pyram idal process

Infratemporal crest

Medial pterygoid plate

Lateral pterygoid plate Foram en spinosum

B

Foram en ovale

Ta ble 6.8 Borde rs and ope nings of the pte ryg opalatine fossa Borde r

Structure

Fo rame n/ ssures/canals

Superior

Sphenoid bone (greater wing)

Inferior orbit al ssure (runs beside sphenoid bone in roof of pterygopalatine fossa)

Inferior

Greater palatine canal

Greater palatine canal (continuous with pterygopalatine fossa)

Anterior

Maxilla (infratem poral [posterior] surface)

Posterior

Sphenoid, root of the pterygoid process

Foram en rotundum Pterygoid (vidian) canal Palatovaginal (pharyngeal) canal

Medial

Palatine bone (perpendicular plate)

Sphenopalatine foram en

Lateral

Pterygom axillary ssure

Pterygom axillary ssure

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Fig. 6.23 Communications of the pte ryg opalatine fossa Left lateral view of left fossa (det ail from Fig. 6.22A). The pterygopalatine fossa contains the pterygopalatine ganglion, the parasym pathetic ganglion of CN VII that is a liated with the m axillary nerve (CN V2 , sensory). Sensory bers from the face, m axillary dentition, nasal cavit y, oral cavit y, nasopharynx, and paranasal sinuses pass through the ganglion without synapsing and enter the m iddle cranial fossa as the m axillary nerve (CN V2 ). These sensory bers also serve as “sca olding” for the peripheral distribution of postganglionic autonom ic parasym pathetic bers from the pterygopalatine ganglion and postganglionic sym pathetic bers derived from the internal carotid plexus. See Table 4.23 for a com plete treatm ent of the m axillary nerve and pterygopalatine ganglion.

Foram en rotundum (from m iddle cranial fossa)

Inferior orbital fissure (to orbit) Sphenopalatine foramen (to nasal cavit y)

Pterygoid canal (from m iddle cranial fossa)

Greater palatine canal (to oral cavit y)

Palatovaginal (pharyngeal) canal from nasopharynx Pterygopalatine fossa

Ta ble 6.9 Communications of the pte ryg opalatine fossa Communication

Dire ctio n

Via

Transmitte d structure s

Middle cranial fossa

Posterosuperiorly

Foram en rotundum

• Maxillary n. (CN V2 )

Middle cranial fossa

Posteriorly in anterior wall of foram en lacerum

Pterygoid (vidian) canal

• N. of pterygoid canal, form ed from : ◦ Greater petrosal n. (preganglionic parasym pathetic bers from CN VII) ◦ Deep petrosal n. (postganglionic sym pathetic bers from internal carotid plexus) • A. of pterygoid canal • Vv. of pterygoid canal

Orbit

Anterosuperiorly

Inferior orbit al ssure

• Branches of m axillary n. (CN V2 ): ◦ Infraorbit al n. ◦ Zygom atic n. • Infraorbit al a. and vv. • Com m unicating vv. bet ween inferior ophthalm ic v. and pterygoid plexus of vv.

Nasal cavit y

Medially

Sphenopalatine foram en

• Nasopalatine n. (CN V2 ), lateral and m edial superior posterior nasal branches • Sphenopalatine a. and vv.

Oral cavit y

Inferiorly

Greater palatine canal (foram en)

• Greater (descending) palatine n. (CN V2 ) and a. • Branches that em erge through lesser palatine canals: ◦ Lesser palatine nn. (CN V2 ) and aa.

Nasopharynx

Inferoposteriorly

Palatovaginal (pharyngeal) canal

• CN V2 , pharyngeal branches, and pharyngeal a.

Infratem poral fossa

Laterally

Pterygom axillary ssure

• Maxillary a., pterygopalatine (third) part • Posterior superior alveolar n., a., and v.

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Topography of the Pterygopalatine Fossa

The pterygopalatine fossa is a sm all inverted pyram idal space just inferior to the apex of the orbit. It is continuous with the infratem poral fossa through the pterygopm axillary ssure. The pterygopalatine fossa

is a crossroads for neurovascular structures traveling bet ween the m iddle cranial fossa, orbit, nasal cavit y, and oral cavit y.

Pterygom axillary fissure

S Inferior orbital fissure

F

A D

Zygom atic process (cut)

G Pterygoid process, lateral plate

Lesser palatine artery Greater palatine artery

Fig. 6.24 Arte ries in the pte ryg opalatine fossa Left lateral view into area. The m axillary artery passes either super cial

Maxillary artery

or deep to the lateral pterygoid in the infratem poral fossa and enters the pterygopalatine fossa through the pterygom axillary ssure.

Ta ble 6.10 Branche s of the maxillary arte ry w ithin the pte ryg opalatine fossa Part of maxillary arte ry Pterygopalatine part

Arte ry

Distributio n

Infraorbit al a.

Cheek, upper lip, nose, lower eyelid

Sphenopalatine a.

Anterior and m iddle superior alveolar aa.

Maxillary anterior teeth (to prem olars), m axillary sinus

Lateral posterior nasal aa.

Lateral wall of nasal cavit y, choanae, paranasal sinuses (front al, m axillary, ethm oidal, and sphenoidal)

Posterior sept al branches

Nasal septum and conchae

Posterior superior alveolar a.

Maxillary prem olars, m olars, gingiva, m axillary sinus

A. of pterygoid canal

Pharygot ym panic (auditory) tube, t ym panic cavit y, upper pharynx

Descending palatine a.

Greater palatine a.

Hard palate, nasal cavit y (inferior m eatus), m axillary gingiva

Lesser palatine a.

Soft palate, palatine tonsil, pharyngeal wall

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6. Tempora l, Infra tempora l, & Pterygopa la tine Fossa e

A

Ganglionic branches

Inferior orbital fissure

D S

F K

Posterior superior alveolar nerve

G

Pterygopalatine ganglion

K H

Pharyngeal nerve

J

Fig. 6.25 Ne rves in the pte ryg opalatine fossa Left lateral view. The m axillary division of the trigem inal nerve (CN V2 ) passes from the m iddle cranial fossa through the foram en rotundum into the pterygo palatine fossa (see Table 6.11). The parasym pathetic pterygopalatine ganglion receives presynaptic bers from the greater petrosal nerve

(the parasym pathetic root of the nervus interm edius branch of the facial nerve). The preganglionic bers of the pterygopalatine ganglion synapse with ganglion cells that innervate the lacrim al, sm all palat al, and sm all nasal glands. The sym pathetic bers of the deep petrosal nerve (sensory root) pass through the pterygoapaltine ganglion without synapsing.

Ta ble 6.11 Ne rves that e me rg e from pte rygopalatine fossa* Transmitte d nerves

Distribution

Infraorbit al n.

Sensory to lower eyelid, m axillary sinus, and upper incisors, canines, and prem olars.

Zygom atic n.

Sensory to skin of the tem ple (zygom aticotem poral n.) and cheek (zygom aticofacial n.)

Orbit al branches (from CN V2 )

Sensory to orbit al periosteum , sphenoid sinus, and ethm oidal air cells

Maxillary n. (CN V2 )

Gives o only sensory branches within pterygopalatine fossa

N. of pterygoid canal (vidian n.)

• Greater petrosal n. carries preganglionic parasym pathetic bers to the pterygopalatine ganglion (from CN VII); • Deep petrosal n. carries postganglionic sym pathetic bers to the ptergopalatine ganglion

Greater palatine n.

Sensory to gingiva, m ucosa, and glands of the posterior t wo thirds of the hard palate

Lesser palatine nn.

Sensory to soft palate, palatine tonsils, and uvula

Medial and lateral posterior superior and posterior inferior nasal branches (from nasopalatine n., CN V2 )

Sensory to the posterosuperior nasal cavit y; m edial branches also sensory to posterior nasal roof and septum ; lateral branches also sensory to posterior ethm oid air cells and m ucosa overlying the superior and m iddle nasal conchae

*Because the pterygopalatine fossa cont ains all branches of CN V2 , it is the site of needle placem ent for a m axillary division block (see p. 478)

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Nose: Nasal Skeleton

Nasom axillary suture

Major alar cartilage, lateral crus

Glabella Nasion

Major alar cartilage, m edial crus

Nasal bone Maxilla, frontal process

Naris

Lateral nasal cartilage

Nasal ala

Septal cartilage

Major alar cartilage

Anterior nasal spine Minor alar cartilages

Fig. 7.1 Skeleton of the e xte rnal nose Left lateral view. The skeleton of the nose is com posed of bone, carti lage, and connective tissue. It s upper portion is bony and frequently involved in m idfacial fractures, whereas it s lower, distal portion is car tilaginous and therefore m ore elastic and less susceptible to injury. The proxim al lower portion of the nostrils (alae) is com posed of connective tissue with sm all em bedded pieces of cartilage. The lateral nasal carti lage is a winglike lateral expansion of the cartilaginous part of the nasal septum rather than a separate piece of cartilage.

Ethm oid bone Frontal bone

Fig. 7.2 Nasal cartilag e Inferior view. Viewed from below, each of the m ajor alar cartilages is seen to consist of a m edial and lateral crus. This view also displays the t wo nares, which open into the nasal cavities. The right and left nasal cavities are separated by the nasal septum , whose inferior cartilagi nous portion is just visible in the diagram .

Ethm oid bone, perpendicular plate

Sphenoid bone

Frontal bone

Sphenoid bone

Nasal bone

Nasal bone Occipital bone

Lacrim al bone

Occipital bone

Septal cartilage

Vom er Inferior nasal concha Incisive canal

Major alar cartilage

Maxilla

Palatine bone, perpendicular plate

Fig. 7.3 Bones of the late ral w all of the rig ht nasal cavity Left lateral view. The lateral wall of the right nasal cavit y is form ed by seven bones: the m axilla, nasal bone, ethm oid bone, inferior nasal con cha, palatine bone, lacrim al bone, and sphenoid bone. Of the nasal concha, only the inferior is a separate bone; the m iddle and superior conchae are part s of the ethm oid bone.

Maxilla, palatine process

Palatine bone, horizontal plate

Fig. 7.4 Bones of the nasal se ptum Parasagit t al section. The nasal septum is form ed by six bones. The eth m oid and vom er bones are the m ajor com ponent s of the septum . The sphenoid bone, palatine bone, m axilla, and nasal bone (roof of the sep tum ) contribute only sm all bony projections to the nasal septum .

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Regions of the Hea d

Anterior cranial fossa

Cribriform plate

7. Nose & Nasa l Ca vit y

Superior m eatus

Frontal sinus Crista galli

Sphenoid bone, lesser wing

Frontal bone

Middle cranial fossa

Nasal bone

Hypophyseal fossa

Lacrimal bone Sphenoid sinus

Maxilla, frontal process

Superior concha (ethm oid bone) Body of sphenoid bone

Anterior nasal aperture

Medial pterygoid plate, (sphenoid bone) Choana (posterior nasal aperture)

Middle m eatus

Lateral pterygoid plate (sphenoid bone) Inferior concha (independent bone) Maxilla, palatine process

Inferior m eatus

Middle concha (ethm oid bone)

Fig. 7.5 Late ral w all of the rig ht nasal cavity Medial view. Air enters the bony nasal cavit y through the anterior nasal aperture and travels through the three nasal passages: the superior m e atus, m iddle m eatus, and inferior m eatus, which are the spaces infero

Anterior cranial fossa

Palatine bone, horizontal plate

lateral to the superior, m iddle, and inferior conchae, respectively. Air leaves the nose through the choanae (posterior nasal apertures), enter ing the nasopharynx.

Cribriform plate

Crista galli Sphenoid sinus

Frontal sinus Nasal bone

Hypophyseal fossa

Ethm oid bone, perpendicular plate

Sphenoid crest Vom er

Septal cartilage

Choana

Major alar cartilage, m edial crus

Posterior process Nasal crest

Palatine bone, horizontal plate

Incisive canal

Maxilla, palatine process

Fig. 7.6 Nasal se ptum Parasagit tal section viewed from the left. The left lateral wall of the na sal cavit y has been rem oved with the adjacent bones. The nasal septum consist s of an anterior sept al cartilage and a posterior bony part com posed of several bones. The posterior process of the cartilaginous sep

tum extends deep into the bony septum . Deviations of the nasal septum are com m on and m ay involve the cartilaginous part of the septum , the bony part, or both. Cases in which the septal deviation is su cient to cause obstruction of nasal breathing can be surgically corrected.

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7. Nose & Nasa l Ca vit y

Overview of the Nasal Cavity & Paranasal Sinuses

Crista galli

Ethm oid air cells

Orbit Vitreous body

Ethm oid bulla

Sclera

Ethm oid, perpendicular plate

Middle nasal concha Infraorbital nerve Maxilla

Maxillary sinus

Cartilaginous nasal septum

Inferior nasal concha Inferior m eatus

Vom er

Root of m axillary tooth

Maxilla, palatine process

Alveolar process

Tongue

A

Oral cavit y

Anterior ethm oid air cells Ethm oid, perpendicular plate

Lens Vitreous body

Medial rectus

Orbit

Lateral rectus Optic nerve Posterior ethm oid air cells

Temporalis

Sphenoid sinus

Internal carotid artery

Temporal lobe Dorsum sellae B

Fig. 7.7 Ove rview of the nose and paranasal sinuses A Coronal section through nasal cavit y, anterior view. B Transverse section, inferior view. The nasal cavities and paranasal sinuses are arranged in pairs. The left and right nasal cavities are separated by the nasal septum and have an approxim ately triangular shape. Below the base of the triangle is the oral cavit y. Note the relations of the infraorbit al nerve and m axillary dentition to the m axillary sinus. The close proxim it y of the root s of the m axillary teeth (canine to sec ond m olar) to the m axillary sinus (antrum ) is very signi cant in clinical dentistry. Sinus pathology, for exam ple, acute m axillary sinusitis due to an upper respiratory infection (URTI), can often be confused as den t al pain originating from these teeth. diagnosis is m ade by exclusion of dent al pathology and observation of URTI sym ptom s, such as nasal dis

charge and stu ness. Furtherm ore, the pain of acute m axillary sinusitis is often worsened by bending the head forward. There would also be tenderness on palpation of the cheeks. The close proxim it y is also signi cant because the root s or the entire tooth can be displaced into the m axillary sinus during extractions, re quiring surgical rem oval (see Fig. 7.17). Extracted upper m olars m ay also cause an oro-antral stula, an abnorm al com m unication bet ween the oral cavit y and the m axillary si nus. Post-extraction re ux of uids into the nose or m inor nosebleeds should raise the dentist's index of suspicion of this condition. Diagno sis is con rm ed by get ting the patient to hold their nose and blow: air bubbles will be seen at the tooth socket. Sm all oro-antral stulas close spont aneously; others require suturing of the m ucosal ap.

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Regions of the Hea d

Frontal sinus

Ethm oid air cells

Frontal sinus

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Ethm oid air cells

Age 20 Age 12 Age 8 Age 1

Age 4

Age 4

Age 1

Age 8 Age 12 Age 20 Age 60+ Maxillary sinus

A

B

Maxillary sinus

Sphenoid sinus

Fig. 7.8 Proje ction of the paranasal sinuses onto the skull A Anterior view. B Left lateral view. The paranasal sinuses are air- lled cavities that reduce the weight of the skull. They are subject to in am m ation that m ay cause pain over the a ected sinus (e.g., front al headache due to front al sinusitis). Knowing the location and sensory supply of the sinuses is helpful in m aking the correct diagnosis.

Anterior cranial fossa

Cribriform plate

Crista galli

Frontal sinus

Fig. 7.9 Pne umatization of the maxillary and frontal sinuses Anterior view. The front al and m axillary sinuses develop gradually dur ing the course of cranial growth (pneum atization), unlike the ethm oid air cells, which are already pneum atized at birth. As a result, sinusitis in children is m ost likely to involve the ethm oid air cells (with risk of or bit al penetration: red, swollen eye).

Ethm oid bone, perpendicular plate Superior m eatus and concha

Ethm oid bone, orbital plate

Nasal septum

Nasal cavit y

Orbit Middle m eatus and concha

Middle ethm oid air cells

Ostium of m axillary sinus

Maxilla

Mucosal folds on the m iddle turbinate

Septum

Uncinate process

Inferior m eatus Inferior concha

Maxillary sinus

Maxillary sinus

Vom er

Fig. 7.10 Bony structure of the paranasal sinuses Anterior view. The central structure of the para nasal sinuses is the ethm oid bone (red). It s cribriform plate form s a portion of the anterior skull base. The frontal and m axil lary sinuses are grouped around the ethm oid bone. The inferior, m iddle, and superior m e atuses of the nasal cavit y are bounded by the accordingly nam ed conchae. The bony ostium of the m axillary sinus opens into the m iddle m eatus, lateral to the m iddle concha. Below the m iddle concha and above the m axillary sinus ostium is the ethm oid bulla, which con

Maxilla, palatine process

tains the m iddle ethm oid air cells. At it s an terior m argin is a bony hook, the uncinate process, which bounds the m axillary sinus os tium anteriorly. The m iddle concha is a useful landm ark in surgical procedures on the m ax illary sinus and anterior ethm oid. The lateral wall separating the ethm oid bone from the orbit is the paper thin orbit al plate (= lam ina papyracea). In am m atory processes and tum ors m ay penetrate this thin plate in either direction. Note: The m axilla form s the oor of the orbit and roof of the m axillary sinus. In addition, root s of the m axillary dentition m ay project into the m axillary sinus.

Cavernous sinus

Sphenoid sinus Pituitary gland

Internal carotid artery

Fig. 7.11 Nasal cavity and paranasal sinuses Transverse section viewed from above. The m ucosal surface anatomy has been left intact to show how narrow the nasal passages are. Even relatively m ild swelling of the m ucosa m ay obstruct the nasal cavit y, im peding aera tion of the paranasal sinuses. The pituit ary gland, located behind the sphe noid sinus in the hypophyseal fossa, is acces sible via transnasal surgical procedures.

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Nasal Cavity Anterior cranial fossa

Cribriform plate

Orifices of posterior ethm oid air cells

Sphenoethm oidal recess

Frontal sinus

Superior nasal concha (cut)

Crista galli Frontal bone

Hypophyseal fossa

Nasal bone

Sphenoid sinus

Frontonasal duct Sphenopalatine foram en

Ethm oid bulla

Sphenoid bone

Lacrim al bone Uncinate process Maxilla, frontal process Sem ilunar hiatus Inferior nasal concha (cut)

Medial pterygoid plate

Opening of nasolacrim al canal Maxilla, palatine process A

Oral cavit y

Maxillary hiatus

Cut edge of m iddle nasal concha (ethm oid bone)

Palatine bone, perpendicular plate

Fig. 7.12 Rig ht nasal cavity A Sagit tal section, m edial view, with conchae rem oved to reveal the openings of the nasolacrim al duct and the paranasal sinuses. B Drainage of the nasolacrim al duct and the paranasal sinuses (see Table 7.1); ar rows indicate ow of m ucosal secretions into the nasal cavit y.

B

Ta ble 7.1 Drainage of the nasolacrimal duct and the paranasal sinuses Duct/Sinuses

Via

Drains to

Nasolacrim al duct (red)

Nasolacrim al canal

Inferior m eatus

Front al sinus (yellow)

Frontonasal duct

Middle m eatus

Maxillary sinus (orange)

Direct

Middle m eatus

Posterior ethm oid air cells (green)

Direct

Superior m eatus

Sphenoid sinus (blue)

Direct

Sphenoethm oid recess

Anterior and m iddle ethm oid air cells (green)

Fig. 7.13 Oste ome atal unit (comple x) Coronal section. Arrows indicate ow of m ucosal secretions. The osteom eatal unit (com plex) is that part of the m iddle m eatus into which the frontal and m ax illary sinuses drain along with the anterior and m iddle ethm oid air cells. When the m ucosa (ciliated respira tory epithelium ) in the ethm oid air cells (green) be com es swollen due to in am m ation (sinusitis), it blocks the ow of secretions from the front al sinus (yellow) and m axillary sinus (orange) in the osteom e at al unit (red). Because of this blockage, m icroorgan ism s also becom e trapped in the other sinuses, where they m ay incite an in am m ation. Thus, whereas the anatom ical focus of the disease lies in the ethm oid air cells, in am m atory sym ptom s are also m anifested in the front al and m axillary sinuses. In patient s with chronic sinusitis, the narrow sites can be surgically wid ened to est ablish an e ective drainage route.

Frontal sinus Orbit Nasal cavit y

Superior concha Ethm oid air cells

Middle concha

Nasal septum Maxillary sinus Inferior concha

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Ostium

Frontal sinus

Ethm oid sinus

7. Nose & Nasa l Ca vit y

Sphenoid sinus

Posterior wall of frontal sinus

Choanae

A

Medial wall of m axillary sinus

Ostium Nasopharynx

B

Ethm oid infundibulum

Fig. 7.14   Ciliary beating  and f uid f ow  in the  rig ht maxillary and  frontal sinuses Schem atic coronal sections of the right m axillary sinus (A) and front al sinus (B), anterior view. Beating of the cilia produces a ow of uid in the paranasal sinuses that is always directed toward the sinus ostium . This clears the sinus of par ticles and m icroorganism s that are trapped in the m ucous layer. If the ostium is obstructed due to swelling of the m ucosa, in am m ation m ay develop in the a ected sinus (sinusitis). This occurs m ost com m only in the osteom eat al com plex of the m iddle m eatus.

Maxillary sinus

Fig. 7.15 Normal drainag e of se cre tions from the paranasal sinus Left lateral view. The beating cilia propel the m ucous blanket over the cilia and through the choana into the nasopharynx, where it is swallowed.

Orom axillary opening

Trocar

Interior of m axillary sinus Endoscope

Fig. 7.16 Endoscopy of the maxillary sinus Anterior view. The m axillary sinus is not accessible to direct inspection and m ust therefore be exam ined with an endoscope. To enter the m ax illary sinus, the exam iner pierces the thin bony wall below the inferior concha with a trocar and advances the endoscope through the open ing. The scope can then be angled and rot ated to inspect all of the m ucosal surfaces. At t achm ent of a suction device also facilit ates the drainage of secretions. Drainage of the m axillary sinus can also be achieved via the Caldwell Luc procedure (see Fig. 7.17).

Fig. 7.17 Caldw ell-Luc Proce dure In the Caldwell Luc procedure, a window (fenestration) is created in the anterior wall of the m axillary sinus. It is used to rem ove teeth or tooth root s that have been displaced during extractions (see Fig 7.7); to rem ove cyst s, polyps, tum ors, and other foreign bodies; to close oro an tral stulas; to reduce facial fractures; and to drain the sinus (rare now due to endoscopy). It can also be used to gain access to the ethm oid air cells, the sphenoid sinus, and the pterygom axillary fossa (which lies be hind m axillary sinus).

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Mucosa of the Nasal Cavity Sphenoid sinus

Hypophyseal fossa Dorsum sellae

Frontal sinus

Clivus Pharyngeal tonsil

Nasal septum

Choana Torus tubarius Pharyngeal orifice of pharyngot ym panic (auditory) tube

Incisive canal

Dens of axis

Maxilla

Hard palate

Incisive foram en Upper lip

Atlas (anterior arch)

Soft palate, palatine septum

A

Sphenoid sinus

Sphenoethm oidal recess

Superior nasal concha

Superior m eatus

Middle nasal concha

Middle m eatus

Pharyngeal tonsil Torus tubarius

Inferior nasal concha

Salpingopharyngeal fold

Lim en nasi Nasal vestibule B

Inferior m eatus Pharyngeal orifice of pharyngot ympanic (auditory) tube

Pharyngeal tonsil

Basilar part of occipital bone Middle nasal concha

Pharyngeal recess

Vom er

Choana (“posterior nasal aperture”)

Inferior nasal concha Soft palate

Palatopharyngeal arch Uvula

Tongue base with lingual tonsil C

Pharyngeal recess

Palatine tonsil Epiglot tis

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Fig. 7.18 Mucosa of the nasal cavity A Mucosa of the nasal septum , parasagit t al section viewed from the left side. B Mucosa of the right lateral nasal wall, viewed from the left side. C Posterior view through the choanae into the nasal cavit y. Although the m edial wall of the nasal cavit y is sm ooth, it s lateral wall is raised into folds by the three conchae (superior, m iddle, and inferior concha), which increase the surface area of the nasal cavit y, enabling it to warm and hum idify the inspired air m ore e ciently. They also create turbulence, m ixing olfactory stim ulant s (see p. 118 for olfactory nerve). The choanae (posterior nasal apertures) (C) are the posterior openings by which the nasal cavit y com m unicates with the nasopharynx. Note the close proxim it y of the choanae to the pharyngot ym panic (auditory) tube and pharyngeal tonsil in A.

Regions of the Hea d

Middle nasal concha

7. Nose & Nasa l Ca vit y

Kinociliabearing epithelial cells

Pseudostratified ciliated epithelium (“respiratory epithelium ”)

Sem ilunar hiatus

Goblet cells

Uncinate process

Fibrous lam ina propria

Nasal septum , vom er

Maxillary sinus Inferior nasal concha with decongested m ucosa

Congested m ucosa of the inferior concha

Fig. 7.19 Functional states of the nasal mucosa Coronal section, anterior view. The function of the nasal m ucosa is to warm and hum idify the inspired air and m ix olfactory stim ulant s. This is accom plished by an increase of blood ow through the m ucosa, placing it in a congested (swollen) st ate. The m ucous m em branes are not sim ult aneously congested on both sides, but undergo a norm al cycle of congestion and decongestion that last s approxim ately six hours (the right side is decongested in the drawing). Exam ination of the nasal cav it y can be facilit ated by rst adm inistering a decongest ant to shrink the m ucosa.

Fig. 7.20 Histolog y of the nasal mucosa The surface of the pseudostrati ed respiratory epithelium of the nasal m ucosa consist s of kinocilia bearing cells and goblet cells, which se crete their m ucus into a watery lm on the epithelial surface. Serous and sero m ucous glands are em bedded in the connective tissue and also release secretions into the super cial uid lm . The directional uid ow produced by the cilia is an im portant com ponent of the nonspeci c im m une response. If coordinated beating of the cilia is im paired, the patient will su er chronic recurring infections of the respiratory tract.

I

Middle concha

Pharyngeal tonsil

Choana

Posterior m argin of septum

Pharyngeal orifice of pharyngot ympanic tube

Inferior concha Soft palate

Base of tongue A

II

B

Uvula

Fig. 7.21 Ante rior and poste rior rhinoscopy A Ante rior rhinoscopy is a procedure for inspection of the nasal cav it y. Two di erent positions (I, II) are used to ensure that all of the anterior nasal cavit y is exam ined. B In poste rior rhinoscopy, the choanae and pharyngeal tonsil are accessible to clinical exam ination. The rhinoscope can be angled and rotated to dem onstrate the structures shown in the com pos ite im age. Today the rhinoscope is frequently replaced by an endo scope.

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Nose & Paranasal Sinuses: Histology & Clinical Anatomy

Olfactory bulb

Cribriform plate

Olfactory tract (CN I)

Anterior ethm oidal artery (from ophthalm ic artery)

Sphenoid sinus Basilar artery Medial superior posterior nasal branches (from CN V2 )

Olfactory fibers (from CN I) Anterior septal branches (from CN V1 )

Posterior septal branches (from sphenopalatine artery)

Medial nasal branches (from CN V1 )

Torus tubarius

Kiesselbach’s area

Septal branches of superior labial artery Incisive canal (with nasopalatine nerve and greater palatine artery)

Choana

Nasopalatine nerve (from CN V2 ) Incisive fossa (opening of incisive foram en)

Olfactory bulb and olfactory fibers (CN I)

Fig. 7.22 Ne urovasculature of the nasal se ptum Parasagit t al section, left lateral view. The nasal septum is supplied antero superiorly by CN V1 and posteroinferiorly by CN V2 . It receives blood prim arily from branches of the ophthalm ic and m axillary arter ies, with contribution from the facial artery (sept al branches of the superior labial artery).

Superior nasal concha

Posterosuperior lateral nasal branches

Posterior ethm oidal artery (from ophthalm ic artery)

Anterior ethm oidal artery (from ophthalm ic artery) Pterygopalatine ganglion

Middle nasal concha Posteroinferior lateral nasal branches and lateral posterior nasal arteries (descending palatine artery)

Descending palatine artery and nerve Greater and lesser palatine nerves

Inferior nasal concha Incisive canal (with nasopalatine nerve and greater palatine artery ) Greater palatine artery and nerve

Fig. 7.23 Ne urovasculature of the late ral nasal w all Left m edial view of right lateral nasal wall. The pterygopalatine gan glion (located in the pterygopalatine fossa but exposed here) is an im port ant relay in the parasym pathetic nervous system . The CN V2 nerve bers pass through it to the sm all nasal glands of the nasal conchae,

Lesser palatine artery and nerve

Uvula

along with palatine glands. The anterosuperior portion of the lateral nasal wall is supplied by branches of the ophthalm ic artery and CN V1 . Note: Olfactory bers (CN I) pass through the cribriform plate to the olfactory m ucosa at the level of the superior concha.

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Regions of the Hea d

Posterior ethm oidal artery

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Ophthalm ic artery

Anterior ethm oidal artery

Fig. 7.24 Arte ries of the nasal se ptum Left lateral view of left side of septum . The ves sels of the nasal s eptum arise from branches of the external and internal carotid arteries. The anterior part of the septum cont ains a highly vascularized area called Kiesselbach’s area, which is supplied by vessels from both m ajor arteries. This area is the m ost com m on site of signi cant nosebleed due to anastom oses.

Sphenopalatine artery via sphenopalatine foram en

Anterior septal branches

Maxillary artery Internal carotid artery

Kiesselbach’s area Nasal branch of greater palatine artery

Posterior septal branches Greater palatine artery

Septal branch of superior labial artery (facial artery)

Cribriform plate

Frontal sinus

Fig. 7.25 Ne rves of the nasal se ptum Left lateral view of right lateral nasal wall. The nasal septum receives it s general sen sory innervation from branches of the tri gem inal nerve (CN V). The anterosuperior part of the septum is supplied by branches of the ophthalm ic division (CN V1 ) and the rest by branches of the m axillary division (CN V2 ). Bundles of olfactory nerve bers (CN I) arise from receptors in the olfactory m ucosa on the superior part of the septum , pass through the cribriform plate, and enter the olfactory bulb. (see p. 118 for discussion of olfactory nerve [CN I]).

Descending palatine artery

Olfactory bulb (CN I)

Anterior ethm oidal nerve (CN V1 ) Olfactory nerve fibers (CN I)

CN V2

Medial nasal branches (CN V1 )

CN V1 Trigem inal ganglion (CN V) CN V3 Pterygopalatine ganglion in pterygopalatine fossa

Medial superior posterior nasal branches (CN V2 ) Vom er

Nasopalatine nerve (CN V2 )

Posterior ethm oidal artery Anterior ethm oidal artery

External carotid artery

Anterior ethm oidal nerve (CN V1 )

Ophthalm ic artery

Zygom atic process of m axilla

Cribriform plate

Sphenopalatine foram en (opened)

Middle nasal concha

Sphenopalatine artery Descending palatine artery (gives rise to greater and lesser palatine arteries)

Lateral superior posterior nasal branches (CN V2 )

External nasal branch

Pterygopalatine ganglion

Maxillary artery

Posteroinferior lateral nasal branches (from desending palatine nerve)

Internal carotid artery Alar branches of lateral nasal artery Greater palatine artery

Lesser palatine nerves

Lateral nasal branches

External carotid artery Lateral posterior nasal arteries

Internal nasal branches

Fig. 7.26 Arte ries of the rig ht late ral nasal w all Left lateral view of right lateral nasal wall. The nasal wall is supplied prim arily by branches of the ophthalm ic artery (anterosuperiorly) and m axillary artery (posteroinferiorly), with contributions from the facial artery (alar branches of the lateral nasal artery).

Sphenoid sinus

Inferior nasal concha

Greater palatine nerve

Fig. 7.27 Ne rves of the right late ral nasal w all Left lateral view of the right lateral nasal wall. The nasal wall derives it s sensory innervation from branches of the ophthalm ic division (CN V1 ) and the m axillary division (CN V2 ). Receptor neurons in the olfac tory m ucosa send their axons in the olfactory nerve (CN I) to the olfac tory bulb.

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7. Nose & Nasa l Ca vit y

Olfactory System (Smell)

Medullary stria of thalam us Longitudinal striae

Interpeduncular nucleus

Medial olfactory stria

Habenular nuclei Tegm ental nucleus

Olfactory bulb

Uncus, with amygdala below

Olfactory fibers

Olfactory bulb

Reticular form ation Dorsal longitudinal fasciculus Lateral olfactory stria A

Olfactory m ucosa

• Som e of the axons of the olfactory tract run in the late ral o lfacto ry stria to the olfactory centers: the amygdala, sem ilunar gyrus, and am bient gyrus. The prepiriform area (Brodm ann area 28) is consid ered to be the prim ary olfactory cortex in the strict sense. It cont ains the third neurons of the olfactory pathway. Note: The prepiriform area is shaded in B, lying at the junction of the basal side of the fron t al lobe and the m edial side of the tem poral lobe. • Other axons of the olfactory tract run in the me dial o lfactory stria to nuclei in the septal (subcallosal) area, which is part of the lim bic system , and to the olfactory tubercle, a sm all elevation in the ante rior perforated subst ance. • Yet other axons of the olfactory tract term inate in the ante rio r o lfactory nucle us, where the bers that cross to the opposite side branch o and are relayed. This nucleus is located in the olfactory trigone, which lies bet ween the t wo olfactory striae and in front of the anterior perforated substance.

Prepiriform area

Medial olfactory stria

Prepiriform area

Fig. 7.28 Olfactory syste m: olfactory mucosa and ce ntral conne ctions Olfactory tract viewed in m idsagit t al section (A) and inferiorly (B). The olfactory m ucosa is located in the roof of the nasal cavit y. The olfactory cells (= prim ary sensory cells) are bipolar neurons. Their pe ripheral receptor bearing processes term inate in the epithelium of the nasal m ucosa, and their central processes pass to the olfactory bulb. The olfactory bulb, where the second neurons of the olfactory pathway (m itral and tufted cells) are located, is considered an extension of the telencephalon. The axons of these second neurons pass centrally as the olfactory tract. In front of the anterior perforated subst ance, the olfac tory tract widens to form the olfactory trigone and split s into the lat eral and m edial olfactory striae.

Olfactory tract

Olfactory trigone Amygdala (deep to brain surface)

Lateral olfactory stria Am bient gyrus B

Sem ilunar gyrus

Diagonal stria

Anterior perforated substance

Note: None of these three tract s are routed through the thalam us. Thus, the olfactory system is the only sensory system that is not re layed in the thalam us before reaching the cortex. There is, however, an indirect route from the prim ary olfactory cortex to the neocortex passing through the thalam us and term inating in the basal forebrain. The olfactory signals are further analyzed in these basal portions of the forebrain (not shown). The olfactory system is linked to other brain areas well beyond the pri m ary olfactory cortical areas, with the result that olfactory stim uli can evoke com plex em otional and behavioral responses. Noxious sm ells induce nausea, and appetizing sm ells evoke watering of the m outh. Presum ably these sensations are processed by the hypothalam us, thal am us, and lim bic system via connections est ablished m ainly by the m edial forebrain bundle and the m edullary striae of the thalam us. The m edial forebrain bundle distributes axons to the following structures: • • • •

Hypothalam ic nuclei Reticular form ation Salivatory nuclei Dorsal m otor nucleus

The axons that run in the m edullary striae of the thalam us term inate in the habenular nuclei. This tract also continues to the brainstem , where it stim ulates salivation in response to sm ell.

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Olfactory fibers

7. Nose & Nasa l Ca vit y

Olfactory bulb

Connective tissue

Cribriform plate

Basal cells Light cells

Subm ucosa

Dark cells

Basal cell

Olfactory cell

Supporting cell Olfactory cilia

A

Bowm an gland

Fig. 7.29 Olfactory mucosa and vome ronasal (Jacobson’s) organ (VNO) The olfacto ry muco sa occupies an area of approxim ately 2 cm 2 on the roof of each nasal cavit y, and 10 7 prim ary sensory cells are concen trated in each of these areas (A). At the m olecular level, the olfactory receptor proteins are located in the cilia of the sensory cells (B). Each sensory cell has only one specialized receptor protein that m ediates signal trans duction when an odorant m olecule binds to it. Although hum ans are m icrosm atic, having a sense of sm ell that is feeble com pared with other m am m als, the olfactory receptor proteins still m ake up 2 % of the hum an genom e. This underscores the im port ance of olfac tion in hum ans. The prim ary olfactory sensory cells have a life span of approxim ately 60 days and regenerate from the basal cells (life long division of neurons). The bundled central processes (axons) from hundreds of olfactory cells form olfactory bers (A) that pass through the cribriform plate of the ethm oid bone and term inate in the olfactory bulb, which lies above the cribriform plate. The VNO (C) is located on both sides of the anterior nasal septum . It is an accessory olfactory or gan and is generally considered vestigial in adult hum ans. However, it responds to steroids and evokes subconscious reactions in subject s (possibly in uences the choice of a m ate). Mate selection in m any anim al species is known to be m ediated by olfactory im pulses that are perceived in the VNO.

Axons Subm ucous gland Subm ucosa

Olfactory cells Bowm an gland

Microvilli Cilia with receptor proteins

B

C

Mucus–water film

To/from opposite side Olfactory tract

Anterior olfactory nucleus

Olfactory bulb

Granule cell

Mitral cell

Apical dendrite Olfactory glomerulus

Periglom erular cells

Fig. 7.30 Synaptic patte rns in an olfactory bulb Specialized neurons in the olfactory bulb, called m itral cells, form api cal dendrites that receive synaptic contact from the axons of thou sands of prim ary sensory cells. The dendrite plus the synapses m ake up the olfactory glomeruli. Axons from sensory cells with the sam e recep tor protein form glom eruli with only one or a sm all num ber of m itral cells. The basal axons of the m itral cells form the olfactory tract. The axons that run in the olfactory tract project prim arily to the olfactory cortex but are also distributed to other nuclei in the central nervous system . The axon collaterals of the m itral cells pass to granule cells: both granule cells and periglom erular cells inhibit the activit y of the m itral cells, causing less sensory inform ation to reach higher centers. These inhibitory processes are believed to heighten olfactory contrast, which aids in the m ore accurate perception of sm ells. The tufted cells, which also project to the prim ary olfactory cortex, are not shown.

Olfactory fibers

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Oral Cavity: Overview Fig. 8.1 Lips and labial cre ases Anterior view. The upper and lower lips (labia) m eet at the angle of the m outh. The oral ssure opens into the oral cavit y. Changes in the lips noted on visual inspection m ay yield im portant diagnostic clues: Blue lips (cyanosis) suggest a disease of the heart, lung, or both, and deep nasolabial creases m ay re ect chronic diseases of the digestive tract.

Philtrum Nasolabial crease

Upper lip

Oral fissure

Angle of m outh

Lower lip

Verm illion border Labiom ental groove

Fig. 8.2 Oral cavity A Anterior view. B Anterior view showing ventral surface of tongue. C Left lateral view. The dent al arches (with the alveolar processes of the m axilla and m andible) subdivide the oral cavit y into t wo part s:

Upper lip Frenulum of upper lip

• Oral vestibule : portion out side the dental arches, bounded on one side by the lips and cheeks and on the other side by the dent al arches. • Oral cavity pro pe r: region within the dent al arches.

Oral vestibule Palatoglossal arch Palatopharyngeal arch Faucial isthm us Oral cavit y proper

Oral vestibule

Hard palate Soft palate Uvula Palatine tonsil Dorsum of tongue

Frenulum of lower lip Lower lip

Apex of tongue

A Fimbriated fold Lingual frenulum Sublingual fold Sublingual papilla B

Buccal frenulum Papilla and orifice of parotid duct Mucobuccal fold Labial gingiva Alveolar m ucosa

C

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Frontal sinus Nasal septum Sphenoid sinus Torus tubarius with lymphatic tissue (tonsilla tubaria) Pharyngeal tonsil in nasopharynx Pharyngeal orifice of pharyngot ympanic tube Salpingopharyngeal fold with lateral lymphatic band

Right choana

Anterior arch of atlas (C1) and dens of axis (C2)

Soft palate Uvula

Palatine tonsil in oropharynx

Palatoglossal arch

Palatopharyngeal arch

Genioglossus

Lingual tonsil (on postsulcal portion of the tongue)

Geniohyoid

Vallecula

Mylohyoid Hyoid bone

Epiglot tis

Thyrohyoid ligam ent

Laryngopharynx

Vestibular fold Vocal fold

Cricoid cartilage

Esophagus Thyroid gland Trachea

Fig. 8.3 Topog raphy of the oral cavity and pharynx Midsagit t al section, left lateral view. The oral cavit y is located inferior to the nasal cavit y and anterior to the pharynx. The roof of the oral cavit y is form ed by the hard palate in it s anterior t wo thirds and by the soft

A

palate (velum ) in it s posterior one third. It s inferior boundary is form ed by the mylohyoid m uscle. Laterally, the oral cavit y is bounded by the cheeks; posteriorly, it is continuous with the oropharynx.

B

Fig. 8.4 Oral cance r A Cancerous lesion of the oral oor. B Cancerous lesion of the tongue. Most oral cancers are squam ous cell carcinom as and can be at tributed to the use of alcohol and tobacco (synergistic e ect). They t ypically occur on the oral oor or the ventral (inferior) or lateral surface of the tongue and present as a painless ulcer which is rm with raised edges

and an indurated, in am ed base. Other present ations include an area of leukoplakia (a white patch), erythroplakia (red patch), or a com bination of the t wo. Lesions that occur on the oral oor tend to undergo m alignant transform ation m ore readily than those in other locations in the oral cavit y. Pain from oral cancer occurs later in the pathogenesis and is usually due to superinfection.

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Vasculature of the Oral Cavity Fig. 8.5 Maxillary arte ry Left lateral view. A Schem atic. B Course of the m axillary artery. A The m axillary artery can be divided into three part s: m andibular ( blue); pterygoid (green), and pterygopalatine (yellow). B The m axillary artery is the principle artery supplying the oral cavit y. The m andibular part supplies the m andibular teeth, gingiva, and m ucosa, and contributes to the supply of cert ain m uscles of m astication and of the soft palate. The pterygoid part supplies the m uscles of m astication and the buccal m ucosa. The pterygopalatine part supplies the m axillary teeth, gingiva, m ucosa, hard palate, and soft palate, and contributes to the supply of the upper lip. Note. This only represent s those part s of the m axillary artery that contribute to the blood supply of the structures of the oral cavit y only. For full det ails of the structures that the m axillary artery supplies, see Table 3.6, p. 57. Other arteries that contribute to the blood supply of the oral cavit y include the lingual artery (p. 52), which supplies the tongue and oral oor, and the facial artery (p. 53), which supplies the lower lip (inferior labial branch) and upper lip (superior labial branch).

A

Infraorbital artery Sphenopalatine artery Deep temporal arteries Posterior superior alveolar artery Anterior and m iddle superior alveolar arteries

Pterygoid branch

Superficial temporal artery Maxillary artery Posterior auricular artery Masseteric artery Buccal artery Facial artery Occipital artery Lingual artery Inferior alveolar artery B

Mental branch

Mylohyoid branch

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Superior thyroid artery

Regions of the Hea d

Supratrochlear vein

Supraorbital vein

Deep tem poral veins

Cavernous sinus

8. Ora l Cavit y & Pha rynx

Superficial temporal vein Sphenoidal em issary veins

Superior ophthalm ic vein

Superior and inferior petrosal sinuses

Angular vein Inferior ophthalm ic vein

Sigm oid sinus

Facial vein Deep facial vein

Pterygoid plexus Maxillary vein Retrom andibular vein Posterior division of retrom andibular vein Internal jugular vein Anterior division of retrom andibular vein Com m on facial vein

Mental vein

Inferior alveolar vein

Facial vein

Lingual vein

External palatine vein

Fig. 8.6 Ve nous drainag e of the oral cavity Left lateral view. Veins within the m andibular teeth, gingiva, and m ucosa com bine to form inferior alveolar veins, which drain to the pterygoid plexus. Likewise, veins within the m axillary teeth, gingiva, and m ucosa form the superior alveolar veins, which drain to the pterygoid

plexus. Veins from the hard and soft palate also drain to the pterygoid plexus . Middle and anterior superior alveolar veins drain into the infraorbital vein which drains into the pterygoid plexus of veins. The lingual vein drains the tongue and oral oor. The facial vein contributes to the venous drainage of the m andibular teeth.

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Innervation of the Oral Cavity

Recurrent m eningeal nerve (nervus spinosum )

Maxillary division (CN V2 , via foram en rotundum )

Trigem inal nerve (CN V)

Pterygopalatine ganglion

Posterior Middle Anterior

Superior alveolar nerves

Zygom atic nerve Infraorbital nerve (and foram en)

Mandibular division (CN V3 , via foram en ovale)

Superior labial nerves

Long buccal nerve Medial and lateral pterygoid nerves

Auriculotemporal nerve

Masseteric nerve Mylohyoid nerve Lingual nerve

Inferior alveolar nerve (in m andibular canal)

Fig. 8.7 Trig e minal ne rve Right lateral view. The m axillary division of the trigem inal nerve (CN V2 ) and the m andibular division of the trigem inal nerve (CN V3 ) innervate the structures of the oral cavit y via their m any branches. For full det ails see pp. 126–129.

Inferior dental branches Mental nerve (and foram en)

Superior labial branches Anterior and m iddle superior alveolar branches

Nasopalatine nerve

Nasopalatine nerve Incisive foram en Median palatine suture

Posterior superior alveolar branches

Greater palatine nerve

Greater palatine nerve and artery Greater palatine foram en

Long buccal nerve

Lesser palatine foram en Vom er

Lesser palatine nerve and artery A

B

Lesser palatine n.

Pterygoid process

Fig. 8.8 Ne urovasculature of the hard palate Inferior view. A The hard palate receives sensory innervation prim arily from the term inal branches of the m axillary division of the trigem inal nerve (CN V2 ). Note: The long buccal nerve is a branch of the m andibu-

lar division of the trigem inal nerve (CN V3 ). B The arteries of the hard palate arise from the m axillary artery (a branch of the external carotid artery)

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Fig. 8.9 Inne rvation of the  muscles of the  oral  oor A Left lateral view with left half of the m andible rem oved. B Left lateral view of the m uscles of the oral oor. The m uscles of the oral oor include the mylohyoid and geniohyoid. The mylohyoid is innervated by the nerve to mylohyoid (from CN V3 ); the geniohyoid is innervated by the C1 spinal nerve via the hypoglossal nerve (CN XII).

Trigem inal ganglion

Mandibular division (CN V3 ) Inferior alveolar nerve Chorda t ympani (CN VII) Lingual nerve Mylohyoid nerve

Subm andibular ganglion

A

Mylohyoid

Digastric, anterior belly

Lingual nerve

Hypoglossal nerve (CN XII)

C1 spinal nerve (anterior ram us)

Geniohyoid

Geniohyoid branch (C1)

Superior root of ansa cervicalis (descendens hypoglossi)

Inferior root of ansa cervicalis (descendens cervicalis)

Ansa cervicalis

B

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Teeth in situ & Terminology Hum ans have t wo successive set s of teeth: deciduous teeth and their perm anent replacem ent s. There are four di erent form s of teeth: incisor, canine, prem olar (not present in the deciduous dentition), and m olar. Teeth are set in socket s com posed of alveo lar bone and held in place by the elastic connective tissue.

Incisive fossa

Incisors

Canine

Alveolar bone

Incisive suture

Prem olars

Median palatine suture Interalveolar septum Molars

Interradicular septum Transverse palatine suture

A

Fig. 8.10 Pe rmane nt te eth in adults A Inferior view of the m axilla (with teeth rem oved on left side). B Superior view of the m andible (with teeth rem oved on left side). The 16 teeth in both the m axilla and the m andible in hum ans are aligned in a bilateral, sym m etrical fashion to suit their different chewing functions. The teeth in each half of the m axilla and m andible consist of: t wo incisors, one canine, t wo prem olars, and three m olars. The incisors and canine are responsible for ripping the food while the m olars are responsible for grinding it. The teeth have been rem oved on right side of each im age to reveal the alveoli, which hold the teeth. In the anterior area (where the incisors and canines are located), the labial plate of com pact bone is extrem ely thin (ap proxim ately 0.1 m m ) and the root s of these teeth are palpable. The interalveolar sept a separate the alveoli of t wo adjacent teeth. The interradicular sept a separate the root s of teeth with m ultiple root s. Alveolar ostitis (dry socket), an in am m ation of the alveolar bone, m ay occur following tooth extraction when the blood clot that would norm ally occupy the socket does not form properly (e.g., due to sm oking) or is displaced (e.g., by m outh rinsing), exposing the underlying bone and nerves and allowing an infection to ourish.

Coronoid process Interalveolar septum Molars Interradicular septum Prem olars

Alveoli

Canine B

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Incisors

8. Ora l Cavit y & Pha rynx

Regions of the Hea d

1

16 2

3

4

5

6

7

32

9

8

10

11

12

13

14

15 17

18

31 30

29

28

27

26

25

Fig. 8.11 Coding the pe rmane nt te e th In the United States, the perm anent teeth are num bered sequentially, not assigned to quadrant s. Progressing in a clockwise fashion (from

24

23

22

21

20

19

the perspective of the dentist), the teeth of the upper arc are num bered 1 to 16, and those of the lower are considered 17 to 32. Note: The third upper m olar (wisdom tooth) on the patient’s right is considered 1.

Labial Mesial Distal

Lingual Buccal

Buccal

Palatal

Distal

Mesial Labial A

B

Occlusal

Distal

C

Distoapproxim al

Mesial

Coronalapical

Cervical Buccal

Lingual

Mesioapproxim al

Fig. 8.12 Desig nation of tooth surfaces A Inferior view of the m axillary dent al arch. B Superior view of the m andibular dental arch. C Buccal, dist al, and occlusal views of the right m andibular rst m olar (tooth 30). The mesial and distal tooth surfaces are those closest to and farthest from the m idline, respectively. The term labial is used for incisors and canine teeth, and buccal is used for prem olar and m olar teeth. Palatal denotes the inside surface of m axillary teeth, and lingual denotes the inside surface of m andibular teeth. C shows the coronal, apical, and cervical directions of a tooth and the approxim al surfaces, which contact, or face, the adjacent teeth. These designations are used to describe the precise location of sm all carious lesions.

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Structure of the Teeth & Periodontium The periodontium includes all the structures that bind the tooth to its bony socket: • • • •

Cusp of tooth

gingiva, cementum, periodontal ligament, and alveolar bone.

Enam el

Crown

Its essential functions include: • anchoring the teeth in alveolar bone and transforming chewing pressure into tensile stress, • mediating the sensation of pain and regulating chewing pressure through nerve bers and sensitive nerve endings, • defending against infection through e cient separation of the oral cavit y and the dental root region and by having a large number of defense cells, and • rapid metabolism and high regenerative capacit y, via its rich blood supply

Dentine

Pulp cham ber Cem entoenam el junction Neck

Gingiva Cem entum

Periodontal ligam ent Root Alveolar bone

Fig. 8.13 Parts of the tooth Cross section of a tooth (mandibular incisor). The teeth consist of an enamel-covered crown that meets the cementum -covered roots at the neck (cementoenamel junction). The body of the tooth is primarily dentine.

Apex of root Apical foram en

Ta ble 8.1 Structures of the tooth Pro te ctive cove ring s: These hard, avascular layers of t issue prote ct t he underlying body of t he toot h. They m eet at t he cervical m argin (neck, cem entoenam el junction). Failure to do so exposes the underlying dentine, which has extrem ely sensitive pain responses.

Enamel: Hard, translucent covering of the crown of the tooth. Maxim um thickness (2.5 m m ) occurs over the cusps. Enam el prism s lie parallel to each other and are com posed of hydroxyapatite [Ca 5 (PO4 )3 (OH)]. The enam el covering m eet s the cem entum at the neck (cervical m argin, cem entoenam el junction).

Body o f the tooth: The tooth is prim arily com posed of dentine, which is supported by the vascularized dent al pulp.

De ntine : Tough tissue com posing the m ajorit y of the body of the tooth. It consist s of extensive net works of S-shaped tubules (intratubular dentine) surrounded by peritubular dentine. The tubules connect the underlying dent al pulp to the overlying tissue. Exposed dentine is extrem ely sensitive due to extensive innervation via the dent al pulp.

Ce me ntum: Bonelike covering of the dent al root s, lacking neurovascular structures.

De ntal pulp: Located in the pulp cham ber and root canals, the dent al pulp is a well-vascularized layer of loose connective tissue. Neurovascular structures enter the apical foram en at the apex of the root. The dent al pulp receives sym pathetic innervation from the superior cervical ganglion and sensory innervation from the trigem inal ganglion (CN V). Pe riodo ntium: The tooth is anchored and supported by the periodontium , which consist s of several tissue t ypes. Note: The cem entum is also considered part of the periodontium .

Pe riodo ntal lig ame nt: Dense connective tissue bers that connect the cem entum of the root s in the osseous socket to the alveolar bone. Alve o lar bone (alveolar processes of m axilla and m andible): The portion of the m axilla or m andible in which the dent al root s are em bedded are considered the alveolar processes (the m ore proxim al portion of the bones are considered the body). Ging iva: The at t ached gingivae bind the alveolar periosteum to the teeth; the free gingiva com poses the 1 m m tissue radius surrounding the neck of the tooth. A m ucogingival line m arks the boundary bet ween the keratinized gingivae of the m andibular arch and the nonkeratinized lingual m ucosa. The palat al m ucosa is m asticatory (orthokeratinized), so no visual distinction can be m ade with the gingiva of the m axillary arch. Third m olars (wisdom teeth) often erupt through the m ucosogingival line. The oral m ucosa cannot support the tooth, and food can becom e trapped in the regions lacking at t ached gingiva.

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Enam el Interdental papillae Pulp cham ber

Free gingiva

Gingival m argin

At tached gingiva See B

Junctional epithelium Alveolar crest

Mucogingival line

Periodontal ligam ent Cem entum

Alveolar m ucosa

Dentine

Dentogingival fibers

Root canal Cribriform layer Spongy bone

Compact bone

Alveolargingival fibers

A

Gingival sulcus Enam el

Sulcular epithelium

Dentine

Gingival epithelium

Junctional epithelium

Connective tissue papilla

Cem entum Enam el

Gingival connective tissue

Hem idesm osom es

Neutrophil

Lam ina lucida

• Fre e g ing iva surrounds the neck of the tooth like a cu and is at t ached only to the cervical enam el. The gingiva sulcus is a channel that runs around the tooth bet ween the free gingival and the junctional epithelium . • Attache d g ing iva extends from the gingival sulcus to the m ucogingival border. It is tightly bound to both the cem entum at the neck of the tooth and the alveolar crest by dentogingival bers. B The junctional epithelium at taches to the surface of the cem entum by hem idesm osom es and basal lam ina, thereby ensuring a com plete at tachm ent of the oral m ucosa to the tooth surface. The junctional epithelium becom es broader in the apical-coronal direction. Note: The integrit y of the junctional epithelium is a precondition for the health of the entire periodontium . If bacterial colonization from dent al plaque leads to in am m ation of the neck of tooth, the junctional epithelium detaches from the tooth and so -called “gingival pocket s” form in the area around the gingival sulcus. This is called periodontitis.

External basal layer

Internal basal lam ina Suprabasal layer

Gingiva Sharpey fibers

Decussating interdental fibers

Alveolar wall

Interdental papilla

Cem entum A

Fig. 8.14 Ging iva A Gingiva. B Junctional epithelium . A The gingiva extends from the gingival m argin to the m ucogingival border. There, the gingival epithelium blends into the considerably m ore reddish alveolar epithelium . There is a clinical distinction bet ween t wo t ypes of gingiva:

Basal layer

Lam ina densa

B

8. Ora l Cavit y & Pha rynx

Circular fibers B

Fig. 8.15 Pe ridontal ligame nt A The Sharpey bers of the periodont al ligam ent pass obliquely downward from the alveolar bone and insert into the cem entum of the tooth. This arrangem ent transform s m asticatory pressures on the dent al arch into tensile stresses acting on the bers and anchored bone (pressure would otherwise lead to alveolar bone atrophy). B Many of the tough collagenous ber bundles in the connective tissue core of the gingiva above the alveolar bone are arranged in a screwlike pat tern around the tooth further strengthening it s at tachm ent.

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Maxillary Permanent Teeth

Buccal

Distal

Palatal

Labial

Distal

Palatal

Labial

Distal

Palatal

2. incisor Canine

Labial

Distal

Palatal

1. incisor 8

7 1. Prem olar 6 Buccal

Distal

Palatal 2. Prem olar 5

4

1. Molar Buccal

Distal

Palatal 3

2. Molar

Buccal

Distal

2

Palatal 1 3. Molar

Buccal

Distal

Palatal

Fig. 8.16 Morpholog y of the maxillary pe rmane nt te eth Right m axilla, occlusal view and isolated teeth shown in various views. Incisors: Incisors are used for cut ting o chunks of food. Accordingly, they are sharp-edged (scoop-shaped). In addition, they largely determ ine the esthetic appearance of the oral region. In general, all incisors are single-rooted and have one root canal. The upper central incisor is the largest, the lower central incisor the sm allest. The palat al surfaces of the t wo upper incisors often bear a blind pit, the foram en cecum , which is a site of predilection for dent al caries. The m axillary incisors are considerably larger than the m andibular incisors, resulting in a cusp-and- ssure occlusion (see Fig 8.18). Canines: Canines consist of a single cusp. Typically they have one long root (the longest root of all teeth) cont aining one root canal, and they support the incisors. Eruption of the m axillary canine tends to correct the splayed orient ation of the m axillary lateral incisor and any m edian diastem a (space bet ween the t wo m axillary central incisors) and so often orthodontic treatm ent is delayed until this tooth erupt s to m onitor

how m uch the teeth will “self-correct”. The canine teeth (both m axillary and m andibular) also play an im port ant role in occlusion. Pre mo lars: Prem olars represent a transitional form bet ween the incisors and the m olars. They have cusps and ssures. They are m ore im port ant in grinding than biting o food. Maxillary prem olars have t wo cusps, one buccal and one palat al, separated by a central ssure. The rst m axillary prem olar has t wo root s, each cont aining a root canal. The second m axillary prem olar t ypically has one root, but this m ay cont ain one or t wo root canals. Molars: Molars are the largest of the perm anent teeth and have an occlusal suface with m ultiple cusps. In order to absorb the powerful chewing pressure, the m axillary m olars have three root s, each of which cont ains a root canal (although the m esial root m ay cont ain t wo canals). Third m olars (wisdom teeth) are the exception. The root s of third m olars are often fused and therefore their root canal system is com plex (root canal therapy is rarely at tem pted in these teeth).

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Ta ble 8.2 Morpholog y of the maxillary pe rmane nt te eth To o th

Crow n

Surfaces

Root(s)

Ro ot canal(s)

Central incisors (8, 9) Lateral incisors (7, 10)

Roughly trapezoidal in the labial view; cont ains an incisal edge with 3 tubercles (m am elons)

Labial: convex Palat al: concavoconvex

1 rounded root

Usually 1

Canines (6, 11)

Roughly trapezoidal with 1 labial cusp

Labial: convex Palat al: concavoconvex

1 root; the longest of the teeth

Usually 1

1 st prem olar (5, 12)

2 cusps (1 buccal, 1 palat al), separated by a central ssure

Buccal, dist al, palat al, and m esial: all convex, slightly at tened. The m esial surface often bears a sm all pit that is di cult to clean and vulnerable to caries Occlusal: m ore oval than the m andibular prem olars

2 root s (1 buccal, 1 palat al)

Usually 2, one per root

1 root divided by a longitudinal groove and cont aining 2 root canals

1 or 2

1 st m olar (3, 14)

4 cusps (1 at each corner of it s occlusal surface); a ridge connect s the m esiopalat al and distobuccal cusps

Buccal, dist al, palat al, and m esial: all convex, slightly at tened Occlusal: rhom boid

3 root s (2 buccal, 1 palat al)

3 or 4 (m esial root m ay have 2 canals)

2 nd m olar (2, 15)

4 cusps (though the distopalat al is often sm all or absent

3 root s (2 buccal, 1 palat al), occasionally fused

3 or 4 (m esial root m ay have 2 canals)

3 rd m olar (1, 16)

3 cusps (no distopalat al)

3 root s (2 buccal, 1 palat al), often fused

Com plex canal system

2 nd prem olar (4, 13)

The m axillary teeth are supplied by the posterior superior alveolar a. (m olars), m iddle superior alveolar a. (prem olars), and the anterior superior alveolar a. (incisors and canines); venous drainage is via the alveolar vv. that drain to the pterygoid plexus. Innervation is via the posterior, m iddle, and anterior superior alveolar nn. (sam e distribution as the arteries). Lym ph from the m axillary teeth drain to the subm andibular nodes.

Buccal Cusp tip Fossae Marginal ridge Marginal ridge

Longitudinal fissure

Transverse fissure A

Cusp tip Palatal Mesial fossa

Mesiobuccal cusp

Mesiopalatine cusp

Central fossa

Cusp of Carabelli

Distobuccal cusp

B

Distopalatal cusp

Distal fossa

Fig. 8.17   Maxillary  rst pre molar and  rst molar Occlusal view.

Fig. 8.18   Cusp-and- ssure  occlusion With the m outh closed (occlusal position), the m axillary teeth are opposed to their m andibular counterpart s. They are o set relative to one another such that the cusps of one tooth t into the ssures of the t wo opposing teeth (cusp-and- ssure occulsion). Because of this arrangem ent, every tooth com es into contact with t wo opposing teeth. This o set result s from the slightly greater width of the m axillary incisors. A class I occlusion is a “norm al” occlusion where the lower anterior teeth occlude with the cingulum of the upper anterior teeth. A class II occlusion is when the lower teeth occlude behind the cingulum of the upper anterior teeth. A class III occlusion is when the lower anterior teeth occlude in front of the cingulum of the upper anterior teeth. Crossbites are when the teeth are not in the usual buccal-lingual relationship.

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Mandibular Permanent Teeth

Buccal

Distal

Lingual

32

Buccal

Distal

Lingual 31

30 Buccal

Distal

Lingual

29

28 Buccal

Distal

Lingual 27 26

Buccal

Distal

25

Lingual

Labial

Distal

Fig. 8.19 Morpholog y of the mandibular pe rmane nt te eth The general m orphology of the m andibular teeth is sim ilar to that of the m axillary teeth. Incisors: Mandibular incisors are sm aller than their m axillary counterpart s but have one root cont aining one root canal. Canines: The m andibular canine is sim ilar to the m axillary canine. Pre mo lars: The m andibular rst prem olar has a less well de ned lingual cusp. It t ypically has one root with one canal.

Lingual

Labial

Distal

Lingual

Labial

Distal

Lingual

Molars: Mandibular rst m olars have ve cusps, t wo root s, and bet ween t wo and four root canals. Mandibular second m olars have four cusps but are otherwise sim ilar to the rst m olars. Mandibular third m olars are often im pacted (do not erupt into the arch) and have t wo fused root s with a com plex canal system .

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Ta ble 8.3 Morpholog y of the mandibular pe rmane nt te e th To o th

Crow n

Surfaces

Root(s)

Ro ot canal(s)

Central incisors (24, 25) Lateral incisors (23, 26)

Roughly trapezoidal in the labial view; cont ains an incisal edge with 3 tubercles (m am elons)

Labial: convex Palat al: concavoconvex

1 root, slightly at tened

1

Canines (22, 27)

Roughly trapezoidal with 1 labial cusp

Labial: convex Palat al: concavoconvex

1 root; the longest of the teeth (Note: m andibular canines are occassionally bi d)

1

1 st prem olar (21, 28)

2 cusps (1 t all buccal cusp connected to 1 sm aller lingual cusp; the groove bet ween the cusps creates a m esial and distal occlusal pit.

1 root (occasaionally bi d)

1

2 nd prem olar (20, 29)

3 cusps (1 t all buccal cusp separated from 2 sm aller lingual cusps by a m esiodist al ssure)

Buccal, dist al, lingual, and m esial: all convex, slightly at tened. The m esial surface often bears a sm all pit that is di cult to clean and vulnerable to caries Occlusal: m ore oval than the m andibular prem olars m andibular prem olars

1 root

1

1 st m olar (19, 30)

5 cusps (3 buccal and 2 lingual), all of which are separated by ssures

Buccal, dist al, lingual, and m esial: all convex, slightly at tened Occlusal: rect angular

2 root s (1 m esial and 1 dist al); widely spaced

2–4

2 nd m olar (18, 31)

4 cusps (2 buccal; 2 lingual)

2 root s (1 m esial and 1 dist al)

2–4

3 rd m olar (17, 32)

May resem ble either the 1st or 2nd m olar

2 root s, often fused

Com plex canal system

The m andibular teeth are supplied by the inferior alveolar a. (m olars and prem olars) or it s incisive branch (incisors and canines); venous drainage is via the inferior alveolar v., which drains to the pterygoid plexus. Innervation is via the inferior alveolar n. (m olars and second prem olar) or it s incisive branch (incisors, canines, and rst prem olars). Lym ph from these teeth drain to the subm andibular nodes.

Distal pit

Distolingual cusp

Distal cusp

Central pit

Distobuccal cusp

Mesiolingual cusp Mesiobuccal cusp

Mesial pit

Fig. 8.20   Mandibular  rst molar Occlusal view.

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Deciduous Teeth

A B T

S

C

D

R

Q

E P

O

H

G

F N

M

I J L K

Fig. 8.21 Coding the de ciduous te eth The upper right m olar is considered A. The let tering then proceeds clockwise along the upper arc and back across the lower.

A

B

C

D

E

Fig. 8.22 De ciduous te e th Left side. The deciduous dentition consist s of only 20 teeth. Each of the four quadrant s cont ains the following teeth: A Central incisor. B Lateral incisor. C Canine. D First m olar. E Second m olar. To distinguish the deciduous teeth from the perm anent teeth, they are coded with let ters. The upper arch is labeled A to J, the lower is labeled K to T.

Perm anent canine Second perm anent m olar Second perm anent prem olar

Perm anent lateral incisor First perm anent prem olar Deciduous central incisor

A

Deciduous Deciduous lateral incisor canine

First deciduous m olar

Second deciduous m olar

Second deciduous m olar

First perm anent m olar

First deciduous m olar

First perm anent m olar

Deciduous canine Deciduous lateral incisor Perm anent central incisor Second perm anent m olar

Perm anent lateral incisor

Fig. 8.23 Te eth of a 6-year-old child A Maxillary teeth, left lateral view. B Mandibular teeth, left lateral view . The anterior bony plate over the root s of the deciduous teeth has been rem oved to display the underlying perm anent tooth buds (blue). At six years of age, all the deciduous teeth have erupted and are still present along with the rst perm anent tooth, the rst m olar. Note: The root s of deciduous m olars are m ore divergent than those of perm anent m olars. This is because the perm anent prem olars form in bet ween these root s and they are guided by them into the dent al arch as they erupt. In addition to this di erence bet ween deciduous teeth and perm anent teeth, deciduous teeth have thinner enam el, larger

B

Second perm anent prem olar Permanent canine

First perm anent prem olar

pulp horns, their pulpal outline follows the cem entoenam el junction (CEJ) m ore closely, they have narrower occlusal surfaces, broader cont act point s, thin pulpal oors, and the pulp within the root canals is m ore tortuous and branching. Furtherm ore, alveolar bone is m ore perm eable in young children often allowing the clinician to achieve adequate anesthesia via in ltration injections (see p. 470).

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Ta ble 8.4 Eruption of the te e th

Birth

The eruptions of the deciduous and perm anent teeth are called the rst and second dentitions, respectively. Types of teeth are ordered by the tim e of eruption; individual teeth are listed from left to right (viewer’s perspective). Type o f to oth

To oth

8. Ora l Cavit y & Pha rynx

6 m onths

Time of e ruptio n

First de ntition (de ciduous te e th)

Central incisor

E, F

P, O

6–8 m onths

Lateral incisor

D, G

Q, N

8–12 m onths

First m olar

B, I

S, L

12–16 m onths

Canine

C, H

R, M

15–20 m onths

Second m olar

A, J

T, K

20–40 m onths

1 year

2½ years

Se co nd de ntition (pe rmane nt te e th)

First m olar

3, 14

30, 19

6–8 years (“6-yr m olar”)

Central incisor

8, 9

25, 24

6–9 years

Lateral incisor

7, 10

26, 23

7–10 years

First prem olar

5, 12

28, 21

9–13 years

Canine

6, 11

27, 22

9–14 years

Second prem olar

4, 13

29, 20

11–14 years

Second m olar

2, 15

31, 18

10–14 years (“12-yr m olar”)

Third m olar

1, 16

32, 17

16–30 years (“wisdom tooth”)

4 years

6 years

8 years

10 years

12 years

Fig. 8.24 Eruption patte rn of the de ciduous and pe rmane nt te eth Left m axillary teeth. Deciduous teeth (black), perm anent teeth (red). Eruption tim es can be used to diagnose growth delays in children.

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Radiographs of Teeth

Maxillary sinus

Nasal septum

Orbit

Articular tubercle (em inence)

Mandibular (glenoid) fossa Condyle

1

16

17 32 Third m olar (wisdom tooth)

Mandible, angle

31

Mandibular canal

30 29

28

27

26

25

Fig. 8.25 De ntal panoramic tomogram The dental panoram ic tom ogram (DPT) is a survey radiograph that allows a prelim inary assessm ent of the temporom andibular joint s, m axillary sinuses, m axilla, m andible, and dent al status (carious lesions, location of the wisdom teeth). It is based on the principle of conventional tom ography in which the x-ray tube and lm are m oved about the plane of interest to blur out the shadows of structures out side the

Bite guide of scanner

sectional plane. The plane of interest in the DPT is shaped like a parab ola, conform ing to the shape of the jaws. If the DPT raises suspicion of caries or root disease, it should be followed with spot radiographs so that speci c regions of interest can be evaluated at higher resolution. (Tom ogram courtesy of Prof. Dr. U. J. Rother, director of the Departm ent of Diagnostic Radiology, Center for Dentistry and Orom axillofacial Surgery, Eppendorf Universit y Medical Center, Ham burg, Germ any.)

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Generally, radiographic im ages of the teeth and gum s are taken by directing the X-ray beam perpendicular to a tangent to the dental arch, or, to put it m ore sim ply, perpendicular to the outer surface of the tooth or teeth. Thus, the radiograph shows all consecutive structures in the beam path and so they overlap. In teeth with m ultiple root s, the individual root canals cannot be clearly evaluated. This is only possible with the help of so-called eccentric im ages, in which the X-ray beam is directed to the tangent at a particular angle, so that the consecu-

8. Ora l Cavit y & Pha rynx

tive structures are clearly distinguishable. Bitewing radiographs (see Fig 8.31) only show the crown of the tooth, and not the entire tooth. The patient bites down on a m ount that holds a sm all piece of lm perpendicular to it. The resulting radiograph shows the crown of both m axillary and m andibular teeth in the sam e radiograph, which helps in detection of caries (tooth decay) underneath llings or on the cont act surfaces. (Radiographs courtesy of Christian Friedrichs, DDM.)

Metal (am algam ) filling

Cavit y

Fig. 8.26 Mandibular incisors Single-rooted teeth have t wo root canals in one third of all cases. This radiograph shows a cross section of the dental root and a double periodont al space (see arrows).

Zygom atic arch

Fig. 8.27 Maxillary incisors The radioopaque spot s shown here distally on tooth 9 could indicate caries, open cavities, or non-radioopaque lling m aterial (as in the case here).

Root filling

Periapical area

Fig. 8.28 Mandibular te eth 28–31 Radiolucencies, such as those seen here near the crowns of teeth 30 and 31, can be the result of m et al inlays, crowns, am algam llings, or m odern zinc oxide ceram ics.

Pulp stone

Deep carious lesion

Fig. 8.29 Maxillary te eth 2–5 In this area of the m axilla, superim position of teeth and the zygom atic arch frequently occurs (see the upper left m argin). The root s of the m olars are less clearly visible.

Fig. 8.30 Maxillary te eth 12–15 An infection of the root canal system , which has spread to the periapical bone can lead to the form ation of a stula. In order to be able to exactly locate the infection, a gut ta-percha root- lling point is inserted into the stula from out side. Around the distobuccal root of tooth 14, a periapical radioopaque area indicating the infection is visible. Tooth 15 has been capped with a crown.

Dentine caries

Enam el caries

Fig. 8.31 Bitew ings for the diag no sis o f caries There is m assive carious dam age on the distal surface of tooth 30 and there are also enam el caries and the beginning of dentine caries at the cont act point s of alm ost all teeth. In addition to the occlusal surfaces, the cont act point s represent sites of predilection for caries. Note the pulp stones visible in the lum en of the pulp cham bers.

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Lingual Mucosa Palatopharyngeal arch

Epiglot tis

Lingual tonsil

Foram en cecum Palatine tonsil Palatoglossal arch

Posterior (pharyngeal) part

Sulcus term inalis

Dorsum

See detail in Fig. 8.33A

Anterior (oral) part

Fig. 8.32 Surface anatomy of the ling ual mucosa Superior view. The part s of the tongue are the root, the ventral (inferior) surface, the apex, and the dorsal (superior) surface. The V-shaped furrow on the dorsum (sulcus term inalis) divides the dorsal surface into an oral portion (com prising the anterior t wo thirds) and a pharyngeal portion (com prising the posterior one third). The tongue’s very powerful m uscular body m ake possible it s m otor functions in m astication, swallowing, and speaking. It s specialized m ucosal coat covering the dorsum of the tongue m ake possible it s equally im port ant sensory functions (including t aste and ne tactile discrim ination). The hum an tongue contains approxim ately 4600 t aste buds, in which the secondary sensory cells for t aste perception are collected. The t aste buds are em bedded in the epithelium of the lingual m ucosa and it s surface expansions, the papillae (see Fig 8.33). Additionally, isolated t aste buds are located in the m ucous m em branes of the soft palate and pharynx. Hum ans can perceive ve basic t aste qualities: sweet, sour, salt y, bit ter, and um am i.

Median furrow

Apex

Filiform papillae

Circumvallate papilla

Fungiform papilla

Papilla

Nonkeratinized, stratified squam ous epithelium Lingual aponeurosis Lingual m uscles

Sulcus Wall of papilla Taste buds

Excretory duct of a serous gland Keratinized squam ous epithelium on tips of papillae

A

B

Foliate papillae

Tip of papilla (partially covered by keratinized epithelium )

Taste buds

Connective tissue nerve

C

Serous glands (von Ebner glands)

Excretory duct of gland

D

Serous gland

E

Fig. 8.33 Papillae of the tong ue The m ucosa of the anterior dorsum is com posed of num erous papillae (A) and the connective tissue bet ween the m ucosal surface and m usculature, which cont ains m any sm all salivary glands. The papillae are divided into four m orphologically distinct t ypes (see Table 8.5): • Circumvallate (B): Encircled and containing t aste buds. • Fungiform (C): Mushroom -shaped and cont aining m echanical and

therm al receptors and t aste buds. • Filiform (D): Thread-shaped and sensitive to t actile stim uli (the only lingual papillae without t aste buds). • Folliate (E): Cont aining t aste buds. The surrounding serous glands of the tongue (Von Ebner glands), which are m ost closely associated with circumvallate papilla, const antly wash the t aste buds clean to allow for new t asting.

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Ta ble 8.5 Re g ions and structures of the tong ue Re g io n

Structure s

Ante rior (oral, presulcal) po rtion o f the to ng ue

The anterior ⅔ of the tongue cont ains the apex and the m ajorit y of the dorsum . It is tethered to the oral oor by the lingual frenulum . • Mucosa: ◦ Dorsal lingual m ucosa: This portion (with no underlying subm ucosa) cont ains num erous papillae. ◦ Ventral m ucosa: Covered with the sam e sm ooth (nonkeratinized, strati ed squam ous epithelial) m ucosa that lines the oral oor and gingiva. • Inne rvation: The anterior portion is derived from the rst (pharyngeal) arch and is therefore innervated by the lingual nerve, a branch of the m andibular nerve (CN V3 ).

Me dian furrow (midline se ptum): The furrow running anteriorly down the m idline of the tongue; this corresponds to the position of the lingual septum . Note: Muscle bers do not cross the lingual septum . Papillae (Fig . 8.33A): The dorsal m ucosa, which has no subm ucosa, is covered with nipplelike projections (papillae) that increase the surface area of the tongue. There are four t ypes, all of which occur in the presulcal but not post sulcal portion of the tongue. • Circumvallate (Fig . 8.33B): Encircled by a wall and cont aining abundant t aste buds. • Fungiform (Fig . 8.33C): Mushroom -shaped papillae located on the lateral m argin of the posterior oral portion near the palatoglossal arches. These have m echanical receptors, therm al receptors, and t aste buds. • Filiform (Fig . 8.33D): Thread-shaped papillae that are sensitive to t actile stim uli. These are the only papillae that do not cont ain t aste buds. • Foliate (Fig . 8.33E): Located near the sulcus term inalis, these cont ain num erous t aste buds.

Sulcus te rminalis

The sulcus term inalis is the V-shaped furrow that divides the tongue functionally and anatom ically into an anterior and a posterior portion.

Forame n ce cum: The em bryonic rem nant of the passage of the thyroid gland that m igrates from the dorsum of the tongue during developm ent. The foram en cecum is located at the convergence of the sulci term inalis.

Poste rior (pharyng e al, postsulcal) portio n o f the tong ue

The base (root) of the tongue is located posterior to the palatoglossal arches and sulcus term inalis. • Mucosa: The sam e m ucosa that lines the palatine tonsils, pharyngeal walls, and epiglot tis. The pharyngeal portion of the tongue does not cont ain papillae. • Inne rvation: The posterior portion is innervated by the glossopharyngeal nerve (CN IX). A sm all m idline area at the root of the tongue is innervated by the vagus nerve (CN X)

Ling ual tonsils: The subm ucosa of the posterior portion cont ains em bedded lym ph nodes known as the lingual tonsils, which create the uneven surface of the posterior portion. Oro pharynx: The region posterior to the palatoglossal arch. The oropharynx, which cont ains the palatine tonsils, com m unicates with the oral cavit y via the oropharyngeal isthm us (de ned by the palatoglossal arches).

Glossoe pig lottic folds and e pig lottic valle culae : The (nonkeratinized, strati ed squam ous) m ucosal covering of the posterior tongue and pharyngeal walls is re ected onto the anterior aspect of the epiglot tis, form ing one m edian and t wo lateral glossoepiglot tic folds. The m edian glossoepiglot tic fold is anked by t wo depressions, the epiglot tic valleculae.

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Glossal Muscles There are t wo set s of lingual m uscles: extrinsic and intrinsic. The extrinsic m uscles, which are at t ached to speci c bony sites out side the tongue, m ove the tongue as a whole. The intrinsic m uscles, which have

no at t achm ent s to skelet al structures, alter the shape of the tongue. With the exception of the palatoglossus, the glossal m uscles are innervated by the hypoglossal nerve (CN XII).

Dorsum of tongue Palatoglossus (cut)

St yloid process

Apex of tongue

St ylom andibular ligam ent St ylopharyngeus

St yloglossus Middle pharyngeal constrictor Mandible

Hyoglossus

Hyoid bone

A

Genioglossus

Geniohyoid

Lingual aponeurosis

Inferior pharyngeal constrictor

Fig. 8.34 Extrinsic and intrinsic ling ual muscles A Left lateral view. B Anterior view of coro nal section.

Lingual m ucosa

Superior longitudinal m uscle Vertical m uscle of tongue

Lingual septum

Transverse m uscle of tongue

Inferior longitudinal m uscle Hyoglossus Genioglossus

Sublingual gland Mylohyoid

B Geniohyoid

Digastric, anterior belly

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Ta ble 8.6 Muscle s of the tong ue Muscle

Orig in

Inse rtion

Inne rvation

Action

Inferior bers: Hyoid body (anterosuperior surface)

Hypoglossal n. (CN XII)

Protrusion of the tongue

Extrinsic ling ual muscles

Genioglossus

Mandible (superior genial [m ent al] spine via an interm ediate tendon); m ore posteriorly the t wo genioglossi are separated by the lingual septum

Bilaterally: Makes dorsum concave Unilaterally: Deviation to opposite side

Interm ediate bers: Posterior tongue Superior bers: Ventral surface of tongue (m ix with intrinsic m uscles)

Hyoglossus

Hyoid bone (greater horn and anterior body)

Lateral tongue, bet ween st yloglossus and inferior longitudinal m uscle

Depresses the tongue

St yloglossus

St yloid process of tem poral bone (anterolateral aspect of apex) and st ylom andibular ligam ent

Longitudinal part: Dorsolateral tongue (m ix with inferior longitudinal m uscle)

Elevates and retract s the tongue

Oblique part : Mix with bers of the hyoglossus Palatoglossus

Palatine aponeurosis (oral surface)

Lateral tongue to dorsum and bers of the transverse m uscle

Vagus n. (CN X) via the pharyngeal plexus

Elevates the root of the tongue; closes the oropharyngeal isthm us by contracting the palatoglossal arch

Superior longitudinal m uscle

Thin layer of m uscle inferior to the dorsal m ucosa; bers run anterolaterally from the epiglot tis and m edian lingual septum

Hypoglossal n. (CN XII)

Shortens tongue; m akes dorsum concave (pulls apex and lateral m argin upward)

Inferior longitudinal m uscle

Thin layer of m uscle superior to the genioglossus and hyoglossus; bers run anteriorly from the root to the apex of the tongue

Shortens tongue; m akes dorsum convex (pulls apex down)

Transverse m uscle

Fibers run laterally from the lingual septum to the lateral tongue

Narrows tongue; elongates tongue

Vertical m uscle

In the anterior tongue, bers run inferiorly from the dorsum of the tongue to it s ventral surface

Widens and at tens tongue

Intrinsic ling ual muscle s

Fig. 8.35 Unilate ral hypog lossal ne rve palsy Active protrusion of the tongue with an int act hypoglossal nerve (A) and with a unilateral hypoglossal nerve lesion (B). When the hypoglossal nerve is dam aged on one side, the genioglossus m uscle is paralyzed on the a ected side. As a result, the healthy (innervated) genioglossus on the opposite side dom inates the tongue across the m idline toward the a ected side. When the tongue is protruded, therefore, it deviates toward the paralyzed side.

Paralyzed genioglossus on affected side

A

Apex of tongue

B

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Neurovasculature of the Tongue Deep lingual artery

Lingual nerve

St yloid process

Glossopharyngeal nerve Preganglionic branches Subm andibular ganglion Dorsal lingual artery Hypoglossal nerve Hyoglossus

Mandible

Lingual artery and vein Deep lingual vein C1 fibers to thyrohyoid

A

Subm ental artery and vein (from facial artery and vein)

Sublingual artery

Hyoid bone

Sublingual vein

Thyrohyoid m em brane

Postganglionic branches

Fig. 8.36 Ne rves and vessels of the tong ue A Left lateral view. B View of the inferior surface of the tongue. The tongue is supplied by t he lingual artery (from t he e xternal carot id artery), which divides into it s term inal branches, t he deep lingual artery and t he sublingual artery. The dorsal lingual artery supplies t he root of t he tongue in t he oropharynx. The lingual vein usually runs parallel to t he artery but on t he m edial surface of t he hyoglossus m uscle and drains into t he internal jugular vein. The anterior t wo t hirds of t he lingual m ucosa receives it s somatosensory innervat ion (sensit ivit y to t herm al and t act ile st im uli) from t he lingual nerve, which is a branch of t he t rigem inal nerve’s m andibular division (CN V3 ). The lingual nerve t ransm it s fibers from t he chorda t ym pani of t he facial nerve (CN VII), am ong t hem t he afferent t aste fibers for t he anterior t wo t hirds of the tongue. The chorda t ym pani also cont ains presynapt ic, parasym pat het ic viscerom otor axons t hat synapse in t he subm andibular ganglion, whose neurons in t urn innervate t he subm andibular and sublingual glands. The palatoglossus receives it s somatomotor innervat ion from the vagus nerve (CN X) via t he pharyngeal plexus, t he ot her glossal m uscles from t he hypoglossal nerve (CN XII).

Apex of tongue

Anterior lingual glands

Frenulum

Sublingual fold Sublingual papilla

B

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Deep lingual artery and vein Lingual nerve Subm andibular duct

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Taste

Somatic sensation

Vagus nerve (CN X)

Vagus nerve (CN X)

Glossopharyngeal nerve (CN IX)

Glossopharyngeal nerve (CN IX)

Lingual nerve (m andibular nerve, CN V3 )

Facial nerve (CN VII via chorda tym pani)

Fig. 8.37 Inne rvation of the tong ue Anterior view. Left side: Som atosensory innervation. Right side: Taste innervation. The posterior one third of the tongue (post sulcal part) prim arily receives som atosensory and t aste innervation from the glossopharyngeal nerve (CN IX), with additional t aste sensation conveyed by the vagus nerve (CN X) via the internal laryngeal nerve. The anterior t wo thirds

of the tongue (presulcal part) receives it s som atosensory innervation (e.g., touch, pain, and tem perature) from the lingual nerve (branch of CN V3 ) and it s t aste sensation from the chorda t ym pani branch of the facial nerve (CN VII) distributed by the lingual nerve (CN V3 ). Disturbances of sensation in the presulcal tongue can therefore be used to determ ine facial or trigem inal nerve lesions.

Ta ble 8.7 Blood supply to the tong ue Blo od supply

So urce

Branches

Distributio n

Lingual a.

External carotid a.

Dorsal lingual aa.

Dorsal surface of posterior one third of tongue, palatoglossal arch, palatine tonsil, epiglot tis, soft palate

Sublingual a.

Floor of oral cavit y, sublingual gland and surrounding m ucosa and m uscles

Deep lingual a.

Ventral surface of tongue

Term inal branches

Dorsal surface of anterior t wo thirds of tongue

Subm ent al a.

Facial a. (from external carotid a.)

Anatom oses with sublingual a. to supply sublingual gland and surrounding oor of m outh

Tonsillar a.

Facial a. (from external carotid a.)

Root of tongue

Ascending pharyngeal a.

External carotid a.

Root of tongue

Ta ble 8.8 Ve nous drainag e of the tong ue Ve in

Tributaries

Re g ion draine d

Drains to

Lingual v.

Deep lingual vv.

Ventral surface of tongue

Internal jugular v.

Dorsal lingual vv.

Dorsum of tongue

Subm ent al v.

Anatom oses with branches of lingual vv. to help drain tongue

Facial v.

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Gustatory Pathw ay

Ventral posterom edial nucleus of thalam us

Postcentral gyrus

Insula

Dorsal tegm ental nucleus Dorsal trigem inothalam ic tract Oval nucleus Facial nerve Medial parabrachial nucleus

Geniculate ganglion Inferior (petrosal) ganglion

Gustatory part

Chorda t ympani

Solitary tract nucleus Dorsal m otor nucleus

Lingual nerve Inferior (nodose) ganglion

Spinal nucleus of trigem inal nerve

Vagus nerve

Epiglot tis

Glossopharyngeal nerve

Fig. 8.38 Gustatory pathw ay The receptors for the sense of t aste are the t aste buds of the tongue (see Fig . 8.39). Unlike other receptor cells, the receptor cells of the t aste buds are specialized epithelial cells (secondary sensory cells, as they do not have an axon). When these epithelial cells are chem ically stim ulated, the base of the cells releases glut am ate, which stim ulates the peripheral processes of a erent cranial nerves. These di erent cranial nerves serve di erent areas of the tongue. It is rare, therefore, for a com plete loss of t aste (ageusia) to occur. • The anterior two thirds of the tongue is supplied by the facial nerve (CN VII), the a erent bers rst passing in the lingual nerve (branch of the trigem inal nerve) and then in the chorda t ym pani to the geniculate ganglion of the facial nerve. • The posterior third of the tongue and the vallate papillae are supplied by the glossopharyngeal nerve (CN IX). A sm all area on the posterior third of the tongue is also supplied by the vagus nerve (CN X). • The epiglottis and valleculae are supplied by the vagus nerve (CN X). Peripheral processes from pseudounipolar ganglion cells (which correspond to pseudounipolar spinal ganglion cells) term inate on the t aste buds. The central portions of these processes convey taste inform ation to the gustatory part of the nucleus of the solit ary tract. Thus, they function as the rst a erent neuron of the gust atory pathway. Their

cell bodies are located in the geniculate ganglion for the facial nerve, in the inferior (petrosal) ganglion for the glossopharyngeal nerve, and in the inferior (nodose) ganglion for the vagus nerve. After synapsing in the gust atory part of the nucleus of the solit ary tract, the axons from the second neuron are believed to term inate in the m edial parabrachial nucleus, where they are relayed to the third neuron. Most of the axons from the third neuron cross to the opposite side and pass in the dorsal trigem inothalam ic tract to the contralateral ventral posterom edial nucleus of the thalam us. Som e of the axons travel uncrossed in the sam e structures. The fourth neurons of the gustatory pathway, located in the thalam us, project to the postcentral gyrus and insular cortex, where the fth neuron is located. Collaterals from the rst and second neurons of the gustatory a erent pathway are distributed to the superior and inferior salivatory nuclei. A erent im pulses in these bers induce the secretion of saliva during eating (“salivary re ex”). The parasym pathetic preganglionic bers exit the brainstem via cranial nerves VII and IX (see the descriptions of these cranial nerves for det ails). Besides this purely gust atory pathway, spicy foods m ay also stim ulate trigem inal bers (not shown), which contribute to the sensation of t aste. Finally, olfaction (the sense of sm ell), too, is a m ajor com ponent of the sense of taste as it is subjectively perceived: patient s who cannot sm ell (anosm osia) report that their food tastes abnorm ally bland.

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Epiglot tis Taste bud

Lateral glossoepiglot tic fold

Vallecula

Median glossoepiglot tic fold

Foram en cecum

Serom ucous glands

Sulcus term inalis Circumvallate papilla (B)

Foliate papillae (D)

B

Taste bud

Taste bud

Fungiform papillae (C)

A

C

Fig. 8.39 Organization of the taste re ce ptors in the tong ue The hum an tongue contains approxim ately 4600 t aste buds in which the secondary sensory cells for taste perception are collected. The t aste buds are em bedded in the epithelium of the lingual m ucosa and are located on the surface expansions of the lingual m ucosa —the circumvallate papillae (principal site, B), the fungiform papillae (C), and the foliate papillae (D). Additionally, isolated t aste buds are located in

Nonkeratinized squam ous epithelium

Taste pore

Light taste cell

D

the m ucous m em branes of the soft palate and pharynx. The surrounding serous glands of the tongue (Ebner glands), which are m ost closely associated with the circumvallate papillae, const antly wash the t aste buds clean to allow for new t asting. Hum ans can perceive ve basic t aste qualities: sweet, sour, salt y, bit ter, and a fth “savory” qualit y, called um am i, which is activated by glut am ate (a t aste enhancer).

Fig. 8.40 Microscopic structure of a taste bud Nerves induce the form ation of t aste buds in the oral m ucosa. Axons of cranial nerves VII, IX, and X grow into the oral m ucosa from the basal side and induce the epithelium to di erentiate into the light and dark t aste cells (= m odi ed epithelial cells). Both t ypes of t aste cell have m icro villi that extend to the gust atory pore. For sour and salt y, the t aste cell is stim ulated by hydrogen ions and other cations. The other t aste qualities are m ediated by receptor proteins to which the lowm olecular-weight avored substances bind (details m ay be found in textbooks of physiology). When the low-m olecular-weight avored subst ances bind to the receptor proteins, they induce signal transduction that causes the release of glutam ate, which excites the peripheral processes of the pseudounipolar neurons of the three cranial nerve ganglia. The taste cells have a life span of approxim ately 12 days and regenerate from cells at the base of the t aste buds, which di erentiate into new taste cells. Note: The old notion that particular areas of the tongue are sensitive to speci c t aste qualities has been found to be false.

Dark taste cell

Nerve

Basal cell

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Floor of the Oral Cavity

St yloid process Mastoid process Digastric, posterior belly Hyoglossus Mylohyoid

St ylohyoid Digastric, interm ediate tendon

Digastric, anterior belly

Connective tissue sling Infrahyoid muscles (sternohyoid, thyrohyoid, and om ohyoid)

Hyoid bone

A

Sublingual fold

Sublingual papilla

Oral m ucosa

Genioglossus (cut)

Geniohyoid

Mylohyoid

Hyoid bone

Hyoglossus St ylohyoid

B

Fig. 8.41   Muscles of the  oral  oor A Left lateral view. B Superior view. Strictly speaking the oor of the oral cavit y is com posed only of the mylohyoid and geniohyoid m uscles. However, other suprahyoid m uscles contribute to this region. The suprahyoid m uscles also play an im port ant role in swallowing

(see Table 8.6). The suprahyoid and infrahyoid m uscles at t ach to the hyoid bone inferiorly and superiorly, respectively. The infrahyoid m uscles depress the hyoid m uscles during phonation and swallowing. These m uscles are discussed in detail on pages 312 and 313.

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Ta ble 8.9 Muscle s contributing  to the  oral  oor and surrounding  re g ions Muscle

Orig in

Inse rtion

Mylohyoid

Mandible (mylohyoid line)

Hyoid bone (body)

Geniohyoid

Digastric*

Inne rvation

Action

Via m edian tendon of insertion (mylohyoid raphe)

Mylohyoid n. (CN V3 )

Tightens and elevates oral oor; draws hyoid bone forward (during swallowing); assist s in opening m andible and m oving it side to side (m astication)

Mandible (inferior genial [m ent al] spines)

Directly insert s into hyoid

Anterior ram us of C1

Draws hyoid bone forward (during swallowing); assist s in opening m andible

Anterior belly

Mandible (digastric fossa)

Mylohyoid n. (CN V3 )

Posterior belly

Tem poral bone (m astoid notch, m edial to m astoid process)

Via an interm ediate tendon with a brous loop

Elevates hyoid bone (during swallowing); assist s in depressing m andible

Via a split tendon

Facial n. (CN VII)

St ylohyoid*

Tem poral bone (st yloid process)

Facial n. (CN VII)

* Not true m uscles of the oor of the oral cavit y.

Sublingual papilla Sublingual fold

Oral m ucosa Genioglossus Sublingual gland

Geniohyoid

Subm andibular duct

Mylohyoid Lingual nerve

Subm andibular gland

Inferior alveolar nerve

Mylohyoid nerve

Lingual artery

Hyoid bone

Hyoglossus St ylohyoid

Fig. 8.42   Topography of the  oral  oor The geniohyoid m uscle is supplied by the sublingual artery, a branch of the lingual artery, and the subm ent al artery, a branch of the facial artery. The sublingual artery also supplies the ventral surface of the tongue and m ucosa of the oral oor. The mylohyoid m uscle is supplied by the mylohyoid branch of the inferior alveolar artery. Venous drainage is via the sublingual vein, which drains into the internal jugular vein. Sensory innervation is via the lingual nerve (CN V3 ). Lym phatic drainage is via the subm ent al and subm andibular nodes.

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Salivary Glands Fig. 8.43 Major salivary g lands A Left lateral view. B Superior view. There are three m ajor (large, paired) salivary glands: parotid, subm andibular, and sublingual. They collectively produce 0.5 to 2.0 liters of saliva per day, excreted into the oral cavit y via excretory duct s. The saliva keeps the oral m ucosa m oist. It also has digestive and protective functions: saliva cont ains the starch-split ting enzym e amylase and the bactericidal enzym e lysozym e.

Accessory parotid gland

1. Parotid glands: Largest of the salivary glands; wedge-shaped but variable; the facial nerve splits the parotid gland into super cial and deep lobes, which are connected by an isthm us; the parotid duct (Stensen’s duct) arises from the deep lobe and crosses the face super cial to the masseter, pierces the buccinators, and opens into the oral vestibule opposite the second upper molar (see Fig 8.1C); it is a purely serous gland (watery secretions). Malignant tumors of the parotid gland m ay invade surrounding structures directly or indirectly via regional lymph nodes (see Fig 3.27). They m ay also spread systematically through the vascular system . 2. Submandibular glands: Second largest of the salivary glands is located in the oor of the oral cavit y, where it wraps around the posterior border of mylohyoid; the submandibular duct (Wharton’s duct) opens on to the sublingual papilla behind the lower incisors; it is a mixed serom ucous gland (watery and mucus secretions). 3. Sublingual glands: The sm allest of the three m ajor salivary glands; it is located anterior in the oor of the oral cavit y bet ween the oral m ucosa and the mylohyoid; the sublingual gland has m any sm aller excretory ducts that open on the sublingual fold or into the subm andibular gland; it is predom inantly a m ucus-secreting gland (mucoserous). The salivary glands are a potential site of tumor form ation. The majorit y of such tumors are benign and occur in the supercial lobe of the parotid gland. These are pleom orphic adenom as. The tum ors cells can lie outside the capsule and so treatment involves surgical excision of the super cial lobe with a m argin. Malignant tumors of the parotid gland, for example, adenolymphom a, are suspected if there is pain, rapid growth, xation to surrounding tissues, and involvem ent of the facial nerve. Tumors of the subm andibular, sublingual, and minor salivary glands are more likely to be malignant.

Parotid gland

Parotid duct

Buccinator Masseter A

Facial artery and vein

Subm andibular gland

Sublingual fold

Sternocleidom astoid

Sublingual papilla Oral m ucosa Genioglossus Sublingual gland

Geniohyoid

Subm andibular duct

Mylohyoid

Subm andibular gland, intraoral lobe

Lingual nerve Inferior alveolar nerve

Mylohyoid nerve

Lingual artery

B

Hyoid bone

Subm andibular gland, extraoral lobe Hyoglossus Stylohyoid

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Labial glands

Subm andibular gland

Palatine glands

Sublingual gland Lymph node

Pharyngeal glands

Fig. 8.44 Minor salivary g lands In addition to the three m ajor paired glands, 700 to 1000 m inor glands secrete saliva into the oral cavit y. They produce only 5 to 8 percent of the tot al output, but this am ount su ces to keep the m outh m oist when the m ajor salivary glands are not functioning.

Fig. 8.45 Bimanual e xamination of the salivary g lands The t wo salivary glands of the m andible, the subm andibular gland and sublingual gland, and the adjacent lym ph nodes are grouped around the m obile oral oor and therefore m ust be palpated against resist ance. This is done with bim anual exam ination.

Ta ble 8.10 Summary of salivary glands Gland and duct

Autono mic inne rvatio n

Blood supply

Parotid - Parotid duct (Stensen’s duct)

Glossopharyngeal n. (CN IX) — Preganglionic parasym pathetic bers arise from the inferior salivary nucleus in the m edulla and travel with the inferior petrosal n. (from CN IX) to the otic ganglion — Postganglionic parasym pathetic bers arise in the otic ganglion and travel with the auriculotem pral nerve (of CN V3 ) to the parotid gland

Glandular branches from the external carotid a. and super cial tem poral a.

Subm andibular - Subm andibular duct (Wharton’s duct)

Facial n. (CN VII) — Preganglionic parasym pathetic bers arise from the superior salivary nucleus in the pons. In the facial canal it gives rise to t wo parasym pathetic branches: the greater petrosal n. and the chorda t ym pani n. o The greater petrosal n. joins the deep petrosal n. (sym pathetic) to form the nerve of the pterygoid canal (vidian n.). It then travels to the pterygopalatine ganglion. o The chorda t ym pani joins the lingual n. and travels to the subm andibular ganglion. — Postganglionic parasym pathetic bers from the ptergopalatine ganglion travel with CN V2 to the nasal, palatine, pharyngeal and superior labial glands. Other postganglionic parasym pathetic bers travel via CN V2 to the lacrim al n. (of CN V1 ) to the lacrim al gland. — Postganglionic parasym pathetic bers from the subm andibular ganglion travel to the subm andibular and sublingual glands.

Glandular branches of facial a.

Sublingual - Multiple sm all duct s that open on the sublingual fold or into the subm andibular duct Minor salivary glands - Sm all duct s open directly on the m ucosa of the oral cavit y and oropharynx

Glandular branches of sublingual a.

Lym ph from the parotid gland drains to the super cial and deep cervical nodes; lym ph from the subm andibular gland drains to the deep cervical nodes; lym ph from the subm andibular gland drains to the subm andibular nodes.

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Hard & Soft Palates The palate form s the roof or the oral cavit y and the oor of the nasal cavit y. It is divided into a bony hard palate and a m uscular soft palate.

Incisive papilla

Rugae Nasopalatine nerve

Incisive fossa

Palatine raphe

Greater palatine artery and nerve

Palatine glands

Greater palatine foram en Superior constrictor

Palatine aponeurosis

Pterygom andibular raphe

Lesser platine artery and nerves (from lesser palatine foram en)

Buccinator Uvular m uscle Palatine tonsil

Palatoglossus Palatopharyngeus

Fig. 8.46 Hard palate Anterior view. The hard palate is form ed by the palatine process of the m axilla and the horizont al plate of the palatine bone. It is covered with tough m asticatory m ucosa, which form s irregular folds anteriorly, known as ruggae, which aid in guiding food toward the pharynx. The m ucosa is tightly bound to the periosteum of the bones of the hard palate. The m ucosa m ay becom e stripped o of the periosteum when local anesthetic solution is introduced into the palate, which is very painful. The hard palate receives it blood supply from the greater palatine artery which arises from the m axillary artery. Veins drain to the pterygoid plexus. Lym ph from the hard palate m ost com m only drains to the subm andibular nodes or directly to the superior deep cervical nodes. The hard palate is innervated by branches of the m axillary division of

the trigem inal nerve (CN V2 ). The anterior one third of the palate is innervated by the nasopalatine nerve, which em erges from the incisive foram en. The posterior t wo thirds is innervated by the greater palatine nerve, which em erges from the greater palatine foram en along with the greater palatine artery (and the lesser palatine nerves and artery, which innervates and supplies the soft palate). This view also shows the pterygom andibular raphe, which is a ligam ent form ed from the buccopharngeal fascia. It at t aches superiorly to the pterygoid ham ulus and inferiorly to the mylohyoid line of the m andible. The buccinator m uscle is at t ached to the pterygom andibular raphe anteriorly and the superior constrictor of the pharynx posteriorly. The raphe form s an im port ant landm ark for the adm inistration of an inferior alveolar nerve block (see p. 483).

Ta ble 8.11 Ne urovasculature of the hard palate Blo od supply

Ve nous drainag e

Inne rvation

Lymphatic drainag e

Greater palatine a., sphenopalatine a.*

Pterygoid plexus

- Anterior one third: nasopalatine n. (from CN V2 ) - Posterior t wo thirds: greater palatine n. (from CN V2 )

- Subm andibular nodes - Superior deep cervical nodes - Retropharyngeal nodes (rarely)

*Supplies the aspect of the hard palate that form s the oor of the nasal cavit y.

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Ta ble 8.12 Muscle s of the soft palate Muscle

Orig in

Inse rtion

Inne rvation

Actio n

Tensor veli palatini

Sphenoid bone (scaphoid fossa of pterygoid process and m edial aspect of the spine; it is connected to the anterolateral m em branous wall of the pharyngot ym panic (auditory tube)

Palatine aponeurosis and palatine bone (horizont al plate) via a tendon that is redirected m edially by the pterygoid ham ulus

N. to m edial pterygoid (CN V3 )

Bilaterally: tenses anterior portion of the soft palate and at tens it s arch, separating the nasopharynx from oropharynx. Opens pharyngot ym panic (auditory) tube. Unilaterally: deviates soft palate laterally.

Levator veli palatini

Vaginal process and petrous part of tem poral bone (via a tendon, anterior to the carotid canal); it is connected to the inferior portion of the pharyngot ym panic tube

Palatine aponeurosis (the t wo levators com bine to form a m uscular sling)

Vagus n. (CN X) via pharyngeal plexus

Bilaterally: pulls the posterior portion of the soft palate superoposteriorly, separating the nasopharynx from the oropharynx.

Uvular m uscle (m usculus uvulae)

Palatine bone (posterior nasal spine) and palatine aponeurosis (superior surface)

Mucosa of the uvula

Pulls the uvula posterosuperiorly, separating the nasopharynx from the oropharynx.

Palatoglossus (palatoglossal arch)

Palatine aponeurosis (oral surface)

Lateral tongue to dorsum or intrinsic transverse m uscle

Bilaterally: pulls the root of the tongue superiorly narrowing the oropharngeal isthm us, separating the oral cavit y from the oropharynx.

Sensory innervation: lesser palatine nn. (from CN V2 ) Blood supply: lesser palatine a. (from m axillary a.), ascending palatine a. (from facial a.), palatine branch of the ascending pharyngeal a. (from external carotid a.) Venous drainage: greater and lesser palatine vv. to pterygoid plexus Lym phatic drainage: subm andibular nodes, retropharyngeal nodes

Masticatory m ucosa lining hard palate

Palatine bone (posterior portion of hard palate)

Palatine aponeurosis

Pterygoid ham ulus

Uvular muscle

Lateral pterygoid plate (sphenoid bone)

Uvula

Tensor veli palatini Soft palate

Levator veli palatini Pharyngeal tubercle (occipital bone)

Carotid canal

Fig. 8.47 Muscles of the soft palate and pharyng otympanic tube Inferior view. The soft palate is the aponeurotic and m uscular region hanging from the hard palate at the posterior portion of the oral cavit y. It separates the oropharynx from the nasopharynx, particularly during swallowing when it is tensed. The palatoglossus restrict s the com m unication bet ween the oral cavit y and oropharynx. The tensor veli palatini has a signi cant role in keeping open the pharyngot ym panic (auditory) tube.

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Pharynx: Divisions & Contents Sphenoid bone Groove for sigm oid sinus Middle nasal turbinate

Pharyngeal tonsil Pharyngeal recess

Nasal septum

Choanae

Inferior nasal turbinate

St ylohyoid Digastric m uscle, posterior belly

Salpingopharyngeal fold

Masseter

Soft palate

Faucial (oropharyngeal) isthm us, posterior border

Uvula

Medial pterygoid Palatine tonsil

Palatopharyngeal arch

Aryepiglot tic fold

Root of tongue

Laryngeal inlet

Epiglot tis

Cuneiform tubercle Piriform recess

Corniculate tubercle Pharyngeal raphe (cut)

Thyroid gland

Trachea Esophagus

Fig. 8.48 Pharyng eal mucosa and musculature Posterior view. A Mucosal lining. B Internal m usculat ure. The m uscular posterior wall of t he pharynx has been divided along t he m id-

line (pharyngeal raphe) and spread open to dem onst rate it s m ucosal anatom y.

Ta ble 8.13 Levels of the pharynx The anterior portion of the m uscular pharyngeal tube com m unicates with three cavities (nasal, oral, and laryngeal). The three anterior openings divide the pharynx into three part s with corresponding vertebral levels. Re g io n

Level

Descriptio n

Co mmunicatio ns

Nasopharynx (Epipharynx)

C1

Upper portion, lying bet ween the roof (form ed by sphenoid and occipit al bones) and the soft palate

Nasal cavit y

Via choanae

Tym panic cavit y

Via pharyngot ym panic tube

Oropharynx (Mesopharynx)

C2–C3

Middle portion, lying bet ween the uvula and the epiglot tis

Oral cavit y

Via oropharyngeal isthm us (form ed by the palatoglossal arch)

Laryngopharynx (Hypopharynx)

C4–C6

Lower portion, lying bet ween the epiglot tis and the inferior border of the cricoid cartilage

Larynx

Via laryngeal inlet

Esophagus

Via cricopharyngeus (pharyngeal sphincter)

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Fig. 8.49 Waldeye r’s ring Posterior view of the opened pharynx. Waldeyer’s ring is com posed of im m unocom petent lymphatic tissue (tonsils and lymph follicles). The tonsils are “im m unological sentinels” surrounding the passageways from the m outh and nasal cavit y to the pharynx. The lymph follicles are dis tributed over all of the epithelium , showing m arked regional variations. Waldeyer’s ring consists of the following structures: • Unpaired pharyngeal tonsil on the roof of the pharynx • Paired palatine tonsils in the oropharynx bet ween the anterior and posterior pillars (the palatoglossal arch and the palatopharyngeal arch) • Lingual tonsil, the lym ph nodes em bedded in the post sulcal portion of the tongue • Paired tubal tonsils (tonsillae tubariae), which m ay be thought of as lateral extensions of the pharyngeal tonsil • Paired lateral bands in the salpingopharyngeal fold

8. Ora l Cavit y & Pha rynx

Roof of pharynx (sphenoid and occipital bones)

Pharyngeal tonsil

Tubal tonsil

Nasal conchae Soft palate

Uvula Palatine tonsil

Lymphatic tissue of lateral bands (salpingopharyngeal fold)

Palatopharyngeal arch Lingual tonsil (postsulcal portion of tongue) Epiglot tis

Enlarged palatine tonsil

Choana

Enlarged pharyngeal tonsil

A B

Fig. 8.50 Abnormal e nlarg e me nt of the pharyng e al and palatine to nsils A Anterior view of the oral cavit y. B Sagit tal section through the roof of the pharynx. A Severe enlargem ent of the palatine tonsil (due to viral or bacterial infection, as in tonsillitis) m ay signi cantly narrow the outlet of the oral cavit y, causing di cult y in swallowing (dysphagia). Tonsillectomy, surgical rem oval of the palatine tonsil from the tonsillar bed along with it s accom panying fascia, m ay dam age the glossopharyngeal nerve (CN IX), which lies on the lateral wall of the pharynx. This could result in

loss of sensation and t aste from the posterior one third of the tongue. B An enlargem ent of the pharyngeal tonsil is very com m on in preschool-aged children. Chronic recurrent nasopharyngeal infections at that age often evoke a heightened im m une response in the lym phatic tissue, causing “adenoids” or “polyps.” The enlarged pharyngeal tonsil blocks the choanae, obstructing the nasal airway and forcing the child to breathe through the m outh. Because the m outh is const antly open during respiration at rest, an experienced exam iner can quickly diagnose the adenoidal condition by visual inspection.

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Muscles of the Pharynx (I) Tensor veli palatini

Levator veli palatini

1st gap Pterygopharyngeal part Buccopharyngeal part Mylopharyngeal part

Superior pharyngeal constrictor

Ta ble 8.14 Pharyng eal gaps

Glossopharyngeal part Chondropharyngeal part

2nd gap

Ceratopharyngeal part

Hyoid bone 3rd gap

Cricothyroid

Thyropharyngeal part

Straight part

Cricopharyngeal part

Oblique part

Middle pharyngeal constrictor

Gap

Transmitte d structure s

1st gap

Pharyngot ym panic tube Levator veli palatini

2nd gap

St ylopharyngeus (insert s on larynx) Glossopharyngeal n. (CN IX)

Inferior pharyngeal constrictor

3rd gap

Internal laryngeal n. Superior laryngeal a. and v.

4th gap

Recurrent laryngeal n.

4th gap

Inferior laryngeal a.

Esophagus

Trachea

Fig. 8.51 Pharyng eal constrictors Left lateral view.

Ta ble 8.15 Pharyng eal constrictors Muscle

Superior pharyngeal constrictor

Middle pharyngeal constrictor

Inferior pharyngeal constrictor

Orig in

Inse rtio n

Inne rvatio n

Actio n

Pterygopharyngeus

Pterygoid ham ulus (occasionally to the m edial pterygoid plate)

Vagus n. (CN X) via pharyngeal plexus

Constrict s the upper pharynx

Buccopharyngeus

Pterygom andibular raphe

Mylopharyngeus

Mylohyoid line of m andible

Glossopharyngeus

Lateral tongue

Occipit al bone (pharyngeal tubercle of basilar part, via m edian pharyngeal raphe)

Chondropharyngeus

Hyoid (lesser horn) and st ylohyoid ligam ent

Ceratopharyngeus

Hyoid (greater horn)

Thyropharyngeus

Thyroid lam ina and hyoid bone (inferior horn)

Cricopharyngeus

Cricoid cartilage (lateral m argin)

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Constrict s the m iddle pharynx

Constrict s the lower pharynx

Recurrent laryngeal n. (CN X) and/or external laryngeal n.

Sphincter at intersection of laryngopharynx and esophagus

Regions of the Hea d

Corticonuclear tract

To thalam us and cortex (m edial lem niscus)

Mesencephalic nucleus of trigem inal nerve (CN V)

To nucleus of reticular form ation (gag and swallowing reflex)

Principal sensory (pontine) nucleus of trigem inal nerve (CN V)

Solitary nucleus Glossopharyngeal nerve (CN IX)

Sensation (pain, tem perature, touch)

Nucleus am biguus IX

From the ear (t ympanic nerve)

8. Ora l Cavit y & Pha rynx

Superior and inferior ganglia

X

Vagus nerve (CN X)

Sensation Direct m otor branch to st ylopharyngeus

Taste Spinal nucleus of trigem inal nerve (CN V)

St ylopharyngeus

Pharyngeal plexus

Pharyngeal constrictor

Branchiom otor General som atic sensory Special visceral sensory General visceral sensory

Larynx

Fig. 8.52 Pharyng eal ple xus The pharynx receives sensory and m otor innervation via the pharyngeal plexus, form ed by both the glossopharyngeal (CN IX) and vagus (CN X) nerves, along with postganglionic sympathetic bers from the superior cervical ganglion. Note: Only the vagus nerve contributes m otor bers to the plexus (the st ylopharyngeus is supplied directly by CN IX).

Soft palate

Epiglot tic cartilage

Oral floor

Thyrohyoid

Hyoid bone

Cricoid cartilage

A

Epiglot tic cartilage

Oral floor

Thyroid cartilage

Hyoid bone

Passavant ridge (contracted superior pharyngeal constrictor)

Soft palate

Thyrohyoid B

Fig. 8.53 Sw allow ing The larynx, part of the airway, is located at the inlet to the digestive tract (A). During swallowing (B), the airway m ust be occluded to keep food from entering the larynx and the trachea (preventing choking). Swallowing consist s of three phases: 1. Oral st age (voluntary initiation): The lingual m uscles m ove the food bolus to the oropharyngeal isthm us, which rst expands and then contract s.

Thyroid cartilage Cricoid cartilage Esophagus

2. Pharyngeal stage (re ex closure of airway): The longitudinal pharyngeal m uscles elevate the larynx. The lower airway (laryngeal inlet) is covered by the epiglot tis. Meanwhile, the soft palate is tensed and elevated against the posterior pharyngeal wall, sealing o the upper airway. 3. Pharyngoesophageal st age (re ex transport): The constrictors m ove the food bolus to the stom ach.

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Muscles of the Pharynx (II)

Tensor veli palatini

Levator veli palatini

Pharyngobasilar fascia

Superior pharyngeal constrictor St ylohyoid Buccinator St yloglossus Digastric posterior belly St ylopharyngeus Hyoglossus

Mylohyoid

Middle pharyngeal constrictor Thyrohyoid m em brane

Digastric anterior belly

Inferior pharyngeal constrictor

Sternohyoid Thyrohyoid Straight part Cricothyroid Oblique part

Esophagus Trachea

Fig. 8.54 Pharyng eal musculature Left lateral view.

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Ta ble 8.16 Pharyng e al elevators Muscle

Orig in

Inse rtion

Inne rvation

Action

Palatopharyngeus (palatopharyngeal arch)

Palatine aponeurosis (superior surface) and posterior border of palatine bone

Thyroid cartilage (posterior border) or lateral pharynx

Vagus n. (CN X) via pharyngeal plexus

Bilaterally: Elevates the pharynx anterom edially.

Salpingopharyngeus

Cartilaginous pharyngot ym panic tube (inferior surface)

Along salpingopharngeal fold to palatopharyngeus

St ylopharyngeus

St yloid process (m edial surface of base)

Lateral pharynx, m ixing with pharyngeal constrictors, palatopharyngeus, and thyroid cartilage (posterior border)

Bilaterally: Elevates the pharynx; m ay also open pharyngot ym panic tube. Glosso pharyngeal n. (CN IX)

Bilaterally: Elevates the pharynx and larynx.

Fig. 9.55 Muscle s of the soft palate and pharnyg eal elevators Posterior view.

Roof of pharynx (sphenoid and occipital bones)

Pharyngeal tonsil Cartilaginous part of pharyngot ympanic (auditory) tube

Levator veli palatini Salpingopharyngeus

Tubal orifice Tensor veli palatini

Superior pharyngeal constrictor

Medial pterygoid plate (sphenoid bone)

Uvular m uscle Palatopharyngeus

Pterygoid ham ulus

Vom er

Foram en ovale

Medial pterygoid plate

Fig. 9.56 Pharyng o basilar fascia at the base of the skull Inferior view. The pharyngeal m usculature arises from the base of the skull by a thick sheet of connective tissue, the pharyngobasilar fascia it s outline is (shown in red). The pharyngobasilar fascia ensures that the nasopharynx is always open.

Foram en lacerum Carotid canal Body of sphenoid bone

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Muscles of the Pharynx (III) & Innervation

Pharyngobasilar fascia

Superior pharyngeal constrictor

Masseter, deep part

Digastric, posterior belly

Masseter, superficial part

St ylohyoid Medial pterygoid St ylopharyngeus Middle pharyngeal constrictor

Hyoid bone, greater horn

Thyropharyngeus (inferior pharyngeal constrictor)

Pharyngeal raphe

Thyroid gland Cricopharyngeus (inferior pharyngeal constrictor)

A

Fig. 8.57 Pharyng eal musculature A Posterior view. B Internal m usculature. The pharynx is a m uscular tube com posed of three pharyngeal constrictors (Table 8.15) and three pharyngeal elevators (Table 8.16).

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Regions of the Hea d

Tensor veli palatini

8. Ora l Cavit y & Pha rynx

Levator veli palatini

St yloid process St ylohyoid Superior pharyngeal constrictor

Digastric, posterior belly Masseter, superficial and deep heads

Salpingopharyngeus Pharyngeal elevators

Uvular m uscle

Palatopharyngeus

Medial pterygoid Angle of m andible

St ylopharyngeus

Middle pharyngeal constrictor

Oblique arytenoid

Transverse arytenoid Inferior pharyngeal constrictor Posterior cricoarytenoid

Circular m uscle fibers of esophagus

B

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Neurovascular Topography of the Pharynx

Occipital bone Vagus nerve (CN X) Sigm oid sinus

Pharyngobasilar fascia

Superior jugular bulb (cut)

Pharyngeal raphe

Accessory nerve (CN XI)

Occipital artery

Hypoglossal nerve (CN XII)

Superior pharyngeal constrictor

St ylopharyngeus Superior cervical ganglion

Middle pharyngeal constrictor

Glossopharyngeal nerve (CN IX)

Internal jugular vein

Superior laryngeal nerve

Sternocleidom astoid

External carotid artery Internal carotid artery Ascending pharyngeal artery

Middle cervical ganglion

Hypoglossal nerve (CN XII) and decendens hypoglossi Carotid body

Pharyngeal venous plexus

Sympathetic trunk Inferior pharyngeal constrictor

Superior thyroid artery Vagus nerve (CN X)

Thyroid gland Parathyroid gland Esophagus A

Fig. 8.58 Ne urovascular topog raphy of the pharynx A Posterior view with fascia rem oved. B Posterior view with pharynx opened along pharyngeal raphe. The m ajorit y of the pharyngeal m uscles are supplied by m otor bers from the pharyngeal nerve plexus. Exceptions are the st ylopharyngeus m uscle, which is innervated by a m otor branch from glossopharyngeal nerve (CN IX), and the cricopharyngeus m uscle (the inferior head of the inferior constrictor), which is generally supplied by the recurrent laryngeal nerve and/or the external laryngeal nerve (occasionally by the pharyngeal plexus). The pharyngeal nerve plexus is com posed of both m otor and sensory bers. The glossopharyngeal and vagus nerves (CN

IX and CN X, respectively) both contribute sensory bers to the nerve plexus; only the vagus nerve distributes m otor bers to the pharyngeal plexus (som e of these bers m ay be considered to have originated from the spinal accessory nerve [CN XI]). Regardless of origin, they are distributed by the vagus nerve. The plexus also receives autonom ic bers from the cervical sym pathetic chain. Arteries in the region of the pharynx, prim arily branches of the external carotid artery, contribute to the vascular supply of the pharyngeal structures. The venous drainage of the posterior wall of the pharynx is prim arily into the pharyngeal venous plexus, which in turn drains into the internal jugular vein.

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Regions of the Hea d

Choanae, of nasal cavit y

Abducent nerve (CN VI)

Trochlear nerve (CN IV) and oculom otor nerve (CN III)

8. Ora l Cavit y & Pha rynx

Trigem inal nerve (CN V)

Middle nasal turbinate

Vestibulocochlear nerve (CN VIII) and facial nerve (CN VII)

Inferior nasal turbinate

CN IX, X, and XI

Glossopharyngeal nerve (CN IX) Occipital artery

Uvular m uscle

Superior cervical ganglion

Palatopharyngeus

Salpingopharyngeus

Hypoglossal nerve (CN XII)

Accessory nerve (CN XI)

Vagus nerve (CN X)

Sternocleidom astoid Superior laryngeal nerve

Root of tongue

Epiglot tis

Vagus nerve (CN X)

Sympathetic trunk

Cuneiform tubercle

Internal laryngeal nerve Corniculate tubercle

Superior laryngeal artery and vein

Arytenoid m uscle, oblique part

Left recurrent laryngeal nerve

Arytenoid m uscle, transverse part

Internal jugular vein Posterior cricoarytenoid Com m on carotid artery Middle cervical ganglion Recurrent (inferior) laryngeal nerve

Inferior thyroid artery External jugular vein

Vertebral artery (cut) Left subclavian artery Right recurrent laryngeal nerve Right brachiocephalic vein

Vertebral ganglion

Brachiocephalic trunk

Left recurrent laryngeal nerve

Vagus nerve (CN X) Superior vena cava

Aortic arch

B

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Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Potential Tissue Spaces in the Head & Spread of Dental Infections

Geniohyoid Mylohyoid B

A

Digastric anterior belly

Ta ble 8.17 Pote ntial tissue spaces of the head Pote ntial tissue space

Is locate d

Communicate s w ith

Subm ent al space

Below inferior border of m andible and beneath mylohyoid m uscle, at m idline of neck (corresponds to subm ent al triangle region)

Subm andibular spaces on both sides

Subm andibular space

Below inferior border of m andible and beneath mylohyoid m uscle, bounded by anterior and posterior bellies of digastic m uscle

Sublingual, subm ental, and parapharyngeal spaces

Above m ylohyoid m uscle and below the tongue

Subm andibular and paraphayngeal spaces

In cheek, lateral to buccinator m uscle

Canine, subm asseteric, and paraphayngeal spaces, and cavernous sinus

Subm asseteric space

Bet ween lateral surface of ram us of m andible and m asseter m uscle

Parapharyngeal spaces

Pterygom andibular space

Bet ween m edial surface of ram us and the m edial pterygoid m uscle

Buccal, infratem poral, parotid, subm asseteric, paraphayngeal, and peritonsillar spaces

Parotid space

Behind ram us of m andible, in and around parotid gland

Parapharyngeal then retropharyngeal spaces with potential spread to m ediastinum

Parapharyngeal space

Lateral to the pharynx in the suprahyoid region of neck

Continuous with retropharyngeal space

Retropharyngeal space

• Bet ween buccopharyngeal fascia anteriorly and prevertebral fascia posteriorly • Extends from base of skull to retrovisceral space in infrahyoid region of neck

Parapharyngeal, subm andibular, sublingual, subm asseteric, and peritonsillar spaces, and m ediastinum

Around palatine tonsils bet ween pillars of fauces, bounded by the m edial surface of the superior constrictor m uscle

Subm andibular and sublingual spaces

Canine space

Bet ween levator anguli oris and levator labii superioris

Cavernous sinus

Palat al space

Bet ween periosteum and m ucosa of hard palate m ucosa

None

Within infratem poral fossa

Pterygom andibular and buccal spaces, cavernous sinus (via pterygoid plexus)

Around mandible

Sublingual space Buccal space

Peritonsillar

Around maxilla

Infratem poral space

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C

D

Fig. 8.59 Pote ntial tissue spaces in the head A Transverse section at the level of the occlusal plane of the m andibular teeth, superior view. B Coronal section through the m olar region of the oral cavit y. C Floor of the m outh, inferior oblique view. D Floor of the m outh, superior view. Potential tissue spaces in the head becom e true spaces when they are in ltrated by bacterial product s of infection, such as hyaluronidase, which break down the connective tissue in these spaces. These spaces, de ned by the positions of bones, m uscles, and fascia, initially con ne an infection, but because of com m unication bet ween spaces, infections can travel.

Regions of the Hea d

8. Ora l Cavit y & Pha rynx

Nasal cavit y To m axillary sinus

Maxillary sinus

Maxillary sinus

To superficial space

Buccinator

To vestibule

Vestibule

Vestibule Genioglossus Sublingual gland

To vestibule

Geniohyoid Digastric anterior belly

A

Mylohyoid

B

Ta ble 8.18 Route of infe ction from de ntal source Source of infe ctio n

Ro ute o f infe ction

Symptoms

Mandibular anterior teeth

Below at t achm ent of mylohoid to subm ent al space

Swelling under chin

Mandibular m olars

Below at t achm ent of mylohyoid to subm andibular space

Swelling in subm andibular region, resulting in di cult y swallowing (dysphagia), di cult y breathing (dyspnea), and di cult y articulating speech (dysarthria), and neck pain and swelling, drooling, earache, and m alaise (=Ludwig angina)

Mandibular prem olars/m olars

Below geniohyoid and above mylohyoid to sublingual space

Swelling in oor of m outh, resulting in elevated tongue and di cult y speaking and swallowing

Maxillary or m andibular prem olars/m olars

Above (for m axillary teeth) or below (for m andibular teeth) the at t achm ent of buccinators to buccal space

Extensive swelling of cheek, which m ay extend to the upper lip or eye

Mandibular third m olars

Posterolaterally bet ween lateral aspect of ram us of m andible and m asseter to subm assateric space

Pain, trism us*, swelling of tonsillar pillars

Posteriorly bet ween the m edial aspect of ram us of m andible and m edial pterygoid to pterygom andibular space

Trism us*, intraoral swelling along the m edial aspect of the m andible

Maxillary or m andibular m olars

Posterom edially to enter parapharyngeal space then to retropharyngeal space

Pain, trism us*, swollen soft palate with deviated uvula, di cult y swallowing, di cult y breathing (airway obstruction could be life-threatening)

Maxillary anterior teeth (usually canines)

Above origin of levator anguli oris to canine space

Swelling along lateral border of nose, which m ay extend to periorbital region; eyelids m ay becom e swollen shut

Maxillary prem olars or m olars

From the palat al root into palat al space

Sm all, painful swelling of palate

Maxillary m olars

Posteriorly to space

Severe trism us*, bulging of tem poralis, intraoral swelling in region of m axillary tuberosit y

infratem poral

* Trism us is spasm of the m uscles of m astication that result s in the inabilit y to open the m outh.

ERRNVPHGLFRVRUJ

Parotid gland Ram us

Medial pterygoid

Inferior alveolar nerve, artery, and vein

Superior constrictor

Masseter Mandibular third m olar C

Buccal fat pad Buccinator

Fig. 8.60 Pote ntial ro utes for the spread of infe ction fro m apical de ntal abscesses A Sagit tal section through canines (anterior teeth). B Coronal section through m olars (posterior teeth). C Transverse section of area posterior to the third m olar tooth, superior view. Apical dental infections m ay spread to a num ber of regions in the head and neck, including the super cial facial space, the palate, the vestibule, the m axillary sinus, and the sublingual, subm andibular, and subm ental spaces. Infections entering into the sublingual and subm andibular spaces m ay ultim ately reach the m ediastinum through their posterior com m unications with the parapharyngeal spaces; these spaces in turn com m unicate with the retropharyngeal space and the carotid sheaths. Infections in m andibular third m olar teeth m ay spread to the buccal, subm asseteric, pterygopalatine, and parapharyngeal spaces.

227

Regions of the Hea d

9. Orbit & Eye

Bones of the Orbit

Frontal bone, supraorbital m argin

Frontal bone, orbital surface Sphenoid bone, orbital surface of lesser wing Ethm oid bone, orbital plate (lam ina papyracea)

Sphenoid bone, orbital surface of greater wing

Maxilla, frontal process Zygom atic bone, frontal process

Nasal bone

Zygom atic bone, orbital surface

Anterior cranial fossa

Lacrim al bone, orbital surface Palatine bone, orbital process

A

Maxilla, zygom atic process

Frontal bone, orbital surface

Frontal bone, supraorbital m argin

Maxilla, orbital surface

Nasion Nasal bone Sphenoid bone, lesser wing Ethm oid bone, orbital plate (lam ina papyracea) B

Frontal bone, orbital surface Zygom atic bone, orbital surface Maxilla, orbital surface (floor) Infraorbital canal Maxillary sinus

Maxilla, frontal process Palatine bone, orbital process

Maxilla, orbital surface (floor)

Lacrim al bone, orbital surface

Sphenoid bone, lesser wing Sphenoid bone, greater wing

Inferior orbital fissure Pterygom axillary fissure Palatine bone, pyram idal process

C

Fig. 9.1 Bones of the orbit Right orbit. A,D Anterior view. B,E Lateral view with lateral orbit al wall rem oved. C,F Medial view with m edial orbit wall rem oved. The orbit is form ed by seven bones: the front al, zygom atic, ethm oid, sphenoid, lacrim al, and palatine bones, and the m axilla. The neurovascular struc tures of the orbit com m unicate with the surrounding spaces via sev eral m ajor passages (see Table 9.1): the superior and inferior orbit al ssures, the optic canal, the anterior and posterior ethm oidal foram ina, the infraorbit al canal, and the nasolacrim al duct. The neurovascu

lar structures of the orbit also com m unicate with the super cial face by passing through the orbit al rim . Note: The exposed m axillary sinus can be seen in E. The m axillary hiatus cont ains the ostium by which the m axillary sinus opens into the nasal cavit y superior to the inferior nasal concha. The inferior orbit al ssure is contiunuous inferoposteriorly with the pterygom axillary ssure, which is the boundary bet ween the infratem poral and pterygopalatine fossae. The infratem poral fossa is on the lateral side of the pterygom axillary ssure; the pterygopalatine fossa is on the m edial side.

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Regions of the Hea d

9. Orbit & Eye

Frontal incisure Supraorbital foram en

Posterior ethm oidal foram en Anterior ethm oidal foram en

Zygomaticoorbital foram en

Optic canal Nasal bone

Superior orbital fissure

Lacrim al bone Inferior orbital fissure Infraorbital groove

D

Infraorbital foram en

Lacrim al bone

Frontal sinus

Glabella Anterior ethm oidal foram en

Nasion Posterior lacrim al crest (lacrim al bone)

Posterior ethm oidal foram en

Anterior lacrim al crest (m axilla) Optic canal

Fossa of lacrim al sac (with opening for nasolacrim al duct)

Superior orbital fissure (opened) Foram en rotundum Inferior orbital fissure

Infraorbital canal

Pterygom axillary fissure E

Frontal sinus

Pterygopalatine fossa

Maxillary ostium

Maxillary sinus

Infraorbital foram en

Superior orbital fissure

Lacrim al fossa Zygomaticoorbital foram en

Sphenoid bone, lesser wing Sphenoid bone, greater wing

Maxilla, orbital surface Infraorbital canal Inferior orbital fissure

Pterygom axillary fissure

Maxillary sinus

F

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Regions of the Hea d

9. Orbit & Eye

Communications of the Orbit

Fig. 9.2 Bones of the orbit and adjace nt cavities Co ro nal se ct io n, ant e rio r vie w. The b one s o f t he orb it also form port ions of t he walls of ne ighb oring cavit ie s. Disease processes m ay originate in the orbit and spread to these cavi ties, or originate in these cavities and spread to the orbit.

Frontal sinus

Ethm oid bone

Anterior cranial fossa

Optic canal (leads to m iddle cranial fossa) Frontal bone, orbital surface

Parietal bone

Sphenoid bone, orbital surface of lesser wing

Temporal bone Ethm oid air cells

Sphenoid bone, orbital surface of greater wing

Superior orbital fissure (leads to m iddle cranial fossa)

Zygom atic bone, orbital surface

Maxilla, orbital surface

Maxillary sinus

Inferior nasal concha

Frontal sinus

Vom er

Crista galli

Ethm oid air cells

Ethm oid bone, perpendicular plate

Optic canal Ethm oid bone, orbital plate (lam ina papyracea)

Superior orbital fissure Superior nasal concha (ethm oid bone)

Middle nasal m eatus

Inferior orbital fissure Infraorbital canal

Orbital floor (m axilla) Middle nasal concha (ethm oid bone)

Maxillary sinus

Inferior nasal concha and m eatus

Vom er Maxilla, palatine process

Fig. 9.3 Orbits and ne ighboring structures Coronal section through both orbit s, anterior view. The walls separat ing the orbit from the ethm oid air cells (0.3 m m , lam ina papyracea) and from the m axillary sinus (0.5 m m , orbit al oor) are very thin. Thus, both of these walls are susceptible to fractures and provide routes for

Maxilla, alveolar process

the spread of tum ors and in am m atory processes into or out of the orbit. The superior orbit al ssure com m unicates with the m iddle cranial fossa, and so several structures that are not pictured here—the sphe noid sinus, pituit ary gland, and optic chiasm —are also closely related to the orbit.

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Regions of the Hea d

9. Orbit & Eye

Ta ble 9.1 Communications of the orbit Structure

Communicate s

Via

Ne urovascular structure s in canal/ ssure

Front al sinus and anterior ethm oid air cells

Superiorly

Unnam ed canaliculi

• Sensory lam ent s

Medially

Anterior ethm oidal canal

• Anterior ethm oidal a. (from ophthalm ic a.) • Anterior ethm oidal v. (to superior ophthalm ic v.) • Anterior ethm oidal n. (CN V1 )

Sphenoid sinus and posterior ethm oid air cells

Medially

Posterior ethm oidal canal

• Posterior ethm oidal a. (from ophthalm ic a.) • Posterior ethm oidal v. (to superior ophthalm ic v.) • Posterior ethm oidal n. (CN V1 )

Middle cranial fossa

Posteriorly

Superior orbit al ssure

• Cranial nerves to the extraocular m uscles (oculom otor n. [CN III], trochlear n. [CN IV], and abducent n. [CN VI]) • Ophthalm ic n. (CN V1 ) and branches: ◦ Lacrim al n. ◦ Front al n. (branches into supraorbit al and supratrochlear nn.) ◦ Nasociliary n. • Superior (and occasionally inferior) ophthalm ic v. (to cavernous sinus) • Recurrent m eningeal branch of lacrim al a. (anastom oses with m iddle m eningeal a.)

Posteriorly

Optic canal

• Optic n. (CN II) • Ophthalm ic a. (from internal carotid a.)

Pterygopalatine fossa

Posteroinferiorly (m edially)

Inferior orbit al ssure*

Infratem poral fossa

Posteroinferiorly (laterally)

• • • • •

Nasal cavit y

Inferom edially

Nasolacrim al canal

• Nasolacrim al duct

Maxillary sinus

Inferiorly

Unnam ed canaliculi

• Sensory lam ent s

Face and tem poral fossa

Anteriorly

Zygom aticofacial canal

• Zygom aticofacial n. (CN V2 ) • Anastom otic branch of lacrim al a. (to transverse facial and zygom atico orbit al aa.)

Zygom aticotem poral canal

• Zygom aticotem poral n. (CN V2 ) • Anastom otic branch of lacrim al a. (to deep tem poral aa.)

Supraorbit al foram en (notch)

• Supraorbit al n., lateral branch (CN V1 ) • Supraorbit al a. (from ophthalm ic a.) • Supraorbit al v. (to angular v.)

Front al incisure

• Supratrochlear a. (from ophthalm ic a.) • Supratrochlear n. (CN V1 ) • Supraorbit al n., m edial branch (CN V1 )

Orbit al rim , m edial aspect

• Infratrochlear n. (CN V1 ) • Dorsal nasal a. (from ophthalm ic a.) • Dorsal nasal v. (to angular v.)

Orbit al rim , lateral aspect

• Lacrim al n. (CN V1 ) • Lacrim al a. (from ophthalm ic a.) • Lacrim al v. (to superior ophthalm ic v.)

Face

Anteriorly

Infraorbit al a. (from m axillary a.) Infraorbit al v. (to pterygoid plexus)* Infraorbit al n. (CN V2 ) Zygom atic n. (CN V2 ) Inferior ophthalm ic v. (variable, to cavernous sinus)

* The infraorbit al a., v., and n. travel in the infraorbit al canal on the oor of the orbit and em erge at the inferior orbit al ssure. The inferior orbit al ssure is continuous inferiorly with the pterygom axillary ssure, which is the boundary bet ween the infratem poral and the pterygopalatine fossa. The infratem poral fossa lies on the lateral side of the pterygom axillary ssure; the pterygopalatine fossa lies on the m edial side.

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Extraocular Muscles

Inferior oblique

Tendon of superior oblique

Trochlea

Superior rectus

Superior oblique

Superior rectus

Superior oblique Inferior rectus Medial rectus Com m on tendinous ring

Lateral rectus

Lateral rectus

Inferior rectus

Optic canal (opened)

Fig. 9.4 Extraocular (e xtrinsic eye ) muscles Right eye. A Superior view. B Anterior view. The eyeball is m oved in the orbit by four rectus m uscles (superior, m edial, inferior, lateral) and t wo oblique m uscles (superior and inferior). The four rectus m uscles arise from a tendinous ring around the optic canal (com m on tendinous ring, com m on annular tendon) and insert on the sclera of the eyeball. The superior and inferior obliques arise from the body of the sphenoid and the m edial orbital m argin of the m axilla, respectively. The supe rior oblique passes through a tendinous loop (trochlea) at t ached to the supero m edial orbital m argin (frontal bone); this redirect s it at an acute

Superior orbital fissure (opened) Optic nerve (CN II)

Com m on tendinous ring

B

angle to it s insertion on the superior surface of the eyeball. The coordi nated interaction of all six functionally com petent extraocular m uscles is necessary for directing both eyes toward the visual t arget. The brain then processes the t wo perceived retinal im ages in a way that provides binocular vision perception. Im paired function of one or m ore extra ocular m uscles causes deviation of the eye from it s norm al position, re sulting in diplopia (double vision). This im paired function m ay be due to traum a to CN III, IV, and VI or due to diseases that a ect nerves, e.g., m ultiple sclerosis (MS) or diabetes.

Levator palpebrae superioris

Medial rectus

Superior oblique Superior rectus

Oculom otor nerve (CN III)

Lateral rectus

Trochlear nerve (CN IV) Internal carotid artery

Inferior oblique

Abducent nerve (CN VI)

Inferior rectus

Foram en rotundum

Inferior orbital fissure

Clivus Foram en ovale

Medial rectus

Inferior oblique

Levator palpebrae superioris (cut)

Optic nerve (CN II) A

Foram en spinosum

Sphenoid bone

Maxillary sinus

Sphenopalatine foram en

Fig. 9.5 Inne rvation of the e xtraocular muscle s Right eye, lateral view with the lateral wall of the orbit rem oved. The extraocular m uscles are supplied by cranial nerves III, IV, and VI (see Table 9.2). Note: Levator palpebrae superioris is also supplied by CN III. After em erging from the brainstem , these cranial nerves rst

traverse the cavernous sinus, where they are in close proxim it y to the internal carotid artery. From there they pass through the superior or bit al ssure to enter the orbit and supply their respective m uscles. The optic nerve (CN II) enters the orbit via the m ore m edially located optic canal (see Fig . 9.1D).

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Fig. 9.6 Actions of the e xtraocular muscles Right eye, superior view with orbital roof removed. Primary actions (red), secondary actions (blue).

A

B

D

C

E

F

Ta ble 9.2 Actions and inne rvation of the e xtraocular muscles Muscle

Primary action

Se co ndary actio n

Inne rvation

A Lateral rectus

Abduction

—

Abducent n. (CN VI)

B Medial rectus

Adduction

—

C Inferior rectus

Depression

Adduction and lateral rot ation

D Inferior oblique

Elevation and abduction

Lateral rot ation

E Superior rectus

Elevation

Adduction and m edial rot ation

Oculom otor n. (CN III), superior branch

F Superior oblique

Depression and ab duction

Medial rot ation

Trochlear n. (CN IV)

Inferior oblique

Oculom otor n. (CN III), inferior branch

Superior rectus

Lateral rectus

Inferior oblique

Medial rectus

Superior oblique

Inferior rectus

Up and to the right

Inferior oblique

Lateral rectus

Superior rectus

Superior oblique Up and to the left

Superior rectus

To the right

Lateral rectus

To the left

Medial rectus

Dow n and to the right

Superior oblique

Inferior oblique

Inferior rectus

Medial rectus

Lateral rectus

Dow n and to the left

Inferior rectus

Superior oblique

Fig. 9.7 The six cardinal dire ctions of gaze In the clinical evaluation of ocular m otilit y to diagnose oculomotor palsies, six cardinal direc tions of gaze are tested (see arrows). Note that di erent m uscles m ay be activated in each eye for any particular direction of gaze. For exam ple, gaze to the right is e ected by the com bined actions of the lateral rectus of the right eye and the m edial rectus of the left eye. These t wo m uscles, m oreover, are supplied by di erent cranial nerves (VI and III, respectively). If one m uscle is weak or paralyzed, deviation of the eye will be noted during certain ocular m ovem ent s (see Fig. 9.9).

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Innervation of the Extraocular Muscles (CN III, IV, & VI) Short ciliary nerves

Levator palpebrae superioris

Superior rectus

Trochlea

Ciliary ganglion Com m on tendinous ring

CN III

Superior oblique

Mesencephalon Lateral rectus (cut) Pons

CN IV

Pontom edullary junction CN VI

A

Inferior oblique

Internal carotid artery and plexus Lateral rectus (cut)

CN III, inferior division

Sympathetic root (postganglionic fibers from superior cervical ganglion via internal carotid plexus)

Parasym pathetic root (preganglionic fibers from CN III)

Supraorbital nerve (cut)

Trochlea

Levator palpebrae superioris

Superior oblique

Superior rectus

Medial rectus

Lacrim al gland

Inferior rectus

Lateral rectus

Frontal nerve (CN V1 )

CN VI

CN IV

CN IV

Superior ophthalm ic vein

Levator palpebrae superioris

Superior rectus Lacrimal nerve (CN V1 )

Superior oblique

CN III

Optic nerve (CN II) Optic nerve (CN II)

Medial rectus CN III Inferior rectus

B

C

Fig. 9.8 Ne rves supplying the ocular muscles Right orbit. A Lateral view with tem poral wall rem oved. B Superior view of opened orbit. C Anterior view. Cranial nerves III, IV, and VI enter the orbit through the superior orbit al ssure, lateral to the optic canal (CN IV then passes lateral to the com m on tendinous ring, and CN

Lateral rectus

CN VI

Inferior oblique

III and VI pass through it). All three nerves supply som atom otor inner vation to the extra ocular m uscles. See Chapter 4 for a full discussion of CN III, IV, and VI. Of the three, only the oculom otor nerve (CN III) con tains both som atic and visceral bers; it is also the only one that innervates m ultiple extraocular and intraocular m uscles.

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A

9. Orbit & Eye

C

B

Fig. 9.9 Oculomotor palsies Palsy of the right side shown during at tem pted straight ahead gaze. A Com plete oculom otor palsy. B Trochlear palsy. C Abducent palsy. Oculom otor palsies m ay result from lesions involving the cranial nerve nucleus, the course of the nerve, or the eye m uscle it self. Depending on the involved m uscle, sym ptom s m ay include deviated position of the a ected eye and diplopia. The patient at tem pt s to com pensate for this by adjusting the position of the head. A Comple te oculomotor (CN III) palsy: A ect s four extraocular m uscles, t wo intra ocular m uscles (see Table 9.3), and the levator palpe brae superioris. Sym ptom s and a ected m uscle(s): Eyeball deviates toward lower outer quadrant = disabled superior, inferior, and m e

dial recti and inferior oblique. Mydriasis (pupil dilation) = disabled pupillary sphincter. Loss of near accom m odation = disabled ciliary m uscle. Ptosis (drooping of eyelid) = disabled levator palpebrae su perioris. The palpebral ssure cannot be opened during com plete ptosis in which both the levator palpebrae superioris (CN III) and superior t arsus (sym pathetic) m uscles are paralyzed. Diplopia will therefore not be observed. B Trochle ar ne rve (CN IV) palsy: Eye deviates slightly superom edially, causing diplopia = disabled superior oblique. C Abduce nt ne rve (CN VI) palsy: Eye deviates m edially, causing dip lopia = disabled lateral rectus.

Ta ble 9.3 Cranial ne rve s of the e xtraocular muscles Course*

Fibe rs

Nucle i

Functio n

E e cts of ne rve injury

Som atic e erent

Oculom otor nucleus

Innervates: • Levator palpebrae superioris • Superior, m edial, and inferior rectus • Inferior oblique

Visceral e erent

Visceral oculom otor (Edinger Westphal) nucleus

Synapse with neurons in ciliary ganglia. Innervates: • Pupillary sphincter • Ciliary m uscle

Com plete oculom otor palsy (paralysis of extraand intraocular m uscles): • Ptosis (drooping of eyelid) • Downward and lateral gaze deviation • Diplopia (double vision) • Mydriasis (pupil dilation) • Accom m odation di culties (ciliary paralysis)

Som atic e erent

Nucleus of the trochlear n.

Innervates: • Superior oblique

• Diplopia • A ected eye is higher and deviated m edially (dom inance of inferior oblique)

Som atic e erent

Nucleus of the abducent n.

Innervates: • Lateral rectus

• Diplopia • Medial strabism as (due to unopposed actionof m edial rect us)

Oculom otor nerve (CN III) Runs anteriorly from m esencephalon

Trochlear nerve (CN IV) Em erges from posterior surface of brainstem near m idline, courses anteriorly around the cerebral peduncle Abducent nerve (CN VI) Follows a long extradural path**

* All three nerves enter the orbit through the superior orbit al ssure; CN III and CN VI pass through t he com m on tendinous ring of the extraocular m uscles. ** The abducent nerve follows an extradural course; abducent nerve palsy m ay therefore develop in association with m eningitis and subarachnoid hem orrhage.

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Neurovasculature of the Orbit Episcleral space

Orbital roof (frontal bone)

Bulbar fascia (Tenon’s capsule)

Periorbita

Levator palpebrae superioris

Periorbital fat

Ophthalm ic artery Superior orbital septum

Superior rectus

Eyeball

Optic nerve (CN II) with dural sheath Inferior rectus

Inferior orbital septum Central retinal artery Inferior oblique Sclera Infraorbital nerve (CN V2 )

Orbital floor (m axilla, orbital surface)

Fig. 9.10 Uppe r, middle, and low e r levels of the orbit Right orbit. Sagit t al section viewed from the m edial side. The orbit is lined with periosteum (periorbit a) and lled with periorbital fat, which is bounded anteriorly by the orbit al sept a and toward the eyeball by a m obile sheath of connective tissue (bulbar fascia, Tenon’s capsule). The narrow space bet ween the bulbar fascia and sclera is called the episcleral space. Em bedded in the periorbit al fat are the eyeball, optic

Ta ble 9.4

Maxillary sinus

nerve, lacrim al gland, extraocular m uscles, and associated neurovas cular structures. Topographically, the orbit is divided into three levels: • Upper level: orbit al roof to levator palpebrae superioris • Middle level: superior rectus to optic nerve • Lower level: optic nerve to orbit al oor

Ne urovascular conte nts of the orbit

Orbital level

Arte rie s and ve ins

Ne rves

Upper level

• • • •

• Lacrim al n. (CN V1 ) • Front al n. (CN V1 ) and term inal branches: ◦ Supraorbit al n. ◦ Supratrochlear n. • Trochlear n. (CN IV)

Middle level

• Ophthalm ic a. (from internal carotid a.) and branches: ◦ Central retinal a. ◦ Posterior ciliary aa. • Superior ophthalm ic v. (to cavernous sinus)

• Nasociliary n. (CN V1 ) • Abducent n. (CN VI) • Oculom otor n. (CN III), superior branch and bers from inferior branch (to ciliary ganglion) • Optic n. (CN II) • Ciliary ganglion and root s: ◦ Parasym pathetic root (presynaptic autonom ic bers from CN III) ◦ Sym pathetic root (post synaptic bers from superior cervical ganglion) ◦ Sensory root (sensory bers from eyeball to nasociliary n.) • Short ciliary nn. ( bers from /to ciliary ganglion)

Lower level

• Infraorbit al a. (term inal branch of m axillary a.) • Inferior ophthalm ic v. (to cavernous sinus and/or pterygoid plexus)

• Infraorbit al n. (CN V2 ) • Oculom otor n. (CN III), inferior branch

Lacrim al a. (from ophthalm ic a.) Lacrim al v. (to superior ophthalm ic v.) Supraorbit al a. (term inal branch of ophthalm ic a.) Supraorbit al v. (form s angular v. with supratrochlear v.)

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Supratrochlear artery

Dorsal nasal vein

Dorsal nasal artery Supraorbital artery

Medial palpebral artery

Supratrochlear vein

Lacrim al vein

Angular vein

Cavernous sinus

Lacrim al artery

Anterior ethm oidal artery

Supraorbital vein

Superior ophthalm ic vein

Long posterior ciliary arteries

Short posterior ciliary arteries

9. Orbit & Eye

Ophthalm ic artery

Posterior ethm oidal artery Optic nerve (CN II) Optic canal (opened) Internal carotid artery

Ophthalm ic vein

Superior orbital fissure

Middle m eningeal artery

Infraorbital vein

Facial vein

Fig. 9.12 Ve ins of the orbit Right orbit, lateral view with the lateral orbit al wall rem oved and the Anastom otic branch through lacrim al foram en m axillary sinus opened. The veins of the orbit com m unicate with the (sphenoid bone) veins of the super cial and deep facial region and with the cavernous sinus (potential spread of infectious pathogens, see Fig . 3.23).

Fig. 9.11 Branches of the ophthalmic arte ry Superior view of opened right orbit. While running below CN II in the optic canal, the ophthalm ic artery gives o the central retinal artery, which pierces and travels with CN II. The ophthalm ic artery then exit s the canal and branches to supply the intraorbit al structures (including the eyeball).

Internal carotid artery with internal carotid plexus

CN III

Inferior ophthalm ic vein

Comm unicating branch bet ween lacrim al (CN V1) and zygom atic (CN V2 ) nerves Frontal nerve CN III, superior (CN V1 ) branch

Lacrim al nerve (CN V1 ) Supraorbital nerve (CN V1 ) Lacrim al gland Infratrochlear nerve (CN V1 ) Long ciliary nerves

CN IV

Nasociliary nerve (CN V1 )

CN V1

Short ciliary nerves (from ciliary ganglion)

CN V

Ciliary ganglion

Trigem inal ganglion

CN V3

Parasympathetic (m otor) root of ciliary ganglion (from CN III)

CN V2 CN VI CN II CN III, inferior branch

Zygom atic nerve (CN V2 ) distributes parasympathetic fibers from pterygopalatine ganglion

Fig. 9.13 Inne rvation of the orbit Lateral view of opened right orbit. The extraocular m uscles receive m o tor innervation from three cranial nerves: oculom otor (CN III), troch lear (CN IV), and abducent (CN VI). The ciliary ganglion distributes parasympathetic bers to the intraocular m uscles via the short ciliary nerves. Parasym pathetic bers reach the ganglion via the inferior branch of CN III. Sym pathetic bers from the superior cervical ganglion travel along the internal carotid artery to the superior orbital ssure. In the orbit, sympathetic bers run with the nasociliary nerve (CN V1 ) and/or ophthalm ic artery and pass through the ciliary ganglion

Sympathetic root of ciliary ganglion (from superior cervical ganglion)

Sensory root of ciliary ganglion (to nasociliary nerve)

(the nasociliary nerve also gives o direct sensory branches, the long ciliary nerves, which m ay carry postganglionic sympathetic bers). Sensory bers from the eyeball pass through the ciliary ganglion to the nasociliary nerve (CN V1 ). Note: Parasym pathetic bers to the lacrim al gland are distributed by the lacrim al nerve (CN V1 ), which com m uni cates with the zygom atic nerve (CN V2 ) via a com m unicating branch from the zygom aticotem poral nerve. The zygom atic nerve distributes ”hitchhiking” the postganglionic bers from the pterygopalatine ganglion (the preganglionic bers arise from CN VII).

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Topography of the Orbit (I)

Fig. 9.14 Intracave rnous course of the cranial ne rves that e nte r to the orbit Anterior and m iddle cranial fossae on the right side, superior view. The lateral and superior walls of the cavernous sinus have been opened. The trigem inal ganglion has been retracted slightly laterally, the or bital roof has been rem oved, and the periorbita has been fenestrated. All three of the cranial nerves that supply the ocular m uscles (oculom otor nerve, troch lear nerve, and abducent nerve) enter the cavernous sinus, where they com e into close relationship with the rst and second divisions of the trigem inal nerve and with the internal carotid artery. While the third and fourth cranial nerves course in the lateral wall of the cavernous sinus with the ophthalm ic and m axil lary divisions of the trigem inal nerve, the abducent nerve runs directly through the cavernous sinus in close proxim it y to the internal carotid artery. Be cause of this relationship, the abducent nerve m ay be dam aged as a result of sinus throm bosis or an in tracavernous aneurysm of the internal carotid artery.

Periorbita (periosteum of the orbit) Medial branch Lateral branch

Supraorbital nerve

Supratrochlear nerve Periorbital fat

Frontal nerve (CN V1 )

Anterior cranial fossa

Ophthalm ic artery Internal carotid artery Optic chiasm (CN II) Trochlear nerve (CN IV) Oculom otor nerve (CN III) Cavernous sinus

Abducent nerve (CN VI)

Trigem inal ganglion

Superior orbital fissure

Fig. 9.15 Ne urovasculature in the optic canal and supe rio r o rbital ssure Right orbit, anterior view with m ost of the or bit al content s rem oved. Optic canal: optic nerve (CN II) and ophthal m ic artery. Superior orbital ssure (inside com m on tendinous ring): abducent (CN VI), nasociliary (CN V1 ), and oculom otor (CN III) nerves. Superior orbit al ssure (out side com m on tendinous ring): superior and inferior ophthalm ic veins, frontal (CN V1 ), lacrim al (CN V1 ), and trochlear (CN IV) nerves. Inferior orbit al ssure (content s not shown): zygom atic (CN V2 ) nerve and branches of CN V2 , infraorbital artery, vein, and nerve in infra orbital canal.

Trigem inal nerve (CN V), m otor root

Frontal nerve (CN V1 )

Trigem inal nerve (CN V), sensory root

Levator palpebrae superioris

Middle cranial fossa

Superior rectus Superior oblique

Lacrim al nerve (CN V1 ) Superior ophthalm ic vein

Optic nerve (CN II) Com m on tendinous ring

Trochlear nerve (CN IV)

Ophthalm ic artery

Oculom otor nerve (CN III), superior branch

Superior orbital fissure

Nasociliary nerve (CN V1 )

Medial rectus

Lateral rectus Inferior orbital fissure

Oculom otor nerve (CN III), inferior branch Abducent nerve (CN VI)

Infraorbital groove and canal

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Inferior ophthalm ic vein

Inferior rectus

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Trochlea Medial branch

Infratrochlear nerve

Lateral branch

Cribriform plate

Supraorbital nerve

Supratrochlear nerve

Anterior ethm oidal artery and nerve

Levator palpebrae superioris

Supratrochlear artery

Lacrim al gland

Posterior ethm oidal artery and nerve

Lacrim al artery and nerve (CN V1 )

Supraorbital nerve

Superior rectus

Supraorbital artery

Abducent nerve (CN VI)

Nasociliary nerve (CN V1 )

Superior ophthalm ic vein

Trochlear nerve (CN IV)

Frontal nerve (CN V1 )

Ophthalm ic artery Optic nerve (CN II) Internal carotid artery Optic chiasm

Fig. 9.16 Topog raphy of the right orbit : conte nts of the uppe r level Superior view. The bony roof of the orbit, the periorbit a, and the retro orbit al fat have been rem oved.

Infundibulum Oculom otor nerve (CN III) Trochlear nerve (CN IV)

Medial rectus Superior oblique Superior ophthalm ic vein

Levator palpebrae superioris Superior rectus

Anterior ethm oidal artery and nerve Posterior ethm oidal artery and nerve

Lacrim al gland

Nasociliary nerve

Lacrim al artery and nerve

Short ciliary nerves Long ciliary nerves

Eyeball

Lateral rectus

CN IV Ophthalm ic artery Short posterior ciliary arteries CN II CN III

Inferior ophthalm ic vein CN VI Ciliary ganglion

Fig. 9.17 Topography of the rig ht orbit : co nte nts o f the middle level Superior view. The levator palpe brae superioris and the superior rectus have been divided and re ected backward, and all fat t y tissue has been rem oved to bet ter expose the optic nerve. Note: The ciliary ganglion is approx im ately 2 m m in diam eter and lies lateral to the optic nerve approxi m ately 2 cm behind the eyeball. The ciliary ganglion relays para sym pathetic bers to the eye and intraocular m uscles via the short ciliary nerves. The short ciliary nerves also cont ain sensory and sym pathetic bers (see Fig. 9.13).

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Topography of the Orbit (II)

Site of em ergence of lacrim al artery and nerve

Supraorbital artery and nerve

Dorsal nasal artery and vein, with infratrochlear nerve

Supratrochlear artery, vein, and nerve

Depressor supercilii

Procerus

Orbicularis oculi, palpebral part

Superior palpebral branches of supraorbital nerve

Orbicularis oculi, orbital part

Orbital septum

A

Infraorbital nerve and artery

Levator palpebrae superioris

Facial artery and vein

Supraorbital artery and nerve

Medial palpebral ligam ent

Angular artery and vein

Supratrochlear nerve

Superior oblique

Superior tarsal m uscle

Nasalis

Trochlea Infratrochlear nerve

Orbital septum

Dorsal nasal artery and vein

Lacrim al gland, orbital part

Lacrim al sac

Lacrim al gland, palpebral part

Angular artery and vein

Lateral palpebral ligam ent Superior tarsus

B

Inferior tarsus

Infraorbital nerve and artery

Facial artery

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Lateral nasal artery

Levator labii superioris alaeque nasi

Inferior palpebral branches of infraorbital nerve

Fig. 9.18 Supe r cial and de e p ne urovascular structures of the o rbital re g io n Right eye, anterior view. A Super cial layer. The orbit al septum on the right side has been exposed by rem oval of the orbicularis oculi. B Deep layer. Anterior orbit al structures have been exposed by partial re m oval of the orbital septum . The regions supplied by the internal carotid artery (supraorbit al artery) and external carotid artery (infraorbit al artery, facial artery) m eet in this region. The extensive anastom o sis bet ween the angular vein (extracranial) and superior ophthalm ic veins (intracranial) creates a port al of entry by which m icro organism s m ay reach the cavernous sinus (risk of sinus throm bosis, m eningitis, see p. 66). It is som etim es necessary to ligate this ana s tom osis in the orbit al region, as in patient s with extensive infections of the external facial region. Note the passage of the supra and infraor bital nerves (branches of CN V1 and CN V2 ) through the accordingly nam ed foram ina. The sensory function of these t wo trigem inal nerve divisions can be tested at these nerve exit point s.

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Lateral canthus of eyelids

Fig. 9.19 Surface anatomy of the eye Right eye, anterior view. The m easurem ent s indicate the width of the norm al palpebral ssure. It is im portant to know these m easurem ent s because there are a num ber of diseases in which they are altered. For exam ple, the palpebral ssure m ay be widened in peripheral facial paralysis or narrowed in ptosis (drooping of the eyelid) due to oculom o tor palsy.

Eyebrow

Upper eyelid 3 mm

2 mm 9 m m (6 –10)

Palpebral fissure Orbital roof

9. Orbit & Eye

Medial canthus of eyelids

28 –30 m m

Lower eyelid

Periorbita

Levator palpebrae superioris

Superior orbital septum

Superior rectus Superior conjunctival fornix

Orbicularis oculi, orbital part

Superior tarsal m uscle Superior tarsus with tarsal glands Lens

Upper eyelid

Superior fornix

Cornea Iris Ciliary body

Ocular conjunctiva

Inferior tarsus Ciliary and sebaceous glands Palpebral fissure

Retina

Palpebral (tarsal) conjunctiva

Sclera Inferior tarsal m uscle Lower eyelid

Inferior orbital septum

Fornical conjunctiva

Orbicularis oculi, palpebral part

Inferior fornix

Infraorbital nerve B

A

Fig. 9.20 Structure of the eyelids and conjunctiva A Sagit t al section through the anterior orbital cavit y. B Anatomy of the conjunctiva. The eyelid consist s clinically of an outer and an inner layer with the fol lowing com ponent s:

tiva (tunica conjunctiva) is a vascularized, thin, glistening m ucous m em brane that is subdivided into the palpebral conjunctiva (green), fornical conjunctiva (red), and ocular conjunctiva (yellow). The ocular conjunctiva borders directly on the corneal surface and com bines with it to form the conjunctival sac, whose functions include:

• Outer layer: palpebral skin, sweat glands, ciliary glands (= m odi ed sweat glands, Moll glands), sebaceous glands (Zeis glands), and t wo striated m uscles, the orbicularis oculi and levator palpebrae (up per eyelid only), innervated by the facial nerve and the oculom otor nerve, respectively. • Inner layer: the tarsus ( brous tissue plate), the superior and inferior tarsal m uscles (of Müller; smooth m uscle innervated by sym pathetic bers), the t arsal or palpebral conjunctiva, and the t arsal glands (m eibom ian glands).

• facilitating ocular m ovem ent s, • enabling painless m otion of the palpebral conjunctiva and ocular conjunctiva relative to each other (lubricated by lacrim al uid), and • protecting against infectious pathogens (collections of lym phocytes along the fornices).

Regular blinking (20 to 30 tim es per m inute) keeps the eyes from dry ing out by evenly distributing the lacrim al uid and glandular secretions. Mechanical irritant s (e.g., grains of sand) evoke the blink re ex, which also serves to protect the cornea and co njunctiva. The conjunc-

The superior and inferior fornices are the sites where the conjunctiva is re ected from the upper and lower eyelid, respectively, onto the eyeball. They are convenient sites for the instillation of ophthalm ic m edi cations. In ammation of the conjunctiva is com m on and causes a dilation of the conjunctival vessels resulting in “pink eye.” Conversely, a de ciency of red blood cells (anem ia) m ay lessen the prom inence of vascular m arkings in the conjunctiva. This is why the conjunctiva should be routinely inspected in every clinical exam ination.

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9. Orbit & Eye

Lacrimal Apparatus

Supraorbital foram en

Frontal incisure (notch)

Levator palpebrae superioris

Orbital septum

Periorbital fat Lacrim al caruncle

Lacrim al gland, orbital part

Superior and inferior lacrim al canaliculi

Lacrim al gland, palpebral part

Medial palpebral ligam ent

Upper eyelid Lacrim al sac Superior and inferior puncta

Lower eyelid

Nasolacrim al duct Nasolacrim al canal

Infraorbital foram en

Fig. 9.21 Lacrimal apparatus Right eye, anterior view. The orbit al septum has been partially rem oved, and the tendon of insertion of the levator palpebrae superioris has been divided. The hazelnut sized lacrimal g land is located in the lacrim al fossa of the frontal bone and produces m ost of the lacrim al uid. Sm aller accessory lacrimal glands (Krause or Wolfring glands) are also present. The tendon of levator palpebrae subdivides the lacrim al gland, which nor m ally is not visible or palpable, into an orbital lobe (t wo thirds of gland) and a palpebral lobe (one third). The sym pathetic bers innervating the lacrim al gland originate from the superior cervical ganglion and travel along arteries to reach the lacrim al gland. Parasym pathetic bers reach the lacrim al gland via the lacrim al nerve (CN V1 ). The lacrim al nerve com m unicates with the zygom atic nerve (CN V2 ), which relays postganglionic parasym pathetic bers from the pterygopalatine ganglion. The preganglionic parasym pathetic bers that synapse in the pterygo palatine ganglion travel as the greater petrosal nerve, which arises from the genu of the facial nerve (CN VII) (see Fig . 4.90).

Inferior nasal concha

The lacrimal apparatus can be understood by tracing the ow of lacrim al uid obliquely downward from the superolateral m argin of the orbit (by the lacrim al gland) to the inferom edial m argin (see Fig . 9.23). From the superior and inferior puncta, the lacrim al uid enters the superior and inferior lacrimal canaliculi, which direct the uid into the lacrimal sac. Finally, it drains through the nasolacrimal duct to an outlet below the inferior concha of the nose. “Watery eyes” are a t yp ical cold sym ptom caused by obstruction of the inferior opening of the naso lacrim al duct. Dry eyes, on the other hand, is a sym ptom of Sjögren syndrom e, an autoim m une disease causing keratoconjuctivi tis sicca (dim inished tear production) and xerostom ia (dry m outh). It is associated with rheum atoid arthritis (in 50% of cases) and lupus. Lym phocytes and plasm a cells in ltrate secretory glands and cause injury. Dim inished tear production causes dry, itchy, grit t y eyes, while dim inshed saliva production m akes swallowing di cult and increases the likelihood of developm ent of dent al caries. Rhem atoid arthritis causes joint pain, swelling and sti ness.

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9. Orbit & Eye

Temporal

Nasal

Goblet cells

Superior and inferior puncta Superior and inferior lacrim al canaliculi

Lacrim al sac

Orbicularis oculi

Fig. 9.22 Distribution of g oblet cells in the conjunctiva Goblet cells are m ucus secreting cells with an epithelial covering. Their secretions (m ucins) are an im port ant constituent of the lacrim al uid. Mucins are also secreted by the m ain lacrim al gland.

Fig. 9.23 Me chanical propulsion of the lacrimal uid During closure of the eyelids, contraction of the orbicularis oculi pro ceeds in a tem poral to nasal direction. The successive contraction of these m uscle bers propels the lacrim al uid toward the lacrim al passages. Note: Facial paralysis prevent s closure of the eyelids, causing the eye to dry out.

Superior lacrim al canaliculi

Lipid layer, approx. 0.1 µm

Meibom ian glands

Prevent s rapid evaporation Irrigation tube Aqueous layer, approx. 8 µm

A

Lacrim al gland

B

Inferior lacrim al canaliculus

Irrigating fluid, sm oothes surface irregularities Mucin layer, approx. 0.8 µm

Conjunctival goblet cells

Gel-like consistency stabilizes the tear film

C

Fig. 9.24 Structure of the tear lm The tear lm is a com plex uid with several m orphologically distinct layers, whose com ponent s are produced by individual glands. The outer lipid layer, produced by the m eibom ian glands, protect s the aqueous m iddle layer of the tear lm from evaporating.

Com m on lacrim al canaliculus

D

Lacrim al sac

Fig. 9.25 Obstructions to lacrimal drainag e Sites of obstruction in the lacrim al drainage system can be located by irrigating the system with a special uid. A No obstruction to lacrim al drainage. B,C Stenosis in the inferior or com m on lacrim al canaliculus. The steno sis causes a dam m ing back of lacrim al uid behind the obstructed site. In B the uid re uxes through the inferior lacrim al canaliculus, and in C it ows through the superior lacrim al canaliculus. D Stenosis below the level of the lacrim al sac (postlacrim al sac steno sis). When the entire lacrim al sac has lled with uid, the uid begins to re ux into the superior lacrim al canaliculus. In such cases, the lacrim al uid often has a purulent, gelatinous appearance.

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9. Orbit & Eye

Eyeball

Iris

Lens

Cornea

Posterior cham ber

Anterior cham ber Cham ber angle

Canal of Schlem m

Corneoscleral lim bus

Pigm ent epithelium of the ciliary body

Ciliary body, ciliary m uscle

Ocular conjunctiva

Zonular fibers

Hyaloid fossa

Ora serrata

Vitreous body

Medial rectus

Lateral rectus

Retina Choroid

Layers of the eyeball

Optic disk Sclera Lam ina cribrosa Central retinal artery (from ophthalm ic artery)

Fovea centralis Optic nerve (CN II)

Fig. 9.26 Eyeball Right eye, superior view of transverse section. Most of the eyeball is com posed of three concentric layers surrounding vitreous hum or: the sclera, the choroid, and the retina. Posterior portion of the eyeball: The scle ra is the posterior portion of the outer coat of the eyeball. It is a rm layer of connective tissue that gives at t achm ent to the tendons of all the extraocular m uscles. The m iddle layer of the eye, the cho ro id, is the m ost highly vascularized re gion in the body and serves to regulate the tem perature of the eye and to supply blood to the outer layers of the retina. The inner layer of the eye, the retina, includes an inner layer of photosensitive cells (sensory retina) and an outer layer of retinal pigm ent epithelium . The axons of the optic nerve (CN II) pierce the lam ina cribrosa of the sclera at the optic disk. The fovea centralis is a depressed area in the central retina approxim ately 4 m m tem poral to the optic disk. Incident light is nor m ally focused on the fovea centralis, the site of greatest visual acuit y. Anterior portion: The anterior portion of the eyeball has a di erent structure that is continuous with the posterior portion. The outer brous

coat is the cornea, the “window of the eye,” which bulges forward. At the corneoscleral lim bus, the cornea is continuous with the less convex sclera. In the angle of the anterior cham ber, the sclera form s the tra becular m eshwork, which is connected to the canal of Schlem m . Be neath the sclera is the vascular coat of the eye, also called the uveal tract. It consist s of three part s: the iris, ciliary body, and choroid. The iris shields the eye from excessive light and covers the lens. It s root is continuous with the ciliary body, which contains the ciliary m uscle for visual accom m odation (alters the refractive power of the lens). The epithelium of the ciliary body produces the aqueous hum or. The ciliary body is continuous at the ora serrat a with the choroid. The outer layer of the retina (pigm ent epithelium ) is continued forward as the pigm ent epithelium of the ciliary body and the epithelium of the iris. Globe rupture involves a full-thickness defect in the cornea and/or sclera. It m ay occur following penetrating or blunt traum a. It is a true ophthalm ologic em ergency that requires prom pt surgical repair to prevent perm anent loss of vision or poor eye functionalit y.

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At tachm ent to ora serrata (vitreous base of Salzm ann)

Cornea

9. Orbit & Eye

At tachm ent to posterior lens capsule (Wieger ligam ent) Hannover space Garnier space

Meridian Petit space Berger space

Equator

Hyaloid canal At tachm ent to optic disk (Martegiani ring) Vitreous body

Optic nerve (CN II)

Fovea centralis Optic nerve (CN II)

Fig. 9.27 Re fe re nce lines and points on the eye The line m arking the greatest circum ference of the eyeball is the equator. Lines perpendicular to the equator are called meridians.

Myopia (nearsightedness) Incident light rays

Norm al (em m etropic) eye

Fig. 9.28 Vitre ous body (vitre ous humor) Right eye, transverse section, superior view. Sites where the vitreous body is at t ached to other ocular structures are shown in red, and adjacent spaces are shown in green. The vitreous body st abilizes the eyeball and protect s against retinal det achm ent. Devoid of nerves and vessels, it consist s of 98% water and 2% hyaluronic acid and collagen. The “hyaloid canal” is an em bryological rem nant of the hyaloid artery. For the treatm ent of som e diseases, the vitreous body m ay be surgi cally rem oved (vitrectomy) and the resulting cavit y lled with physiological saline solution.

Hyperopia (farsightedness)

Eyeball

Cornea

Superior oblique

Retina Superior rectus

Lens

Medial rectus

Fig. 9.29 Light re fraction In a norm al (em m etropic) eye, parallel rays from a dist ant light source are refracted by the cornea and lens to a focal point on t he ret inal surface. • In myopia (nearsightedness), the rays are focused to a point in front of the retina. • In hyperopia (farsightedness), the rays are focused behind the retina. • In astigm atism (asym m etrical lens curvature in the horizontal and vertical axes) som e rays are focused in front of the retina and som e behind.

Lateral rectus

23°

Optical axis

Orbital axes

Fig. 9.30 Optical axis and orbital axis Superior view of both eyes showing the m edial, lateral, and superior recti and the superior oblique. The optical axis deviates from the orbit al axis by 23 degrees. Because of this disparit y, the point of m axim um visual acuit y, the fovea centralis, is lateral to the “blind spot” of the optic disk.

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9. Orbit & Eye

Eye: Blood Supply

Lesser arterial circle of iris

Cornea

Scleral venous sinus

Iris

Anterior conjunctival artery

Greater arterial circle of iris

Lens

Anterior ciliary arteries

Retina Sclera

Arterial circle of Zinn (and von Haller)

Vorticose vein

Long posterior ciliary arteries

Choroid (choroidocapillary layer)

Short posterior ciliary arteries Pial vascular plexus

Central retinal artery and vein Optic nerve (CN II)

Fig. 9.31 Blood supply of the eye Transverse section through the right eye at the level of the optic nerve, superior view. All of the arteries that supply the eye arise from the ophthalmic artery, a branch of the internal carotid artery. It s ocular branches are: • Central retinal artery to the retina • Short posterior ciliary arteries to the choroid • Long posterior ciliary arteries to the ciliary body and iris, where they supply the greater and lesser arterial circles of the iris (see Fig. 9.41)

• Anterior ciliary arteries, which arise from the vessels of the rectus m uscles of the eye and anastom ose with the posterior ciliary vessels Blood is drained from the eyeball by four to eight vorticose veins, which pierce the sclera behind the equator and open into the superior or in ferior ophthalm ic vein. The superior ophthalm ic vein com m unicates with cavernous sinus via the superior orbital ssure; the inferior ophthalm ic vein com m unicates posteriorly with the pterygoid plexus of veins via the inferior orbit al ssure and with the cavernous sinus.

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9. Orbit & Eye

Vessels to optic nerve

Fig. 9.32 Arte ries of the optic ne rve (CN II) Lateral view. The central retinal artery, the rst branch of the ophthalm ic artery, enters the optic nerve from below approxim ately 1 cm behind the eyeball and courses with it to the retina while giving o m ultiple sm all branches. The posterior ciliary artery also gives o several sm all branches that supply the optic nerve. The distal part of the optic nerve receives it s arterial blood supply from an arterial ring (circle of Zinn and von Haller) form ed by anastom oses am ong the side branches of the short posterior ciliary arteries and central retinal artery.

Long posterior ciliary arteries Short posterior ciliary arteries Circle of Zinn (and von Haller)

Ophthalm ic artery

Posterior ciliary artery

Nasal

Central retinal artery

Temporal

Fovea centralis

Physiological cup

Optic disk (blind spot) Sites of entry and em ergence of central retinal artery and vein Branch of central retinal vein Branch of central retinal artery B

A

Fig. 9.33 Ophthalmoscopic e xamination of the optic fundus A Exam ination technique (direct ophthalm oscopy). B Norm al appearance of the optic fundus. In direct ophthalm oscopy, the following structures of the optic fundus can be directly evaluated at approxim ately 16 x m agni cation: • • • •

The The The The

Macula lutea (yellow spot)

condition of the retina blood vessels (particularly the central retinal artery) optic disk (where the optic nerve em erges from the eyeball) m acula lutea and fovea centralis

Because the retina is transparent, the color of the optic fundus is deter m ined chie y by the pigm ent epithelium and the blood vessels of the choroid. It is uniform ly pale red in light skinned persons and is consid erably browner in dark skinned persons. Abnorm al det achm ent of the retina is usually associated with a loss of retinal transparency, and the retina assum es a yellowish white color. The central retinal artery and vein can be distinguished from each other by their color and caliber: arteries have a brighter red color and a sm aller caliber than the veins.

This provides a m eans for the early detection of vascular changes (e.g., stenosis, wall thickening, m icroaneurysm s), such as those occurring in diabetes m ellitus (diabetic retinopathy) or hypertension. The optic disk norm ally has sharp m argins, a yellow orange color, and a central depres sion, the physiological cup. The disk is subject to changes in pathologi cal conditions such as elevated intracranial pressure (papilledem a with ill-de ned disk m argins). On exam ination of the macula lutea, which is 3 to 4 m m tem poral to the optic disk, it can be seen that num erous branches of the central retinal artery radiate toward the m acula but do not reach it s center, the fovea centralis (the fovea receives it s blood supply from the choroid). A com m on age related disease of the m ac ula lutea is m acular degeneration. It is caused by the buildup of yellow deposit s, or drusen, on the m acula that dam ages the rods and cones. Sym ptom s are insidious and m ay a ect one or both eyes. They include blurriness or loss of central vision, which m ay m anifest as di cult y reading and di cult y recognizing faces, decreased color intensit y, and decreased adaptation to dark environm ent s.

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9. Orbit & Eye

Eye: Lens & Cornea

Fig. 9.34 Position of the le ns and cornea Transverse section through the cornea, lens, and suspensory apparatus of the lens. The nor m al lens is clear, transparent, and only 4 m m thick. It is suspended in the hyaloid fossa of the vitreous body. The lens is at tached by rows of brils (zonular bers) to the ciliary m uscle, whose contractions alter the shape and focal length of the lens. Thus, the lens is a dynam ic structure that can change it s shape in re sponse to visual requirem ent s. The anterior cham ber of the eye is situated in front of the lens, and the posterior cham ber is located be t ween the iris and the anterior epithelium of the lens. The lens, like the vitreous body, is de void of nerves and blood vessels and is com posed of elongated epithelial cells (lens bers).

Anterior cham ber

Cornea

Posterior cham ber

Iris Canal of Schlem m

Scleral spur Ocular conjunctiva Ciliary m uscle Sclera

Pars plana

Pars plicata

Ciliary body

Pupil

Zonular fibers

Lens

Epithelium of ciliary body

Trabecular m eshwork

Iris

Lens Pupil

Ciliary body, pars plicata Ciliary body, pars plana

Fig. 9.35 Le ns and ciliary body Posterior view. The curvature of the lens is regulated by the m uscle bers of the annular ciliary body. The ciliary body lies bet ween the ora serrat a and the root of the iris and consist s of a relatively at part (pars plana) and a part that is raised into folds (pars plicat a). The lat ter part is ridged by approxim a tely 70 to 80 radially oriented ciliary processes, which sur round the lens like a halo when viewed from behind. The ciliary processes cont ain large capillaries, and their epithelium secretes the aqueous hum or. Very ne zonular bers extend from the basal layer of the ciliary pro cesses to the equator of the lens. These bers and the spaces bet ween them constitute the suspensory apparatus of the lens, called the zonule. Most of the ciliary body is occupied by

Sclera Choroid Retina, optical part

Zonular fibers Ciliary processes

Ciliary m uscle

the ciliary m uscle, a sm ooth m uscle com posed of m eridional, radial, and circular bers. It arises m ainly from the scleral spur (a rein forcing ring of sclera just below the canal of Schlem m ), and it at t aches to structures in cluding the Bruch m em brane of the choroid and the inner surface of the sclera. When the

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Ora serrata

ciliary m uscle contract s, it pulls the choroid forward and relaxes the zonular bers. As these bers becom e lax, the intrinsic resilience of the lens causes it to assum e the m ore convex relaxed shape that is necessary for near vision. This is the basic m echanism of vi sual accom m odation.

Regions of the Hea d

9. Orbit & Eye

Ciliary m uscle relaxed, zonular fibers tense, lens flat tened Light rays in distant accom m odation

Equator

Lens

Lens capsule

Anterior pole

Posterior pole Light rays in near accom m odation

A

B

Axis

Fig. 9.36 Re fe re nce lines and dynamics, obligue late ral view of the le ns A Principal refe re nce lines of the le ns: The lens has an anterior and posterior pole, an axis passing bet ween the poles, and an equator. The lens has a biconvex shape with a greater radius of curvature pos teriorly (16 m m ) than anteriorly (10 m m ). It s function is to trans m it light rays and m ake ne adjustm ent s in refraction. It s refractive power ranges from 10 to 20 diopters, depending on the st ate of accom m odation. The cornea has a considerably higher refractive

power of 43 diopters. B Lig ht refraction and dynamics o f the le ns, sag ittal se ctio n: • Upper half of diagram : ne adjustm ent of the eye for far vision. Parallel light rays arrive from a dist ant source, and the lens is attened. • Lower half of diagram : For near vision (accom m odation to object s less than 5 m from the eye), the lens assum es a m ore rounded shape. This is e ected by contraction of the ciliary m uscle (parasympathetic innervation from the oculomotor nerve), causing the zonular bers to relax and allowing the lens to assum e a m ore rounded shape because of it s intrinsic resilience.

Em bryonic nucleus

Stratified nonkeratinized squam ous epithelium

External view of lens capsule

Fetal nucleus

Ciliary m uscle contracted, zonular fibers lax, lens m ore rounded

Basem ent m em brane Bowm an m em brane

Cortex Epithelium Capsule

Strom a

A

Infantile nucleus

Adult nucleus

B

Fig. 9.37 Grow th of the le ns and zones of discontinuity A Anterior view. B Lateral view. The lens continues to grow throughout life, doing so in a m anner op posite to that of other epithelial structures (i.e., the youngest cells are at the surface of the lens, whereas the oldest cells are deeper). Due to the const ant proliferation of epithelial cells, which are all rm ly incorporated in the lens capsule, the tissue of the lens becom es increas ingly dense with age. A slit lam p exam ination will dem onstrate zones of varying cell densit y (zones of discontinuit y). The zone of highest cell densit y, the embryonic nucleus, is at the center of the lens. With further growth, it becom es surrounded by the fetal nucleus. The infantile nucleus develops after birth, and nally the adult nucleus begins to form during the third decade of life. These zones are the basis for the m or phological classi cation of cateract s, a structural alteration in the lens or it s capsule, causing opacit y, that is m ore or less norm al in old age (present in 10% of all 80 year olds). It produces blurred, cloudy vision.

Descem et m em brane Endothelium

Fig. 9.38 Structure of the cornea The cornea is covered externally by strati ed, nonkeratinized squam ous epithelium whose basal lam ina borders on the anterior lim iting lam ina (Bowm an m em brane). The strom a (subst antia propria) m akes up approxim ately 90% of the corneal thickness and is bounded on it s deep surface by the posterior lim iting lam ina (Descem et m em brane). Beneath is a single layer of corneal endothelium . The cornea does have a nerve supply (for corneal re exes), but it is not vascularized and therefore has an im m unologically privileged st atus: norm ally, a corneal transplant can be perform ed without fear of a host rejection response.

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9. Orbit & Eye

Eye: Iris & Ocular Chambers

Cornea

Iris

Anterior cham ber

Pupillary sphincter Pupillary dilator

Cham ber angle

Canal of Schlem m

Ciliary m uscle

Ocular conjunctiva

Ciliary body

Zonular fibers Posterior cham ber

Pupil

Fig. 9.39 Iris and chambe rs of the eye Transverse section through the anterior segm ent of the eye, superior view. The iris, the choroid, and the ciliary body at the periphery of the iris are part of the uveal tract. In the iris, the pigm ent s are form ed that determ ine eye color. The iris is an optical diaphragm with a central ap erture, the pupil, placed in front of the lens. The pupil is 1 to 8 m m in diam eter; it constrict s on contraction of the pupillary sphincter (parasympathetic innervation via the oculom otor nerve and ciliary ganglion)

Sclera

Lens

and dilates on contraction of the pupillary dilator (sympathetic innervation from the superior cervical ganglion via the internal carotid plexus). Together, the iris and lens separate the anterior cham ber of the eye from the posterior cham ber. The posterior cham ber behind the iris is bounded posteriorly by the vitreous body, centrally by the lens, and lat erally by the ciliary body. The anterior cham ber is bounded anteriorly by the cornea and posteriorly by the iris and lens.

Ta ble 9.5 Chang es in pupil size : causes

A

B

Fig. 9.40 Pupil size A Norm al pupil size. B Maxim um constriction (m iosis). C Maxim um dilation (mydriasis). The regulation of pupil size is aided by the t wo intraocular m uscles, the pupillary sphincter and pupillary dilator. The pupillary sphincter (parasym pathetic innervation) narrows the pupil, and the pupillary dilator (sym pathetic inner vation) enlarges the pupil. Pupil size is norm ally adjusted in response to incident light and serves m ainly to optim ize visual acuit y.

C

Norm ally, the pupils are circular in shape and equal in size (3 to 5 m m ). Various in uences m ay cause the pupil size to vary over a range from 1.5 m m (m iosis) to 8 m m (mydriasis). A greater than 1 m m discrepancy of pupil size bet ween the right and left eyes is called anisocoria. Mild anisocoria is physiological in som e individuals. Pupillary re exes such as convergence and the consensual light response are described on pp. 258 and 259.

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Pupil co nstriction (parasympathe tic)

Pupil dilatio n (sympathe tic)

Light

Darkness

Sleep, fatigue

Pain, excitem ent

Miotic agent s: • Parasympathomi metics (e.g., tear gas, VX and sarin, Alzheimer’s drugs such as rivastigmine) • Sympatholytics (e.g., antihyper tensives)

Mydriatic agent s: • Parasym patholytics (e.g., atropine) • Sym pathom im etics (e.g., epinephrine)

Horner syndrom e (also causes ptosis and narrowing of palpebral ssure)

Oculom otor palsy

General anesthesia, m orphine

Migraine at t ack, glaucom a at t ack

Regions of the Hea d

Cornea

Pupillary sphincter

Pupillary dilator

Lesser arterial circle of iris Iris strom a

Greater arterial circle of iris

Trabecular m eshwork with Fontana spaces

Two layers of pigm ented iris epithelium

9. Orbit & Eye

Fig. 9.41 Structure of the iris Transverse and parasagit tal section, superior view. The basic structural fram ework of the iris is the vascularized strom a, which is bounded on it s deep surface by t wo layers of pigm ented iris epithelium . The loose, collagen containing strom a of the iris contains outer and inner vas cular circles (greater and lesser arterial circles), which are interconnected by sm all anasto m otic arteries. The pupillary sphincter is an annular m uscle located in the strom a border ing the pupil. The radially disposed pupillary dilator is not located in the strom a; rather, it is composed of num erous myo brils in the iris epithelium (myoepithelium ). The strom a of the iris is perm eated by pigm ented connective tissue cells (m elanocytes). When heavily pig m ented, these m elanocytes of the anterior border zone of the strom a render the iris brown or “black.” Otherwise, the characteris tics of the underlying strom a and epithelium determ ine eye color, in a m anner that is not fully understood.

Anterior cham ber

Cornea

Canal of Schlem m Conjunctiva

Scleral spur Episcleral veins

A

Sclera Zonular fibers Ciliary body

Cham ber angle

Posterior cham ber

Iris

Lens

Fig. 9.42 Normal drainage of aque ous humor The aqueous hum or (approxim ately 0.3 m L per eye) is an im port ant determ inant of the intraocular pressure. It is produced by the non pigm ented ciliary epithelium of the ciliary processes in the posterior cham ber (approxim ately 0.15 m L/hour) and passes through the pupil into the anterior cham ber of the eye. The aqueous hum or seeps through the spaces of the trabecular m eshwork (Font ana spaces) in the cham ber angle and enters the canal of Schlem m (venous sinus of the sclera), through which it drains to the episcleral veins. The draining aqueous hum or ows toward the cham ber angle along a pressure gradient (intra ocular pressure = 15 m m Hg, pressure in the episcleral veins = 9 m m Hg) and m ust surm ount a physiological resist ance at t wo sites: • Pupillary resistance (bet ween the iris and lens) • Trabecular resistance (narrow spaces in the trabecular m eshwork)

B

Fig. 9.43 Obstruction of aque ous drainag e and glaucoma Norm al function of the optical system requires norm al intraocular pres sure (15 m m Hg in adult s). This m aint ains a sm ooth curvature of the corneal surface and helps keep the photoreceptor cells in contact with the pigm ent epithelium . Obstruction of the norm al drainage of aque ous hum or causes an increase in intraocular pressure. This constrict s the optic nerve at the lam ina cribrosa, where it em erges from the eye ball through the sclera. Such constriction eventually leads to blindness. There are t wo t ypes of glaucom a: A Acute (closed angle) glaucom a: The cham ber angle is obstructed by iris tissue. Aqueous uid cannot drain into the anterior cham ber and pushes portions of the iris upward, blocking the cham ber angle. This t ype of glaucom a often develops quickly. B Chronic (open angle) glaucom a: The cham ber angle is open, but drainage through the trabecular m eshwork is im paired. Ninet y per cent of all glaucom as are prim ary chronic open angle glaucom as. This is increasingly prevalent after 40 years of age. Treatm ent op tions include parasympathom im etics (to induce sust ained contrac tion of the ciliary m uscle and pupillary sphincter), prost aglandin analogues (to im prove aqueous drainage), and bet a adrenoceptor agonist s (to decrease production of aqueous hum or).

Approxim ately 85% of the aqueous hum or ows through the trabe c ular m eshwork into the canal of Schlem m . Only 15% drains through the uveoscleral vascular system into the vortical veins (uveoscleral drain age route).

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Eye: Retina

Nonvisual retina

Optic part of retina

Macula lutea

Fig. 9.44 Ove rview of the retina Sagit t al section. The retina is the third, inner m ost layer of the eyeball. It consist s m ainly of a photosensitive optic part and a sm aller, nonphoto sensitive forward prolongation called the nonvisual retina. The optic part of the retina (yellow) varies in thickness. It over lies the pigm ent epithelium of the uveal tract and is pressed against it by the intraocular pressure. The optic part of the retina ends at a jagged m argin, the ora serrat a, which is where the nonvisual retina begins. The site on the retina where visual acuit y is highest is the fovea centralis, a sm all depression at the cen ter of a yellowish area, the macula lutea. The optic part of the retina is particularly thin at this site; it is thickest at the point where the optic nerve em erges from the eyeball at the lam ina cribrosa.

Sclera Uveal tract Fovea centralis

Optic nerve (CN II)

Optic disk Ora serrata

Cornea

Ocular conjunctiva Iris

Ciliary body

Ora serrata

Iridial part of retina Ciliary part of retina

Neural layer

Nonvisual retina

Pigm ented layer Sclera

Optical part of retina

Fig. 9.45 Parts of the retina Transverse section, superior view. The posterior surface of the iris bears a double layer of pigm ent epithelium , the iridial part of the retina. Just peripheral to it is the ciliary part of the retina, also form ed by a double layer of epithelium (one of which is pigm ented) and covering the pos terior surface of the ciliary body. The iridial and ciliary part s of the ret

ina together constitute the nonvisual retina —the portion of the retina that is not sensitive to light. The nonvisual retina ends at a jagged line, the ora serrat a, where the light sensitive optic part of the retina begins. Consistent with the developm ent of the retina from the em bryonic op tic cup, t wo layers can be distinguished within the optic part : • An outer layer nearer the sclera: the pigmented layer, consisting of a single layer of pigm ented retinal epithelium . • An inner layer nearer the vitreous body: the neural layer, com prising a system of receptor cells, interneurons, and ganglion cells.

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Inner lim iting m em brane Incident light

Blood vessels

10. Inner lim iting m em brane

7. Inner plexiform layer

Am acrine cells

6. Nuclei of bipolar cells (inner nuclear layer)

Second neurons (bipolar cells)

5. Outer plexiform layer

Horizontal cell

Outer lim iting m em brane

4. Nuclei of photoreceptor cells (outer nuclear layer) 3. Outer lim iting m em brane

Pigm ent epithelium

2. Processes of photoreceptor cells

First neurons (photoreceptors)

Müller cells A

Bruch m em brane

9. Nerve fiber layer 8. Nuclei of ganglion cells

Third neurons (ganglion cells)

Excitation

9. Orbit & Eye

Choroid

B

Fig. 9.46 Structure of the retina A Retinal neurons of the visual pathway. B Anatom ical layers of the retina. Light passes through all the layers of the retina to be received by the photoreceptors on the outerm ost surface of the retina. Sensory inform ation is then transm it ted via three retinal neurons of the visual pathway to the optic disk: • First ne urons (pink): Phot ore ce pt or cells (light se nsit ive se nsory cells) t hat t ransform light st im uli (p hot ons) int o ele ct roche m i cal signals. The t wo t ypes of phot ore ce pt ors are rods and cones, nam e d for t he shap e of t he ir re ce pt or se gm e nt . The ret ina con t ains 100 m illion t o 125 m illion rods, which are responsible for t wilight and night vision, but only ab out 6 m illion t o 7 m illion cones. Diffe re nt cones are spe cialize d for t he pe rce pt ion of re d, gre e n, and blue. The processes and nucle i of t he first ne urons com p ose anat om ical laye rs 2 t o 4 (se e B). • Second neurons (yellow): Bipolar cells that receive im pulses from the photoreceptors and relay them to the ganglion cells. These neu rons com pose anatom ical layers 5 to 7.

Bruch m em brane

Choroid

Second neurons (bipolar cells)

First neurons (photoreceptors)

1. Pigm ent epithelium

• Third neurons (green): Retinal ganglion cells whose axons converge at the optic disk to form the optic nerve (CN II) and reach the lateral geniculate and superior colliculus. These neurons com pose anatom ical layers 8 to 10. There are approxim ately 1 m illion retinal ganglion axons per eye. Support cells: Müller cells (blue) are glial cells that span the neural layer ra dially from the inner to the outer limiting membranes, creating a support ing framework for the neurons. In addition to the vertical connections, horizontal and amacrine cells (gray) function as interneurons that estab lish lateral connections. Impulses transmit ted by the receptor cells are thereby processed and organized within the retina (signal convergence). Pigment epithelium: The outer layer of the retina (the pigm ent epithe lium , brown) is at tached to the Bruch m em brane, which cont ains elas tic bers and collagen brils and m ediates the exchange of substances bet ween the adjacent choroid (choriocapillaris) and the photoreceptor cells. Note: The photoreceptors are in cont act with the pigm ent epi thelium but are not at t ached to it. The retina m ay becom e det ached (if untreated, this leads to blindness).

Fovea centralis

Optic disk

Ganglion cells Inner nuclear layer

Lam ina cribrosa Central retinal artery

Third neurons (ganglion cells)

Meninges

Outer nuclear layer

Subarachnoid space

Fig. 9.47 Optic disk (“blind spot”) and lamina cribrosa The unmyelinated axons of the third neurons (retinal ganglion cells) pass to a collecting point at the posterior pole of the eye. There they unite to form the optic nerve and leave the retina through num erous perforations in the sclera (lam ina cribrosa). (Note: The optic disk has no photoreceptors and is therefore the physiological blind spot.) In the optic nerve, these axons are myelinated by oligodendrocytes. The optic nerve (CN II) is an extension of the diencephalon and therefore has all the coverings of the brain (dura m ater, arachnoid, and pia m ater). It is surrounded by a subarachnoid space that contains cerebrospinal uid (CSF) and com m unicates with the subarachnoid spaces of the brain and spinal cord.

Pigm ent epithelium Blood vessels

Bruch m em brane

Choroid

Fig. 9.48 Macula lute a and fovea ce ntralis Tem poral to the optic disk is the m acula lutea. At it s center is a funnel shaped depression approxim ately 1.5 m m in diam eter, the fovea cen tralis, which is the site of m axim um visual acuit y. At this site the inner retinal layers are heaped toward the m argin of the depression, so that the cells of the photoreceptors (just cones, no rods) are directly exposed to the incident light. Furtherm ore blood vessels detour around the fo vea. This arrangem ent signi cantly reduces scat tering of the light rays.

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Visual System (I): Overview & Geniculate Part

Optic nerve

Lateral ventricle

Optic tract

Optic nerve

Lateral geniculate body Optic radiation for lower visual field

Incident light

Third neuron: ganglion cells Second neuron: bipolar cells Impulse conduction

Striate area

A

Optic chiasm

Anterior temporal lobe

Optic radiation for upper visual field

Fig. 9.49 Ove rview of the visual pathw ay Left lateral view. The visual pathway extends from the eye, an anterior prolongation of the diencephalon, back to the occipit al pole. Thus, it encom passes alm ost the entire longitudinal axis of the brain. The prin cipal st ations are as follows: Retina: The rst three neurons of the visual pathway (B): • First neuron: photoreceptor rods and cones, located on the deep retinal surface opposite the direction of the incom ing light (“inver sion of the retina”). • Second neuron: bipolar cells. • Third neuron: ganglion cells whose axons are collected to form the optic nerve. Optic ne rve (CN II), o ptic chiasm, and o ptic tract : This neural portion of the visual pathway is part of the central nervous system and is surrounded by m eninges. Thus, the optic nerve is actually a tract rather than a true nerve. The optic nerves join below the base of the di encephalon to form the optic chiasm , which then divides into the t wo optic tract s. Each of these tract s divides in turn into a lateral and m e dial root.

B

First neuron: photoreceptor rods and cones

C

Stria of Gennari

Late ral g e niculate bo dy: Ninet y percent of the axons of the third neu ron (= 90 % of the optic nerve bers) term inate in the lateral geniculate body on neurons that project to the striate area (visual cortex, see below). This is the geniculate part of the visual pathway. It is concerned with conscious visual perception and is conveyed by the lateral root of the optic tract. The rem aining 10% of the third neuron axons in the visual pathway do not term inate in the lateral geniculate body. This is the nongeniculate part of the visual pathway (m edial root, see Fig . 9.54), and it s signals are not consciously perceived. Optic radiatio n and visual co rte x (striate area): The optic radiation begins in the lateral geniculate body, form s a band that winds around the inferior and posterior horns of the lateral ventricles, and term inates in the visual cortex or striate area (= Brodm ann area 17). Located in the occipital lobe, the visual cortex can be grossly identi ed by a prom inent stripe of white m at ter in the otherwise gray cerebral cortex (the stria of Gennari, see C). This white stripe runs parallel to the brain sur face and is shown in the inset, where the gray m at ter of the visual cor tex is shaded light red.

Nasal visual field of right eye Left half of visual field Right half of visual field

Temporal visual field of right eye Temporal retina Nasal retina

Fig. 9.50 Re prese ntation of each visual eld in the contralate ral visual corte x Superior view. The light rays in the nasal part of each visual eld are projected to the temporal half of the retina, and those from the tem poral part are projected to the nasal half. Because of this arrangem ent, the left half of the visual eld project s to the visual cortex of the right occipit al pole, and the right half project s to the visual cortex of the left occipit al pole. For clarit y, each visual eld in the diagram is divided into t wo halves. Note: The axonal bers from the nasal half of each retina cross to the opposite side at the optic chiasm and then travel with the uncrossed bers from the tem poral half of each retina.

Optic nerve (CN II) Optic chiasm Optic tract Lateral geniculate body Visual cortex (striate area)

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Macular visual field

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Blind spot

Visual field

Fovea centralis Representation of visual field as determ ined by perim etry

Temporal crescent 1

Blind spot

2

Fig. 9.52 Informal visual eld e xamination w ith the confrontation test The visual eld exam ination is an essential step in the exam ination of lesions of the visual pathway (see Fig. 9.53). The confrontation test is an informal test in which the exam iner (with an intact visual eld) and the patient sit face-to-face, cover one eye, and each xes their gaze on the other’s open eye, creating identical visual axes. The exam iner then m oves his or her index nger from the outer edge of the visual eld toward the center until the patient signals that he or she can see the nger. With this test the exam iner can m ake a gross assessm ent as to the presence and approxi m ate location of a possible visual eld defect. The precise location and extent of a visual eld defect can be determ ined by perimetry, in which point s of light replace the exam iner’s nger. The result s of the test are entered in chart s that resem ble the sm all diagram s in Fig. 9.53.

3

4 5 6

7

Optic nerve

8

Optic chiasm

Optic tract

Lateral geniculate body

9

Fig. 9.51 Ge niculate part of visual pathw ay: topog raphic o rganizatio n The visual eld is divided into four quadrant s: upper tem poral, upper nasal, lower nasal, and lower tem poral. The lower nasal quadrant is in dented by the nose. The represent ation of this subdivision is contin ued into the visual cortex. Note: Only the left visual hem i eld (blue) is shown here (com pare to Fig. 9.50). 1 Visual he mi eld: Each visual hem i eld is divided into three zones (indicated by color shading): • Fovea centralis: The sm allest and darkest zone is at the center of the visual eld. It corresponds to the fovea centralis, the point of m axim um visual acuit y on the retina. The fovea centralis has a high receptor densit y; accordingly, a great m any axons pass centrally from it s receptors. It is therefore represented by a dispro portionately large area in the visual cortex. • Macular visual eld: The largest zone in the visual hem isphere; it also cont ains the blind spot. • Tem poral crescent : The tem poral, m onocular part of the visual eld. This corresponds to m ore peripheral portions of the retina that cont ain fewer receptors and therefore fewer axons, resulting in a sm aller represent ational area in the visual cortex.

cam era. Up/down and nasal/tem poral are therefore reversed when the im age is projected on the retina. 3,4 Optic ne rve : In the dist al part of the optic nerve, the bers that represent the m acular visual eld initially occupy a lateral position (3), then m ove increasingly toward the center of the nerve (4). 5 Optic chiasm: While traversing the optic chiasm , the bers of the nasal retina of the optic nerve cross the m idline to the opposite side. 6 Start o f the o ptic tract: Fibers from the corresponding halves of the retinas unite (e.g., right halves of the left and right retinas in the right optic tract). The im pulses from the left visual eld (right retinal half) will therefore term inate in the right striate area. 7 End o f the o ptic tract: Fibers are collected to form a wedge before entering the lateral geniculate body. 8 Late ral g e niculate body: Macular bers occupy alm ost half of the wedge. After the bers are relayed to the fourth neuron, they pro ject to the posterior end of the occipit al pole (= visual cortex). 9 Visual co rte x: There exist s a point to point (retinotopic) correlation bet ween the num ber of axons in the retina and the num ber of axons in the visual cortex (e.g., the central part of the visual eld is represented by the largest area in the visual cortex, due to the large num ber of axons concentrated in the fovea centralis). The central lower half of the visual eld is represented by a large area on the occipit al pole above the calcarine sulcus; the central upper half of the visual eld is represented below the sulcus.

2 Retinal proje ctio n: All light that reaches the retina m ust pass through the narrow pupil, which functions like the aperture of a

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Visual System (II): Lesions & Nongeniculate Part

Temporal

Nasal

Right visual field

Left visual field

Nasal

Temporal

1

1

2

2

3

3 1 2

4

4

3 5

6

5

5

4

6

7

7

6

7

Fig. 9.53 Visual eld defe cts and lesions of the visual pathw ay Circles represent the perceived visual disturbances (scotom as, or areas of darkness) in the left and right eyes. These characteristic visual eld defect s (anopias) result from lesions at speci c sites along the visual pathway. Lesion sites are illustrated in the left visual pathway as red wedges. The nature of the visual eld defect often point s to the lo cation of the lesion. Note: Lesions past the optic chiasm will all be ho m onym ous (sam e visual eld in both eyes). 1 Unilateral optic nerve lesion: Blindness (am aurosis) in the a ected eye. 2 Lesion of optic chiasm : Bitem poral hem ianopia (think of a horse wearing blinders). Only bers from the nasal portions of the retina (representing the tem poral visual eld) cross in the optic chiasm . 3 Unilateral optic tract lesion: Contralateral hom onym ous hem i anopia. The lesion interrupt s bers from the tem poral portion of the retina on the ipsilateral side and nasal portions of the retina on the contra lateral side. The patient therefore has visual im pairm ent of the sam e visual hem isphere in both eyes.

4 Unilateral lesion of the optic radiation in the anterior tem poral lobe: Contralateral upper quadrant anopia (“pie in the sky” de cit). Lesions in the anterior tem poral lobe a ect only those bers winding under the inferior horn of the lateral ventricle (see Fig . 9.49). These bers represent only the upper half of the visual eld (in this case the nasal portion). 5 Unilateral lesion of the optic radiation in the pariet al lobe: Contra lateral lower quadrantanopia. Fibers from the lower half of the visual eld course superior to the lateral ventricle in the parietal lobe. 6 Occipit al lobe lesion: Hom onym ous hem ianopia. The lesion a ect s the optic radiations from both the upper and lower visual elds. However, as the optic radiation fans out widely before entering the visual cortex, foveal vision is often spared. These lesions are m ost com m only due to intracerebral hem orrhage; the visual eld defect s vary considerably with the size of the hem orrhage. 7 Occipit al pole lesion (con ned to cortical area): Hom onym ous hem ianopic central scotom a. The cortical areas of the occipit al pole rep resent the m acula.

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Suprachiasm atic nucleus

9. Orbit & Eye

Visual cortex (striate area)

Pulvinar of thalam us

Superior colliculus

Optic radiation Pretectal area Lateral geniculate body

Term inal nuclei

Reticular form ation

Fig. 9.54 Nonge niculate part of the visual pathw ay Approxim ately 10% of the axons of the optic nerve do not term inate on neurons in the lateral geniculate body for projection to the visual cor tex. They continue along the m edial root of the optic tract, form ing the nongeniculate part of the visual pathway. The inform ation from these bers is not processed at a conscious level but plays an im port ant role in the unconscious regulation of various vision related processes and in visually m ediated re exes (e.g., the a erent lim b of the pupillary light re ex). Axons from the nongeniculate part of the visual pathway term inate in the following regions: • Axons to the superior colliculus transm it kinetic inform ation that is necessary for tracking m oving object s by unconscious eye and head m ovem ent s (retinotect al system ). • Axons to the pretect al area transm it a erent s for pupillary responses and accom m odation re exes (retinopretect al system ). Subdivision

Afferent fibers

Efferent fibers

Optic nerve (CN II)

Oculomotor nerve (CN III) Trigem inal nerve (CN V)

Vestibulocochlear nerve (CN VIII)

Pupillary reflex Vestibuloocular reflex

Facial nerve (CN VII) Corneal reflex

• •

•

•

into speci c nuclei has not yet been accom plished in hum ans, and so the term “area” is used. Axons to the suprachiasm atic nucleus of the hypothalam us in uence circadian rhythm s. Axons to the thalam ic nuclei (optic tract) in the tegm entum of the m esencephalon and to the vestibular nuclei transm it a erent bers for opto kinetic nyst agm us (= jerky, physiological eye m ovem ent s during the tracking of fast m oving object s). This has also been called the “accessory visual system .” Axons to the pulvinar of the thalam us form the visual association cortex for oculom otor function (neurons are relayed in the superior colliculus). Axons to the parvocellular nucleus of the reticular form ation func tion during arousal.

Fig. 9.55 Brainste m re e xes Brainstem re exes are im port ant in the exam ination of com atose patient s. Loss of all brainstem re exes is considered evidence of brain death. Three of these re exes are described below: Pupillary re e x: The pupillary re ex relies on the nongeniculate part s of the visual pathway (see Fig. 9.57). The a erent bers for this re ex com e from the optic nerve, which is an extension of the diencephalon. The e erent s for the pupillary re ex com e from the accessory nucleus of the oculom otor nerve (CN III), which is located in the brainstem . Loss of the pupillary re ex m ay signify a lesion of the diencephalon (interbrain) or m esencephalon (m idbrain). Vestibulo -ocular re e x: Irrigating the ear canal with cold water in a norm al individual evokes nystagm us that beat s toward the oppo site side (a erent bers are conveyed in the vestibulocochlear nerve [CN VIII], e erent bers in the oculom otor nerve [CN III]). When the vestibulo-ocular re ex is absent in a com atose patient, it is considered a poor sign because this re ex is the m ost reliable clinical test of brainstem function. Corneal re e x: This re ex is not m ediated by the visual pathway. The a erent bers for the re ex (elicited by stim ulation of the cornea, as by touching it with a sterile cot ton wisp) are conveyed in the trigem i nal nerve (CN VI) and the e erent bers (contraction of the orbicularis oculi in response to corneal irrit ation) in the facial nerve (CN VII). The relay center for the corneal re ex is located in the pontine region of the brainstem . Loss of the corneal re ex can be due to sensory loss in CN V1 , weakness or paralysis of the facial nerve (CN VII), or to brainstem disease.

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Visual System (III): Re exes

Ciliaris Pupillary sphincter Medial rectus Short ciliary nerves

Ciliary ganglion

Optic nerve Optic tract

Oculom otor nerve

Perlia’s nucleus

Lateral geniculate body

Nucleus of oculom otor nerve (m edial rectus) Edinger-Westphal nuclei Pretectal area

Area 19 (secondary visual cortex)

Area 17 (prim ary visual cortex) Area 18

Fig. 9.56 Pathw ays for conve rge nce and accommodation When the dist ance bet ween the eyes and an object decreases, three processes m ust occur in order to produce a sharp, three dim ensional visual im pression (the rst t wo are sim ult aneous): 1. Convergence (red): The visual axes of the eyes m ove closer together. The t wo m edial rectus m uscles contract to m ove the ocular axis m e dially. This keeps the im age of the approaching object on the fovea centralis. 2. Accom m odation: The lenses adjust their focal length. The curvature of the lens is increased to keep the im age of the object sharply fo cused on the retina. The ciliary m uscle contract s, which relaxes the tension on the lenticular bers. The intrinsic pressure of the lens then causes it to assum e a m ore rounded shape. (Note: The lens is at tened by the contraction of the lenticular bers, which are at t ached to the ciliary m uscle.) 3. Pupillary constriction: The pupil is constricted by the pupillary sphincter to increase visual acuit y. Convergence and accom m odation m ay be conscious ( xing the gaze on a near object) or unconscious ( xing the gaze on an approaching autom obile). Pathw ays: The pathways can be broken into three com ponent s: 1. Geniculate visual pathway (purple): Axons of the rst neurons (photoreceptors) and second neurons (bipolar cells) relay sensory infor m ation to the third neurons (retinal ganglion cells), which course in the optic nerve (CN II) to the lateral geniculate body. There they

synapse with the fourth neuron, whose axons project to the prim ary visual cortex (area 17). 2. Visual cortexes to cranial nerve nuclei: Interneurons (black) con nect the prim ary (area 17) and secondary (area 19) visual cortexes. Synaptic relays (red) connect area 19 to the pretect al area and ulti m ately Perlia’s nucleus (yellow), located bet ween the t wo Edinger Westphal (visceral oculom otor) nuclei (green). 3. Cranial nerves: At Perlia’s nucleus, the pathway for convergence diverges with the pathways for accom m odation and pupillary con striction: • Convergence: Neurons relay im pulses to the som atom otor nu cleus of the oculom otor nerve, whose axons pass directly to the m edial rectus m uscle via the oculom otor nerve (CN III). • Accom m odation and pupillary constriction: Neurons relay impulses to the Edinger Westphal nucleus, whose preganglionic parasympa thetic axons project to the ciliary ganglion. After synapsing in the ciliary ganglion, the postganglionic axons pass either to the ciliary m uscle (accomm odation) or the pupillary sphincter (pupillary con striction) via the short ciliary nerves. Note: The pupillary sphincter light response is abolished in tertiary syphilis, while accom m odation (ciliary m uscle) and convergence (m e dial rectus) are preserved. This phenom enon, called an Argyll Robert son pupil, indicates that the connections to the ciliary and pupillary sphincter m uscles are m ediated by di erent tract s, although the anatomy of these tract s is not yet fully understood.

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Pupillary sphincter

Short ciliary nerves Ciliary ganglion Optic nerve Oculom otor nerve (parasympathetic portion)

Optic tract

Lateral geniculate body

Visceral oculom otor (Edinger-Westphal) nuclei

Medial geniculate body

Fig. 9.57 Pupillary lig ht re e x The pupillary light re ex enables the eye to adapt to varying levels of brightness. When a large am ount of light enters the eye (e.g., beam of a headlight), the pupil constrict s to protect the photoreceptors in the retina; when the light fades, the pupil dilates. This re exive pathway t akes place without conscious input via the nongeniculate part of the visual pathway. The re ex can be broken into com ponent s: 1. A erent lim b: The rst (photoreceptor) and second (bipolar) neurons relay sensory inform ation to the third (retinal ganglion) neu rons, which com bine to form the optic nerve (CN II). Most third neurons (purple) synapse at the lateral geniculate body (genicu late part of the visual pathway). The third neurons responsible for the light re ex (blue) synapse at the pretectal area in the m edial root of the optic tract (nongeniculate part of the visual pathway). Fourth neurons from the pretect al area pass to the parasym pathetic Edinger Westphal nuclei. Note: Because both nuclei are innervated, a consensual light response can occur (contraction of one pupil will cause contraction of the other). 2. E erent lim b: Fifth neurons from the Edinger-Westphal nuclei (preganglionic parasym pathetic neurons) synapse in the ciliary gan glion. Sixth neurons (postganglionic parasym pathetic neurons) pass to the pupillary sphincter via the short ciliary nerves. Lo ss of lig ht respo nse : Because fourth neurons from the pretec t al area pass to both Edinger Westphal nuclei, a consensual light re sponse can occur (contraction of one pupil will cause contraction of the other). The light response m ust therefore be tested both directly and indirectly:

Pretectal area

• Direct light response: Tested by covering both eyes of the conscious, cooperative patient and then uncovering one eye. After a short la tency period, the pupil of the light exposed eye will contract. • Indirect light response: Tested by placing the exam iner’s hand on the bridge of the patient’s nose, shading one eye from the beam of a ashlight while shining it into the other eye. The object is to test whether shining the light into one eye will cause the pupil of the shaded eye to contract as well (consensual light response). Lesions can occur all along the pathway for the pupillary light re ex. The direct and indirect light responses can be used to determ ine the level: • Unilateral optic nerve lesion: This produces blindness on the af fected side. If the patient is unconscious or uncooperative, the light responses can determ ine the lesion, as the a erent lim b of the pupillary light re ex is lost. A ected side: No direct light response and no consensual light response on the opposite side. Una ected side: Direct light response and consensual light response on the opposite (a ected) side. Because the e erent lim b of the re ex is not m ediated by the optic nerve, the functional a erent lim b can bypass the im paired a erent lim b. • Lesion of the parasym pathetic Edinger Westphal nucleus or the cili ary ganglion: The e erent lim b of the pupillary light re ex is lost. A ected side: No direct or indirect pupillary light response on the opposite side. Una ected side: Direct light response, no indirect light response on the opposite (a ected) side. • Lesion of the optic radiation or visual cortex (geniculate part of the visual pathway): Intact pupillary re ex (direct and indirect light response on both sides).

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Visual System (IV): Coordination of Eye Movement

Rostral interstitial nucleus of m edial longitudinal fasciculus (riMLF)

Nucleus of oculom otor nerve Nucleus of trochlear nerve

Mesencephalic reticular form ation (MRF)

Medial longitudinal fasciculus (MLF)

Param edian pontine reticular form ation (PPRF)

Nucleus of abducent nerve

Nucleus prepositus hypoglossi

riMLF A

III

IV

PPRF

B

Fig. 9.58 Oculomotor nucle i and conne ctions in the brainste m A Midsagit t al section viewed from left side. B Circuit diagram show ing the supranuclear organization of eye m ovem ent s. The extraocular m uscles receive m otor innervation from the oculom o tor (CN III), trochlear (CN IV), and abducent (CN VI) nerves. The con certed m ovem ent of the extraocular m uscles allows for shifting of gaze, the swift m ovem ent of the visual axis toward the intended t arget. These rapid, precise, “ballistic” eye m ovem ent s are called saccades. They are preprogram m ed and, once initiated, cannot be altered until the end of the saccadic m ovem ent. The nuclei of CN III, IV, and VI (red) are involved in these saccadic m ovem ent s. They are interconnected for this purpose by the m edial longitudinal fasciculus (MLF, blue). Because these com plex m ovem ent s involve all the extraocular m uscles and their associated nerves, the activit y of the nuclei m ust be coordinated at a higher, or supranuclear, level. For exam ple, gazing to the right re quires four concerted m ovem ent s:

• • • •

PPRF

VI

Contract right lateral rectus (CN VI nucleus activated) Relax right m edial rectus (CN III nucleus inhibited) Relax left lateral rectus (CN VI nucleus inhibited) Contract left m edial rectus (CN III nucleus activated)

These conjugate eye m ovem ent s are coordinated by prem otor nuclei (purple) in the m esencephalic reticular form ation (green). Horizont al gaze m ovem ent s are program m ed in the nuclear region of the para m edian pontine reticular form ation (PPRF). Vertical gaze m ovem ent s are program m ed in the rostral interstitial nucleus of the m edial lon gitudinal fasciculus (riMLF). Both gaze centers establish bilateral con nections with the nuclei of CN III, IV, and VI. The tonic signals for m aintaining the new eye position originate from the nucleus preposi tus hypoglossi.

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Nucleus of oculom otor nerve (CN III) Nucleus of trochlear nerve (CN IV)

Corticonuclear fibers

Cerebral aqueduct Medial longitudinal fasciculus

Corticospinal tract

Nucleus of abducent nerve (CN VI)

Right

Left

Internuclear ophthalmoplegia (red arrow s: abducting nystag mus)

Gaze to the right

Convergence

A Anterior view. Left Medial rectus (not activated)

Right

Lateral rectus (intact)

Oculom otor nerve (CN III)

Abducent nerve (CN VI)

Medial longitudinal fasciculus

Nucleus of oculom otor nerve Nucleus of trochlear nerve

Area 8 (frontal gaze center)

Fig. 9.59 Course of the me dial long itudinal fasciculus in the brainste m Midsagit tal section viewed from the left side. The m edial longitudinal fasciculus (MLF) runs anterior to the cerebral aqueduct on both sides and continues from the m esencephalon to the cervical spinal cord. It transm it s bers for the coordination of conjugate eye m ove m ent s. A lesion of the MLF result s in internu clear ophthalm oplegia (see Fig . 9.60).

Fig. 9.60 Inte rnuclear ophthalmople g ia The m edial longitudinal fasciculus (MLF) inter connect s the oculom otor nuclei and also con nect s them with the opposite side. When this “information highway” is interrupted, inter nuclear ophthalm oplegia develops. This t ype of lesion m ost com m only occurs bet ween the nuclei of the abducent and the oculom otor nerves. It m ay be unilateral or bilateral. Typi cal causes are m ultiple sclerosis and dim in ished blood ow. The lesion is m anifested by the loss of conjugate eye movements. With a lesion of the left MLF, as shown here, the left m edial rectus m uscle is no longer activated during gaze to the right. The eye cannot be m oved inward on the side of the lesion (loss of the m edial rectus), and the opposite eye goes into an abducting nyst agm us (lateral rectus is intact and innervated by the abducent nerve). Re ex m ovem ent s such as convergence are not im paired, as there is no peripheral or nu clear lesion, and this reaction is not m ediated by the MLF.

Lesion Nucleus of abducent nerve

B Superior view.

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Regions of the Hea d

10. Ea r

Overview & External Ear (I)

External acoustic m eatus

Arcuate em inence

Posterior sem icircular canal

Lateral sem icircular canal

Anterior sem icircular canal Vestibule Vestibular root Cochlear root

Vestibulocochlear nerve (CN VIII)

Petrous apex Cochlea Malleus, head Temporal bone, petrous part Stapes Tensor t ympani Pharyngot ympanic (Eustachian or auditory) tube

Tympanic cavit y

Incus

Tympanic m em brane

St yloid process

Mastoid process External auditory canal

External ear

A

Inner ear

Fig. 10.1 Auditory and vestibular apparatus in situ A Coronal section through the right ear, anterior view. B Auditory apparatus: external ear (yellow), m iddle ear (blue), and inner ear (green). The auditory and vestibular apparatus are located deep in the petrous part of the temporal bone. The auditory apparatus consist s of the external ear, m iddle ear, and inner ear. Sound waves are captured by the auricle and travel through the external auditory canal to the t ympanic m em brane (the lateral boundary of the m iddle ear). The sound waves set the t ympanic m em brane into m otion, and these m echanical vibrations are transm it ted by the chain of auditory ossicles in the m iddle ear to the oval window, which leads into the inner ear. The ossicular chain induces vibrations in the m em brane covering the oval window, and these in turn cause a uid colum n in the inner ear to vibrate, set ting receptor cells in m otion. The transform ation of sound waves into electrical impulses takes place in the inner ear, which is the actual organ of hearing. The external ear and m iddle ear, on the other hand, constitute the sound conduction apparatus. The organ of balance is the vestibular apparatus, which is also located in the inner ear. It contains the semicircular canals for the perception of angular acceleration (rotational head m ovem ents) and the saccule and utricle for the perception of linear acceleration. Diseases of the vestibular apparatus produce dizziness (vertigo).

Middle ear

B

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Regions of the Hea d

10. Ea r

Temporal bone, t ympanic part

Malleus Sebaceous and cerum en glands

Incus Lateral ligam ent of m alleus

Bony part of external auditory canal

Stapes Handle (m anubrium )

Cartilaginous part of external auditory canal

Tympanic m em brane

Fig. 10.2 Exte rnal auditory canal, tympanic me mbrane, and tympanic cavity Coronal section, right ear, anterior view. The t ym panic m em brane (eardrum ) separates the external auditory canal from the t ym panic cavit y of the m iddle ear. The external auditory canal is an S-shaped tunnel that is approxim ately 3 cm long with an average diam eter of 0.6 cm . The outer third of the ear canal is cartilaginous. The inner t wo thirds of the canal are osseous, the wall being form ed by the t ym panic part of

the tem poral bone. The cartilaginous part in particular bears num erous sebaceous and cerum en glands beneath the keratinized strati ed squam ous epithelium . The cerum en glands produce a watery secretion that com bines with the sebum and sloughed epithelial cells to form a protective barrier (cerum en, “earwax”) that screens out foreign bodies and keeps the epithelium from drying out. If the cerum en absorbs water (e.g., after swim m ing), it m ay obstruct the ear canal (cerum en im paction), tem porarily causing a partial loss of hearing.

Tympanic m em brane

Malleolar prom inence

Tym panic incisure

Posterior m alleolar fold

Pars flaccida Anterior m alleolar fold

Incus Stapes A

B

IV

I

Um bo

Head of m andible

Tympanic bone

C

Fig. 10.3 Curvature of the e xte rnal auditory canal Right ear, anterior view (A) and transverse section (B). The external auditory canal is m ost curved in it s cartilaginous portion. When the t ym panic m em brane is inspected with an otoscope, the auricle should be pulled backward and upward in order to straighten the cartilaginous part of the ear canal so that the speculum of the oto scope can be introduced (C). Note the proxim it y of the cartilaginous anterior wall of the external auditory canal to the tem porom andibular joint (TM). This allows the exam iner to palpate m ovem ent s of the head of the m andible within the TMJ by inserting the sm all nger into the outer part of the ear canal.

Pars tensa Malleolar stria

III

II

Cone of light

Fig. 10.4 Tympanic me mbrane Right t ym panic m em brane, lateral view. The healthy t ym panic m em brane has a pearly gray color and an oval shape with an average surface area of approxim ately 75 m m 2 . It consist s of a lax portion, the pars f accida (Shrapnell m em brane), and a larger taut portion, the pars tensa, which is drawn inward at it s center to form the um bo (“navel”). The um bo m arks the lower tip of the handle (m anubrium ) of the m alleus, which is at t ached to the t ym panic m em brane all along it s length. It is visible through the pars tensa as a light-colored streak (m alleolar stria). The t ym panic m em brane is divided into four quadrant s in a clockwise direction: anterosuperior (I), anteroinferior (II), posteroinferior (III), posterosuperior (IV). The boundary lines of the quadrant s are the m alleolar stria and a line intersecting it perpendicularly at the um bo. The quadrant s of the t ym panic m em brane are clinically im port ant because they are used in describing the location of lesions. A triangular area of re ected light can be seen in the anteroinferior quadrant of a norm al t ym panic m em brane. The location of this “cone of light” is helpful in evaluating the tension of the t ym panic m em brane.

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Regions of the Hea d

10. Ea r

External Ear (II): Auricle Posterior auricular artery

Parietal branch Frontal branch

Crura of antihelix

Scaphoid fossa

Triangular fossa Cym ba conchae External auditory canal

Helix

Tragus

Anterior auricular arteries

Perforating branches

Transverse facial artery Superficial temporal artery

Intertragic incisure Antihelix

Antitragus Concha

Maxillary artery

Earlobe

Posterior auricular artery

Fig. 10.5 Rig ht auricle The auricle of the ear encloses a cartilaginous fram ework (auricular cartilage) that form s a funnel-shaped receptor for acoustic vibrations.

A

External carotid artery

Superior auricular m uscle Helicis m ajor Helicis m inor

Posterior auricular muscle

External auditory canal

Antitragus

Perforating branches Posterior auricular m uscle

Anastom otic arcades

Tragus

A Posterior auricular artery

Superior auricular m uscle

Obliquus auriculae

Anterior auricular m uscle

Transversus auriculae

External auditory canal

Insertions of posterior auricular m uscle

B

Fig. 10.6 Cartilage and muscle s of the auricle A Lateral view of the external surface. B Medial view of the posterior surface of the right ear. The skin (rem oved here) is closely applied to the elastic cartilage of the auricle (light blue). The m uscles of the ear are classi ed as m uscles of facial expression and, like the other m em bers of this group, are supplied by the facial nerve (CN VII). Prom inent in other m am m als, the auricular m uscles are vestigial in hum ans, with no signi cant function.

B

External carotid artery

Fig. 10.7 Arte rial supply of the auricle Lateral view (A) and posterior view (B) of right auricle. The proxim al and m edial portions of the laterally directed anterior surface of the ear are supplied by the anterior auricular arteries, which arise from the super cial tem poral artery. The other part s of the auricle are supplied by branches of the posterior auricular artery, which arises from the external carotid artery. These vessels are linked by extensive anastom oses, so operations on the external ear are unlikely to com prom ise the auricular blood supply. The copious blood ow through the auricle contributes to tem perature regulation: dilation of the vessels helps dissipate heat through the skin. The lack of insulating fat predisposes the ear to frostbite, which is particularly com m on in the up per third of the auricle. The auricular arteries have corresponding veins that drain to the super cial tem poral vein.

264

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Regions of the Hea d

Posterior zone

10. Ea r

Anterior zone

External auditory canal

Superficial parotid lym ph nodes

Mastoid lymph nodes (retroauricular)

Parotid fascia

Lower zone

Deep parotid lym ph nodes Internal jugular vein

Parotid gland

Fig. 10.8 Auricle and e xte rnal auditory canal: lymphatic drainag e Right ear, oblique lateral view. The lym phatic drainage of the ear is divided into three zones, all of which drain directly or indirectly into the deep cervical lym ph nodes along the internal jugular vein. The lower zone drains directly into the deep cervical lym ph nodes. The anterior zone rst drains into the parotid lym ph nodes, the posterior zone into the m astoid lym ph nodes.

Deep cervical lymph nodes

Facial nerve (CN VII)

Trigem inal nerve (CN V3 ) via auriculotemporal nerve

Trigem inal nerve (CN V3 ) via auriculotemporal nerve

Vagus nerve (CN X)

Vagus nerve (CN X)

Facial nerve (CN VII)

A

Cervical plexus via lesser occipital and great auricular nerves

B

Fig. 10.9 Se nsory inne rvation of the auricle Right ear, lateral view (A) and posterior view (B). The auricular region has a com plex nerve supply because, developm ent ally, it is located at the boundary bet ween the cranial nerves (pharyngeal arch nerves) and branches of the cervical plexus. Three cranial nerves contribute to the innervation of the auricle: • Trigem inal nerve (CN V3 ) • Facial nerve (CN VII; the skin area that receives sensory innervation from the facial nerve is not precisely known) • Vagus nerve (CN X)

Cervical plexus via lesser occipital and great auricular nerves

Two branches of the ce rvical ple xus are involved: • Lesser occipit al nerve (C 2) • Great auricular nerve (C 2, C 3) Note: Because the vagus nerve contributes to the innervation of the external auditory canal (auricular branch), m echanical cleaning of the ear canal (by inserting an aural speculum or by irrigating the ear) m ay evoke coughing and nausea. The auricular branch of the vagus nerve passes through the m astoid canaliculus and through a space bet ween the m astoid process and the t ym panic part of the tem poral bone (t ym panom astoid ssure, see p. 33) to the external ear and external auditory canal.

265

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10. Ea r

Regions of the Hea d

Middle Ear (I): Tympanic Cavity & Pharyngotympanic Tube

Pharyngot ympanic (auditory) tube Tympanic cavit y Internal carotid artery

Malleus

Cochlea

Incus Anterior sem icircular canal

Facial nerve Cochlear nerve

External auditory canal

Vestibular nerve

Lateral sem icircular canal

Vestibule Cochlear aqueduct

Mastoid air cells

Endolymphatic sac Posterior sem icircular canal

Fig. 10.10 Middle ear and associate d structure s Right petrous tem poral bone, superior view. The m iddle ear (light blue) is located within the petrous part of the tem poral bone bet ween the external ear (yellow) and inner ear (green). The t ym panic cavit y of the m iddle ear cont ains the chain of auditory ossicles, of which the m alleus (ham m er) and incus (anvil) are visible here. The t ym panic cavit y com m unicates anteriorly with the nasopharynx via the pharyngot ym panic (auditory) tube and posteriorly with the m astoid air cells. Infections can spread from the nasopharynx to the m astoid air cells by this route.

Auricle

Sigm oid sinus

Aditus (inlet) to m astoid antrum

Lesser petrosal nerve (from t ympanic plexus)

Malleus

Facial nerve (CN VII) Prom inence of lateral sem icircular canal

Incus Chorda t ympani (CN VII)

Prom inence of facial canal

Tensor t ympani

Stapes Tendon of insertion of stapedius

Prom ontory

Tympanic m em brane

Tympanic plexus

External auditory canal

Tympanic nerve (from CN IX) via t ympanic canaliculus

Fig. 10.11 Walls of the tympanic cavity Coronal section anterior view with the anterior wall rem oved. The t ym panic cavit y is a slightly oblique space that is bounded by six walls: • Lateral (m em branous) wall: boundary with the external ear; form ed largely by the t ym panic m em brane. • Medial (labyrinthine) wall: boundary with the inner ear; form ed largely by the prom ontory, or the bony em inence, overlying the basal turn of the cochlea. • Inferior (jugular) wall: form s the oor of the t ym panic cavit y and borders on the bulb of the jugular vein.

• Posterior (m astoid) wall: borders on the air cells of the m astoid process, com m unicating with the cells through the aditus (inlet) of the m astoid antrum . • Superior (tegm ent al) wall: form s the roof of the t ym panic cavit y. • Anterior (carotid) wall (removed here): includes the opening to the pharyngot ympanic (auditory) tube and borders on the carotid canal. The lateral side of the t ympanic m em brane is innervated by three cranial nerves: CN V3 (auriculotem poral nerve), CN VII (posterior auricular nerve; pathway uncert ain), and CN X (auricular branch). The m edial side of the t ym panic m em brane is innervated by CN IX (t ym panic branch).

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Regions of the Hea d Anterior sem icircular canal

Roof of t ym panic cavit y (tegm en t ympani)

Geniculate ganglion

Posterior sem icircular canal

10. Ea r

Facial nerve (CN VII) Opening for tendon of tensor t ympani

Lateral sem icircular canal

Greater petrosal nerve Lesser petrosal nerve

Oval window (fenestra vestibuli)

Sem icanal of tensor t ympani

Facial nerve canal

Internal carotid artery

Sigm oid sinus

Pharyngot ympanic (auditory) tube

Prom ontory

Internal carotid artery with internal carotid plexus

Posterior wall of t ympanic cavit y

Anterior wall of t ympanic cavit y

Mastoid air cells Chorda t ympani

Floor of t ympanic cavit y Facial nerve (CN VII)

Round window (fenestra cochleae)

Tympanic plexus

Fig. 10.12 Ne rves in the petrous bone Oblique sagittal section showing the medial wall of the t ympanic cavit y (see Fig. 10.11). The t ympanic nerve branches from CN IX as it passes through the jugular foramen, and conveys sensory and preganglionic parasympathetic bers into the t ympanic cavit y by passing through the t ym panic canaliculus. The bers from the t ympanic plexus provide sensory innervation to the t ympanic cavit y (including the medial surface of the t ympanic membrane), mastoid air cells, and part of the pharyngot ympanic tube. Note: The lateral surface of the t ympanic membrane receives sensory innervation from branches of CN V3 , CN VII, and CN X (see Fig. 10.11). The preganglionic parasym pathetic bers of the t ym panic nerve are reform ed from the t ym panic plexus as the lesser petrosal nerve. These bers synapse in the otic ganglion; the postganglionic parasym pathetic bers travel with the auriculotem poral nerve (a branch of CN V3 ) to supply the parotid gland.

Internal jugular vein

Tympanic nerve (CN IX) entering t ympanic canaliculus

In the facial canal, the facial nerve (CN VII) gives o a num ber of branches: the greater petrosal nerve, the nerve to the st apedius, the chorda t ym pani, and an auricular branch. The greater petrosal nerve and the chorda t ym pani both carry taste bers and preganglionic parasym pathetic bers. The greater petrosal nerve joins with the deep petrosal nerve (postganglionic sym pathetic) to form the nerve of the pterygoid canal (vidian nerve). The preganglionic parasym pathetic bers in the nerve of the pterygoid canal synapse at the pterygopalatine ganglion. The postganglionic parasym pathetic bers are then distributed by branches of the m axillary nerve to the lacrim al gland, palatine glands, superior labial glands, and m ucosa of the paranasal sinuses and nasal cavit y. The preganglionic parasym pathetic bers of the chorda t ym pani synapse at the subm andibular ganglion, and the postganglionic bers are distributed to the subm andibular and sublingual glands.

Internal carotid artery Sphenoid sinus

Pharyngot ym panic tube, bony part

Superior m eatus

Tympanic m em brane Pharyngeal tonsil

Middle m eatus

Pharyngot ympanic tube, cartilaginous part

Inferior m eatus

Pharyngeal orifice of pharyngot ympanic tube Tensor veli palatini Pharyngot ympanic tube, m em branous lam ina

Levator veli palatini

Salpingopharyngeus

Fig. 10.13 Pharyng otympanic (Eustachian or auditory) tube Medial view of right nasal cavit y. The pharyngot ym panic tube creates an open channel bet ween the m iddle ear and nasopharynx. Air passing through the tube serves to equalize the air pressure on the t wo sides of the t ym panic m em brane. This equalization is essential for m aint aining norm al t ym panic m em brane m obilit y, necessary for norm al hearing. One third of the tube is bony (in the petrous bone). The cartilaginous t wo thirds continue toward the nasopharynx, expanding to form a

hook (ham ulus) that is at t ached to a m em branous lam ina. The bers of the tensor veli palatini arise from this lam ina; when they tense the soft palate (during swallowing), these bers open the pharyngot ym panic tube. The tube is also opened by the salpingopharyngeus and levator veli palatini. The tube is lined with ciliated respiratory epithelium : the cilia beat toward the pharynx, inhibiting the passage of m icroorganism s into the m iddle ear.

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10. Ea r

Regions of the Hea d

Middle Ear (II): Auditory Ossicles & Tympanic Cavity

Head of m alleus

Articular surface for incus

Neck

Neck

Lateral process

Lateral process

Malleus Incus Stapes

Handle A

Anterior process

B

Body of incus

Oval window with annular stapedial ligam ent

Tympanic m em brane

Tym panic cavit y

Body Articular surface for m alleus

Short process

C

A Short process Long process

D

Oval window with annular stapedial ligam ent

Stapedius tendon

Lenticular process

Head of stapes

Pyram idal em inence

B

C

Neck

Posterior crus

Malleus

Anterior crus

Incus

E Axis of m ovem ent

Incudom alleolar joint F

Base

Oval window

Head of m alleus Neck of m alleus

Short process

Anterior process

Body of incus Incudostapedial joint

Handle

Posterior crus

G

Anterior crus Base of stapes

Fig. 10.14 Auditory ossicles Auditory ossicles of the left ear. The ossicular chain (G) of the m iddle ear establishes an articular connection bet ween the t ym panic m em brane and the oval window. It consist s of three sm all bones: • Malleus (“ham m er”): A Posterior view. B Anterior view. • Incus (“anvil”): C Medial view. D Anterolateral view. • St apes (“stirrup”): E Superior view. F Medial view. Note the synovial joint articulations bet ween the m alleus and incus (incudom alleolar joint) and the incus and st apes (incudost apedial joint).

D

Stapes

Fig. 10.15 Function of the ossicular chain Anterior view. A Sound waves (periodic pressure uctuations in the air) set the t ym panic m em brane into vibration. The ossicular chain transm it s the vibrations of the t ym panic m em brane (and thus the sound waves) to the oval window, which in turn com m unicates them to an aqueous m edium (perilymph). Conductive deafness occurs when there is im paired transm ission of sound waves. Although sound waves encounter very lit tle resistance in air, they encounter considerably higher impedance when they reach the uid interface of the inner ear. The sound waves m ust therefore be ampli ed (“impedance m atching”). The di erence in surface area bet ween the t ympanic m em brane and oval window increases the sound pressure by a factor of 17. This is augm ented by the 1.3-fold m echanical advantage of the lever action of the ossicular chain. Thus, in passing from the t ympanic m em brane to the inner ear, the sound pressure is am pli ed by a factor of 22. If the ossicular chain fails to transform the sound pressure bet ween the t ym panic m em brane and stapes base (footplate), the patient will experience conductive hearing loss of m agnitude approxim ately 20 dB. B, C Sound waves im pinging on the t ym panic m em brane induce m otion in the ossicular chain, causing a tilting m ovem ent of the st apes (B norm al position, C tilted position). The m ovem ent s of the stapes base against the m em brane of the oval window (st apedial m em brane) induce corresponding waves in the uid colum n in the inner ear. D The m ovem ent s of the ossicular chain are essentially rocking m ovem ent s (the dashed line indicates the axis of the m ovem ent s, the arrows indicate their direction). Two m uscles a ect the m obilit y of the ossicular chain: the tensor t ym pani and the st apedius (see Fig. 10.16).

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Regions of the Hea d

Posterior ligam ent of incus

Incus

10. Ea r

Superior ligam ent of incus and superior ligam ent of m alleus Incudom alleolar joint

Annular stapedial ligam ent

Malleus Tendon of tensor t ym pani

Stapedial footplate

Tensor t ympani

Incudostapedial joint

Internal carotid artery

Pyram idal em inence

Petrot ym panic fissure

Stapedius with nerve to the stapedius (CN VII)

Anterior ligam ent of m alleus

St ylom astoid artery

Chorda t ympani (CN VII)

Facial nerve

Posterior t ympanic artery

Chorda t ympani (CN VII)

Tympanic m em brane, lateral surface

Fig. 10.16 Ossicular chain in the tympanic cavity Lateral view of the right ear. The joint s and their stabilizing ligam ent s can be seen with the t wo m uscles of the m iddle ear—the st apedius and tensor t ympani. The stapedius (innervated by the stapedial branch of the facial nerve) insert s on the stapes. When it contract s, it sti ens the sound conduction apparatus and dam pens sound transm ission to the inner ear. This ltering function is believed to be particularly im portant at high sound frequencies (“high-pass lter”). When sound is transm itted into the m iddle ear through a probe placed in the external ear canal,

Anterior process of m alleus

one can m easure the action of the stapedius (stapedius re ex test, p. 277 by m easuring the change in acoustic im pedance (i.e., the am pli cation of the sound waves). Contraction of the tensor tympani (innervated by the trigem inal nerve CN V3 via the m edial pterygoid nerve) sti ens the t ympanic m em brane, thereby reducing the transm ission of sound. Both m uscles undergo a re ex contraction in response to loud acoustic stim uli. Note: The chorda t ympani (from CN VII) passes through the m iddle ear without a bony covering (m aking it susceptible to injury during otological surgery).

Incus

Superior malleolar fold Chorda t ympani Stapedius tendon Malleolar stria Um bo

Anterior t ym panic artery

Epit ympanum

Stapes

Malleus Lateral ligam ent of m alleus Superior recess of t ym panic m em brane Malleolar prom inence Tympanic m em brane

Fig. 10.17 Mucosal lining of the tympanic cavity Posterolateral view with the t ym panic m em brane partially rem oved. The t ym panic cavit y and the structures it cont ains (ossicular chain, tendons, nerves) are covered with m ucosa. The epithelium consist s m ainly of a sim ple squam ous t ype, with areas of ciliated colum nar cells and goblet cells. Because the t ym panic cavit y com m unicates directly with the respiratory tract (nasopharynx) through the pharyngot ym panic tube, it can also be interpreted as a specialized paranasal sinus. Like the sinuses, it is susceptible to frequent infections (otitis m edia), which m ay cause ear pain, a hearing de cit, a purulent discharge from the ear, and balance problem s.

Incus

Tendon of tensor t ympani

Malleus External auditory canal Tympanic m em brane

Mesot ympanum Hypot ympanum Pharyngot ympanic tube

Fig. 10.18 Clinically important levels of the tympanic cavity The t ym panic cavit y is divided into three levels in relation to the t ym panic m em brane: • Epit ym panum (epit ym panic recess, at tic) above the t ym panic m em brane • Mesot ym panum m edial to the t ym panic m em brane • Hypot ym panum (hypot ym panic recess) below the t ym panic m em brane The epit ym panum com m unicates with the m astoid air cells, and the hypot ym panum com m unicates with the pharyngot ym panic tube.

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Regions of the Hea d

10. Ea r

Inner Ear (I): Overview & Innervation (CN VIII)

Lateral sem icircular duct

Posterior sem icircular duct

Anterior sem icircular duct

Anterior sem icircular canal

Internal acoustic m eatus

Temporal bone, petrous part

Dura m ater Endolymphatic sac

Cochlea

Ampullary crest s

45°

Endolymphatic duct

Lateral sem icircular canal

90°

Utricle Macula of utricle Oval window

45°

Macula of saccule

Stapes

Saccule

Round window

A

Anterior sem icircular canal

Posterior sem icircular canal

Facial nerve and vestibulocochlear nerve

Cochlea Posterior sem icircular canal

Ductus reuniens

Anterior sem icircular canal

Cochlear aqueduct Scala t ympani

Helicotrem a

Scala vestibuli

Temporal bone, squam ous part

Cochlear duct

Vestibule

Fig. 10.19 Inne r ear The inner ear, em bedded within the petrous part of the tem poral bone, is form ed by a m em branous labyrinth, which oat s within a sim ilarly shaped bony labyrinth, loosely at t ached by connective tissue bers. Me mbranous labyrinth (blue ): The m em branous labyrinth is lled with endolym ph. This endolym phatic space (blue) com m unicates with the endolym phatic sac, an epidural pouch on the posterior surface of the petrous bone via the endolym phatic duct. Note: The auditory and vestibular endolym phatic spaces are connected by the ductus reuniens. Bo ny labyrinth (be ig e ): The bony labyrinth is lled with perilym ph. This perilym phatic space (beige) is connected to the sub arachnoid space by the cochlear aqueduct (perilym phatic duct), which ends at the posterior surface of the petrous part of the tem poral bone, inferior to the internal acoustic m eatus. The inner ear contains the auditory apparatus (hearing) and the vestib ular apparatus (balance). Auditory apparatus (see pp. 274–275): The sensory epithelium of the auditory apparatus (organ of Corti) is found in the cochlea. The cochlea consist s of the m em branous cochlear duct and bony cochlear labyrinth. Dam age to the cochlea or cochlear nerve, which com bines with the vestibular nerve to form CN VIII, leads to sensineural deafness. Vestibular apparatus (see pp. 278–279): The sensory epithelium of the vestibular apparatus is found in the saccule, the utricle, and the three m em branous sem icircular duct s. The saccule and utricle are enclosed in the bony vestibule, and the duct s are enclosed in bony sem icircular canals.

Cochlea Canthom eatal plane

30°

Lateral sem icircular canal B Mastoid process

External acoustic m eatus

Fig. 10.20 Proje ction of the inne r e ar onto the bony skull A Superior view of the petrous part of the tem poral bone. B Right lateral view of the squam ous part of the tem poral bone. The apex of the cochlea is directed anteriorly and laterally—not up ward as one m ight intuitively expect. The bony sem icircular canals are oriented at an approxim ately 45-degree angle to the cardinal body planes (coronal, transverse, and sagit t al). It is im port ant to know this arrangem ent when interpreting thin-slice CT scans of the petrous bone. Note: The location of the sem icircular canals is of clinical im port ance in therm al function test s of the vestibular apparatus. The lateral (horizont al) sem icircular canal is directed 30 degrees forward and up ward. If the head of the supine patient is elevated by 30 degrees, the horizont al sem icircular canal will assum e a vertical alignm ent. Because warm uids tend to rise, irrigating the auditory canal with warm (44° C) or cool (30° C) water (relative to the norm al body tem perature) can induce a therm al current in the endolym ph of the sem icircular canal, causing the patient to m anifest vestibular nyst agm us (jerky eye m ovem ent s, vestibulo -ocular re ex). Because head m ovem ent s always stim ulate both vestibular apparatuses, caloric testing is the only m ethod of separately testing the function of each vestibular apparatus (im port ant in the diagnosis of un explained vertigo).

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Anterior sem icircular duct

Anterior ampullary nerve

Vestibular ganglion, superior part

10. Ea r

Vestibulocochlear nerve (CN VIII), vestibular part Facial nerve (CN VII)

Vestibular aqueduct

Vestibular ganglion, inferior part

Dura m ater

Cochlear com m unicating branch

Endolymphatic sac

Nervus interm edius (CN VII)

Lateral ampullary nerve

Vestibulocochlear nerve (CN VIII), cochlear part

Com m on crus

Saccular nerve

Utricular nerve

Posterior ampullary nerve

Lateral sem icircular duct

Modiolus Spiral ganglion of cochlea

Posterior sem icircular duct Posterior ampulla

Oval window

Round window

Fig. 10.21 Inne rvation of the me mbranous labyrinth Right ear, anterior view. A erent im pulses from the vestibular and auditory m em branous labyrinths are relayed via dentritic processes to cell bodies in the vestibular and spiral ganglia, respectively. The central processes of the vestibular and spiral ganglia form the vestibular and cochlear part s of the vestibulocochlear nerve (CN VIII), respectively (see pp. 134–135 for a full discussion of CN VIII). CN VIII relays a erent im pulses to the brainstem through the internal acoustic m eatus and cerebellopontine angle. Vestibular ganglion: The cell bodies of a erent

Transverse crest

Greater petrosal nerve

Geniculate ganglion

Fig. 10.22 Cranial ne rves in the rig ht inte rnal acoustic meatus Posterior oblique view of the fundus of the internal acoustic m eatus. The approxim ately 1 cm -long internal auditory canal begins at the internal acoustic m eatus on the posterior wall of the petrous bone. It cont ains:

Facial nerve Nervus interm edius (from CN VII)

• Vestibulocochlear nerve (CN VIII) with it s cochlear and vestibular part s • Facial nerve (CN VII), along with it s parasym pathetic and t aste bers (nervus interm edius) • Labyrinthine artery and vein (not shown)

Internal carotid artery

Cochlear nerve Vestibular nerve

neurons (bipolar ganglion cells) in the superior part of the vestibular ganglion receive a erent im pulses from the anterior and lateral sem icircular canals and the saccule; cell bodies in the inferior part receive a erent im pulses from the posterior sem icircular canal and utricle. Spiral ganglia: Located in the central bony core of the cochlea (m odio lus), the cell bodies of bipolar ganglion cells in the spiral ganglia receive a erent im pulses from the auditory apparatus via their dentritic processes.

SacculoUtriculoPosterior ampullary nerve ampullary nerve ampullary nerve

Given the close proxim it y of the vestibulocochlear nerve and facial nerve in the bony canal, a tum or of the vestibulocochlear nerve (acoustic neuroma) m ay exert pressure on the facial nerve, leading to peripheral facial paralysis. Acoustic neurom a is a benign tum or that originates from the Schwann cells of vestibular bers, so it would be m ore accurate to call it a vestibular schwannoma. Tum or growth always begins in the internal auditory canal; as the tum or enlarges, it m ay grow into the cerebellopontine angle (see p. 134). Acute, unilateral inner ear dysfunction with hearing loss (sudden sensorineural hearing loss), often accom panied by tinnitus (ringing in the ears), t ypically re ect s an underlying vascular disturbance (vaso spasm of the labyrinthine artery causing decreased blood ow).

from vestibular nerve

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Regions of the Hea d

10. Ea r

Arteries & Veins of the Middle & Inner Ear The structures of the external and m iddle ear are supplied prim arily by branches of the external carotid artery. (Note: The caroticot ym panic arteries arise from the internal carotid artery.) The inner ear is supplied by the labyrinthine artery, which arises from the basilar artery. Venous drainage of the auricle is to the super cial tem poral vein (via auricular veins), whereas drainage of the external ear is to the external jugular and m axillary veins and the pterygoid plexus. The veins of the t ym panic cavit y drain to the pterygoid plexus and superior petrosal sinus; the inner ear drains to the labyrinthine vein, which em pties into the superior petrosal or transverse sinuses.

Ta ble 10.1 Arte ries of the ear Arte ry

Orig in

Distribution

Caroticot ympanic aa.

Internal carotid a.

Pharyngot ym panic (auditory) tube and anterior wall of t ym panic cavit y

St ylomastoid a.

Posterior auricular a. or occipital a.

Tym panic cavit y, m astoid air cells and antrum , st apedius m uscle, st apes

Inferior t ympanic a.

Ascending pharyngeal a.

Medial wall of t ympanic cavit y, promontory

Deep auricular a.

Maxillary a.

External surface of t ym panic m em brane

Posterior t ympanic a.

St ylomastoid a.

Chorda t ym pani, t ym panic m em brane, m alleus

Superior t ympanic a.

Middle meningeal a.

Tensor t ym pani, roof of t ym panic cavit y, st apes

Anterior t ympanic a.

Maxillary a.

Tym panic m em brane, m astoid antrum , m alleus, incus

Tubal a.

Ascending pharyngeal a.

Pharyngot ym panic tube and anterior t ym panic cavit y

Tympanic branches

A. of pterygoid canal

Tym panic cavit y and pharyngot ym panic tube

(Super cial) petrosal a.

Middle meningeal a.

Facial n. in facial canal and t ympanic cavit y

Labyrinthine a. (internal auditory a.)

Basilar a. directly or via it s anterior inferior cerebellar branch

Cochlea and vestibular system

Note: The arteries supplying the t ym panic cavit y and it s content s form a rich arterial anastom otic net work within the m iddle ear. The venous drainage of the m iddle ear is prim arily into the pterygoid plexus of veins located in the infratem poral fossa or into dural venous sinuses. Subarcuate artery

Ascending branch of superficial petrosal artery Labyrinthine Facial nerve artery (CN VII)

Descending branch of superficial petrosal artery

Superficial petrosal artery with greater petrosal nerve Superior t ym panic artery with lesser petrosal nerve

Anterior crural artery

Internal carotid artery

Posterior crural artery St ylom astoid artery, posterior t ympanic branch Branches to stapedius (stapedial branch)

Incudostapedial joint (incus rem oved)

Pharyngot ympanic (auditory) tube Tensor t ympani with superior t ym panic artery

Facial nerve (CN VII) St ylom astoid artery

Tendon of tensor t ympani (cut) Caroticot ympanic arteries Mastoid artery

Posterior t ympanic Deep auricular artery (from artery st ylom astoid artery)

Inferior t ympanic artery

Fig. 10.23 Arte ries of the tympanic cavity and mastoid air cells Right petrous bone, anterior view. The m alleus, incus, chorda t ym pani, and anterior t ym panic artery have been rem oved (see Fig. 10.24).

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Tubal artery

Regions of the Hea d

10. Ea r

Tegm en t ym pani

Incus

Mastoid antrum

Superior t ympanic artery (from m iddle m eningeal artery) Facial nerve (CN VII)

Tensor t ym pani

Stapedial artery Anterior t ympanic artery

Incudostapedial joint (stapes rem oved)

Handle of m alleus

Chorda t ympani (CN VII) Posterior t ympanic artery

Pharyngot ympanic (auditory) tube

St ylom astoid artery

Tympanic m em brane

Deep auricular artery

Fig. 10.24 Arte ries of the ossicular chain and tympanic me mbrane Medial view of the right t ym panic m em brane (see Fig. 10.13 for orient ation). This region receives m ost of it s blood supply from the anterior

Vestibular artery

Inferior t ym panic artery

t ym panic artery. With in am m ation of the t ym panic m em brane, the arteries m ay becom e so dilated that their course in the t ym panic m em brane can be seen, as illustrated here.

Vestibular ganglion, superior part

Vestibular nerve (CN VIII) Facial nerve (CN VII)

Vein of vestibular aqueduct

Labyrinthine artery and veins

Nervus interm edius (CN VII) Cochlear nerve (CN VIII) Com m on cochlear artery Cochlear veins Vestibulocochlear artery Cochlear artery proper

Vein of round window Vein of cochlear aqueduct

Fig. 10.25 Arte ries and ve ins of the inne r ear Right anterior view. The labyrinth receives it s arterial blood supply from the labyrinthine (internal auditory) artery, which generally arises

directly from the basilar artery, but m ay arise from the anterior inferior cerebellar artery. Venous blood drains to the labyrinthine vein and into the inferior petrosal sinus or the transverse sinuses.

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Regions of the Hea d

10. Ea r

Inner Ear (II): Auditory Apparatus

Modiolus

Greater petrosal nerve

Lesser petrosal nerve

Scala vestibuli

Helicotrem a

Stria vascularis

Cochlear nerve (CN VIII) Tympanic cavit y Spiral ganglion

Cochlear nerve (CN VIII) Facial nerve (CN VII)

Internal acoustic m eatus

B

Petrous bone

Tectorial m em brane Spiral ligam ent

Bony spiral lam ina

Chorda t ympani (CN VII)

Vestibular nerve (CN VIII)

A

Cochlear duct

Lim bus of spiral lam ina

Geniculate ganglion

Cochlea

Vestibular (Reissner) m em brane

Organ of Corti

Scala t ym pani

Basilar m em brane

Sem icircular canals Vestibular (Reissner) m em brane

Scala vestibuli

Spiral ligam ent

Nuel space Inner hair cell

Spiral lim bus

Cochlear duct

Bony spiral lam ina

Stria vascularis Tectorial m em brane Outer hair cells

Spiral ganglion

Basilar m em brane

Fig. 10.26 Location and structure of the cochlea A Cross section through the cochlea in the petrous bone. B The three compartments of the cochlear canal. C Cochlear turn with sensory apparatus. The bony canal of the cochlea (spiral canal) is approxim ately 30 to 35 m m long in the adult. It m akes t wo and a half turns around it s bony axis, the modiolus, which is perm eated by branched cavities and contains the spiral ganglion (perikarya of the a erent neurons). The base of the cochlea is directed toward the internal acoustic m eatus (A). A cross section through the coch lear canal displays three m em branous com partm ent s arranged in three levels (B). The upper and lower com partm ent s, the scala vestibuli and scala tympani, each contain perilym ph; the m iddle level, the cochlear duct (scala m edia), contains endolym ph. The perilym phatic spaces are interconnected at the apex by the helicotrema, and the endolym phatic space ends blindly at the apex. The cochlear duct, which is triangular in cross section, is separated from the scala vestibuli by the vestibular (Reissner) membrane and from the scala t ym pani by the basilar membrane. The basilar m em brane represent s a bony projection of the m odiolus (spiral lamina) and

Internal spiral sulcus

Corti tunnel

Bony wall

Scala tympani

C

widens steadily from the base of the cochlea to the apex. High frequencies (up to 20,000 Hz) are perceived by the narrow portions of the basilar m em brane, whereas low frequencies (down to about 200 Hz) are perceived by it s broader portions (tonotopic organization). The basilar m em brane and bony spiral lam ina thus form the oor of the cochlear duct, upon which the actual organ of hearing, the organ of Corti, is located. This organ consist s of a system of sensory cells and supporting cells covered by an acellular gelatinous ap, the tectorial membrane. The sensory cells (inner and outer hair cells) are the receptors of the organ of Corti (C). These cells bear approxim ately 50 to 100 stereocilia, and on their apical surface synapse on their basal side with the endings of a erent and e erent neurons. They

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have the abilit y to transform m echanical energy into electrochem ical potentials. A m agnied cross-sectional view of a cochlear turn (C) also reveals the stria vascularis, a layer of vascularized epithelium in which the endolym ph is form ed. This endolym ph lls the m em branous labyrinth (appearing here as the cochlear duct, which is part of the labyrinth). The organ of Corti is located on the basilar m em brane. It transform s the energy of the acoustic traveling wave into electrical im pulses, which are then carried to the brain by the cochlear nerve. The principal cell of signal transduction is the inner hair cell. The function of the basilar m em brane is to transm it acoustic waves to the inner hair cell, which transform s them into im pulses that are received and relayed by the cochlear ganglion.

Regions of the Hea d

Malleus

10. Ea r

Incus

Stapes

Oval window

Scala vestibuli

Traveling wave

Stapes Annular stapedial ligam ent Oval window Round window

Round window

Basilar m em brane

Basilar m em brane

Tympanic m em brane

A

Fig. 10.27 Sound conduction during hearing A Sound conduction from the middle e ar to the inne r ear: Sound waves in the air de ect the t ym panic m em brane, whose vibrations are conducted by the ossicular chain to the oval window. The sound pressure induces m otion of the oval window m em brane, whose vibrations are, in turn, transm it ted through the perilym ph to the basilar m em brane of the inner ear (see B). The round window equalizes pressures bet ween the m iddle and inner ear.

Inner hair cells

Tectorial m em brane

Scala t ym pani

B

B Formation of a traveling w ave in the cochlea: The sound wave begins at the oval window and travels up the scala vestibuli to the apex of the cochlea (“traveling wave”). The amplitude of the traveling wave gradually increases as a function of the sound frequency and reaches a m axim um value at particular sites (shown greatly exaggerated in the drawing). These are the sites where the receptors of the organ of Corti are stim ulated and signal transduction occurs. To understand this process, one must rst grasp the structure of the organ of Corti (the actual organ of hearing), which is depicted in Fig. 10.28.

Shearing of the stereocilia

Stereocilia

Mem brane deflection

A

Afferent cochlear nerve fibers

Outer hair cells

Basilar m em brane

B

Fig. 10.28   Organ of Corti at rest (A) and de e cte d by a traveling  w ave (B) The traveling wave is generated by vibrations of the oval window m em brane. At each site that is associated with a particular sound frequency, the traveling wave causes a m axim um de ection of the basilar m em brane and thus of the tectorial m em brane, set ting up shearing m ovem ent s bet ween the t wo m em branes. These shearing m ovem ent s

cause the stereocilia on the outer hair cells to bend. In response, the hair cells actively change their length, thereby increasing the local am plitude of the traveling wave. This additionally bends the stereocilia of the inner hair cells, stim ulating the release of glut am ate at their basal pole. The release of this subst ance generates an excit atory potential on the a erent nerve bers, which is transm it ted to the brain.

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10. Ea r

Regions of the Hea d

Auditory Pathw ay

Lateral sulcus Transverse temporal gyri

Area 41, transverse temporal gyri

Acoustic radiation

Nucleus of m edial geniculate body Inferior collicular nucleus Com m issure of inferior colliculi

Transverse temporal gyri

Lateral lem niscus Posterior cochlear nucleus

Nuclei of lateral lem niscus

200 Hz

20,000 Hz (20 kHz) Medullary striae

Cochlear duct Corti organ

Superior olivary nucleus

Spiral ganglion

Nucleus of trapezoid body

Anterior cochlear nucleus

Fig. 10.29 A e re nt auditory pathw ay of the  left ear The receptors of the auditory pathway are the inner hair cells of the organ of Corti. Because they lack neural processes, they are called secondary sensory cells. They are located in the cochlear duct of the basilar m em brane and are studded with stereocilia, which are exposed to shearing forces from the tectorial m em brane in response to a traveling wave. This causes bowing of the stereocilia (see Fig. 10.28). These bowing m ovem ent s act as a stim ulus to evoke cascades of neural signals. Dendritic processes of the bipolar neurons in the spiral ganglion pick up the stim ulus. The bipolar neurons then transm it im pulses via their axons, which are collected to form the cochlear nerve, to the anterior and posterior cochlear nuclei. In these nuclei the signals are relayed to the second neuron of the auditory pathway. Inform ation from the cochlear nuclei is then transm it ted via four to six nuclei to the prim ary auditory cortex, where the auditory inform ation is consciously perceived (analogous to the visual cortex). The prim ary auditory cortex is located in the transverse tem poral gyri (Heschl gyri, Brodm ann area 41). The auditory pathway thus cont ains the following key st ations:

• • • • • • • •

Inner hair cells

Cochlear nerve (CN VIII)

Inner hair cells in the organ of Corti Spiral ganglion Anterior and posterior cochlear nuclei Nucleus of the trapezoid body and superior olivary nucleus Nucleus of the lateral lem niscus Inferior collicular nucleus Nucleus of the m edial geniculate body Prim ary auditory cortex in the tem poral lobe (transverse tem poral gyri = Heschl gyri or Brodm ann area 41)

The individual part s of the cochlea are correlated with speci c areas in the auditory cortex and it s relay stations. This is known as the tonotopic organization of the auditory pathway. This organizational principle is sim ilar to that in the visual pathway. Binaural processing of the auditory inform ation (= stereo hearing) rst occurs at the level of the superior olivary nucleus. At all further stages of the auditory pathway there are also interconnections bet ween the right and left sides of the auditory pathway (for clarit y, these are not shown here). A cochlea that has ceased to function can som etim es be replaced with a cochlear implant.

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Regions of the Hea d

Cochlear nerve (CN VIII)

10. Ea r

Facial nucleus

Facial nerve (CN VII)

Cochlear nucleus

Superior olive with superior olivary nucleus

Facial nucleus

Cochlea Stapes Tym panic m em brane Stapedial nerve Stapedius m uscle

Fig. 10.30 The  stape dius re e x When the volum e of an acoustic signal reaches a certain threshold, the stapedius re ex triggers a contraction of the stapedius m uscle. This re ex can be utilized to test hearing without the patient’s cooperation (“objective” auditory testing). The test is done by introducing a sonic probe into the ear canal and presenting a test noise to the t ym panic m em brane. When the noise volum e reaches a cert ain thre shold, it

evo kes the st apedius re ex, and the t ym panic m em brane sti ens. The change in the resist ance of the t ym panic m em brane is then m easured and recorded. The a erent lim b of this re ex is in the cochlear nerve. Inform ation is conveyed to the facial nucleus on each side by way of the superior olivary nucleus. The e erent lim b of this re ex is form ed by branchiom otor (viscerom otor) bers of the facial nerve.

Inner hair cell

Outer hair cell

Lateral olivocochlear bundle

Medial olivocochlear bundle Lateral neuron Medial neuron

Type I ganglion cell Type II ganglion cell Superior olive

Cochlear nerve

Fig. 10.31 E e re nt  be rs from the  olive  to the  Corti organ Besides the a erent (sensory) bers from (blue) the organ of Corti, which form the vestibulocochlear nerve, there are also e erent (m otor) bers (red) that pass to the organ of Corti in the inner ear and are concerned with the active preprocessing of sound (“cochlear am pli er”) and acoustic protection. The e erent bers arise from neurons that are located in either the lateral or m edial part of the superior olive and project from there to the cochlea (lateral or m edial olivocochlear bun-

dle). The bers of the lateral neurons pass uncrossed to the dendrites of the inner hair cells, whereas the bers of the m edial neurons cross to the opposite side and term inate at the base of the outer hair cells, whose activit y they in uence. When stim ulated, the outer hair cells can actively am plify the traveling wave. This increases the sensitivit y of the inner hair cells (the actual receptor cells). The activit y of the e erent s from the olive can be recorded as otoacoustic em issions (OAE). This test can be used to screen for hearing abnorm alities in newborns.

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Regions of the Hea d

10. Ea r

Inner Ear (III): Vestibular Apparatus

Fig. 10.32 Structure of the vestibular apparatus The vestibular apparatus is the organ of balance. It consist s of the m em branous sem icircular duct s, which cont ain sensory ridges (am pullary crest s) in their dilated portions (am pullae), and of the saccule and utricle with their m acular organs. The sensory organs in the sem icircular duct s respond to angular acceleration; the m acular organs, which have an approxim ately vertical and horizont al orient ation, respond to horizont al (utricular m acula) and vertical (saccular m acula) linear acceleration, as well as to gravit ational forces.

Ampullary crest with anterior ampullary nerve

Anterior sem icircular canal

Vestibular ganglion, superior part

Anterior sem icircular duct

Vestibular ganglion, inferior part

Ampullary crest with lateral ampullary nerve

Utricle Endolymphatic sac

Utricular m acula with utricular nerve Saccular m acula with saccular nerve

Lateral sem icircular duct

Saccule

Fig. 10.33 Structure of the ampulla and ampullary crest Cross section through the am pulla of a sem icircular canal. Each canal has a bulbous expansion at one end (am pulla) that is traversed by a connective tissue ridge with sensory epithelium (am pullary crest). Extending above the am pullary crest is a gelatinous cupula, which is at t ached to the roof of the am pulla. Each of the sensory cells of the am pullary crest (approxim ately 7000 in all) bears on it s apical pole one long kinocilium and approxim ately 80 shorter stereocilia, which project into the cupula. When the head is rotated in the plane of a particular sem icircular canal, the inertial lag of the endolym ph causes a de ection of the cupula, which in turn causes a bowing of the stereocilia. The sensory cells are either depolarized (excitation) or hyperpolarized (inhibition), depending on the direction of ciliary displacem ent.

Fig. 10.34 Structure of the utricular and saccular maculae The m aculae are thickened oval areas in the epithelial lining of the utricle and saccule, each averaging 2 m m in diam eter and cont aining arrays of sensory and supporting cells. Like the sensory cells of the am pullary crest, the sensory cells of the m acular organs bear specialized stereocilia, which project into an otolithic m em brane. The lat ter consist s of a gelatinous layer, sim ilar to the cupula, but it has calcium carbonate cryst als or otoliths (statoliths) em bedded in it s surface. With their high speci c gravit y, these crystals exert traction on the gelatinous m ass in response to linear acceleration, and this induces shearing m ovem ent s of the cilia. The sensory cells are either depolarized or hyperpolarized by the m ovem ent, depending on the orient ation of the cilia. There are t wo distinct categories of vestibular hair cells (t ype I and t ype II); t ype I cells (light red) are goblet shaped.

Posterior sem icircular duct

Endolymphatic duct

Am pullary crest with posterior ampullary nerve

Sem icircular canal

Ductus reuniens

Ampulla Cupula Cilia of sensory cells Supporting cell Sensory cell

Ampullary crest

Otoliths

Otolithic m em brane

Stereocilia of t ype II hair cells Stereocilia of t ype I hair cells Type II hair cell Type I hair cell

Basem ent m em brane Supporting cell

Afferent nerve fiber

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Regions of the Hea d

Fig. 10.35 Stimulus transduction in the vestibular se nsory cells Each of the sensory cells of the m aculae and am pullary crest bears on it s apical surface one long kinocilium and approxim ately 80 stereocilia of graduated lengths, form ing an array that resem bles a pipe organ. This arrangem ent result s in a polar di erentiation of the sensory cells. The cilia are straight while in a resting state. When the stereocilia are de ected toward the kinocilium , the sensory cell depolarizes, and the frequency of action potentials (discharge rate of im pulses) is increased (right side of diagram ). When the stereocilia are de ected away from the kinocilium , the cell hyperpolarizes, and the discharge rate is decreased (left side of diagram ). This m echanism regulates the release of the transm it ter glut am ate at the basal pole of the sensory cell, thereby controlling the activation of the a erent nerve ber (depolarization stim ulates glut am ate release, and hyperpolarization inhibit s it). In this way the brain receives inform ation on the m agnitude and direction of m ovem ent s and changes of position.

Kinocilium

Stereocilia

10. Ea r

Sensory cell

Tim e

Afferent nerve fiber

Anterior ampulla Lateral ampulla Macula of utricle Macula of saccule

Posterior ampulla Cochlear duct

Fig. 10.36 Spe cialize d orie ntations of the ste re ocilia in the vestibular apparatus (ampullary crest and maculae ) Because the stim ulation of the sensory cells by de ection of the stereocilia away from or toward the kinocilium is what initiates signal transduction, the spatial orient ation of the cilia m ust be specialized to ensure that every position in space and every m ovem ent of the head stim ulates or inhibit s cert ain receptors. The ciliary arrangem ent shown here ensures that every direction in space will correlate with the m axim um sensitivit y of a particular receptor eld. The arrows indicate the polarit y of the cilia (i.e., each of the arrowheads point s in the direction of the kinocilium in that particular eld). Note that the sensory cells show an opposite, reciprocal arrangem ent in the sensory elds of the utricle and saccule.

Fig. 10.37 Inte raction of contralate ral se micircular canals during he ad rotatio n When the head rot ates to the right (red arrow), the endolym ph ows to the left because of it s inertial m ass (solid blue arrow, t aking the head as the reference point). Owing to the alignm ent of the stereocilia, the left and right sem icircular canals are stim ulated in opposite fashion. On the right side, the stereocilia are de ected toward the kinocilium (dot ted arrow; the discharge rate increases). On the left side, the stereocilia are de ected away from the kinocilium (dot ted arrow; the discharge rate decreases). This arrangem ent heightens the sensitivit y to stim uli by increasing the stim ulus contrast bet ween the t wo sides. In other words, the di erence bet ween the decreased ring rate on one side and the increased ring rate on the other side enhances the perception of the kinetic stim ulus.

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10. Ea r

Regions of the Hea d

Vestibular Pathw ay

Nucleus of posterior com m issure (Darkschewit sch nucleus) Interstitial nucleus (Cajal nucleus)

Red nucleus

Nucleus of oculom otor nerve (CN III) Nucleus of trochlear nerve (CN IV)

Globose nucleus

Uncinate fasciculus

Fastigial nucleus

Vestibular nuclei

Nucleus of abducent nerve (CN VI)

Vestibulocerebellar fibers

Flocculonodular lobe

Vestibulocochlear nerve (CN VIII)

Vestibular ganglion (CN VIII)

Ampullary crest

Reticular form ation Dorsal motor nucleus (CN X)

Utricle

Nucleus of accessory nerve (CN XI)

Saccule

Medial longitudinal fasciculus Lateral vestibulospinal tract Reticulospinal tract To sacral cord Afferent (sensory) Efferent (m otor)

To cervical cord

Proprioceptive pathways within CNS

Fig. 10.38 Ce ntral conne ctions of the vestibular ne rve (CN VIII) Three system s are involved in the regulation of hum an balance: • Vestibular system • Proprioceptive system • Visual system The peripheral receptors of the vestibular system are located in the m em branous labyrinth, which consist s of the utricle and saccule and the am pullae of the three sem icircular duct s. The m aculae of the utricle and saccule respond to linear acceleration, and the sem icircular duct organs in the am pullary crest s respond to an gular (rot ational) accelera tion. Like the hair cells of the inner ear, the receptors of the vestibular system are secondary sensory cells. The basal portions of the secondary sensory cells are surrounded by dendritic processes of bipo -

lar neurons. Their perikarya are located in the vestibular ganglion. The axons from these neurons form the vestibular nerve and term inate in the four vestibular nuclei. Besides input from the vestibular apparatus, these nuclei also receive sensory input (see Fig . 10.39). The vestibular nuclei show a topographical organization (see Fig . 10.40) and distribute their e erent bers to three t arget s: • Motor neurons in the spinal cord via the lateral vestibulospinal tract. These m otor neurons help to m aint ain an upright st ance, m ainly by increasing the tone of extensor m uscles. • Flocculonodular lobe of the cerebellum (archicerebellum ) via vestib ulocerebellar bers. • Ipsilateral and contralateral oculom otor nuclei via the ascending part of the m edial longitudinal fasciculus.

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Regions of the Hea d

Hypothalam us

Cortex

10. Ea r

Thalam us Brainstem

Superior rectus

Fig. 10.39 Role of the ve stibular nucle i in the mainte nance o f balance The vestibular nuclei receive a erent input from the vestibular system , proprioceptive system (position sense, m uscles, and joint s), and visual system . They then distribute e erent bers to nuclei that control the m otor system s im port ant for balance. These nuclei are located in the: • Spinal cord (m otor support) • Cerebellum ( ne control of m otor function) • Brainstem (oculom otor nuclei for oculom otor function) E erent s from the vestibular nuclei are also distributed to the following regions:

Eye

• Thalam us and cortex (spatial sense) • Hypothalamus (autonomic regulation: vomiting in response to vertigo) Labyrinth

Vestibular nuclei

Cerebellum

Note: Acute failure of the vestibular system is m anifested by rotary vertigo.

Spinal cord

Proprioception

Nucleus of oculom otor nerve (CN III)

Nucleus of trochlear nerve (CN IV)

Medial longitudinal fasciculus

Nucleus of abducent nerve (CN VI)

Cerebellum

Inferior cerebellar peduncle Superior vestibular nucleus

Vestibulocerebellar fibers Vestibular nerve (CN VIII)

Lateral vestibular nucleus Inferior vestibular nucleus Medial vestibular nucleus Medial longitudinal fasciculus

Lateral vestibulospinal tract

Afferent (sensory) Efferent (m otor)

Fig. 10.40 Vestibular nucle i: topographic organization and ce ntral conne ctio ns Four nuclei are distinguished:

• A erent bers from the am pullary crest s of the sem icircular canals term inate in the superior vestibular nucleus, the upper part of the inferior vestibular nucleus, and the lateral vestibular nucleus.

• • • •

The e erent bers from the lateral vestibular nucleus pass to the lateral vestibulospinal tract. This tract extends to the sacral part of the spinal cord, its axons term inating on m otor neurons. Functionally, it is concerned with keeping the body upright, chie y by increasing the tone of the extensor m uscles. The vestibulocerebellar bers from the other three nuclei act through the cerebellum to m odulate m uscular tone. All four vestibular nuclei distribute ipsilateral and contralateral axons via the m edial longitudinal fasciculus to the three m otor nuclei of the nerves to the extraocular m uscles (i.e., the nuclei of the oculom otor [CN III], trochlear [CN IV], and abducent [CN VI] nerves).

Superior vestibular nucleus (of Bechterew) Lateral vestibular nucleus (of Deiters) Medial vestibular nucleus (of Schwalbe) Inferior vestibular nucleus (of Roller)

The vestibular system has a topographic organization: • A erent bers of the saccular m acula term inate in the inferior vestibular nucleus and lateral vestibular nucleus. • A erent bers of the utricular m acula term inate in the m edial part of the inferior vestibular nucleus, the lateral part of the m edial vestibular nucleus, and the lateral vestibular nucleus.

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Bo nes, Lig ame nts, & Muscle s of the Ne ck Vertebral Colum n & Vertebrae Cervical Spine Joint s of the Cervical Spine Ligam ent s of the Vertebral Colum n Ligam ent s of the Cervical Spine Ligam ent s of the Craniovertebral Joint s Muscles of the Neck: Overview Muscles of the Neck & Back (I) Muscles of the Neck & Back (II) Muscles of the Posterior Neck Intrinsic Back Muscles (I): Erector Spinae & Interspinales Intrinsic Back Muscles (II) Intrinsic Back Muscles (III): Short Nuchal & Craniovertebral Joint Muscles Prevertebral & Scalene Muscles Suprahyoid & Infrahyoid Muscles

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Ne urovascular To po g raphy of the Ne ck Arteries & Veins of the Neck Cervical Plexus Cervical Regions (Triangles) Cervical Fasciae Anterior Neck Root of the Neck Lateral Neck Deep Lateral Neck Posterior Neck Peripharyngeal Space (I) Peripharyngeal Space (II)

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284 286 288 290 292 294 296 298 300 302 304 306

314 316 318 320 322 324 326 328 330 332 334

Larynx & Thyroid Gland Larynx Laryngeal Muscles Larynx: Neurovasculature Larynx: Topography Endotracheal Intubation Thyroid & Parathyroid Glands

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11. Bones, Liga ments, & Muscles of the Neck

Vertebral Column & Vertebrae Atlas (C1)

Dens of axis (C2)

Transverse process of atlas (C1)

Axis (C2)

Vertebral bodies (of C3 and C4)

Cervical spine (C1– C7)

Spinous process of C7 (vertebra prom inens)

Cervical (secondary)

Spinous processes (of C7 and T1)

Transverse processes (of T3 and T4) Thoracic spine (T1–T12)

Lum bar spine (L1–L5)

Thoracic (prim ary)

Lam inae (of T5 and T6)

Costal facet of transverse process

Lumbar (secondary)

Superior and inferior costal facets (of T8) Superior and inferior articular facets (of T10)

Sacral (prim ary) Sacrum (fused S1–S5)

Fig. 11.1 Spinal curvature Left lateral view. The spinal (vertebral) colum n is divided into four regions: the cervical, thoracic, lum bar, and sacral spines. In the neonate, all regions dem onstrate an anteriorly concave curvature. This single concave curvature in the neonate is referred to as the prim ary curvature of the vertebral colum n. During developm ent, the cervical and lum bar regions of the vertebral colum n develop anteriorly convex curvatures. These changes are referred to as secondary curvatures. The cervical secondary curvature develops as infant s begin to hold up their heads. The lum bar secondary curvatures are the result of upright bipedal locom otion. Kyphosis is a pathological condition where the thoracic prim ary curvature is abnorm ally exaggerated (hunchback, rounded back). Lordosis is a pathological condition where the secondary curvatures are exaggerated. Lordo sis m ay occur in either the cervical or lum bar regions (swayback) of the vertebral colum n. Di ering from the abnorm al developm ent of prim ary and secondary curvatures, scoliosis is an abnorm al lateral deviation of the vertebral colum n.

Intervertebral disk Mam millary m illary processes (of L1 and L2)

Intervertebral foramina

Articular surface of sacrum

Sacral crest

Sacral foram ina

A

Coccyx

B

Fig. 11.2 Ve rtebral column A Left lateral view. B Posterior view. The vertebral column is divided into four regions: cervical, thoracic, lumbar, and sacral. Each vertebra consists of a vertebral body and vertebral (neural) arch. The vertebral bodies (with intervening intervertebral disks) form the load-bearing component of the vertebral column. The vertebral (neural) arches enclose the vertebral canal, protecting the spinal cord.

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Fig. 11.3 Structure of ve rtebrae Schem atic, left oblique posterosuperior view. Each vertebra consist s of a load-bearing body and an arch that encloses the vertebral foram en. The arch is divided into the pedicle and lam ina. Vertebrae have transverse and spinous processes that provide sites of at t achm ent for m uscles. Vertebrae articulate at facet s on the superior and inferior articular processes. Thoracic vertebrae articulate with ribs at cost al facet s.

11. Bones, Liga ments, & Muscles of the Neck

Vertebral foramen Superior articular process

Vertebral body

Pedicle

Transverse process

Lam ina

Spinous process

Vertebral arch

Inferior articular process Spinous process

Spinous process Lam ina

Lam ina

Costal facet, transverse process

Transverse process

Vertebral foram en Superior articular facet

Pedicle

Vertebral foram en

Superior articular facet

Pedicle

Superior and inferior costal facets

Posterior tubercle Transverse process (with sulcus for spinal nerve)

Transverse foram en A

Vertebral body

Vertebral body

B

Anterior tubercle

Spinous process (sacral crest) Superior articular with facet

Spinous process Mam m illary process

Lam ina

Vertebral foram en (sacral canal)

Superior articular process with facet

Wing

Transverse process Pedicle Superior vertebral notch

C

Vertebral body

Vertebral foram en

Sacral prom ontory

D

Vertebral body (base of sacrum )

Fig. 11.4 Typical ve rtebrae Superior view. A Cervical vertebra (C4). B Thoracic vertebra (T6). C Lum bar vertebra (L4). D Sacrum . The vertebral bodies increase in size cranially to caudally.

Ta ble 11.1 Structural ele me nts of ve rtebrae Each vertebra consist s of a body and an arch that enclose the vertebral foram en. The t ypes of vertebrae can be distinguished particularly easily by exam ining their transverse processes. The sacrum has structures that are analogous to the other vertebrae. Ve rtebrae

Body

Forame n

Transve rse proce ss

Spino us process

Cervical vertebrae C3–C7

Sm all (kidney-shaped)

Large (triangular)

Transverse foram ina

C3–C5: short C7: long C3–C6: bi d

Thoracic vertebrae T1–T12

Medium (heart-shaped) with cost al facet s

Sm all (circular)

Cost al facet s

Long

Lum bar vertebrae L1–L5

Large (kidney-shaped)

Medium (triangular)

Mam m illary processes

Short and broad

Sacrum (fused S1–S5)

Large to sm all (decreases from base to apex)

Sacral canal (triangular)

Fused (form s wing of sacrum )

Short (m edian sacral crest)

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Cervical Spine Posterior arch of atlas (C1)

Superior articular facet

Anterior tubercle C1 (atlas)

Groove for vertebral artery Vertebral foram en Posterior tubercle

Anterior tubercle

Posterior tubercle of atlas (C1)

Transverse foram en

C2 (axis) Spinous process of axis (C2)

Transverse process

A

Transverse process

Posterior arch

Inferior articular facet

Vertebral body Facet (zygapophyseal) joint

Anterior tubercle

Inferior articular process

Posterior tubercle

Superior articular process

Sulcus for spinal nerve

Dens Anterior articular facet

Posterior articular facet

Superior articular facet Spinous process

Transverse foram en Body

Intervertebral foramen

Spinous process of C7

Transverse process

B

Inferior articular facet

Lam ina

C7 (vertebra prom inens)

Transverse foram en

Transverse foram en

Fig. 11.5 Ce rvical spine (C1–C7) Left lateral view. The cervical spine consist s of seven vertebrae. C1 and C2 are at ypical and are discussed individually. Typical ce rvical ve rtebrae (C3–C7): Typical cervical vertebrae have relatively sm all, kidney-shaped bodies. The superior and inferior articular processes are broad and at; their facet s are at and inclined at approxim ately 45 degrees from the horizontal. The vertebral arches enclose a large, triangular vertebral foram en. Spinal nerves em erge from the vertebral canal via the intervertebral foram ina form ed bet ween the pedicles of adjacent vertebrae. The transverse processes of cervical vertebrae are furrowed to accom m odate the em erging nerve (sulcus for spinal nerve). The transverse processes also consist of an anterior and a posterior portion that enclose a transverse foram en. The transverse foram ina allow the vertebral artery to ascend to the base of the skull. The spinous processes of C3–C6 are short and bi d. The spinous process of C7 (vertebra prom inens) is longer and thicker; it is the rst spinous process that is palpable through the skin. Atlas (C1) and axis (C2): The atlas and axis are specialized for bearing the weight of the head and allowing it to m ove in all directions. The body of the axis contains a vertical prom inence (dens) around which the atlas turns. The atlas does not have a vertebral body: it consist s of an anterior and a posterior arch that allow the head to rot ate in the horizont al plane.

Superior articular process

Transverse process

Superior articular facet

Body

Inferior articular process

Sulcus for spinal nerve

C

Spinous process

Inferior articular facet

Transverse foram en

Superior articular process Superior articular facet Transverse process

Body

Inferior articular process D

Spinous process

Inferior articular facet

Fig. 11.6 Le ft late ral view of ce rvical ve rtebrae A Atlas (C1). B Axis (C2). C Typical cervical vertebra (C4). D Vertebra prom inens (C7).

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Posterior arch

11. Bones, Liga ments, & Muscles of the Neck

Posterior tubercle

Vertebral foram en Superior articular facet

Superior articular facet

Anterior arch

Groove for vertebral artery

Lateral m asses

Transverse process Transverse foram en Facet for dens

Transverse foram en

Anterior arch Anterior tubercle

A

Inferior articular facet

Anterior tubercle

Transverse process

A

Spinous process

Vertebral foramen

Anterior articular facet

Lam ina

Inferior articular process

Dens

Dens

Superior articular facet

Transverse process

Transverse process

Superior articular facet

Transverse foram en Anterior articular facet

Vertebral foram en

Body

B

B

Uncinate process

Spinous process

Inferior articular facet

Superior articular process

Vertebral arch Lam ina Superior articular facet

Pedicle

Posterior tubercle

Transverse process with sulcus for spinal nerve

Sulcus for spinal nerve

Transverse foram en Body

C

Uncinate process

Posterior tubercle Anterior tubercle Body

Transverse process

Inferior articular facet Spinous process

Anterior tubercle

C

Spinous process

Uncinate process

Superior articular process

Lam ina Body Vertebral foram en

Transverse foram en Superior articular facet

Inferior articular process

Inferior Inferior articular process articular facet Spinous process

Anterior tubercle Body

Uncinate process

Fig. 11.7 Supe rior view of ce rvical ve rtebrae A Atlas (C1). B Axis (C2). C Typical cervical vertebra (C4). D Vertebra prom inens (C7).

Sulcus for spinal nerve

Transverse foram en

Transverse process

Sulcus for spinal nerve D

Transverse process

D

Fig. 11.8 Ante rior view of ce rvical ve rtebrae A Atlas (C1). B Axis (C2). C Typical cervical vertebra (C4). D Vertebra prom inens (C7).

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Joints of the Cervical Spine

Dens of axis (C2)

Atlanto-occipital joint

Lateral atlantoaxial joint

Median atlantoaxial joint

Atlas (C1)

Lateral atlantoaxial joint

Axis (C2)

Uncinate processes

Uncovertebral joint

Facet (zygapophyseal) joint Vertebral body

Facet (zygapophyseal) joint

Transverse process

Posterior tubercle Anterior tubercle

Intervertebral disk

Sulcus for spinal nerve

Intervertebral joint

A

B

Fig. 11.9 Joints of the ce rvical spine A Left lateral view. B Anterior view. C Radiograph of the cervical spine, left lateral view. The cervical spine has ve t ypes of joint s. Two joint s (intervertebral and facet) are com m on to all regions of the spine, and three are specialized joint s of the cervical spine. Joints of the vertebral column: Adjacent vertebrae articulate at t wo point s: vertebral bodies and articular processes. The bodies of adjacent vertebrae articulate at roughly horizontal intervertebral joint s (via intervertebral disks). The articular processes of adjacent vertebrae articulate at facet (zygapophyseal) joint s. In the cervical spine, the intervertebral joint s are angled slightly anteroinferiorly, and the facet (zygapophyseal) joint s are angled posteroinferiorly (roughly 45 degrees below horizontal). Joints of the ce rvical spine : There are t wo t ypes of joint s that are particular to the cervical spine: 1. Uncovertebral joint s: Upward protrusions of the lateral m argins of cervical vertebral bodies form uncinate processes. These processes m ay articulate with the inferolateral m argin of the adjacent superior vertebra, form ing uncovertebral joint s. 2. Craniovertebral joint s (atlanto-occipital and atlantoaxial joint s): The atlas (C1) and axis (C2) are specialized to bear the weight of the head and facilitate m ovem ent in all directions. This is m ade possible by craniovertebral joint s (see Fig. 11.10). Laxit y of the cervical spine m akes it prone to hyperextension injuries, such as “whiplash,” the excessive and often violent backward m ovem ent of the head, resulting in fractures of the dens of the axis and traum atic spondylolisthesis (anterior or posterior displacem ent of a vertebra in relation to the one below it). Patient prognosis is largely dependent on the spinal level of the injuries.

C

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Inferior articular facet

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Superior nuchal line

11. Bones, Liga ments, & Muscles of the Neck

External occipital protuberance Foram en m agnum

Lateral m ass of atlas

Occipital condyle (occipital bone) Dens of axis (C2)

Axis (C2) A

Posterior arch of atlas (with tubercle)

Median atlantoaxial joint Superior articular facet (lateral m ass of axis)

Dens of axis (C2)

Fig. 11.10 Craniove rtebral joints A Posterior view. B Left oblique posterosuperior view. There are ve craniovertebral joint s. The paired atlanto-occipit al joint s are articulations bet ween the concave superior articular facet s of the atlas (C1) and the convex occipit al condyle of the occipital bone. These allow the head to rock back and forth in the sagit t al plane. The atlantoaxial joint s (t wo lateral and one m edial) allow the atlas to rotate in the horizontal plane around the dens of the axis. The lateral atlantoaxial joint s are the paired articulations bet ween the inferior and superior articular facet s of the atlas and axis, respectively. The m edian atlantoaxial joint is the unpaired articulation bet ween the dens of the axis and the fovea of the atlas. Note: While only the atlanto-occipit al joint s are direct articulations bet ween the cranium and vertebral colum n, the atlantoaxial joint s are generally classi ed as craniovertebral joint s as well.

Vertebral artery in transverse foram en

Dens

Groove for vertebral artery

Transverse process

B

Spinous process

Lateral atlantoaxial joint

C1 spinal nerve

Atlas (C1) Axis (C2) Vertebral artery Uncinate process

Transverse process

C5 spinal nerve

Spinal nerve in sulcus

C7 spinal nerve A

Lateral atlantoaxial joint

Vertebral body (C7)

Spinal cord in vertebral foram en

Anterior root

Superior articular facet

Posterior ram us

Spinal ganglion

White and gray ram i com m unicantes

Anterior ram us

B

Fig. 11.11 Ne urovasculature of the ce rvical spine A Anterior view. B Superior view. The transverse processes of the cervical vertebrae are extrem ely im port ant in com m unicating neurovascular structures. Spinal nerves arise from the spinal cord in the vertebral canal. They exit via the intervertebral foram ina form ed by the pedicles of adjacent vertebrae.

Posterior root

Vertebral artery in transverse foram en

Vertebral body

Transverse process Uncinate process

The transverse processes of cervical vertebrae cont ain grooves (sulci) through which the spinal nerves pass. The transverse processes also cont ain transverse foram ina that allow the vertebral artery to ascend from the subclavian artery and enter the skull via the foram en m agnum . Injury to the cervical spine can com press the neurovascular structures as they em erge and ascend from the vertebral colum n.

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11. Bones, Liga ments, & Muscles of the Neck

Ligaments of the Vertebral Column Fig. 11.12 Ligame nts of the ve rtebral column The ligam ent s of the vertebral colum n bind the vertebrae to one another and enable the spine to withst and high m echanical loads and shearing stresses. The ligam ent s are divided into ligam ent s of the vertebral bodies and arches (Table 11.2).

Superior articular facet

Vertebral body

Intervertebral disk

A Ligam ent s of the vertebral colum n. Left lateral view of T11–L3 with T11 and T12 sectioned m idsagit t ally. B Ligam ent s of the vertebral body (anterior and posterior longitudinal ligam ent s, and intervertebral disk), schem atic. C Ligam ent a ava, schem atic. D Interspinous ligam ents and ligam enta ava, schem atic. E Complete ligaments of the vertebral column, schematic.

Posterior longitudinal ligam ent

Anulus fibrosus Nucleus pulposus

Lam ina

Intervertebral foram en

Ligam enta flava

Anterior longitudinal ligam ent

Spinous processes Interspinous ligam ent s

Supraspinous ligam ent

Transverse process

Ta ble 11.2 Ligame nts of the ve rtebral column

Facet joint capsule Intertransverse ligam ents

Ve rtebral body lig ame nts

Superior articular process

Anterior longitudinal ligam ent (along anterior surface of vertebral bodies) Posterior longitudinal ligam ent (along posterior surface of vertebral bodies, i.e., anterior surface of vertebral canal)

Inferior articular facet A

Intervertebral disk (bet ween adjacent vertebral bodies; the anulus brosus lim it s rot ation, and the nucleus pulposus absorbs com pressive forces)

Anterior longitudinal ligam ent

Ve rtebral (ne ural) arch ligame nts

Ligam ent a ava (bet ween lam inae) Interspinous ligam ent s (bet ween spinous processes) Supraspinous ligam ent s (along posterior border of spinous processes; in the cervical spine, the supraspinous ligam ent is broadened into the nuchal ligam ent)

Vertebral body

Posterior longitudinal ligam ent

Intervertebral disk

Lam ina Ligam enta flava C

B

Intertransverse ligam ent s (bet ween transverse processes)

Transverse process

Interspinous ligam ents

Facet joint capsules (enclose the articulation bet ween the facet s of the superior and inferior articular processes of adjacent vertebrae)

Lam ina Ligam enta flava Spinous process

Inferior articular process Superior articular process E

D

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Intertransverse ligam ent

Supraspinous ligam ent Spinous process

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Transverse process

Intervertebral disk

Vertebral body

11. Bones, Liga ments, & Muscles of the Neck

Nutrient foram ina

Pedicle Posterior longitudinal ligam ent

Intervertebral foram en

Intervertebral disk

Vertebral body

Gap in ligam entous reinforcem ent of the disk

Superior articular facet

Anterior longitudinal ligam ent

Costal process

Fig. 11.13 Individual ligame nts of the ve rtebral column The anterior and posterior longitudinal ligam ent s and ligam ent a ava m aint ain the norm al curvature of the spine.

Inferior articular process

A

A Anterior longitudinal ligam ent. Anterior view. The anterior longitudinal ligam ent runs broadly on the anterior side of the vertebral bodies from the skull base to the sacrum . It s deep collagenous bers bind adjacent vertebral bodies together (they are rm ly at tached to vertebral bodies and loosely at t ached to intervertebral disks). It s super cial bers span m ultiple vertebrae. B Posterior longitudinal ligam ent. Posterior view with vertebral canal windowed (vertebral arches rem oved). The thinner posterior longitudinal ligam ent descends from the clivus along the posterior surface of the vertebral bodies, passing into the sacral canal. The ligam ent broadens at the level of the intervertebral disk (to which it is at tached by t apered lateral extensions). It narrows again while passing the vertebral body (to which it is at t ached at the superior and inferior m argins). C Ligam enta ava and intertransverse ligam ent s. Anterior view with vertebral canal windowed (vertebral bodies rem oved). The ligam entum avum is a thick, powerful ligam ent that connect s adjacent lam inae and reinforces the wall of the vertebral canal posterior to the intervertebral foram ina. The ligam ent consist s m ainly of elastic bers that produce the characteristic yellow color. When the spinal colum n is erect, the ligam ent a ava are tensed, st abilizing the spine in the sagit tal plane. The ligam ent a ava also lim it forward exion of the spine. Note: The tips of the transverse processes are connected by interspinous ligam ent s that lim it the rocking m ovem ent s of vertebrae upon one another.

B

Spinous process

Superior articular process

Transverse process

Lam ina

Intertransverse ligam ents

Ligamenta flava

Facet joint capsule

Inferior articular process

Posterior longitudinal ligam ent

Superior articular process

Anterior longitudinal ligam ent Inferior articular facet C

Spinous process

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Ligaments of the Cervical Spine

Occipital bone

Superior nuchal line

External occipital protuberance

Inferior nuchal line

Posterior atlanto-occipital m em brane

Mastoid process

Atlas (C1)

Opening for vertebral artery Transverse process

Fig. 11.14 Ligame nts of the ce rvical spine A Posterior view. B Anterior view after rem oval of the anterior skull base. C Midsagit t al section, left lateral view. The nuchal ligam ent is the broadened, sagit t ally oriented part of the supraspinous ligam ent that extends from the vertebra prom inens (C7) to the external occipit al protuberance.

Axis (C2)

Ligam enta flava

Nuchal ligam ent

Transverse process

B

A

Spinous process Joint capsule (facet [zygapophyseal] joint)

Vertebra prom inens (C7) A

Internal occipital protuberance Internal occipital crest

Occipital bone, basilar part

Atlanto-occipital joint (atlantooccipital capsule)

Anterior atlanto-occipital m em brane

Atlas (C1)

Transverse process

Transverse foram ina

Lateral atlantoaxial joint (capsule)

Axis (C2) Anterior longitudinal ligam ent Sulcus for spinal nerve

Intervertebral disk B

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Facet (zygapophyseal) joint capsule

Posterior tubercle Anterior tubercle

Vertebra prom inens (C7)

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11. Bones, Liga ments, & Muscles of the Neck

Sella Apical ligam ent Internal Hypoglossal Tectorial turcica of the dens acoustic m eatus canal m em brane

Sphenoid sinus Occipital bone, basilar part

External occipital protuberance

Anterior atlanto-occipital m em brane

Dens of axis (C2)

Anterior arch of atlas (C1)

Transverse ligam ent of atlas

Longitudinal fascicles

Posterior atlanto-occipital m em brane

Posterior arch of atlas

Nuchal ligam ent Facet (zygapophyseal) joint capsule

Ligam enta flava Vertebral arch

Intervertebral disk (nucleus pulposus)

Intervertebral foram en Spinous process

Anterior longitudinal ligam ent

Interspinous ligam ent

Posterior longitudinal ligam ent

C

C7 vertebral body (vertebra prom inens)

Apex of dens (C2)

Body of axis (C2)

Cerebellom edullary cistern Posterior tubercle of atlas (C1) Nuchal ligam ent

Posterior longitudinal ligam ent Vertebral body (C5) Intervertebral disk Vertebra prom inens (C7)

Spinous process of C7

Supraspinous ligam ent Spinal cord Subarachnoid space

Fig. 11.15 Mag netic resonance imag e of the ce rvical spine Midsagit t al section, left lateral view, T2-weighted TSE sequence. (From Vahlensieck M, Reiser M. MRT des Bewegungsapparates. 2nd ed. Stut tgart : Thiem e; 2001.)

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11. Bones, Liga ments, & Muscles of the Neck

Ligaments of the Craniovertebral Joints

Superior nuchal line Atlanto-occipital capsule

Atlanto-occipital capsule

Nuchal ligam ent

External occipital protuberance

Foram en magnum

External occipital crest

External occipital protuberance

Temporal bone

Atlanto-occipital joint

Occipital bone Occipital condyle Tectorial m em brane Atlas (C1) St yloid process

Transverse process Ligam enta flava

Facet (zygapophyseal) joint capsule

Posterior longitudinal ligam ent

Spinous process A

B

Atlanto-occipital capsule

Alar ligam ents

Tectorial m em brane

Tectorial m em brane

Longitudinal fascicles

Transverse foram en

Transverse ligam ent of atlas Intervertebral disk

Posterior arch of atlas Lateral atlantoaxial joint

Vertebral body

Lam inae (cut)

C

Tectorial m em brane

Posterior atlanto-occipital m em brane (cut)

Axis (C2)

Posterior atlanto-occipital m em brane

Posterior arch of atlas

Mastoid process

Posterior longitudinal ligam ent

Cruciform ligam ent of atlas Cruciform ligam ent of atlas

Transverse process

Alar ligam ent s

Lateral m ass of atlas (C1)

Dens, posterior articular surface

Transverse ligam ent of atlas Longitudinal fascicles

Body of axis (C2) Intervertebral disk

Intervertebral foram en D

Fig. 11.16 Ligame nts of the craniove rtebral joints and ce rvical spine Skull and upper cervical spine, posterior view. A The posterior atlanto-occipital m em brane stretches from the posterior arch of the atlas to the posterior rim of the foram en m agnum . This m em brane has been rem oved on the right side. B With the vertebral canal opened and the spinal cord rem oved, the tectorial m em brane, a broadened expansion of the posterior longitudinal ligam ent, is seen to form the anterior boundary of the vertebral canal at the level of the craniovertebral joint s.

Longitudinal Apical ligam ent fascicles of dens

Posterior longitudinal ligam ent

C With the tectorial m em brane rem oved, the cruciform ligam ent of the atlas can be seen. The transverse ligam ent of the atlas form s the thick horizont al bar of the cross, and the longitudinal fascicles form the thinner vertical bar. D The transverse ligam ent of the atlas and longitudinal fascicles have been partially rem oved to dem onstrate the paired alar ligam ent s, which extend from the lateral surfaces of the dens to the corresponding inner surfaces of the occipit al condyles, and the unpaired apical ligam ent of the dens, which passes from the tip of the dens to the anterior rim of the foram en m agnum .

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Median atlantoaxial joint

Anterior tubercle

11. Bones, Liga ments, & Muscles of the Neck

Alar ligam ents (cut)

Superior articular facet

Apical ligam ent of dens

Transverse process

Transverse ligam ent of atlas

Transverse foram en

Dens

Lateral m ass of atlas

Vertebral foram en

Longitudinal fascicles

Groove for vertebral artery Posterior arch of atlas

Posterior tubercle of atlas

Spinous process of axis

A

Posterior atlanto-occipital m em brane Alar ligam ents

Tectorial m em brane

Apical ligam ent of dens

Longitudinal fascicles

Superior articular facet

Dens

Anterior arch of atlas

Median atlantoaxial joint Anterior tubercle of atlas

Lateral atlantoaxial joint

Alar Apical ligam ent ligam ent s of dens

Body of axis

Longitudinal fascicles

Transverse process

Tectorial m em brane

Superior articular facet, lateral m ass of atlas

B Transverse foram en

Transverse ligam ent of atlas

Capsule of lateral atlantooccipital joint

Transverse process Intertransverse ligam ent

Groove for vertebral artery

Posterior arch of atlas Ligam enta flava

C

Fig. 11.17 Ligame nts of the craniove rtebral joints A Superior view of atlas (C1) and axis (C2). B Anterosuperior view of C1–C4. C Posterosuperior view of atlas (C1) and axis (C2). There are ve craniovertebral joint s. The paired atlanto-occipit al joint s are articulations bet ween the concave superior articular facet s of the atlas and the convex occipit al condyles of the occipit al bone. The joint s are st abilized by the atlanto -occipit al joint capsule and the posterior atlantooccipit al m em brane (the equivalent of the ligam ent a ava). The paired lateral atlantoaxial and unpaired m edian atlantoaxial joint s allow the atlas to rot ate in the horizont al plane around the dens of the axis. They are st abilized by the alar ligam ent s, the apical ligam ent of the dens, and the cruciform ligam ent of the atlas (transverse ligam ent and longitudinal fascicles).

Posterior atlanto-occipital m em brane

Nuchal ligam ent

Spinous process

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11. Bones, Liga ments, & Muscles of the Neck

Muscles of the Neck: Overview Fig. 11.18 Ste rnocle idomastoid and trapezius A Sternocleidom astoid, right lateral view. B Trapezius, posterior view.

Ta ble 11.3 Muscles of the ne ck The m uscles of the neck lie at the intersection of the skull, vertebral colum n, and upper lim b. They can therefore be classi ed in m ultiple ways based on location and function. In the pages that follow, the neck m uscles are grouped as follows: Supe rf cial ne ck muscles

Muscles that lie super cial to the deep layer (lam ina) of the deep cervical fascia and are innervated by the anterior ram i of spinal nerves

Clavicular head

Po ste rio r ne ck muscles (intrinsic back muscle s) Sternal head

Muscles that insert on the cervical spine and are innervated by the posterior ram i of spinal nerves • Intrinsic back m uscles (including nuchal m uscles) ◦ Short nuchal/craniovertebral m uscles

A

Ante rio r ne ck muscles

Muscles that insert on the anterior cervical spine and are innervated by the anterior ram i of spinal nerves • Anterior vertebral (prevertebral) m uscles • Lateral vertebral m uscles (scalenes)

Superior part

Muscles that do not insert on the cervical spine • Suprahyoid m uscles • Infrahyoid m uscles

Middle part

Inferior part

B Deep cervical fascia

Fig. 11.19 Supe rf cial ne ck muscles A Left lateral view. B Anterior view of sternocleidom astoid and trapezius. Unlike the rest of the neck m uscles, the super cial neck m uscles are located super cial to the prevertebral layer of the deep cervical fascia and are innervated by the anterior ram i of the spinal nerves. Platysma: The plat ysm a, like the m uscles of facial expression, is not enveloped in it s own fascial sheath, but is instead directly associated with (and in part s inserted into) the skin. (Note: It is innervated by the sam e nerve as the m uscles of facial expression, the facial nerve.) The plat ysm a is highly variable in size — it s bers m ay reach from the lower face to the up per thorax.

Sternocleidom astoid Depressor anguli oris

Plat ysm a

A

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11. Bones, Liga ments, & Muscles of the Neck

Ta ble 11.4 Supe rf cial ne ck muscles Muscle

Orig in

Inse rtion

Inne rvation

Action

Plat ysm a

Mandible (inferior border); skin of lower face and angle of m outh

Skin over lower neck and superior and lateral thorax

Facial n. (CN VII), cervical branch

Depresses and wrinkles skin of lower face and m outh; tenses skin of neck; aids forced depression of m andible

Sternocleidom astoid

Occipit al bone (superior nuchal line); tem poral bone (m astoid process)

Sternal head: sternum (m anubrium )

Accessory n. (CN IX), spinal part

Unilateral: Moves chin up and out (tilt s head to sam e side and rot ates head to opposite side) Bilateral: Extends head; aids in respiration when head is xed

Clavicular head: clavicle (m edial ⅓) Trapezius, superior part*

Occipit al bone; C1–C7 (spinous processes)

Clavicle (lateral ⅓)

Draws scapula obliquely upward; rot ates glenoid cavit y inferiorly

Rhom boid m inor (see Fig . 11.20)

Nuchal ligam ent (inferior part), C7–T1 (spinous processes)

Medial (vertebral) border of the scapula, superior to the intersection with the scapular spine

C4–C5 anterior ram i (C5 bers are from the dorsal scapular n.)

Scapular m ovem ent s (e.g., retraction and rot ation)

Levator scapulae (see Fig . 11.20)

C1–C4 (posterior tubercles of transverse processes)

Scapula (m edial to superior angle)

C3–C5 anterior ram i (C5 bers are from the dorsal scapular n.)

Scapular m ovem ent s (e.g., elevation, retraction, and rot ation)

Serratus posterior superior (see Fig . 11.22)

Nuchal ligam ent (inferior part), C7–T3 (spinous processes)

Ribs 2–5

Anterior ram i of thoracic spinal nn. (intercost al nn.)

Postulated to be an accessory m uscle of respiration; assist s in elevating ribs

*The m iddle and inferior part s are not described here.

Sternocle idomastoid and trapezius: The trapezius lies bet ween the super cial and prevertebral layers of the deep cervical fascia. The super cial layer split s to enclose the sternocleidom astoid and the trapezius. Congenital torticollis (wryneck) is a condition in which shortening of the sternocleidom astoid m uscle causes the head to tilt to one side with the chin pointing upward to the opposite side. This shortening is thought to be the result of traum a at birth causing bleeding and swelling within the m uscle and subsequent scar tissue which renders the m uscle unable to lengthen in the growing neck. It is often associated with hip dysplasia. Sym ptom s that appear in infancy include abnorm al posturing of the head and chin, lim ited range of m otion in the neck, and one side of the face and head m ay at ten as the child sleeps on one side only.

Sternocleidom astoid

Trapezius

B

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Muscles of the Neck & Back (I)

Sternocleidom astoid Deep cervical fascia

Trapezius, superior part

Rhom boid m inor

Trapezius, m iddle part

Levator scapulae

Clavicle Acrom ion, scapula

Scapular spine

Supraspinatus Rhom boid m ajor

Deltoid

Infraspinatus Scapula, m edial border

Teres m inor Teres m ajor

Teres m ajor

Trapezius, inferior part

Serratus anterior

Triceps brachii

Latissim us dorsi (cut)

Latissim us dorsi Serratus posterior inferior

Thoracolum bar fascia, superficial layer

External oblique Olecranon Aponeurotic origin of latissim us dorsi

Internal oblique

Lum bar triangle, internal oblique

Iliac crest

Gluteus m edius

Gluteus m axim us

Fig. 11.20 Muscles of the ne ck and back Posterior view with trapezius and latissim us dorsi cut on right side. The extrinsic back m uscles lie super cial to the thoracolum bar and deep cervical fascia. They are m uscles of the upper lim b (derived from the lim b buds) that have m igrated to the back. The intrinsic back m uscles lie bet ween the thoracolum bar and deep cervical fascia. They are de-

rived from epaxial m uscle. Because of their di erent em bryonic origins, the intrinsic back m uscles are innervated by the posterior ram i of the spinal nerves, and the extrinsic back m uscles are innervated by the anterior ram i. Note: The trapezius and sternocleidom astoid are innervated by the accessory nerve (CN XI).

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Sternothyroid

Sternohyoid

Trachea

11. Bones, Liga ments, & Muscles of the Neck

Visceral pretracheal Esophagus fascia

Om ohyoid

Thyroid gland

Sternocleidom astoid Muscular pretracheal fascia

Internal jugular vein

Deep cervical fascia

Superficial fascia

Carotid sheath

Prevertebral fascia

Vagus nerve Com m on carotid artery

Longus colli Anterior scalene

Brachial plexus

Middle scalene

C6 vertebra

Spinal cord

Levator scapulae Intrinsic back m uscles Deep layer

Trapezius

Nuchal fascia

Superficial layer

A

Abdom inal aorta

Inferior vena cava

Parietal peritoneum , transversalis fascia

Kidney

Renal fascia, anterior layer Transverse abdom inis Internal oblique External oblique Fibrous capsule

L3 vertebra

Perirenal fat Renal fascia, posterior layer

Psoas major

Latissim us dorsi Vertebral arch Serratus posterior inferior

Costal process Spinous process

Quadratus lum borum

Intrinsic back m uscles (latissim us dorsi)

Deep layer Superficial layer

Thoracolum bar fascia

B

Fig. 11.21 Fascial planes Transverse sections, superior view. A Neck at the level of the C6 vertebra. B Posterior trunk wall at the level of the L3 vertebra (with cauda equina rem oved from vertebral canal). The m uscles of the neck and back are separated by layers of deep fascia (see p. 300). The outerm ost layer, the super cial layer of the deep cervical fascia, encloses all m uscles with the exception of the plat ysm a (this is located in the super cial fascia, not to be confused with the super cial layer of the deep cervical fascia). The deep cervical fascia,

located in the anterior neck, is continuous posteriorly with the nuchal fascia in the posterior neck. The super cial layer of the nuchal fascia is continuous inferiorly with the super cial layer of the thoracolum bar fascia. The intrinsic m uscles of the neck and back lie within the deep layer of the nuchal fascia, which is continuous with the prevertebral fascia (anteriorly) and thoracolum bar fascia (inferiorly). The m uscles and structures of the anterior neck are enclosed in individual fascial sheaths (i.e., the visceral pretracheal fascia, m uscular pretracheal fascia, and carotid sheath).

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11. Bones, Liga ments, & Muscles of the Neck

Muscles of the Neck & Back (II)

Deep nuchal fascia

Serratus posterior superior (cut)

Sem ispinalis capitis

Rhom boideus m ajor and m inor (cut)

Serratus posterior superior

Splenius capitis

External intercostal m uscles

Trapezius (cut)

Deep nuchal fascia Superficial layer of thoracolum bar fascia

Splenius cervicis

Latissim us dorsi (cut)

Superficial layer of thoracolum bar fascia

Serratus posterior inferior

Spinalis*

Internal oblique

Latissim us dorsi aponeurosis

Iliocostalis*

External oblique (cut)

External oblique

Longissim us*

External intercostal m uscles

External oblique

Iliac crest External oblique (cut)

Internal oblique

Iliac crest

A

Superficial layer of thoracolum bar fascia

Gluteus m axim us

B

Fig. 11.22 Extrinsic and intrinsic back muscles Po st e rio r vie w. The se d isse ct io ns d e m o nst rat e t he d ist inct io n b e t we e n t he in t rinsic b ack m uscle s and t he su rrou nd ing e xt rin sic b ack m uscle s and t runk m uscle s. The int rinsic b ack m uscle s lie wit h in t h e d e e p n u ch al fascia, wh ich is co n t in u o u s infe rio rly wit h t he su p e rficial laye r o f t he t ho raco lu m b ar fascia. Th e y are d e rive d fro m e p axial m uscle s and t h e re fo re inne rvat e d by t h e p o st e rio r ram i o f sp in al ne rve s (se e p . 3 0 4 ). Th e m u scle s o f t h e t ru n k are d e rive d fro m hyp axial m uscle and t he re fo re inne rvat e d by t he an t e rio r ram i o f sp in al ne rve s. Th e visib le t ru n k m u scle s are t h e ab d o m in al m uscle s (in t e rnal and e xt e rnal o b liq ue s) an d t h e t h o racic m u scle s (e xt e rnal int e rcost als).

Gluteus m axim us

A Removed: Extrinsic back m uscles (with the exception of the serratus posterior and the aponeurotic origin of the latissim us dorsi on the right side). B Removed: All extrinsic back m uscles and portions of the fascial covering (deep nuchal and super cial layers of the thoracolum bar fasciae). *The spinalis, iliocostalis, and longissim us are collectively known as the erector spinae.

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Splenius capitis (cut)

Sem ispinalis capitis

Longissim us capitis

Splenius capitis

Iliocostalis cervicis

Splenius cervicis

11. Bones, Liga ments, & Muscles of the Neck

Splenius capitis (cut)

Sem ispinalis capitis (cut)

Superior nuchal line Rectus capitis posterior m inor

Obliquus capitis superior

Obliquus capitis inferior

Rectus capitis posterior m ajor Longissim us capitis Iliocostalis thoracis

Spinalis cervicis

External intercostal m uscles

Levatores costarum

Spinalis

Interspinales cervicis

Rotatores thoracis longi Levatores costarum longi

Longissim usthoracis

Rotatores thoracis breves

External intercostal m uscles

Spinalis thoracis

Iliocostalis lum borum

Levatores costarum breves

Internal oblique (cut)

Transversus abdom inis

Intertransversarii m edialis lum borum

Iliac crest

Twelfth rib Intertransversarii laterales lum borum

Interspinales lum borum Transversus abdom inis

A

Gluteus m axim us

Multifidus

Deep layer of thoracolum bar fascia

Iliac crest

B

Fig. 11.23 Intrinsic back muscles Posterior view. These dissections reveal the layers of intrinsic back m uscles. The iliocost alis, longissim us, and spinalis collectively form the erector spinae. They lie deep to the super cial layer of the thoracolum bar fascia and cover the other intrinsic back m uscles.

Transverse processes

Deep layer of thoracolum bar fascia

Multifidus

Quadratus lum borum

Gluteus m axim us

A Removed on left side: Longissim us (except cervical portion), splenius capitis and cervicis. Removed on right side: Iliocost alis. Note the deep layer of the thoracolum bar fascia, which gives origin to the internal oblique and transversus abdom inis. B Removed on left side: Iliocost alis, longissim us, and internal oblique. Removed on right side: Erector spinae, m ulti dus, transversus ab dom inis, splenius capitis, and sem ispinalis capitis.

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11. Bones, Liga ments, & Muscles of the Neck

Muscles of the Posterior Neck

Parietal bone

Occipital bone

External occipital protuberance Sem ispinalis capitis (cut) Sternocleidom astoid (cut)

Superior nuchal line

Splenius capitis (cut) Sem ispinalis capitis

Mastoid process Obliquus capitis superior

Sternocleidom astoid

Transverse process of atlas (C1)

Rectus capitis posterior m inor

Obliquus capitis inferior

Rectus capitis posterior m ajor

Longissim us capitis

Splenius capitis Sem ispinalis capitis (cut)

Spinous process of axis (C2) Sem ispinalis cervicis

Splenius capitis (cut) Splenius cervicis

Trapezius, descending (superior) part

Fig. 11.24 Muscles in the nuchal re g ion Posterior view of nuchal region. As the neck is at the intersection of the trunk, head, and upper lim b, it s m uscles can be divided according to em bryonic origin, function, or location. Those m uscles (extrinsic and intrinsic) located in the posterior neck are often referred to as the nuchal m uscles. The nuchal m uscles are further divided into short nu-

chal m uscles, which are intrinsic back m uscles innervated by the posterior ram i of cervical spinal nerves. Based on location, the short nuchal m uscles m ay also be referred to as suboccipit al m uscles. The anterior and posterior vertebral m uscles collectively m ove the craniovertebral joint s.

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Trapezius (cut) Rectus capitis posterior m inor

11. Bones, Liga ments, & Muscles of the Neck

Superior nuchal line External occipital protuberance

Inferior nuchal line

Sem ispinalis capitis (cut) Sternocleidom astoid (cut)

Rectus capitis posterior m ajor

Splenius capitis (cut)

Obliquus capitis superior

Obliquus capitis superior

Mastoid process

Longissim us capitis (cut) Transverse process of atlas

Posterior atlantooccipital m em brane (with opening for vertebral artery)

Rectus capitis posterior m ajor

Posterior arch of atlas (C1)

Obliquus capitis inferior

Spinous process of axis (C2) Interspinales cervicis

Intertransversarii cervicis

Transverse process of C7

Spinous process of C7

A

Sem ispinalis capitis

Rectus capitis posterior m inor

Rectus capitis posterior m ajor

Trapezius Sternocleidom astoid

Splenius capitis

Obliquus capitis superior

Longissim us capitis Obliquus capitis inferior

Interspinales cervicis Intertransversarii cervicis

B

Fig. 11.25 Muscle attachme nts in the nuchal re g ion Posterior view of skull and cervical spine (C1– C7). A Short nuchal m uscles with interspinales and intertransversarii cervicis. The supercial m uscles (trapezius and sternocleidom astoid, innervated by CN XI) have been cut. The intrinsic back m uscles inserting on the skull (splenius, longissim us, and sem ispinalis capitis) have also been cut. The intrinsic back m uscles are all innervated by posterior ram i of spinal nerves. The short nuchal m uscles are innervated by the posterior ram i of the rst spinal nerve (suboccipital nerve). B Muscle origins (red) and insertions (blue).

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11. Bones, Liga ments, & Muscles of the Neck

Intrinsic Back Muscles (I): Erector Spinae & Interspinales

A

B

C

Fig. 11.26 Inte rspinales and e re ctor spinae Schem atic, posterior view. A Interspinales and spinalis. B Iliocost alis. C Longissim us.

Ta ble 11.5 Ere ctor spinae and inte rspinale s Like all intrinsic back m uscles, these m uscles are innervated by posterior ram i of spinal nerves. The erector spinae and interspinales are innervated by lateral branches of the posterior ram i. The longissim us is innervated by spinal nerves C1–L5, the iliocost alis by C8–L1. Muscle

Interspinales

Spinalis*

Iliocost alis*

Longissim us*

Orig in

Inse rtio n

Action

I. cervicis

C1–C7 (bet ween spinous processes of adjacent vertebrae)

Extends cervical spine

I. lum borum

L1–L5 (bet ween spinous processes of adjacent vertebrae)

Extends lum bar spine

S. cervicis

C5–T2 (spinous processes)

C2–C5 (spinous processes)

S. thoracis

T10–L3 (spinous processes, lateral surface)

T2–T8 (spinous processes, lateral surface)

Bilateral: Extends spine Unilateral: Bends laterally to sam e side

I. cervicis

3rd–7th ribs

C4–C6 (transverse processes)

I. thoracis

7th–12th ribs

1st–6th ribs

I. lum borum

Sacrum ; iliac crest ; super cial layer of thoracolum bar fascia

6th–12th ribs; deep layer of thoracolum bar fascia; upper lum bar vertebrae (cost al processes)

L. cervicis

T1–T6 (transverse processes)

C2–C5 (transverse processes)

L. thoracis

Sacrum ; iliac crest ; L1–L5 (spinous processes); lower thoracic vertebrae (transverse processes)

2nd–12th ribs; T1–T12 (transverse processes) ; L1–L5 (cost al processes)

L. capitis

T1–T3 (transverse processes); C4–C7 (transverse and articular processes)

Tem poral bone (m astoid process)

Bilateral: Extends head Unilateral: Flexes and rot ates head to sam e side

*The spinalis, iliocostalis, and longissim us are collectively known as the erector spinae. Note: The iliocost alis and longissim us extend the entire spine. The spinalis act s only on the cervical and thoracic spines.

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Atlas (C1) Axis (C2) Interspinales cervicis

Spinous process of C7 (vertebra prom inens)

Spinalis cervicis Mastoid process Longissim us capitis

Iliocostalis cervicis

Spinalis thoracis

Longissim us cervicis

Iliocostalis thoracis Interspinales lum borum

Longissim us thoracis

Sacrum Transverse processes of L1– L5

Iliocostalis lum borum Iliac crest

A

Sacrum

Fig. 11.27 Inte rspinales and e re ctor spinae muscles The spinalis, iliocost alis, and longissim us are collectively known as the erector spinae. A Interspinales and spinalis. B Iliocost alis and longissim us. B

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11. Bones, Liga ments, & Muscles of the Neck

Intrinsic Back Muscles (II)

A

A

B

Fig. 11.28 Sple nius and se mispinalis Schem atic, posterior view. A Splenius. B Sem ispinalis.

B

C

Fig. 11.29 Inte rtransve rsarii, levatores costarum, multif dus, and rotatores Schem atic, posterior view. A Intertransversarii and levatores cost arum . B Multi dus. C Rot atores.

Ta ble 11.6 Sple nius, se mispinalis, inte rtransve rsarii, levatores costarum, multif dus, and rotatores All intrinsic back m uscles are innervated by the posterior ram i of the spinal nerves except for the intertransversii posteriores cervicis, which are innervated by the anterior ram i of the spinal nerves. The splenius is innervated by spinal nerves C1–C6. Muscle

Splenius

Sem ispinalis

Intertransversarii

Levatores cost arum

Orig in

Inse rtio n

Actio n

S. capitis

C7–T3 (spinous processes)

Occipit al bone (lateral superior nuchal line); tem poral bone (m astoid process)

S. cervicis

T3–T6 (spinous processes)

C1–C2 (transverse processes)

Bilateral: Extends cervical spine and head Unilateral: Flexes and rot ates head to sam e side

S. capitis

C3–T6 (transverse processes)

Occipital bone (bet ween superior and inferior nuchal lines)

S. cervicis

T1–T6 (transverse processes)

C2–C7 (spinous processes)

S. thoracis

T6–T12 (transverse processes)

C6–T4 (spinous processes)

I. anteriores cervicis I. posteriores cervicis

C2–C7 (bet ween posterior tubercles of adjacent vertebrae)

I. m ediales lum borum

L1–L5 (bet ween m am m illary processes of adjacent vertebrae)

I. laterales lum borum

L1–L5 (bet ween cost al processes of adjacent vertebrae)

L.c. brevis

C7–T11 (transverse processes)

L.c. longi

Multi dus

Rot atores

C2–C7 (bet ween anterior tubercles of adjacent vertebrae)

Cost al angle of next lower rib Cost al angle of second lower rib

Bilateral: Extends cervical and thoracic spine and head (st abilizes craniovertebral joint s) Unilateral: Bends head and cervical and thoracic spine to sam e side, rot ates them to opposite side Bilateral: St abilizes and extends cervical and lum bar spine Unilateral: Bends cervical and lum bar spine laterally to sam e side

Bilateral: Extends thoracic spine Unilateral: Bends thoracic spine to sam e side, rotates thoracic spine to opposite side

C4–T4 (transverse and articular processes), L1–L5 (m am m illary processes), ilium , and sacrum superom edially to spinous process of vertbra t wo to four levels higher

Bilateral: Extends spine Unilateral: Flexes spine to sam e side, rot ates spine to opposite side

R. breves

T1–T12 (bet ween transverse process and spinous processes of next higher vertebra)

R. longi

T1–T12 (bet ween transverse process and spinous process of vertebra t wo levels higher)

Bilateral: Extends thoracic spine Unilateral: Flexes spine to sam e side, rot ates spine to opposite side

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11. Bones, Liga ments, & Muscles of the Neck

Superior nuchal line

Inferior nuchal line

Sem ispinalis capitis

Sem ispinalis cervicis Spinous process of C7 (vertebra prom inens)

Superior nuchal line

Semispinalis thoracis Transverse process

Mastoid process

Spinous process

Intertransversarii posteriores cervicis

Rotatores longi

Splenius capitis

Posterior tubercle Spinous process of C7 (vertebra prom inens)

Rotatores brevis

Splenius cervicis

Fifth rib

Transverse processes Multifidus

Levatores costarum brevis

Levatores costarum longi

Sacrum

Transverse process Intertransversarii m ediales lum borum

A

Fig. 11.30 Sple nius w ith transve rsospinal and inte rtransve rse syste ms A Transversospinal system (rotatores, m ulti dus, and sem ispinalis). B Splenius and intertransverse system (intertransversarii and levatores cost arum ).

Mam m illary process Intertransversarii laterales lum borum

B

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11. Bones, Liga ments, & Muscles of the Neck

Intrinsic Back Muscles (III): Short Nuchal & Craniovertebral Joint Muscles Fig. 11.31 Short nuchal and craniove rtebral joint muscles Schematic, posterior view. The short nuchal and craniovertebral joint m uscles are intrinsic back m uscles that are innervated by the posterior ramus of the rst spinal nerve (suboccipital nerve). These m uscles contribute to the extension of the atlanto-occipital joint and rotation about the atlantoaxial joint.

Ta ble 11.7 Short nuchal muscle s Muscle

Rectus capitis posterior

Obliquus capitis

Orig in

Inse rtio n

Inne rvatio n

Action

R.c.p. m inor

C1 (posterior tubercle)

Inferior nuchal line (inner ⅓)

C1 spinal nerve (suboccipit al n.), posterior ram us

Bilateral: Extends head Unilateral: Rot ates head to sam e side

R.c.p. m ajor

C2 (spinous process)

Inferior nuchal line (m iddle ⅓)

O.c. inferior

C2 (spinous process)

C1 (transverse process)

O.c. superior

C1 (transverse process)

Above the insertion of the rectus capitis posterior m ajor or inferior nuchal line (m iddle ⅓)

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Bilateral: Extends head Unilateral: Tilt s head to sam e side; rot ates head to opposite side

Neck

Superior nuchal line

Inferior nuchal line

11. Bones, Liga ments, & Muscles of the Neck

Rectus capitis posterior m inor

Obliquus capitis superior Mastoid process Rectus capitis posterior m ajor

Posterior tubercle of atlas (C1)

Transverse process of atlas (C1)

Spinous process of axis (C2)

Obliquus capitis inferior

A

Transverse process of atlas

Mastoid process

Posterior arch of atlas (C1)

External occipital protuberance

Mandible

Obliquus capitis superior

Atlas (C1) Rectus capitis posterior m inor

Axis (C2)

Rectus capitis posterior m ajor Obliquus capitis inferior

Spinous process of axis (C2)

B

Fig. 11.32 Suboccipital muscles A Posterior view. B Left lateral view. The suboccipit al m uscles collectively act on the craniovertebral joint s. The suboccipital m uscles are the rectus capitis posterior m ajor, rectus capitis posterior m inor, obliquus capitis inferior, and obliquus capitis

superior. The posterior ram us of the rst cervical spinal nerve innervates all four suboccipital m uscles. Note: The suboccipit al triangle is lo cated bet ween the rectus capitis posterior m ajor, the obliquus capitis superior, and the obliquus capitis inferior.

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11. Bones, Liga ments, & Muscles of the Neck

Prevertebral & Scalene Muscles

Fig. 11.34 Scale ne muscles Schem atic, anterior view.

Fig. 11.33 Preve rtebral muscles Schem atic, anterior view.

Ta ble 11.8 Preve rtebral and scale ne muscle s Muscle

Orig in

Inse rtio n

Inne rvatio n

Action

C3–C6 (anterior tubercles)

Occipit al bone, basilar part

Cervical plexus, direct branches (C1–C3)

Bilateral: Flexes head Unilateral: Tilt s and slightly rot ates head to sam e side

C5–T3 (anterior surfaces of vertebral bodies)

C2–C4 (anterior surfaces)

Anterior ram i of C2–C6 spinal nn.

Superior oblique part

C3–C5 (anterior tubercles)

C1 (anterior tubercle)

Bilateral: Flexes cervical spine Unilateral: Tilt s and slightly rot ates cervical spine to sam e side

Inferior oblique part

T1–T3 (anterior surfaces of vertebral bodies)

C5–C6 (anterior tubercles)

R.c. anterior

C1 (lateral m ass)

Occipit al bone (basilar part)

Anterior ram us of C1 spinal n. (suboccipit al n.)

R.c. lateralis

C1 (transverse process)

Occipit al bone (basilar part, lateral to occipit al condyles)

Bilateral: Flexion at atlanto-occipit al joint Unilateral: Lateral exion at atlantooccipit al joint

Anterior scalene

C3–C6 (anterior tubercles)

1st rib (scalene tubercle)

Anterior ram i of cervical spinal nn.

Middle scalene

C1 and C2 (transverse processes); C3–C7 (posterior tubercles)

1st rib (posterior to groove for subclavian a.)

Posterior scalene

C5–C7 (posterior tubercles)

2nd rib (outer surface)

With ribs mobile: Elevate upper ribs (in inspiration) With ribs f xed: Bend cervical spine to sam e side (unilateral contraction); ex cervical spine (bilateral contraction)

Longus capitis

Longus colli m edial

Rectus capitis

Scalenes

Vertical (cervicis) part

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Longus capitis (cut)

11. Bones, Liga ments, & Muscles of the Neck

Rectus capitis anterior

Rectus capitis lateralis

Transverse process of atlas (C1)

Longus capitis

Transverse process of atlas (C2)

Superior oblique part

Vertical part

Longus colli

Inferior oblique part Middle scalene Anterior scalene

Middle scalene

Posterior scalene

Posterior scalene

Interscalene triangle

Anterior scalene (cut)

Groove for subclavian artery

Second rib

Scalene tubercle

First rib

Fig. 11.35 Preve rtebral and scale ne muscle s Anterior view. Removed on left side: Longus capitis and anterior scalene. The prevertebral (anterior vertebral) m uscles are the longus colli, longus capitis, rectus capitis lateralis, and rectus capitis anterior. The an-

terior, m iddle, and posterior scalenes are the lateral vertebral m uscles. The anterior and lateral vertebral m uscles are innervated by the anterior ram i of the cervical spinal nerves.

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11. Bones, Liga ments, & Muscles of the Neck

Suprahyoid & Infrahyoid Muscles

3b 5a

5b

3a

Fig. 11.36 Suprahyoid muscles Schem atic, left lateral view.

Fig. 11.37 Infrahyoid muscles Schem atic, anterior view.

Ta ble 11.9 Suprahyoid and infrahyoid muscle s Muscle

Orig in

Inse rtio n

Inne rvatio n

Actio n

Geniohyoid

Mandible (inferior m ent al spine)

Hyoid bone

Anterior ram us of C1 via hypoglossal n. (CN XII)**

Draws hyoid bone forward (during swallowing); assist s in opening m andible

Mylohyoid

Mandible (mylohyoid line)

Hyoid bone (via m edian tendon of insertion, the mylohyoid raphe)

Mylohyoid n. (from CN V3 )

Tightens and elevates oral oor; draws hyoid bone forward (during swallowing); assist s in opening m andible and m oving it side to side (m astication)

3a

Digastric, anterior belly

Mandible (digastric fossa)

3b

Digastric, posterior belly

Tem poral bone (m astoid notch, m edial to m astoid process)

Hyoid bone (via an interm ediate tendon with a brous loop)

St ylohyoid

Tem poral bone (st yloid process)

Hyoid bone (via a split tendon)

Suprahyoid m uscles

Facial n. (CN VII)

Elevates hyoid bone (during swallowing); assist s in opening m andible

Ansa cervicalis of cervical plexus (C1–C3)

Depresses ( xes) hyoid; draws larynx and hyoid down for phonation and term inal phases of swallowing*

Infrahyoid m uscles 5a

Om ohyoid, superior belly

Interm ediate tendon of om ohyoid

Hyoid bone

5b

Om ohyoid, inferior belly

Scapula (superior border, m edial to suprascapular notch)

Interm ediate tendon of om ohyoid

Sternohyoid

Manubrium and sternoclavicular joint (posterior surface)

Hyoid bone

Sternothyroid

Manubrium (posterior surface)

Thyroid cartilage (oblique line)

Ansa cervicalis C2, C3

Thyrohyoid

Thyroid cartilage (oblique line)

Hyoid bone

Anterior ram us of C1 via hypoglossal n. (CN XII)

Depresses and xes hyoid; raises the larynx during swallowing

*The om ohyoid also tenses the cervical fascia (with an interm ediate tendon). The interm ediate tendon is at t ached to the clavicle, pulling the om ohyoid into a m ore pronounced triangle. **C1 anterior ram us bers travel with the hypoglossal nerve for part of it s pathway to t arget m uscles.

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11. Bones, Liga ments, & Muscles of the Neck

St ylohyoid Digastric, posterior belly

Digastric, anterior belly

Thyrohyoid Mylohyoid

Sternohyoid

Sternothyroid

Om ohyoid, superior and inferior belly

Interm ediate tendon of omohyoid

Coronoid process

Geniohyoid

Mylohyoid line

A

Head of m andible Mandibular foram en

Mylohyoid

Mandibular ram us

Mylohyoid Mylohyoid raphe Hyoid bone

Thyrohyoid Thyroid cartilage Sternothyroid

Digastric, anterior belly Digastric, posterior belly St ylohyoid

Sternohyoid Om ohyoid, superior and inferior belly

B

C

Lesser horn Hyoid bone (body)

Greater horn

Fig. 11.38 Suprahyoid and infrahyoid muscles A Left lateral view. B Anterior view. C Postero superior view. The mylohyoid and anterior digastric are derived from the rst pharyngeal arch and are therefore supplied by the trigem inal nerve (CN V). The mylohyoid nerve arises from the m andibular division of CN V before the m ajorit y of bers enter the m andibular foram en as the inferior alveolar nerve. The st ylohyoid and posterior digastric are derived from the second pharyngeal arch and are therefore supplied by the facial nerve (CN VII). The rem ainder of the suprahyoid and infrahyoid m uscles are supplied by the anterior ram i of the cervical spinal nerves. Fibers from the anterior ram us of C1 travel with the hypoglossal nerve (CN XII) to the geniohyoid and thyrohyoid. Fibers from the anterior ram i of C1–C3 com bine to form the ansa cervicalis, which gives o branches to the om ohyoid, sternohyoid, and sternothyroid.

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12. Neurovascula r Topogra phy of the Neck

Arteries & Veins of the Neck Fig. 12.1 Arte ries of the ne ck Left lateral view. The structures of the neck are supplied by branches of the external ca rotid artery and the subclavian artery (the in ternal carotid artery gives o no branches in the neck). The com m on carotid artery is en closed in a fascial sheath (carotid sheath) along with the internal jugular vein and vagus nerve. The vertebral artery ascends through the transverse foram ina of the cervical verte brae (C6–C1). The internal carotid artery is often a ected by atherosclerosis, a hardening of the arterial walls due to plaque form ation. These plaques can cause stenosis, throm bosis, and em boli zation, which could result in vision loss, tran sient ischem ic at t acks (TIAs), or stroke.

Vertebral artery Ascending pharyngeal artery External carotid artery

Lingual artery

Internal carotid artery

Infrahyoid branch

Deep cervical artery

Superior thyroid artery

Vertebral artery Inferior thyroid artery

Superior laryngeal artery

Ascending cervical artery Com m on carotid artery Transverse cervical artery

Cricothyroid branch

Suprascapular artery

Glandular branches

Thyrocervical trunk Internal thoracic artery

Costocervical trunk Suprem e intercostal artery Subclavian artery

Ta ble 12.1 Arte ries of the ne ck For a com plete treatm ent of the arteries of the head and neck, see Chapte r 3 . Arte ry

Branche s

Se co ndary branches*

External carotid a.

Superior thyroid a.

Superior laryngeal, cricothyroid, infrahyoid, and sternocleidom astoid aa.

Ascending pharyngeal a.

Pharyngeal, palatine, prevertebral, inferior t ym panic, and m eningeal aa.

Lingual a.

Suprahyoid, dorsal lingual, deep lingual, and sublingual aa.

Facial a.

Ascending palatine, tonsillar, glandular, and subm ent al aa.

Occipit al a.

Sternocleidom astoid, descending, m astoid, auricular, and m eningeal aa.

Posterior auricular a.

St ylom astoid and auricular aa.

Super cial tem poral a.

(Branching occurs on the face)

Maxillary a.

(Branches within the infratem poral fossa [see pp. 158 and 159])

Vertebral a.

Spinal aa. and m uscular aa.

Thyrocervical trunk

Inferior thyroid a.

Subclavian a.

Inferior laryngeal, tracheal, esophageal, and ascending cervical aa.

Suprascapular a. Transverse cervical a.

Super cial and deep branches

Internal thoracic a.

(Branching occurs within the thorax)

Descending (dorsal) scapular a.

(When present, it supplies the territory of the deep branch of the transverse cervical a.)

Costocervical trunk

Deep crvical a. Suprem e intercost al a.

*Only branches that arise in the neck are listed here.

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12. Neurovascula r Topogra phy of the Neck

Facial vein

External jugular vein Superior thyroid vein

Internal jugular vein Anterior jugular vein Jugular venous arch

Middle thyroid vein

Transverse cervical vein

Vertebral vein

Suprascapular vein

Inferior thyroid vein

Left brachiocephalic vein

Right brachiocephalic vein

Superior vena cava

Fig. 12.2 Ve ins of the ne ck Anterior view. The veins of the head and neck drain to the superior vena cava via the right and left brachiocephalic veins. The large internal jugular vein com bines with the subclavian vein to form the brachioce phalic vein on each side. The internal jugular vein is located within the

carotid sheath. It receives blood from the anterior neck and the interior of the skull. The subclavian vein receives blood from the neck via the external and anterior jugular veins, which are located within the super cial cervical fascia. Note: The thyroid venous plexus and vertebral veins t ypically drain directly into the brachiocephalic veins.

Ta ble 12.2 Ve ins of the ne ck For a com plete treatm ent of the veins of the head and neck, see Chapte r 3 . Right and left brachiocephalic vv.*

Internal jugular v.

Sigm oid sinus, inferior petrosal sinus, pharyngeal vv., occipit al, (com m on) facial, lingual, and superior and m iddle thyroid vv.

Subclavian v.

External jugular v.

Vertebral v.

Internal and external vertebral venous plexuses; ascending cervical (anterior vertebral) and deep cervical vv.

Inferior thyroid vv.

Thyroid venous plexus

Posterior external jugular, anterior jugular, transverse cervical, and suprascapular vv.**

*The brachiocephalic vein is form ed by the joining of it s t wo prim ary tributaries, the internal jugular vein and the subclavian vein. Only tribut aries within the neck are listed above. **The tribut aries of the external jugular vein m ay on occasion drain directly into the subclavian vein.

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12. Neurovascula r Topogra phy of the Neck

Cervical Plexus The neck receives innervation from the cervical spinal nerves as well as three cranial nerves: glossopharyngeal nerve (CN IX), vagus nerve (CN X), and accessory nerve (CN XI). CN IX and X innervate the pharynx and Fig. 12.3 Ce rvical ple xus The anterior rami of spinal nerves C1–C4 emerge from the intervertebral foramina along the transverse processes of the cervical vertebrae. They emerge bet ween the anterior and poste rior scalenes and give o short direct branches to the scalenes and rectii capitis anterioris before coursing anteriorly to form the cervical plexus. Motor bers: Motor bers from C1 course with the hypoglossal nerve (CN XII). Certain bers continue with the nerve to innervate the thyro hyoid and geniohyoid. The remainder leave CN XII to form the superior root of the ansa cervi calis. The inferior root is formed by motor bers from C2 and C3. The ansa cervicalis innervates the omohyoid, sternothyroid, and sternohy oid. Most motor bers from C4 descend as the phrenic nerve, which innervates the diaphragm. Se nso ry be rs: The sensory bers of C2–C4 em erge from the cervical plexus as periph eral nerves. (Note: The sensory bers of C1 go to the m eninges.) These peripheral sensory nerves em erge from Erb’s point and provide sensory innervation to the anterolateral neck.

larynx; CN XI provides m otor innervation to the trapezius and sterno cleidom astoid. The course and distribution of the cranial nerves are de scribed in Chapte r 4.

To m eninges (sensory) Hypoglossal nerve (CN XII)

C1

C2

C3

Superior root of ansa cervicalis (C1, m otor)

C4

Inferior root of ansa cervicalis (C2–C3, m otor)

C5

Ansa cervicalis Phrenic nerve (C3–C5, m ixed)

Lesser occipital nerve (C2, sensory)

Great auricular nerve (C2–C3, sensory) Transverse cervical nerve (C2–C3, sensory)

Supraclavicular nerves (C3–C4, sensory)

To brachial plexus

Ta ble 12.3 Branche s of the ce rvical ple xus Se nsory branche s

Se nso ry function

Moto r branches

Motor functio n

C1

—

—

C2

Lesser occipit al n.

C2–C3

Great auricular n.

Form sensory part of cervical plexus; innervate anterior and lateral neck

Form s ansa cervicalis (m otor part of cervical plexus) and separate m otor branches of CI

Ansa cervicalis innervates infrahyoid m uscles (except thyrohyoid). CI innervates thyrohyoid and geniohyoid in separate branches traveling with CN XII

Cont ribute to phrenic n.**

Innervate diaphragm and pericardium **

Transverse cervical n. C3–C4

Supraclavicular nn.

** The anterior roots of C3–C5 combine to form the phrenic nerve.

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Hyoglossus

Arc of hypoglossal nerve

12. Neurovascula r Topogra phy of the Neck

St ylohyoid

St yloglossus

Hypoglossal nerve (CN XII)

Anterior ram us of C1 C1 C2 Lingual nerve (CN V3 )

St ylopharyngeus

Genioglossus

C3

Geniohyoid branch (C1)

Thyrohyoid branch (C1) Superior root of ansa cervicalis (C1) Thyrohyoid Inferior pharyngeal constrictor Inferior root of ansa cervicalis (C2–C3)

Om ohyoid, superior belly Sternohyoid Sternothyroid

Ansa cervicalis

Fig. 12.4 Motor ne rves of the ce rvical ple xus Left lateral view.

Om ohyoid, inferior belly

Sternocleidom astoid Parotid gland (within capsule)

Lesser occipital nerve (C2)

Great auricular nerve (C2–C3) Transverse cervical nerve (C2–C3)

Erb’s point

Supraclavicular nerves (C3–C4)

Plat ysm a

Trapezius

Fig. 12.5 Se nsory ne rves of the ce rvical ple xus Left lateral view.

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12. Neurovascula r Topogra phy of the Neck

Cervical Regions (Triangles)

Occipital region

Parietal region

Temporal region

Subm andibular triangle

Carotid triangle

Subm ental triangle

Occipital triangle

Supraclavicular triangle

Lesser supraclavicular fossa

A

B

Fig. 12.6 Ce rvical re g ions A Right lateral oblique view. B Left posterior oblique view. For descriptive purposes, the anterolateral neck is divided into an an terior and a posterior cervical triangle, separated by the sternocleido

m astoid. The posterior portion of the neck is referred to as the nuchal region.

Ta ble 12.4 Ce rvical re gions Re g io n

Subdivision

Anterior cervical region (anterior cervical triangle): Bounded by the m idline, m andible, and sternocleidom astoid.

Subm andibular (digastric) triangle: Bounded by the m andible and the bellies of the digastric m uscle. Carotid triangle: Bounded by the sternocleidom astoid, superior belly of the om ohyoid, and posterior belly of the digastric. Muscular triangle: Bounded by the sternocleidom astoid, superior om ohyoid, and sternohyoid. Subm ent al triangle: Bounded by the anterior bellies of the digastric, the hyoid bone, and the m andible.

Sternocleidom astoid region: The region lying under the sternocleidom astoid m uscle. Lateral cervical region (posterior cervical triangle): Bounded by the sternocleidom astoid, trapezius, and clavicle.

Supraclavicular (om oclavicular or subclavian) triangle: Bounded by the inferior belly of the om ohyoid, the clavicle, and the sternocleidom astoid. Occipit al triangle: Bounded by the inferior belly of the om ohyoid, the trapezius, and the sternocleidom astoid.

Posterior cervical region (nuchal region): Region lying under the trapezius m uscle inferior to it s insertion at the superior nuchal line and superior to the vertebra prom inens (C7).

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12. Neurovascula r Topogra phy of the Neck

Subm andibular triangle

Digastric, posterior belly

Digastric, anterior belly

Sternocleidom astoid Posterior triangle

Subm ental triangle Carotid triangle

Trapezius

Muscular triangle Subm andibular triangle

Digastric, anterior belly

B Lesser supraclavicular fossa

Subm ental triangle

Digastric, posterior belly

Clavicle

Fig. 12.7 Muscle disse ction of the ne ck A Anterior view with the head slightly extended. B Left lateral view.

Hyoid bone Sternocleidom astoid region

Carotid triangle

Om ohyoid, superior belly Muscular triangle

A Posterior triangle

Lesser supraclavicular fossa

Trapezius

External occipital protuberance Suprasternal notch Clavicle

Inferior border of m andible Acrom ion

A

Spinous process of C7 vertebra

Tip of m astoid process

Acrom ion

B

Fig. 12.8 Palpable bony promine nce s in the ne ck A Anterior view. B Posterior view. Cert ain palpable structures de ne the boundaries of the neck. The superior boundaries of the neck are

the inferior border of the m andible, tip of the m astoid process, and external occipit al protuberance. The inferior boundaries are the supra sternal notch, clavicle, acrom ion, and spinous process of the C7 ver tebra.

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12. Neurovascula r Topogra phy of the Neck

Cervical Fasciae Fig. 12.9 Ce rvical fasciae The st ruct ures of t he ne ck are e nclose d by m ult iple laye rs of ce rvical fasciae, she et s of conne ct ive t issue t hat subdivide t he neck int o com part m ent s. The fascial layers are separate d by int e rfascial spaces. The re are four m ajor fascial spaces in t he neck: pret ra cheal, ret ropharyngeal, prevert ebral, and ca rot id. These spaces are not prom inent under norm al condit ions (t he fasciae lie flat against each ot he r). Howeve r, t he spaces m ay pro vide routes for t he spread of inflam m atory processes (e.g., tonsillar infe ct ions in t he in frat e m poral fossa) from re gions of t he head and ne ck into t he m e diast inum .

Muscular pretracheal fascia

Visceral pretracheal fascia

Superficial layer of deep cervical fascia

Retropharyngeal space

Carotid sheath

Prevertebral fascia

Prevertebral layer (deep nuchal fascia)

Buccopharyngeal fascia Superficial layer of deep cervical (superficial nuchal) fascia

Ta ble 12.5 Ce rvical fasciae and fascial spaces Despite generally being continuous, m any of the fascial layers bear di erent nam es in di erent regions of the neck relative to the structures they enclose. Fascial laye r

De scription

Conte nts

Super cial cervical fascia (not shown)

Subcut aneous tissue that lies deep to the skin and cont ains the plat ysm a anterolaterally.

Plat ysm a

Super cial layer of deep cervical fascia (yellow) = Deep cervical fascia + Super cial nuchal fascia

Envelops the entire neck and is continuous with the nuchal ligam ent posteriorly.

Split s around the trapezius and sternocleidom astoid

Prevertebral layer of deep cervical fascia (purple) = Prevertebral fascia + Deep nuchal fascia

At t aches superiorly to the skull base and continues inferiorly into the superior m ediastinum , m erging with the anterior longitudi nal ligam ent. Continues along the subclavian artery and brachial plexus, becom ing continuous with the axillary sheath. • The prevertebral fascia splits into an anterior (alar) and a posterior layer (the “danger space” is located between these layers).

Intrinsic back m uscles and prevertebral m uscles

Pretracheal fascia (green)

Carotid sheath (blue). Derived from deep, prevertebral, and pretracheal layers.

Muscular portion (light green)

Infrahyoid m uscles

Visceral portion (dark green): At t aches to the cricoid cartilage and is continuous posteriorly with the buccopharyngeal fascia. Continues inferiorly into the superior m ediastinum , eventually m erging with the brous pericardium .

Thyroid gland, trachea, esophagus, and pharynx

Consisting of loose areolar tissue, the sheath extends from the base of the skull (from the external opening of the carotid canal) to the aortic arch.

Com m on and internal carotid arteries, internal jugular vein, and vagus nerve (CN X); in addition, CN IX, CN XI, and CN XII brie y pass through the m ost superior part of the carotid sheath.

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12. Neurovascula r Topogra phy of the Neck

Mandible (no fascial layers on face)

Parotid gland with opened capsule Superficial layer, deep cervical fascia

Sternocleidom astoid (cut)

Sternohyoid

Carotid sheath (cut)

Visceral pretracheal fascia

Muscular pretracheal fascia (cut) Prevertebral fascia Trapezius

Clavicle

Sternal and clavicular heads of sternocleidom astoid (cut)

Clavipectoral fascia

A

Superficial layer, deep cervical fascia (superficial nuchal fascia) Nuchal ligam ent Buccopharyngeal fascia Superficial layer, deep cervical fascia

Spinal cord

Muscular pretracheal fascia

Posterior layer Anterior (alar) layer Deep nuchal fascia

Visceral pretracheal fascia

Prevertebral fascia

“Danger space” (bet ween layers of prevertebral fascia) B Retrovisceral fascia

Fig. 12.10 Fascial relationships in the ne ck A Anterior view with skin, super cial cervical fascia, and plat ysm a rem oved. B Left lateral view of m idsagit t al section. The super cial cervical fascia (not shown) lies just deep to the skin and cont ains the cut aneous m uscle of the neck (plat ysm a). The super cial layer of the deep cervical fascia cont ains the rem ainder of the struc tures in the neck. The deep cervical fascia at t aches to the inferior bor der of the m andible and is continuous inferiorly with the clavipectoral fascia (anteriorly) and the super cial nuchal fascia and the thoracolum bar fascia (posteriorly). The super cial layer of the deep cervical fascia split s to enclose the parotid gland in a capsule (A, swelling of the pa rotid gland result s in pain due to constriction by the capsule). It also split s to enclose the sternocleidom astoid and trapezius. In the ante rior neck, the pretracheal layer lies just deep to the super cial layer of the deep cervical fascia. It consist s of a m uscular portion and a visceral

Retropharyngeal space (bet ween retrovisceral and anterior prevertebral fasciae)

portion, which collectively enclose the structures of the anterior neck, including the pharynx, trachea, and esophagus. The portion of the pre tracheal fascia posterior to the esophagus is known as the retrovisceral fascia and is a continuation inferiorly of the buccopharyngeal fascia. (B). It is separated from the prevertebral fascia by the retropharyn geal space. Inferior to the laryngeal inlet, the prevertebral fascia split s into an anterior (alar) and a posterior layer, which are separated by the “danger space” —a potential route for the spread of infection from the pharynx into the superior m ediastinum . With tuberculous osteomyeli tis of the cervical spine, a retrophyarngeal abscess m ay develop in the “danger space” along the prevertebral fascia. Both prevertebral layers are continuous posteriorly with the deep nuchal fascia. Note: The laterally located carotid sheath (A) does not appear in the m idsagit tal sec tion.

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12. Neurovascula r Topogra phy of the Neck

Anterior Neck Mandible

Fig. 12.11 Ante rior ne ck Anterior view. Left neck: Super cial cervical fascia rem oved to expose plat ysm a. Right neck: Plat ysm a rem oved to expose the deep cervical fascia. The super cial layer of the deep cervical fascia lies just deep to the cut aneous plat ysm a m uscle, which is innervated by the cervical branch of the facial nerve (CN VII). It at t aches to the inferior border of the m andible and is continuous inferiorly with the clavipectoral fascia. The super cial layer split s to form a capsule around the parotid gland. In am m ation of the parotid gland (e.g., m um ps) causes conspicuous facial swelling and deform it y in this region (“ham ster cheeks” with prom inent earlobes). The super cial layer also divides into a deep and a posterior lam ina to enclose the sternocleidom astoid. The super cial layer has been cut around the m idline to expose the m uscular pretracheal fascia, which encloses the infrahyoid m uscles.

Parotid gland with opened capsule Superficial layer, deep cervical fascia

Plat ysm a Anterior jugular vein

External jugular vein

Transverse cervical nerve

Great auricular nerve

Muscular pretracheal fascia

Transverse cervical nerve

Posterior lam ina of superficial layer, deep cervical fascia

Supraclavicular nerves

Superior laryngeal artery

Sternocleidom astoid m uscle, sternal head

Internal laryngeal nerve

Internal jugular vein

Fig. 12.12 Ante rior ce rvical triangle Anterior view. The pretracheal fascia has been rem oved to expose the anterior cervical tri angle, bounded by the m andible and the an terior borders of the sternocleidom astoid m uscles. The infrahyoid m uscles are enclosed by the m uscular pretracheal fascia (rem oved). The thyroid gland and larynx are enclosed by the visceral pretracheal fascia (rem oved). The anterior cervical triangle cont ains neurovas culature of the larynx and thyroid gland, in cluding the rst branch of the external carotid artery (the superior thyroid artery). The inter nal and external laryngeal nerves (from the superior laryngeal branch of CN X) are visi ble. C1 m otor bers run with the hypoglossal nerve (CN XII) to the thyrohyoid and geniohy oid (not shown). Cert ain C1 m otor bers leave CN XII to form the superior root of the ansa cervicalis. The inferior root is form ed by m o tor bers from C2 and C3. The ansa cervicalis innervates the om ohyoid, sternothyroid, and sternohyoid.

External laryngeal nerve Right com m on carotid artery Superior thyroid artery External jugular vein

Arch of jugular vein

Thyroid cartilage

Medial supraclavicular nerve

Hypoglossal nerve (CN XII) Nerve to thyrohyoid (C1) Median thyrohyoid ligam ent Thyrohyoid Om ohyoid (cut) Sternocleidom astoid Superior root of ansa cervicalis (C1) Cricothyroid Sternothyroid Sternohyoid (cut)

Inferior thyroid vein

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12. Neurovascula r Topogra phy of the Neck

St ylohyoid Mandible Parotid gland Parotid gland

Mylohyoid Digastric, anterior belly Digastric, posterior belly

Hyoid Sternohyoid Sternocleidom astoid

Thyrohyoid

Thyroid m em brane (m edian thyrohyoid ligam ent)

Superior thyroid artery Superior thyroid vein

Thyroid cartilage Middle scalene

Internal jugular vein

Trapezius

Cricothyroid

Accessory nerve

Pyram idal lobe

Anterior scalene

Phrenic nerve Thyroid gland

Brachial plexus

Right com m on carotid artery

Vagus nerve

Thyrocervical trunk

Phrenic nerve Transverse cervical artery

Subclavian artery Brachiocephalic trunk

Middle thyroid vein

Inferior thyroid veins

Left recurrent laryngeal nerve

Clavicle

Left com m on carotid artery

Fig. 12.13 Root of the ne ck (thoracic inlet) Anterior view. The root of the neck cont ains num erous structures, in cluding the com m on carotid artery, subclavian artery, subclavian vein, internal jugular vein, inferior thyroid vein, vagus nerve, phrenic nerve,

and recurrent laryngeal nerve. A goiter enlarging the inferior pole of the thyroid gland can easily com press neurovascular structures at the thoracic inlet.

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12. Neurovascula r Topogra phy of the Neck

Root of the Neck

Fig. 12.14 Root of the ne ck Anterior view of left neck. Removed: Clavicle (sternal end), rst rib, m anubrium sterni, and thyroid gland. The left com m on carotid artery has been cut to expose sym pathetic ganglia and the ascent of the left recurrent laryngeal nerve from the aortic arch (where it arises from CN X). The brachial plexus can be seen em erging from the interscalene space bet ween the anterior and m iddle scalenes. It courses with the subclavian artery and vein into the axilla. The phrenic nerve descends on the anterior scalene into the m ediastinum , where it innervates the diaphragm . The tho racic duct term inates at the jugulosubclavian venous junction on the left. It receives lym ph from the entire body with the exception of the right upper quadrant, which drains to the right lym phatic duct.

Median thyrohyoid ligam ent

Thyroid cartilage

Com m on carotid artery

Internal jugular vein Vagus nerve (CN X)

External laryngeal nerve

Accessory nerve (CN XI) Trapezius

Middle cervical ganglion

Phrenic nerve

Cricothyroid

Anterior scalene

Sympathetic trunk

Brachial plexus

Inferior thyroid artery

Ascending cervical artery

C8 nerve root

Transverse cervical artery

Vertebral artery

Suprascapular artery

T1 nerve root

Subclavian artery

Recurrent laryngeal nerve

Transverse cervical vein

Stellate (cervicothoracic) ganglion

Subclavian vein Left com m on carotid artery

External carotid artery Thyrolingual trunk

B

Internal thoracic artery

Thyrocervical trunk

Linguofacial trunk

Internal carotid artery

A

Thoracic duct

C

D

Thyrolinguofacial trunk

E

Fig. 12.15 Variants of the carotid arte ries (after Faller and Poisel-Golth) The internal carotid artery m ay arise from the com m on carotid artery posterolateral (49%, A) or anterom edial (9%, B) to the external carotid artery, or at other interm ediate sites. The external carotid artery m ay give o a thyrolingual trunk (4%, C), linguofacial trunk (23%, D), or thyrolinguofacial trunk (0.6%, E).

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Atlas

Vertebral artery Vertebral vein

Longus capitis

Longus colli

Middle scalene Anterior scalene

Phrenic nerve Esophagus

Pleural dom e

Ascending cervical artery

Left com m on carotid artery

Inferior thyroid artery

Vagus nerve Brachial plexus

Transverse cervical artery

Anterior scalene

Suprascapular artery

Costocervical trunk

Thyrocervical trunk

Thoracic duct Subclavian artery

Trachea

Subclavian vein

1st rib

Internal thoracic artery and vein

Brachiocephalic vein Brachiocephalic trunk

Left recurrent laryngeal nerve Inferior thyroid veins

Fig. 12.16 De e pest Laye r of the Ne ck, Ante rior View The larynx, thyroid, trachea, and esophagus have been rem oved to ex pose the prevertebral m uscles and vertebral colum n of the neck. The t wo large vessels (the com m on carotid artery and the internal jugular vein) have been cut away on both sides, so the deeper lying vertebral artery is visible on the left ; on the right it is hidden by the prevertebral m uscles. The vertebral artery runs through the transverse foram ina of the cervical vertebrae, from C6 upward. It stretches over the arch of the atlas and enters the skull, where contributes to the blood supply to the brain and spinal cord. Also visible is the cervical plexus and the phrenic nerve, the lat ter extending down over the anterior scalene m uscle to enter the thorax. It then passes anterior to the root of the lung and is found sandwiched bet ween the m ediastinal pleura and brous pericardium layer of the pericardial sac. The phrenic nerve supplies m otor innervation to the m uscle of the diaphragm and receives sensory in nervation from the diaphragm atic and m ediastinal pleura. Also seen in

this dissection are the t wo bilateral arterial trunks with their branches: • on the right, the thyrocervical trunk is shown with: – the inferior thyroid artery, – the transverse cervical artery with deep and super cial branches, and – the suprascapular artery; – Ascending cervical a. • on the left, the costocervical trunk is shown. See Fig . 12.1 for it s branches: – the deep cervical artery, and the suprem e intercostal artery. The brachial plexus and the subclavian artery em erge from the gap bet ween the anterior and m iddle scalene m uscle; the subclavian vein passes anterior to the anterior scalene m uscle. The thoracic duct en ters the junction of the internal jugular and subclavian veins on the left after draining lym ph from three quarters of the body.

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12. Neurovascula r Topogra phy of the Neck

Lateral Neck

Parotid gland

Fig. 12.17 Late ral ne ck Right lateral view. Removed: Super cial cervical fascia, plat ysm a, and parotid capsule (su per cial layer of the deep cervical fascia). The super cial layer of the deep cervical fascia encloses all the structures of the neck with the exception of the plat ysm a. It split s to enclose the parotid gland in a capsule. The capsule has been opened to show the em ergence of the cervical branch of the facial nerve (CN VII) from the parotid plexus. The cervical branch provides m otor innervation to the plat ysm a. The sensory nerves of the anterolateral neck (lesser occipit al, great auricular, transverse cervical, and supraclavicular) arise from the cervical plexus, form ed by the anterior ram i of C1–C4. They pierce the investing layer at or near Erb’s point, m idway down the posterior border of the sternocleidom astoid. Note: The transverse cervical nerve (sensory) courses deep to the external jugular vein and form s a m ixed anastom osis with the cervical branch (m otor) of CN VII.

Facial nerve (CN VII), cervical branch

Masseter

Lesser occipital nerve (C2) Great auricular nerve (C2–C3) Erb’s point

Facial vein External jugular vein

Lateral supraclavicular nerves (C3–C4)

Posterior border of sternocleidom astoid

Anterior border of trapezius

Transverse cervical nerve and CN VII anastom osis Superficial layer, deep cervical fascia Transverse cervical nerve (C2–C3) Clavicle

Interm ediate supraclavicular nerves (C3–C4)

Fig. 12.18 Poste rior ce rvical triang le Right lateral view. A Super cial layer of the deep cervical fascia rem oved. B Pretracheal fascia rem oved. C Prevertebral fascia re m oved. The super cial layer of the deep cervical fascia split s into anterior and a posterior lam ina to enclose the sternocleidom astoid and trape zius, both of which are innervated by the ac cessory nerve (CN XI). (Note: The accessory nerve m ay be injured during lym ph node bi opsy.) Rem oving the super cial layer bet ween the sternocleidom astoid and trapezius reveals the posterior cervical triangle (bounded infe riorly by the clavicle). This exposes the prever tebral fascia, which encloses the intrinsic and deep m uscles of the neck. The prevertebral fascia is fused to the pretracheal fascia, which envelops the om ohyoid (B). Rem oving the prevertebral fascia exposes the phrenic nerve (C), which arises from the cervical plexus and descends to innervate the diaphragm . The brachial plexus (C) is also visible at it s point of em ergence bet ween the anterior and m iddle scalenes.

Medial supraclavicular nerves (C3–C4)

Lesser occipital nerve Great auricular nerve Accessory nerve (CN XI)

External jugular vein

Erb’s point

Anterior lam ina of superficial layer, deep cervical fascia

Superficial cervical node

Transverse cervical nerve and CN VII anastom osis

Superficial cervical artery

Sternocleidom astoid

Trapezius

Transverse cervical nerve

Supraclavicular nerves

A

Prevertebral fascia

Superficial cervical vein

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Pretracheal fascia

Posterior lam ina of superficial layer, deep cervical fascia

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Lesser occipital nerve

12. Neurovascula r Topogra phy of the Neck

Parotid gland

Great auricular nerve Accessory nerve (CN XI) Lateral supraclavicular nerves

External jugular vein

Interm ediate supraclavicular nerves

Sternocleidom astoid Transverse cervical nerve and CN VII anastom osis

Trapezius

Prevertebral fascia

Transverse cervical artery and vein

Transverse cervical nerve

Om ohyoid, inferior belly

Right subclavian vein

Suprascapular artery and vein B

Sternocleidom astoid Trapezius

Accessory nerve (CN XI) Middle scalene Levator scapulae

Phrenic nerve (C3–C5)

Brachial plexus

Posterior scalene

Anterior scalene

Transverse cervical artery and vein

Suprascapular artery

Om ohyoid, inferior belly

Right subclavian vein

C

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Deep Lateral Neck Fig. 12.19 Carotid triang le Right lateral view. The super cial layer of the deep cervical fascia has been rem oved to ex pose the carotid triangle, a subdivision of the anterior cervical triangle bounded by the ster Accessory nerve (CN XI) nocleidom astoid, superior belly of the om o hyoid, and posterior belly of the digastric. The Superior cervical prevertebral and pretracheal fasciae have also ganglion been rem oved to expose the content s of the carot id triangle, which include the internal Internal and external carot id arteries and t he tribu jugular vein t aries of the internal jugular vein. The sym Com m on pathetic t runk runs bet ween the m ajor blood facial vein vessels along with the vagus nerve (CN X). SternocleidoC1 m otor bers course with the hypoglossal m astoid nerve (CN XII) to the thyrohyoid and genio artery hyoid. Cert ain C1 m otor bers leave to form Vagus nerve the superior root of the ansa cervicalis (the (CN X) inferior root is form ed from C2–C3 bers). The ansa cervicalis innervates the om ohyoid, sternohyoid, and sternothyroid. Carotid body

Digastric, posterior belly

Internal carotid artery

External carotid artery

Facial artery Lingual artery Facial nerve (CN VII), m andibular branch Subm andibular gland Hypoglossal nerve (CN XII) Hyoid bone Internal laryngeal nerve Nerve to thyrohyoid (C1) Superior thyroid artery Sternothyroid Superior root of ansa cervicalis (C1)

External jugular vein

Thyroid gland

Sternocleidom astoid

Internal jugular vein

Fig. 12.20 Impe de d blood ow and ve ins of the ne ck When clinical factors (e.g., chronic lung dis ease, m ediastinal tum ors, or infections) im pede the ow of blood to the right heart , blood dam s up in the superior vena cava and, consequent ly, the external jugular vein (A). This causes conspicuous swelling in the ex ternal jugular (and som etim es m ore m inor) veins (B).

Ansa cervicalis (C1– C3) Inferior root of ansa cervicalis (C2–C3)

Internal jugular vein

External jugular vein

A

Subclavian vein

Om ohyoid

Superior vena cava

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Left brachiocephalic vein

B

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12. Neurovascula r Topogra phy of the Neck

Splenius capitis Sem ispinalis capitis Internal carotid artery

Facial artery and vein

External carotid artery

Hypoglossal nerve (CN XII)

Superior cervical ganglion

Sympathetic trunk

Accessory nerve (CN XI)

Thyrohyoid Om ohyoid, superior belly (cut)

Middle scalene

Carotid bifurcation with carotid sinus and body

Anterior scalene

Superior thyroid artery

Internal jugular vein (cut)

Thyroid gland

Ascending cervical artery

Com m on carotid artery (cut)

Ansa cervicalis

Sternohyoid

Phrenic nerve

Inferior thyroid artery Vagus nerve (CN X)

Brachial plexus

Vertebral artery Om ohyoid m uscle, inferior belly (cut)

Sternothyroid Sternocleidom astoid (cut)

Fig. 12.21 De e p late ral ce rvical re g ion Right lateral view. The sternocleidom astoid region and carotid trian gle have been dissected along with adjacent portions of the posterior and anterior cervical triangles. The carotid sheath has been rem oved in this dissection along with the cervical fasciae and om ohyoid m uscle to dem onstrate im portant neurovascular structures in the neck: • Com m on carotid artery with internal and external carotid arteries • Superior and inferior thyroid arteries • Internal jugular vein • Deep cervical lym ph nodes along the internal jugular vein • Sym pathetic trunk, including ganglia • Vagus nerve (CN X) • Accessory nerve (CN XI) • Hypoglossal nerve (CN XII) • Brachial plexus • Phrenic nerve Massage of the carotid sinus slows heart rate via the baroreceptor re ex: increased stretch of baroreceptors in the carotid sinus increases the rate of ring of action potentials in the carotid sinus nerve (a branch of the glossopharnygeal nerve [CN IX]). Im pulses are relayed to

the vasom otor center in the m edulla oblongat a, which then decreases sym pathetic out ow and increases parasym pathetic out ow (via the vagus nerve) to the heart and blood vessels. This result s in decreased heart rate, contractilit y, and cardiac output. It also causes dilation of vessels. This noninvasive technique is useful for term ination of supra ventricular t achycardia (SVT). The phrenic nerve (C3–C5) originates from the cervical plexus and the brachial plexus. The m uscular landm ark for locating the phrenic nerve is the anterior scalene, along which the nerve descends in the neck. The interscalene triangle is located bet ween the anterior and m iddle scalene m uscles and the rst rib and is traversed by the brachial plexus and subclavian artery. The subclavian vein passes anterior to the ante rior scalene. Dam age to the sym pathetic chain, for exam ple, due to a tum or at the apex of the lung (“Pancoast” tum or), thyrocervical venous dilation, or traum a, causes disruption of the sym pathetic supply to the face. This is known as Horner syndrom e and result s in ipsilateral m iosis (pupillary constriction), enophthalm os (a sunken eye), ptosis (drooping of the upper eyelid), and anhydrosis (loss of sweating) on the a ected side.

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12. Neurovascula r Topogra phy of the Neck

Posterior Neck Occipital region

Occipital artery and vein

Greater occipital nerve (posterior ram us of C2) Occipital lymph nodes

Sem ispinalis capitis

Third occipital nerve (posterior ram us of C3)

Lesser occipital nerve (C2) Sternocleidom astoid Splenius capitis Great auricular nerve (C2–C3) Accessory nerve (CN XI)

Posterior cutaneous branches (posterior ram us of C6)

Trapezius

Fig. 12.22 Poste rior ce rvical (nuchal) re g ion Posterior view. Left side: Super cial layer of super cial nuchal fascia. Right side: All fascia rem oved (super cial cervical fascia, super cial layer of the deep cervical fascia, prevertebral fascia). The posterior cervical region is bounded superiorly by the superior nu chal line (the at t achm ent of the trapezius and sternocleidom astoid to the occipital bone) and inferiorly by the palpable spinous process of the last cervical vertebra, the vertebra prom inens (C7). The posterior cervi cal region, like the rest of the neck, is com pletely enveloped in super cial nuchal fascia (left side). The super cial layer of the deep cervical fascia envelops the trapezius and split s to enclose the sternocleido m astoid.

Both m uscles are innervated by the accessory nerve (CN XI). The deep nuchal fascia (the posterior continuation of the prevertebral fascia) lies deep to the trapezius and sternocleidom astoid and encloses the intrinsic back m uscles (here: sem ispinalis and splenius capitis). The in trinsic back m uscles receive m otor and sensory innervation from the posterior ram i of the spinal nerves (see Fig . 12.25). The great auricular and lesser occipital nerves are also visible in this dissection. They are sensory nerves arising from the cervical plexus (form ed by the anterior ram i of C1–C4). The m ajor artery of the occipital region is the occipit al artery, a posterior branch of the external carotid artery.

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Tendon of trapezius (cut)

Occipital artery

Splenius capitis (cut)

12. Neurovascula r Topogra phy of the Neck

Sternocleidom astoid (cut)

Sem ispinalis capitis (cut) Obliquus capitis superior Rectus capitis posterior m inor Greater occipital nerve (C2)

Suboccipital nerve (C1)

Vertebral artery

Occipital artery

Rectus capitis posterior m ajor

Great auricular nerve

Obliquus capitis inferior Spinous process of axis Third occipital nerve (C3)

Fig. 12.23 Suboccipital triang le Posterior view of right side. The suboccipi t al triangle is a m uscular triangle lying deep to the trapezius, splenius capitis, and sem i spinalis capitis. It is bounded superiorly by the rectus capitis posterior m ajor, laterally by the obliquus capitis superior, and inferi orly by the obliquus capitis inferior. A short segm ent of the vertebral artery runs through the deep part of the triangle after leaving the transverse foram en of the atlas. It gives o branches to the surrounding short nuchal m uscles before exiting the suboccipit al triangle by perforating the posterior atlanto occipital m em brane. The vertebral arteries unite intra cranially to form the basilar artery, a m ajor contributor to cerebral blood ow.

Transverse process of atlas Cervical posterior intertransversarius Longissim us capitis Sem ispinalis capitis

Splenius capitis

Supraorbital nerve (from CN V1 ) Greater occipital nerve

C2 Supraorbital nerve (from CN V1 ) C3

Lesser occipital nerve

Greater occipital nerve (posterior ram us of C2)

C4

Lesser occipital nerve (C2)

A Posterior ram i of spinal nerves

B

Fig. 12.24 Sites of e me rg e nce of the occipital ne rve s Posterior view. The sites where the lesser and greater occipital nerves em erge from the fascia into the subcutaneous connective tissue are clinically im port ant because they are tender to palpation in cert ain diseases (e. g., m eningitis). The exam iner test s the sensation of these nerves by pressing lightly on the circled point s with the thum b. If these point s (but not their surroundings) are painful, the clinician should sus pect m eningitis.

Great auricular nerve (C2–C3) Supraclavicular nerves (C3–C4)

Fig. 12.25 Cutane ous inne rvation of the poste rior ne ck Posterior view. A Segm ental innervation (derm atom es). B Peripheral cut aneous nerves. The occiput and nuchal regions derive m ost of their segm ent al inner vation from the C2 and C3 spinal nerves. Of the speci c cutaneous nerves, the greater occipit al nerve is a branch of the posterior ram us of C2; the lesser occipit al, great auricular, and supraclavicular nerves are branches of the cervical plexus (form ed from the anterior ram i of C1–C4).

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12. Neurovascula r Topogra phy of the Neck

Peripharyngeal Space (I)

Occipital bone Vagus nerve (CN X) Sigm oid sinus

Pharyngobasilar fascia

Accessory nerve (CN XI)

Pharyngeal raphe Occipital artery

Hypoglossal nerve (CN XII)

Superior pharyngeal constrictor

St ylopharyngeus Superior cervical ganglion

Middle pharyngeal constrictor

Glossopharyngeal nerve (CN IX)

Internal jugular vein

Superior laryngeal nerve

Sternocleidom astoid

External carotid artery Internal carotid artery Ascending pharyngeal artery

Middle cervical ganglion

Decendens hypoglossi (CN XII) Carotid body

Pharyngeal venous plexus

Sympathetic trunk Inferior pharyngeal constrictor

Superior thyroid artery

Vagus nerve (CN X)

Thyroid gland Parathyroid gland Esophagus A

Fig. 12.26 Parapharyng eal space Posterior view. A Removed: Fascial layers. B Pharynx opened along pharyngeal raphe. The com m on and internal carotid arteries travel with

Ascending pharyngeal artery

Occipital artery

Facial artery

Internal carotid artery External carotid artery A

B

the internal jugular vein and vagus nerve within the carotid sheath, which at t aches to the skull base.

C

D

Fig. 12.27 Asce nding pharyng eal arte ry: variants (after Tillm ann, Lippert, and Pabst) Left lateral view. The m ain arterial vessel supplying the upper and m id dle pharynx is the ascending pharyngeal artery. In 70% of cases (A) it arises from the posteroinferior surface of the external carotid artery. In approxim ately 20% of cases it arises from the occipit al artery (B). Occasionally (8%) it originates from the internal carotid artery or carotid bifurcation (C), and in 2% of cases it arises from the facial artery (D).

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Choanae, of nasal cavit y

Abducent nerve (CN VI)

12. Neurovascula r Topogra phy of the Neck

Trochlear nerve (CN IV) and oculom otor nerve (CN III)

Trigem inal nerve (CN V)

Middle nasal turbinate

Facial nerve (CN VII) and vestibulocochlear nerve (CN VIII)

Inferior nasal turbinate

CN IX, X, and XI

Glossopharyngeal nerve (CN IX)

Torus tubarius Occipital artery

Uvular m uscle

Superior cervical ganglion

Palatopharyngeus

Salpingopharyngeus

Hypoglossal nerve (CN XII)

Accessory nerve (CN XI)

Vagus nerve (CN X)

Sternocleidom astoid Superior laryngeal nerve

Root of tongue

Epiglot tis

Vagus nerve (CN X)

Sympathetic trunk

Cuneiform tubercle

Internal laryngeal nerve Corniculate tubercle

Superior laryngeal artery and vein

Arytenoid, oblique part

Left recurrent laryngeal nerve (inferior laryngeal nerve)

Arytenoid, transverse part

Internal jugular vein Posterior cricoarytenoid Com m on carotid artery Middle cervical ganglion Right recurrent laryngeal nerve

Inferior thyroid artery External jugular vein

Vertebral artery (cut) Left subclavian artery Right recurrent laryngeal nerve

Left subclavian vein

Right brachiocephalic vein

Vertebral ganglion

Brachiocephalic trunk

Left recurrent laryngeal nerve

Vagus nerve (CN X) Superior vena cava

Aortic arch

B

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12. Neurovascula r Topogra phy of the Neck

Peripharyngeal Space (II)

Lingual tonsil

Sublingual gland Mandible Buccinator

Masseter

Oral vestibule Subm andibular ganglion Lingual nerve

Pharynx

Inferior alveolar nerve and artery

Palatine tonsil

Medial pterygoid

Parotid gland St yloid process

St yloglossus

Parotid duct

Retrom andibular vein

Internal carotid artery External carotid artery

Internal jugular vein

Retropharyngeal lymph nodes

Palatopharyngeus

Dens of axis

Fig. 12.28 Spaces in the ne ck Transverse section, superior view. The pharynx, larynx, and thyroid gland are enclosed by the pretracheal fascia. The posterior portion of t he pretracheal fascia that is in direct cont act with the pharynx is called the buccopharyngeal fascia. The fascial space surrounding the pharynx (peripharyngeal space) is divided into a posterior (ret ropharyngeal) space and a lateral (parapharyngeal) space. The retro

Palatine tonsil

St ylopharyngeal aponeurosis

Vertebral artery

Vagus nerve

pharyngeal space (green) lies bet ween the anterior (alar) layer of the prevertebral fascia (red) and the buccopharyngeal fascia, the posterior portion of the pretracheal fascia. The parapharyngeal space is divided by the st ylopharyngeal aponeurosis into an anterior and a posterior part. The anterior part (yellow) is cont ained wit hin the pretracheal fas cia in the neck (this section is through t he oral cavit y). The posterior part (orange) is cont ained within the carot id sheath.

Subarachnoid space Prevertebral fascia

Orbit Internal jugular vein

Pretracheal fascia

Cavernous sinus

From palatine tonsil

Retropharyngeal space

Superficial layer, deep cervical fascia

Peripharyngeal space

Space bounded by visceral fascia

Carotid artery Parotid gland

Cervical soft tissues B

A

Fig. 12.29 Role of the pe ripharyng e al space in the spread of infe ctio n (after Becker, Naum ann, and Pfalt z) Bacteria and in am m atory processes from the oral and nasal cavities (e.g., tonsillitis, dent al infections) m ay invade the peripharyngeal space. From there, they m ay spread in various directions (A). Invasion of the internal jugular vein m ay lead to bacterem ia and sepsis. Invasion of the subarachnoid space poses a risk of m eningitis. In am m atory processes m ay also track downward into the m ediastinum (gravit a

Mediastinum

“Danger space” (bet ween anterior and posterior layers of prevertebral fascia)

tion abscess), causing m ediastinitus (B). These m ay spread anteriorly in the spaces bet ween the super cial layer of the deep cervical fascia and m uscular pretracheal fascia or in the space within the pretracheal fascia . They m ay also spread posteriorly in the retropharyngeal space bet ween the buccopharyngeal anterior fascia and the (alar) layer of the prevertebral fascia. Infections that enter the “danger space” bet ween the anterior and posterior layers of the prevertebral fascia m ay spread directly into the m ediastinum .

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12. Neurovascula r Topogra phy of the Neck

Foliate papilla

Foram en cecum

Vallate papilla

Palatoglossus Palatine tonsil

Glossopharyngeal nerve (CN IX)

Lingual tonsil

Ascending pharyngeal artery, tonsillar branches

Aryepiglot tic fold

Palatopharyngeus

Epiglot tis

Superior laryngeal artery

Cuneiform tubercle

Internal laryngeal nerve

Piriform recess

Interarytenoid notch

Corniculate tubercle

St ylopharyngeus Posterior cricoarytenoid

Thyroid gland

Inferior thyroid vein Inferior thyroid artery Left recurrent laryngeal nerve (inferior laryngeal nerve)

Right recurrent laryngeal nerve

Esophagus

Trachea

Subm ucosal venous plexus

Fig. 12.30 Ne urovascular structures of the pe ripharynge al space Posterior view of an en bloc specim en com posed of the tongue, larynx, esophagus, and thyroid gland, as it would be resected at autopsy for pathologic evaluation of the neck. This dissection clearly dem onstrates the branching pat tern of the neurovascular structures that occupy the plane bet ween the pharyngeal m uscles.

Note the vascular supply to the palatine tonsil and it s proxim it y to the neurovascular bundle, which creates a risk of hem orrhage during ton sillectomy.

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Larynx

Lesser horn

Hyoid bone (body) Atlas (C1) Axis (C2) Hyoid bone

Cricoid cartilage

Greater horn

Thyrohyoid ligam ent Foram en for superior laryngeal artery and internal laryngeal nerve

Thyroid cartilage Laryngeal prom inence

Thyroid cartilage

Epiglot tis

Superior horn Oblique line

Cricothyroid ligam ent

Inferior horn

Cricotracheal ligam ent

Cricoid cartilage Tracheal cartilage

Fig. 13.1 Location of the larynx Anterior view. The bony structures of the neck have characteristic vertebral levels (shown for upright adult m ale): • Hyoid bone: C3 • Thyroid cartilage (superior border): C4 • Laryngotracheal junction: C6–C7 These structures are a half vertebra higher in wom en and children. The thyroid cartilage is especially prom inent in m ales, form ing the laryngeal prom inence (“Adam ’s apple”).

Vocal ligam ent

Lesser horn

Vestibular ligam ent

Epiglot tic cartilage

Greater horn Corniculate cartilage Arytenoid cartilage

Thyroid cartilage

Fig. 13.2 Larynx: ove rview Oblique left anterolateral view. The larynx consist s of ve cartilages: t wo external cartilages (thyroid and cricoid) and three internal cartilages (epiglot tic, arytenoid, and corniculate). Elastic ligam ent s connect these cartilages to each other as well as to the trachea and hyoid bone. This allows laryngeal m otion during swallowing. The thyroid, cricoid, and arytenoid cartilages are hyaline, and the epiglot tis and corniculate cartilages are elastic brocartilage.

Foram en for superior laryngeal artery and internal laryngeal nerve

Thyrohyoid m em brane Superior horn

Corniculate cartilage

Vocal process Cricoarytenoid joint

Median cricothyroid ligam ent

Thyroepiglot tic ligam ent

Cricoarytenoid ligam ent

Inferior horn Cricoid cartilage

Cricothyroid joint

Cricotracheal ligam ent

B

A

Fig. 13.3 Laryng eal cartilag es and ligame nts A Left m edial view of sagit t al section. B Posterior view. Arrows indi cate m ovem ent in the various joint s. The large t hyroid cart ilage e ncloses m ost of t he ot he r cart ilages. It art iculates wit h t he cricoid cart ilage infe riorly at t he paired crico -

t hyroid joint s, allowing it t o t ilt relat ive to t he cricoid cart ilage. The aryte noid cart ilages m ove during phonat ion: t heir bases can t rans lat e or rot ate relat ive to t he cricoid cart ilage at t he cricoaryt enoid joint .

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Epiglot tic cartilage

Right lam ina

Superior horn

Superior thyroid notch Superior thyroid tubercle

Laryngeal prom inence Left lam ina

Oblique line

Inferior thyroid notch Stalk of epiglot tis

A

B

Inferior thyroid tubercle

C

Fig. 13.4 Epig lottic cartilag e A Laryngeal (posteroinferior) view. B Lingual (anterosuperior) view. C Left lateral view. The elastic epiglot tic cartilage regulates the entrance of m aterial into the larynx. During breathing, it is angled posterosuperiorly, allowing air to enter the larynx and trachea. During swallowing, the larynx is elevated relative to the hyoid bone. The epiglot tis assum es a m ore horizontal position, preventing food from entering the airway.

Articular facet for arytenoid cartilage (cricoarytenoid joint)

Posterior lam ina

Inferior horn

Fig. 13.5 Thyroid cartilag e Oblique left lateral view. The hyaline thyroid cartilage consist s of t wo quadrilateral plates (lam inae) that are joined at the anterior m idline. The superior portion of this junction is the laryngeal prom inence (“Adam ’s apple”). The posterior ends of the lam inae are prolonged form ing the superior and inferior horns, which serve as anchors for ligam ent s.

Corniculate cartilage

Apex of arytenoid cartilage

Corniculate cartilage

Colliculus

Articular facet for thyroid cartilage (cricothyroid joint)

Posterior surface

Anterolateral surface

Vocal process

A A

B Muscular process

Vocal process

C Medial surface

Anterior arch

Arch of cricoid cartilage

Vocal process

Muscular process

Colliculus Articular facet (cricothyroid joint)

C

Corniculate cartilage D

Fig. 13.6 Cricoid cartilag e A Posterior view. B Anterior view. C Left lateral view. The hyaline cricoid cartilage is a ring that is connected inferiorly to the highest tracheal cartilage by the cricotracheal ligam ent. The cricoid ring is expanded posteriorly to form a lam ina. The lam inae each have an upper and lower articular facet for the arytenoid cartilage (cricoarytenoid joint) and thyroid cartilage (cricothyroid joint), respectively.

Muscular process

Vocal ligam ent

Conus elasticus

Anterior arch

Articular facet

Median cricothyroid ligam ent

Thyroid cartilage

B

Articular facet (cricoarytenoid joint)

Apex of arytenoid cartilage

Lam ina of cricoid cartilage

Cricoarytenoid ligam ent

Fig. 13.7 Aryte noid and corniculate cartilage s Right cartilages. A Right lateral view. B Left lateral (m edial) view. C Posterior view. D Superior view. The arytenoid cartilages alter the positions of the vocal cords during phonation. The pyram idshaped hyaline cartilages have three surfaces (anterolateral, m edial, and posterior), an apex, and a base with vocal and m uscular processes. The apex articulates with the tiny corniculate cartilages, which are composed of elastic brocartilage.

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13. La rynx & Thyroid Gla nd

Laryngeal Muscles Arytenoid cartilage, vocal process

Oblique line

Vocalis

Arytenoid cartilage, m uscular process

Conus elasticus

Cricothyroid

Straight part

Inferior horn of thyroid cartilage

Oblique part

Lateral cricoarytenoid

Posterior cricoarytenoid

Middle cricoarytenoid ligam ent

Articular facet for thyroid

B

A Arch of cricoid cartilage

Thyroarytenoid m uscle, thyroepiglot tic part

Oblique arytenoid

Aryepiglot tic fold

Aryepiglot tic fold

Cuneiform tubercle

Cuneiform tubercle

Thyroarytenoid

Transverse arytenoid

Lam ina of cricoid cartilage

Oblique arytenoid

Epiglot tic cartilage

Posterior cricoarytenoid

Thyroarytenoid

Corniculate tubercle

Lateral cricoarytenoid

Posterior cricoarytenoid

D C

Ta ble 13.1 Laryng eal muscles The laryngeal m uscles m ove the laryngeal cartilages relative to one another and a ect the tension and/or position of the vocal folds. Num erous m uscles m ove the larynx as a whole (infrahyoids, suprahyoids, pharyngeal constrictors, st ylopharyngeus, etc.). Muscle

Inne rvatio n

Action

Vo cal folds

Rima g lottidis

Posterior cricoarytenoid

Recurrent laryngeal n.**

Rot ates arytenoid cartilage out ward and slightly to the side

Abduct s

Opens

Lateral cricoarytenoid*

Rot ates arytenoid cartilage inward

Adduct s

Closes

Transverse arytenoid

Moves arytenoids toward each other

Thyroarytenoid

Rot ates arytenoid cartilage inward

Relaxes

Closes

Vocalis***

Regulates tension of vocal folds

Relaxes

None

Tilt s cricoid cartilage forward, acting on the vocalis m uscle to increase tension in the vocal folds

Lengthens

Cricothyroid

External laryngeal n.

*The lateral cricoarytenoid is called the m uscle of phonation as it initiates speech production. **Unilateral loss of the recurrent laryngeal nerve (e.g., due to nodal m et ast ases from a hilar bronchial carcinom a of the left lung) leads to ipsilateral palsy of the posterior cricoarytenoid. This prevent s com plete abduction of the vocal folds, causing hoarseness. Bilateral nerve loss (e.g., due to thyroid surgery) m ay cause asphyxiation. ***The vocalis is derived from the inferior bers of the thyroarytenoid m uscle. These bers connect the arytenoid cartilage with the vocal ligam ent.

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Cricothyroid

Vocalis

Thyroarytenoid Posterior cricoarytenoid E

Lateral cricoarytenoid Transverse arytenoid

A

Fig. 13.8 Laryng eal muscles A Left lateral oblique view of extrinsic laryngeal m uscles. B Left lateral view of intrinsic laryngeal m uscles (left thyroid lam ina and epiglot tis rem oved). C Posterior view. D Left lateral view. E Actions (arrows indicate directions of pull).

B

Fig. 13.9 Indire ct laryng oscopy te chnique A Mirror e xamination of the larynx from the perspective of the exam iner. The larynx is not accessible to direct inspection but can be viewed with the aid of a sm all m irror. The exam iner depresses the tongue with one hand while introducing the laryngeal m irror (or endoscope) with the other hand. A Optical path: The laryngeal m irror is held in front of the uvula, direct ing light from the exam iner’s head m irror down toward the larynx. The im age seen by the exam iner is shown in Fig. 13.10.

Median glossoepiglot tic fold Vallecula

Root of tongue Epiglot tis

Vocal fold

Epiglot tic tubercle

Laryngeal ventricle

Aryepiglot tic fold

Vestibular fold

C

D

E

Piriform sinus

Cuneiform tubercle

Arch of cricoid cartilage

Vocal process

A

B

Corniculate tubercle

Interarytenoid notch

Trachea

Fig. 13.10 Indire ct laryng oscopy and vocal fold position A Laryngoscopic m irror im age. B Norm al respiration. C Vigorous respiration. D Phonation position (vocal folds com pletely adducted). E Whispered speech (vocal folds slightly abducted). Indirect laryngoscopy produces a virtual im age of the larynx in which the right vocal fold appears on the right side of the m irror im age and anterior structures (e.g., tongue base, valleculae, and epiglot tis) appear at the top of the im age. The vocal folds appear as sm ooth-edged bands

(there are no blood vessels or subm ucosa below the strati ed, nonkeratinized squam ous epithelium of the vocal folds). They are therefore m arkedly lighter than the highly vascularized surrounding m ucosa. The glot tis can be evaluated in closed (respiratory) and opened (phonation) position by having the patient alternately inhale and sing “hee.” The clinician can then determ ine pathoanatom ical changes (e.g., redness, swelling, and ulceration) and functional changes (e.g., to vocal fold position).

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Larynx: Neurovasculature

Epiglot tis

Quadrangular m em brane

Epiglot tic cartilage Thyroid cartilage

Glands Rim a vestibuli

Vestibular fold Cut edges Vocal fold

Laryngeal saccule

Laryngeal ventricle

Vestibular ligam ent

Rim a glot tidis

Vocal ligam ent Conus elasticus

Vocalis m uscle

Thyroarytenoid m uscle

Ventricle

A

Vallecula

Lingual tonsil Epiglot tis

Hyoid bone

Piriform recess

Hyoepiglot tic ligam ent

Aryepiglot tic fold

Thyrohyoid ligam ent

Fig. 13.12 Vestibular and vocal folds Coronal histologic section. The vestibular and vocal folds are the m ucosal coverings of underlying ligam ent s. The vocal folds (“vocal cords”) cont ain the vocal ligam ent and vocalis m uscle. The ssure bet ween the vocal folds is the rim a glot tidis (glot tis). The vestibular folds (“false vocal cords”) are superior to the vocal folds. They cont ain the vestibular ligam ent, the free inferior end of the quadrangular m em brane. The ssure bet ween the vestibular folds is the rim a vestibuli, which is broader than the rim a glot tidis. Note: The loose connective tissue of the laryngeal inlet m ay becom e m arkedly swollen (e.g., insect bite, in am m atory process), obstructing the rim a vestibuli. This laryngeal edem a (often incorrectly called “glot tic edem a”) present s clinically with dyspnea and poses an asphyxiation risk.

Cuneiform tubercle

Vestibular fold

Corniculate tubercle

Ventricle Vocal fold

Piriform recess

Laryngeal vestibule

Cricoid cartilage

Median cricothyroid ligam ent

Interm ediate laryngeal cavit y

Esophagus

Tracheal cartilage

Infraglot tic cavit y

Mem branous wall of trachea B

C

Fig. 13.11 Laryng e al mucosa A Posterior view with pharynx and esophagus cut along the m idline and spread open. B Left lateral view of m idsagit t al section. C Posterior view with laryngeal levels. The larynx lies anterior to the laryngopharynx. Air enters through the laryngeal inlet form ed by the epiglot tis and aryepiglot tic folds. Lateral to the aryepiglot tic folds are pear-shaped m ucosal fossae (piriform recesses), which channel food past the larynx and into the laryngopharynx and on into the esophagus. The interior of the larynx is lined with m ucous m em brane that is loosely applied to it s underlying tissue (except at the vocal folds). The laryngeal cavit y can be further subdivided with respect to the vestibular and vocal folds (Table 13.2).

Ta ble 13.2 Divisions of the laryng eal cavity Laryng e al level

Bo undarie s

I: Laryngeal vestibule (supraglot tic space)

Laryngeal inlet (aditus laryngis) to vestibular folds

II: Interm ediate laryngeal cavit y (transglot tic space)

Vestibular folds across the laryngeal ventricle (lateral evagination of m ucosa) to vocal folds

III: Infraglot tic cavit y (subglot tic space)

Vocal folds to inferior border of cricoid cartilage

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Vagus nerve (CN X) Superior thyroid artery

Superior laryngeal nerve

Superior laryngeal artery

Internal laryngeal nerve (sensory)

Com m on carotid artery

External laryngeal nerve (m otor to cricothyroid)

Cricothyroid branch Inferior laryngeal artery

Cricothyroid

Inferior thyroid artery

Left recurrent laryngeal nerve

Thyrocervical trunk Right subclavian artery Right recurrent laryngeal nerve

Vagus nerve (CN X)

Brachiocephalic trunk Aortic arch

Left recurrent laryngeal nerve (a branch of CN X)

A

Facial vein

Superior laryngeal vein Superior thyroid vein

Middle thyroid veins

Inferior laryngeal vein

Thyroid venous plexus Internal jugular vein Inferior thyroid vein Left brachiocephalic vein

Subclavian vein

B

Fig. 13.13 Laryng eal blood vessels and ne rve s A Arteries and nerves, anterior view. B Veins, left lateral view. Arteries: The larynx derives its blood supply primarily from the superior and inferior laryngeal arteries. The superior laryngeal artery arises from the superior thyroid artery (a branch of the external carotid artery). The inferior laryngeal artery arises from the inferior thyroid artery (a branch of the thyrocervical trunk). Ne rve s: The larynx is innervated by the superior laryngeal nerve and the recurrent laryngeal nerve (of the vagus nerve). The superior laryngeal nerve split s into an internal (sensory) and an external (m otor) laryngeal nerve. The external laryngeal nerve innervates the cricothyroid. The rem aining intrinsic laryngeal m uscles receive m otor innervation from the recurrent laryngeal nerve, which branches from the vagus nerve below the larynx and ascends. Note: The left recurrent laryngeal nerve wraps around the aortic arch, and the right recurrent laryngeal nerve wraps around the subclavian artery. A left-sided aortic aneurysm m ay cause left recurrent laryngeal nerve palsy, resulting in hoarseness (see p. 343). Ve ins: The larynx is drained by a superior and an inferior laryngeal vein. The superior laryngeal vein drains to the internal jugular vein (via the superior thyroid vein); the inferior laryngeal vein drains to the left brachiocephalic vein (via the thyroid venous plexus to the inferior thyroid vein).

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Larynx: Topography

Superior laryngeal nerve Internal laryngeal nerve

Hyoid bone

Superior laryngeal vein and artery

Thyrohyoid m em brane

Cricothyrotomy High tracheotomy

Inferior pharyngeal constrictor (thyropharyngeal part)

Thyrohyoid

Fig. 13.15 Approaches to the larynx and trache a Midsagit t al section, left lateral view. When an acute edem atous obstruction of the larynx (e. g., due to an allergic reaction) poses an acute risk of asphyxiation, the following surgical approaches are available for creating an em ergency airway:

External laryngeal nerve

Oblique line

Median cricothyroid ligam ent Straight part Cricothyroid

Oblique part

• Division of the m edian cricothyroid ligam ent (cricothyrotomy) • Incision of the trachea (tracheotomy) at a level just below the cricoid cartilage (high tracheotomy) or just superior to the jugular notch (low tracheotomy).

Middle thyroid vein Thyroid gland

Low tracheotomy

Inferior thyroid artery Esophagus

A Epiglot tis

Recurrent laryngeal nerve

Fig. 13.14 Topog raphy of the larynx Left lateral view. A Super cial dissection. B Deep dissection (cricothyroid and left thyroid lam ina rem oved with pharyngeal m ucosa retracted). Neurovascular structures enter the larynx posteriorly. The larynx receives sensory and m otor innervation from branches of the vagus nerve (CN X). Se nso ry inne rvatio n: The upper larynx (above the vocal folds) receives sensory innervation from the internal laryngeal nerve, and the infraglot tic cavit y receives sensory innervation from the recurrent laryngeal nerve. Mo to r inne rvatio n: The cricot hyroid receives m otor innervat ion from the e xternal laryngeal nerve, and t he rest of t he int rinsic m uscles of t he larynx receive m otor innervat ion from t he recurrent laryngeal nerve.

Internal laryngeal nerve

Hyoid bone

Superior laryngeal vein and artery

Median thyrohyoid ligam ent

Pharyngeal m ucosa

Thyroid lam ina

Galen’s anastom osis (bet ween sensory branches of internal and recurrent laryngeal nerves)

Thyroarytenoid Lateral cricothyroid

Posterior cricoarytenoid

Median cricothyroid ligam ent

Esophagus

Cricothyroid

Middle thyroid vein

Tracheal branches

Inferior thyroid artery

Trachea B

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Recurrent laryngeal nerve

Neck

To glossopharyngeal nerve (CN IX) To superior laryngeal nerve (cricothyroid m uscle)

Brainstem (m edulla oblongata)

Glands

Brainstem lesion (hem orrhage, neoplasm ) Vagus nerve root s Superior (jugular) ganglion

To recurrent laryngeal nerve To accessory nerve (CN XI)

Skull base tum ors

Internal laryngeal nerve

Vestibular fold Laryngeal ventricle (Morgagni space)

Stratified, nonkeratinized squam ous epithelium

Jugular foram en

Pharyngeal branch to pharyngeal plexus

Inferior (nodose) ganglion

Reinke space (loose connective tissue)

Thyroarytenoid

Superior laryngeal nerve

Vocal ligam ent

Carotid surgery

Vocalis

Subglot tic edem a, ciliated respiratory epithelium Conus elasticus

Vagus nerve (CN X)

External laryngeal nerve

Left com m on carotid artery Thyroid surgery

Aortic aneurysm

A

a b c d

Fig. 13.17 Vocal folds Schem atic coronal histologic section, posterior view. The vocal fold, which is exposed to severe m echanical stresses, is covered by nonkeratinized squam ous epithelium , unlike the adjacent subglot tic space, which is covered by ciliated respiratory epithelium . The m ucosa of the vocal folds and subglot tic space overlies loose connective tissue. Chronic irrit ation of the subglot tic m ucosa (e.g., from cigaret te sm oke) m ay cause chronic edem a in the subglot tic space, resulting in a harsh voice. Degenerative changes in the vocal fold m ucosa m ay lead to thickening, loss of elasticit y, and squam ous cell carcinom a.

Left recurrent laryngeal nerve

Ta ble 13.3 Vagus ne rve lesions

Bronchial carcinom a

Lesions of the laryngeal nerves (Fig. 13.16A) may cause sensory loss or motor paralysis, which disrupts the position of the vocal folds (Fig. 13.16B).

Vagus nerve (CN X)

Level of ne rve lesion and e e cts on vocal fo ld po sition

Sites of injury to vagus nerve or its branches

B

13. La rynx & Thyroid Gla nd

Positions of the vocal folds a. Median or phonation position b. Param edian position c. Interm ediate position d. Lateral or respiratory position

Se nsory lo ss

Central lesion (brainstem or higher) E.g., due to tum or or hem orrhage. Spastic paralysis (if nucleus am biguus is disrupted), accid paralysis, and m uscle atrophy (if m otor neurons or axons are destroyed).

b,c

None

b,c

Entire a ected (ipsilateral) side

d

Above vocal fold

a,b

Below vocal fold

Skull base lesion*

Fig. 13.16 Vagus ne rve lesions The vagus nerve (CN X) provides branchiomotor innervation to the pharyngeal and laryngeal muscles and somatic sensory innervation to the larynx. Note: The vagus nerve also conveys parasympathetic motor bers and visceral sensory bers to and from the thoracic and abdominal viscera. Branchiomotor innervation: The nucleus ambiguus contains the cell bodies of lower motor neurons whose branchiomotor bers travel in CN IX, X, and XI. The nuclei of the vagus nerve are located in the middle region of the nucleus ambiguus in the brainstem (the cranial portions of the nucleus send axons via the glossopharyngeal nerve, and the caudal portions send axons via the accessory nerve). Fibers emerge from the middle portion of the nucleus ambiguus as roots and combine into CN X, which passes through the jugular foramen. Branchiomotor bers are distributed to the pharyngeal plexus via the pharyngeal branch and the cricothyroid muscle via the external laryngeal nerve (a branch of the superior laryngeal nerve). The remaining branchiomotor bers leave the vagus nerve as the recurrent laryngeal nerves, which ascend along the trachea to reach the larynx. Se nso ry inne rvatio n: General som atic sensory bers travel from the laryngeal m ucosa to the spinal nucleus of the trigem inal nerve via the vagus nerve. The cell bodies of these prim ary sensory neurons are lo cated in the inferior (nodose) ganglion. Note: The superior (jugular) ganglion cont ains the cell bodies of viscerosensory neurons.

E.g., due to nasopharyngeal tum ors. Flaccid paralysis of all intrinsic and extrinsic laryngeal m uscles on a ected side. Glot tis cannot be closed, causing severe hoarseness. Superior laryngeal nerve lesions* E.g., due to carotid surgery. Hypotonicit y of the cricothyroid, resulting in m ild hoarseness with a weak voice, especially at high frequencies. ,

,

Recurrent laryngeal nerve lesions**

E.g., due to bronchial carcinom a , aortic aneurysm , or thyroid surgery . Paralysis of all intrinsic laryngeal m uscles on a ected side. This result s in m ild hoarseness, poor tonal control, rapid voice fatigue, but not dyspnea.

*Other m otor de cit s include drooping of the soft palate and deviation of the uvula toward the a ected side, dim inished gag and cough re exes, di cult y swallowing (dysphagia), and hypernasal speech due to de cient closure of the pharyngeal isthm us. Sensory defect s include the sensation of a foreign body in the throat. **Transection of both recurrent laryngeal nerves can cause signi cant dyspnea and inspiratory stridor (high-pitched noise indicating obstruction), necessit ating tracheotomy in acute cases.

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Endotracheal Intubation Oral axis Pharyngeal axis Tracheal axis

B

A

Fig. 13.18 Equipme nt and positioning of the head for e ndotracheal intubatio n A Endotracheal (ET) tube with an in atable cu (left) and laryngoscope with handle and curved spatula (right). B, C Unfavorable and optim al positioning of the head for endotracheal intubation. Endotracheal intubation, inserting a tube into the trachea of a patient, is the safest way to keep the airways clear to allow for e ective ventilation. Depending on access there are four ways to achieve endotracheal intubation: • orotracheal = via the m outh (gold st andard), • nasotracheal = via the nose (perform ed if orotracheal intubation is not possible), and • pertracheal = intubation through tracheostomy (used for longterm ventilation), and • cricothyrotomy (used only in an em ergencies when there is the threat of im pending su ocation).

C

Endotracheal intubation requires the use of a laryngoscope and an ET tube (A). The tubes are available in di erent sizes (10–22 cm ) and diam eters (2.5–8 m m ). They have a circular cross piece that has a proxim al connector for a ventilation hose and a beveled distal end. An in at able cu on the ET ensures that the trachea is herm etically sealed (see Fig . 13.20). With orotracheal intubation, the oral, pharyngeal, and tracheal axes should lie on a straight line (the so-called “sni ng position”, see C).This facilit ates direct visualization of the laryngeal inlet (see Fig. 13.19) and shortens the dist ance bet ween the teeth and glottis in young adult s (13–16 cm ). Note: In patient s with suspected cervical spine injury, m anipulation of the head position without m aintaining the st abilit y of the cervical spine is contraindicated.

Laryngoscope Laryngoscope Endotracheal (ET) tube

Laryngoscope spatula Base of the tongue Median glossoepiglot tic fold

Epiglot tis

Esophagus

Palate Trachea

A

Fig. 13.19 Place me nt of the laryng oscope and the e ndotracheal tube (ET) A Handling and placem ent of the laryngoscope from the perspective of the physician. B Placem ent of the ET tube. To place the ET tube, the physician st ands at the head of the patient and introduces the spatula of the laryngoscope into the patient’s m outh. The spatula is then used to push the patient’s tongue to the left to get a clear view of the larynx. Under direct visualization, the spatula tip is then advanced until it s lies in the vallecula. Note: If the spatula is introduced too deep, it s tip reaches behind the epiglot tis, and orient ation is di cult. The physician then pulls the spatula in the direction of oor of m outh without using the upper teeth as a fulcrum . This elevates the epiglottis and the base of the tongue such that the physician now has an unobstructed view of the laryngeal inlet (see Fig. 13.20A). The physician

B

then pushes the ET tube through the rim a glot tis into the trachea (see Fig. 13.20B). Placem ent under laryngoscopic control ensures that the ET tube is placed in the trachea and does not accident ally enter the esophagus. Note: The ET tube has m arkings in centim eter increm ent s that serve as an orient ation aid to the physician. The dist ance from the upper teeth to the center of the trachea in the adult is about 22 cm and is newborns is about 11 cm . Dist ances greater than these m ight indicate that the tube is inserted too deeply and is in the right m ain bronchus.

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Neck

Base of tongue Larygnoscope spatula

Median glossoepiglot tic fold

Vallecula

Epiglot tis

Vestibular folds Aryepiglot tic fold

Trachea

13. La rynx & Thyroid Gla nd

Fig. 13.20 View of the laryng eal inlet and location o f the e ndotrache al tube afte r intubatio n A Laryngoscopic view of larynx, epiglot tis, and m edian glossoepiglot tic fold. B Median sagit t al section viewed from the right of an ET tube in situ with it s cu in ated. The in at able cu seals the trachea in all directions and elim inates leakage during ventilation and prevent s aspiration of foreign bodies, m ucus, or gastric juice. To check if the ET tube has been placed correctly, the physician looks at the patient’s chest to evaluate if chest m ovem ent is sym m etrical, he auscult ates for equal breath sounds over both lung elds and the ab sence of breath sounds over the stom ach. Further indicators that the ET tube is placed correctly include vapor condensation on the inside of the ET tube with exhalation and m easurem ent of end tidal carbon dioxide. If there is any doubt as to the positioning of the tube, it should be rem oved.

Piriform sinus

A

Vocal folds

Corniculate tubercle

Base of the tongue

Median glossoepiglot tic fold Hyoid bone

Trachea Vocal fold

Thyroid cartilage

B

Pharyngeal oriface of pharyngot ym panic tube

Soft palate

ET tube

Epiglot tis

Aryepiglot tic fold

Thyroid

Cricothyroid ligam ent

Cricoid cartilage

Inflated cuff

Esophagus

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13. La rynx & Thyroid Gla nd

Thyroid & Parathyroid Glands

Middle pharyngeal constrictor

Inferior pharyngeal constrictor Thyroid cartilage Superior thyroid artery

Pyram idal lobe Cricothyroid ligam ent Thyroid gland, right lobe Isthm us of thyroid gland

Cricothyroid

Parathyroid glands, superior pair

Thyroid gland, left lobe

Parathyroid glands, inferior pair Inferior thyroid artery

Trachea B

A

Fig. 13.21 Thyroid and parathyroid glands A Anterior view. B Posterior view. The thyroid gland consist s of t wo laterally situated lobes and a central narrowing (isthm us). A pyram idal lobe m ay be found in place of the isthm us; the apex point s to the em bryonic origin of the thyroid at the base of the tongue (on occasion, a persistent thyroglossal duct m ay be present, connecting the pyram idal lobe with the foram en cecum of the tongue). The parathyroid glands (generally four in num ber) show

Parathyroid glands

considerable variation in num ber and location. Note: Because the parathyroid glands are usually cont ained within the thyroid capsule, there is considerable risk of inadvertently rem oving them during thyroid surgery. This causes decreased plasm a calcium (Ca 2+) levels, resulting in tet any (m uscle t witching and cram ps). Tetany involving the laryngeal and respiratory m uscles m ay cause dyspnea (shortness of breath), which could be fat al if untreated.

Trachea

Capsule of thyroid gland (external capsule) Muscular pretracheal fascia

Plat ysm a

Thyroid gland Superficial layer, deep cervical fascia

Sternocleidom astoid

Internal jugular vein

Carotid sheath Vagus nerve

Com m on carotid artery

Esophagus

Prevertebral fascia

Fig. 13.22 Topography of the thyroid g land Transverse section through the neck at the T1 level, superior view. The thyroid gland partially surrounds the trachea and is bordered posterolaterally by the carotid sheath. When the thyroid gland is pathologically enlarged (e. g., due to iodine-de ciency goiter), it m ay gradually com press and narrow the tracheal lum en, causing respiratory distress. The thyroid gland is surrounded by a brous capsule com posed of an internal and external layer. The delicate internal layer (internal capsule, not shown here) directly invest s the thyroid gland and is fused with it s

Recurrent laryngeal nerve

glandular parenchym a. Vascularized brous slips extend from the internal capsule into the subst ance of the gland, subdividing it into lobules. The internal capsule is covered by the tough external capsule, which is part of the pretracheal layer of the deep cervical fascia. This capsule invest s the thyroid gland and parathyroid glands and is also called the “surgical capsule” because it m ust be opened to gain surgical access to the thyroid gland. Bet ween the external and internal capsules is a potential space that is traversed by vascular branches and is occupied by the parathyroid glands.

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13. La rynx & Thyroid Gla nd

Lingual thyroid Foram en cecum Thyroglossal duct Hyoid bone Thyroid cartilage

Pyram idal lobe

Thyroid gland

Trachea

Superior thyroid artery

Inferior thyroid artery

Fig. 13.23 Ectopic Thyroid Gland Left lateral view. Ectopic thyroid is a rare condition in which the entire thyroid gland or thyroid tissues are found out with their norm al position in the neck inferolateral to the thyroid cartilage. Dentist s m ay encounter this as a rm m idline m ass on the dorsal tongue, just posterior to the foram en cecum (the em bryonic origin on the thyroid gland). This m ass m ay appear as light pink to bright red, and m ay be regular or irregular. This is known as a lingual thyroid and represent s approxim ately 90% of ectopic thyroid cases. Sym ptom s of lingual thyroid m ay include cough, pain, dysphagia (di cult y swallowing), dysphonia (di cult y speaking), and dyspnea (shortness of breath). Treatm ent involves adm inistration of thyroxine to suppress thyroid stim ulating horm one (TSH) production and therefore reduce the size of the m ass. Surgical excision m ay be necessary if sym ptom s are severe, especially if they threaten the airway.

External carotid artery

Thyrohyoid m em brane

Superior laryngeal vein

Internal carotid artery

Superior thyroid vein

Internal jugular vein

Vagus nerve (CN X)

Middle thyroid vein

Thyroid venous plexus Inferior bulb of left jugular vein

Inferior bulb of right jugular vein

Thyrocervical trunk Right recurrent laryngeal nerve

Left subclavian artery

Left recurrent laryngeal nerve

Subclavian vein Thoracic duct

Right lym phatic duct Inferior thyroid vein

Left brachiocephalic vein

Right brachiocephalic vein

A

Superior vena cava B

Fig. 13.24 Blood supply and inne rvation of the thyroid g land Anterior view. A Arte rial supply: The thyroid gland derives m ost of it s arterial blood supply from the superior and inferior thyroid arteries. The superior thyroid artery, a branch of the external carotid artery, runs forward and downward to supply the gland. It is supplied from below by the inferior thyroid artery, which branches from the thyrocervical trunk. All of these arteries, which course on the right and left sides of the organ, m ust be ligated during surgical rem oval of the thyroid gland. In addition, a rare branch, the thyroid im a, m ay arise from the brachiocephalic trunk or right com m on carotid artery to supply the gland from below. It is a potential source of bleeding when perform ing m idline procedures on the neck, for exam ple, a tracheostomy.

Note: Operations on the thyroid gland carry a risk of injury to the recurrent laryngeal nerve, which is closely related to the posterior surface of the gland. Because it supplies im port ant laryngeal m uscles, unilateral injury to the nerve will cause postoperative hoarseness; bilateral injury m ay additionally result in dyspnea (di cult y in breathing). Prior to thyroid surgery, therefore, an otolaryngologist should con rm the integrit y of the nerve supply to the laryngeal m uscles and exclude any preexisting nerve lesion. B Ve nous drainag e : The thyroid gland is drained anteroinferiorly by a well-developed thyroid venous plexus, which usually drains through the inferior thyroid vein to the left brachiocephalic vein. Blood from the thyroid gland also drains to the internal jugular vein via the supe rior and m iddle thyroid veins.

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Sectional Anatomy 14

Se ctional Anatomy of the Head & Ne ck Coronal Sections of the Head (I): Anterior Coronal Sections of the Head (II): Posterior Coronal MRIs of the Head Coronal MRIs of the Neck (I): Anterior Coronal MRIs of the Neck (II) Coronal MRIs of the Neck (III): Posterior Transverse Sections of the Head (I): Cranial Transverse Sections of the Head (II) Transverse Sections of the Head (III): Caudal Transverse Sections of the Neck (I): Cranial Transverse Sections of the Neck (II): Caudal Transverse MRIs of the Head Transverse MRIs of the Oral Cavit y Transverse MRIs of the Neck Sagit tal Sections of the Head (I): Medial Sagit tal Sections of the Head (II): Lateral Sagit tal MRIs of the Head Sagit tal MRIs of the Neck

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14. Sectiona l Ana tomy of the Hea d & Neck

Coronal Sections of the Head (I): Anterior

Perpendicular plate of ethm oid

Anterior cranial fossa

Frontal lobe, cerebrum

Levator palpebrae superioris Periorbital fat

Orbital plate, ethm oid bone

Vitreous body

Ethm oid air cells

Medial rectus Inferior rectus

Middle nasal m eatus and concha

Inferior oblique Orbicularis oculi

Infraorbital nerve (from CN V2 ) in infraorbital canal Maxillary sinus

Cartilaginous nasal septum

Inferior nasal m eatus

Inferior nasal concha

Vom er

Superior buccal vestibule

Palatine process, m axilla

Upper first m olar

Greater palatine artery and nerve

Buccinator Intrinsic m uscles of tongue

Oral cavit y

Inferior buccal vestibule Lower first m olar

Genioglossus Geniohyoid

Inferior alveolar nerve, artery, and vein in m andibular canal

Mylohyoid Digastric, anterior belly

Plat ysm a

Fig. 14.1 Coronal se ction through the ante rior orbital marg in Anterior view. This section of the skull can be roughly subdivided into four regions: the oral cavit y, the nasal cavit y and paranasal sinuses, the orbit, and the anterior cranial fossa. Inspecting the region in and around the oral cavity , we observe the m uscles of the oral oor, the apex of the tongue, the neurovascular structures in the m andibular canal, and the rst m olar. The hard palate separates the oral cavit y from the nasal cavity , which is divided into left and right halves by the nasal septum . The inferior and m iddle nasal conchae can be identi ed along with the laterally situated m axillary sinus. Notice in Fig 14.2 and 14.3, as the coronal sections progress backward through the eye, , the m iddle concha no longer is associated with the ethm oidal air cells but instead with the m axillary sinus. The structure bulging down into the roof of the sinus is the infraorbit al canal, which transm it s the infraor-

bit al nerve (branch of the m axillary division of the trigem inal nerve, CN V2 ). The plane of section is so far anterior that it does not cut the lateral bony walls of the orbits because of the lateral curvature of the skull. The section passes through the transparent vitreous body and three of the six extraocular m uscles, which can be identi ed in the periorbit al fat. Two additional m uscles can be seen in the next deeper plane of section (Fig . 14.2). The space bet ween the t wo orbit s is occupied by the ethm oid air cells. Note: The bony orbit al plate is very thin (lam ina papyracea) and m ay be penetrated by infection, traum a, and neoplasm s. In the ante rio r cranial fossa , the section passes through both front al lobes of the brain in the m ost anterior portions of the cerebral gray m at ter. Very lit tle white m at ter is visible at this level.

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Sectiona l Ana tomy

14. Sectiona l Ana tomy of the Hea d & Neck

Superior sagit tal sinus

Falx cerebri

Frontal lobe, cerebrum

Crista galli

Olfactory bulb

Levator palpebrae superioris

Ethm oid air cells

Superior rectus

Temporalis, superficial and deep heads

Superior oblique

Superior nasal concha

Optic nerve (CN II)

Inferior orbital fissure

Medial rectus

Lateral rectus

Inferior rectus

Superior m eatus

Middle nasal concha

Zygom atic arch

Inferior nasal concha

Maxillary sinus Masseter, superficial part

Masseter

Masseter, deep part Long buccal nerve (of CN V3 )

Buccinator Tongue

Buccal vein Lingual nerve, deep lingual vein Inferior alveolar nerve, artery, and vein in m andibular canal Geniohyoid Mylohyoid Digastric, anterior belly

Fig. 14.2 Coronal se ction throug h the re trobulbar space Anterior view. Here, the tongue is cut at a m ore posterior level than in Fig. 14.1 and therefore appears broader. In addition to the oral oor m uscles, we see the m uscles of m astication on the sides of the skull. In the orbit al region we can identify the retrobulbar space with it s fat t y

tissue, the extra ocular m uscles, and the optic nerve. The orbit com m unicates laterally with the infratem poral fossa through the inferior orbital ssure. This section cut s through both olfactory bulbs in the anterior cranial fossa, and the superior sagit t al sinus can be recognized in the m idline.

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14. Sectiona l Ana tomy of the Hea d & Neck

Coronal Sections of the Head (II): Posterior

Superior sagit tal sinus

Falx cerebri

Frontal lobe, cerebrum

Olfactory tract Superior oblique

Superior rectus Lateral rectus

Temporalis

Optic nerve (CN II)

Ethm oid air cells

Medial rectus Inferior rectus

Nasal septum

Maxillary nerve (from CN V2 )

Zygom atic arch

Masseter Maxillary sinus Nasal cavit y

Coronoid process Soft palate

Ram us, m andible

Buccal fat pad Medial pterygoid

Buccinator

Intrinsic m uscles of tongue

Mandible, body Lingual septum Inferior alveolar nerve, artery, and vein in m andibular canal

Genioglossus Lingual nerve, deep lingual artery and vein

Hyoglossus Digastric, anterior belly

Mylohyoid Geniohyoid

Fig. 14.3 Coronal se ction through the orbital ape x Anterior view. The soft palate replaces the hard palate in this plane of section, and the nasal septum becom es osseous at this level. The buccal fat pad is also visible in this plane. The buccal pad fat is reduced in

wasting diseases; this is why the cheeks are sunken in patient s with end-st age cancer. This coronal section is slightly angled, producing an apparent discontinuit y in the m andibular ram us on the left side of the gure (com pare with the continuous ram us on the right side).

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Sectiona l Ana tomy

14. Sectiona l Ana tomy of the Hea d & Neck

Superior sagittal sinus Falx cerebri Lateral ventricle Corpus callosum Parietal lobe

Caudate nucleus, head Internal capsule Putam en

Tem poralis

Optic nerve (CN II)

Anterior cerebral artery

Oculom otor nerve (CN III)

Internal carotid artery

Trochlear nerve (CN IV)

Tem poral lobe

Abducent nerve (CN VI)

Pituitary gland (hypophysis)

Ophthalm ic division (CN V1 )

Cavernous sinus

Maxillary division (CN V2 )

Sphenoid sinus

Middle cranial fossa

Zygom atic process, tem poral bone

Mandibular division (CN V3 ) Masseter

Septum of sphenoid sinus

Lateral pterygoid

Nasopharynx

Lingual nerve

Lingual nerve

Inferior alveolar nerve

Inferior alveolar nerve

Ram us, m andible Medial pterygoid

Uvula Oropharynx

Palatine tonsil

Epiglottis

Laryngopharynx

Fig. 14.4 Coronal se ction throug h the pituitary Anterior view. The nasopharynx, oropharynx, and laryngopharynx can now be identi ed. This section cut s the epiglot tis, below which is the supraglot tic space. The plane cut s the ram us of the m andible on both sides, and a relatively long segm ent of the m andibular division of the trigem inal nerve (CN V3 ) can be identi ed on the left side. Above the roof of the sphenoid sinuses is the pituit ary gland (hypophysis), which lies in the hypophyseal fossa. In the cranial cavit y, the plane of section

passes through the m iddle cranial fossa. Due to the presence of the carotid siphon (a 180-degree bend in the cavernous part of the internal carotid artery), the section cut s the internal carotid artery t wice on each side. Cranial nerves can be seen passing through the cavernous sinus on their way from the m iddle cranial fossa to the orbit. The superior sagit t al sinus appears in cross section at the at t achm ent of the falx cerebri. At the level of the cerebrum , the plane of section passes through the parietal and tem poral lobes.

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14. Sectiona l Ana tomy of the Hea d & Neck

Coronal MRIs of the Head

Superior sagit tal sinus

Falx cerebri with superior frontal gyrus

Ethm oid air cells Roof of orbit

Levator palpebrae superioris, superior rectus, and supraorbital nerve Superior oblique with superior ophthalm ic vein Lacrim al gland Eyeball Lateral rectus Periorbital fat Inferior rectus and inferior oblique

Medial rectus with ophthalm ic artery Zygom atic bone

Infraorbital artery, vein, and nerve Middle and inferior nasal conchae

Maxillary sinus

Nasal septum Maxilla, alveolar process Tongue

Buccinator

Mandibular tooth

Genioglossus

Fig. 14.5 Coronal MRI throug h the eyeball Anterior view. In this plane of section, the falx cerebri com pletely divides the cerebral hem ispheres. The extraocular m uscles can be used to nd the orbital neurovasculature: the supraorbit al nerve runs superior to the levator palpebrae superioris and superior rectus, the superior ophthalm ic vein runs m edial and superior to the superior oblique,

Lingual nerve, deep lingual artery and vein

and the ophthalm ic artery runs inferior to the m edial rectus. The infraorbit al canal (cont aining the infraorbit al artery, vein, and nerve) runs inferior to the inferior rectus and oblique. The region m edial to the m andibular tooth and lateral to the genioglossus cont ains the sublingual gland as well as the lingual nerve, deep lingual artery and vein, hypoglossal nerve (CN XII), and subm andibular duct.

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Sectiona l Ana tomy

Superior frontal gyrus

Superior sagit tal sinus

14. Sectiona l Ana tomy of the Hea d & Neck

Frontal bone

Falx cerebri

Ethm oid air cells Cingulate gyrus Olfactory bulb (CN I) Levator palpebrae superioris and superior rectus with supraorbital nerve

Roof of orbit

Ophthalm ic artery and optic nerve (CN II)

Periorbital fat Ethm oid bone, orbital plate, and m edial rectus

Lateral rectus Temporalis

Inferior rectus above infraorbital artery, vein, and nerve Nasal septum

Zygom atic bone

Maxillary sinus Masseter

Inferior nasal concha

Hard palate Maxilla, alveolar process

Depressor anguli oris

Tongue Mandible, body

Genioglossus

Fig. 14.6 Coronal MRI throug h the poste rior orbit Anterior view. The inferior m argin of the falx cerebri is now superior to the cingulate gyrus. In the orbit, the supraorbit al nerve runs with the levator palpebrae superioris and superior rectus, and the oculom otor nerve (CN III) runs lateral to the inferior rectus, which in turn runs supe-

Subm andibular gland

rior to the infraorbit al canal. The ophthalm ic artery can be used to nd the m ore m edially located optic nerve (CN II), both of which em erge from the optic canal. Note the asym m etrical nature of the nasal cavities. The subm andibular gland is m ore prom inent in this section bet ween the genioglossus and the body of the m andible.

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14. Sectiona l Ana tomy of the Hea d & Neck

Coronal MRIs of the Neck (I): Anterior

Anterior ethm oid air cells

Levator palpebrae superioris and superior rectus Sphenoid bone, lesser wing Optic nerve (CN II)

Lateral rectus Tem poralis

Superior oblique, m edial rectus, and inferior rectus

Zygom atic bone Middle nasal concha Masseter

Maxillary sinus

Hard palate Longitudinal m uscle of tongue Transverse m uscle of tongue

Buccinator

Hyoglossus, genioglossus, and lingual septum

Mandible

Digastric, anterior belly Thyrohyoid cartilage

Mylohyoid and geniohyoid

Vestibular fold

Plat ysm a

Vocalis Infraglot tic cavit y Glot tis

Sternohyoid

Cricoid cartilage Trachea

Fig. 14.7 Coronal MRI of the ling ual muscles Anterior view. This plane of section lies just posterior to the previous one and transect s the extrinsic (genioglossus and hyoglossus) and intrinsic (longitudinal and transverse) lingual m uscles. The m uscles of

m astication (tem poralis and m asseter) are visible, as are the buccinator, mylohyoid, and geniohyoid. This section cut s the larynx and trachea, revealing the vestibular fold, vocalis m uscle, and cricoid cartilage.

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Nasopharynx

14. Sectiona l Ana tomy of the Hea d & Neck

Sphenoid sinus

Vom er

Pharyngot ympanic (auditory) tube, cartilaginous part

Temporalis

Zygom atic bone, temporal process

Sphenoid bone, greater wing Lateral pterygoid

Masseter

Medial pterygoid Levator veli palatini and parapharyngeal space

Soft palate Transverse m uscle of tongue

Mandible, angle

Root of tongue Facial artery and plat ysm a Vallecula Median and lateral glossoepiglot tic folds

Thyroid cartilage Thyroarytenoid

Piriform recess Laryngeal vestibule

Trachea Arytenoid cartilage

Sternocleidom astoid

Thyroid gland with inferior thyroid veins

Subclavian vein Clavicle

Fig. 14.8 Coronal MRI of the soft palate and muscles of mastication Anterior view. This section illustrates the convergence of the air- and foodways in the pharynx. The nasopharynx lies inferior to the sphenoid sinus and superior to the soft palate. It converges with the foodway in the oropharynx, located posterior to the uvula (not shown). The oro -

pharynx continues inferiorly to the epiglot tis (the vallecula lies anterior to this). The air- and foodways then diverge into the larynx and laryngopharynx, respectively. The laryngeal vestibule is the superior portion of the larynx, above the vocal folds. This section reveals the thyroid and arytenoid cartilage of the larynx. Com pare this im age to Fig. 14.9.

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14. Sectiona l Ana tomy of the Hea d & Neck

Coronal MRIs of the Neck (II)

Temporalis

Pharyngot ym panic tube

Sphenoid sinus

Pharyngeal tonsils

Tensor veli palatini

Lateral pterygoid

Maxillary artery and inferior alveolar nerve Zygom atic bone

Nasopharynx and soft palate Parotid gland

Levator veli palatini

Masseter

Medial pterygoid Facial artery

Ram us, m andible

Palatopharyngeus Palatine tonsil Subm andibular gland (extraoral lobe)

Oropharynx

Internal carotid artery

Vallecula External carotid artery

Middle pharyngeal constrictor

Laryngeal vestibule

Com m on carotid artery

Sternocleidom astoid

Trachea

Thyroid gland

Subclavian vein

Internal jugular vein

Right brachiocephalic vein

Right lung

Right subclavian artery

Fig. 14.9 Coronal MRI of the great vessels Anterior view. This im age clearly dem onstrates the course of the great vessels in the neck. This im age is also an excellent dem onstration of the

Aortic arch

Brachiocephalic trunk

Left lung

structures of the oral cavit y. Note the position of the pharyngeal tonsils on the roof of the nasopharynx and the extent of the palatine tonsils in the oropharynx.

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Temporalis

Cavernous sinus

Sphenoid sinus

14. Sectiona l Ana tomy of the Hea d & Neck

Nasopharynx

Internal carotid artery (syphon)

Pharyngot ympanic (auditory) tube

Mandibular fossa, temporal bone

Zygom atic process, m axilla

Articular disk (m eniscus) Head (condyle), m andible Lateral pterygoid

Parotid gland

Maxillary artery Medial pterygoid Levator veli palatini Digastric, posterior belly

Longus capitis Longus colli

Intervertebral disk

Com on carotid artery, internal jugular vein

Sternocleidom astoid External jugular vein

Vertebral body

Spinal nerve ram i Anterior scalene Thyroid gland

Com m on carotid artery

Vertebral artery

Subclavian artery

Vertebral vein

Left lung

Right lung

Brachiocephalic trunk

Trachea

Fig. 14.10 Coronal MRI through the temporomandibular joint (TMJ) Anterior view. This im age clearly dem onstrates the structures of the TMJ, in particular the articular disk and m andibular head. The ram us of

Aorta

Com m on carotid artery

the m andible is seen m edial to the parotid gland. This im age shows the cervical vertebrae with intervertebral disks.

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Coronal MRIs of the Neck (III): Posterior

Temporalis

Atlas (C1), lateral m ass

Axis (C2), dens

Clivus

Temporal bone, petrous part

External acoustic m eatus

Tympanic cavit y

Occipital condyle Parotid gland Atlanto-occipital joint Lateral atlantoaxial joint Atlas (C1), transverse process Internal jugular vein

Alar ligam ents St ylohyoid

Digastric, posterior belly

C4 and C5 spinal nerve roots

Sternocleidom astoid

C6, articular process

Spinal cord

Middle scalene Zygapophyseal (intervertebral facet) joint Posterior scalene

Second rib

Right lung

Esophagus

Fig. 14.11 Coronal MRI throug h the ce rvical ve rtebrae and spinal ne rves Anterior view. This im age clearly shows the C1 through T2 vertebrae. The lateral m asses of the atlas (C1) can be seen anking the dens of the

Left lung

axis (C2). The m ore inferior vertebrae can be counted using the articular processes of the cervical vertebrae. The spinal nerve root s em erge bet ween the articular processes (note for counting purposes: the C3 root em erges inferior to C2 and superior to the articular processes of C3).

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Foram en m agnum

Temporal bone, petrous part Mastoid process, temporal bone

Atlas (C1), posterior arch

Digastric, posterior belly, and obliquus capitis superior Splenius capitis

Vertebral artery

Obliquus capitis inferior Longissim us capitis

Axis (C2), spinous process Sternocleidom astoid Deep cervical artery and vein

Levator scapulae

Splenius cervicis

Multifidus Trapezius

Brachial plexus C7, spinous process

First rib Costal process

Right lung

Spinal cord

Fig. 14.12 Coronal MRI throug h the nuchal muscles Anterior view. This im age clearly shows the relations of the m uscles in the neck. Note: The elongated spinous process of the C7 vertebra (ver-

Left lung

tebra prom inens) is still visible in this section. The spinal cord is visible both during it s passage through the foram en m agnum and m ore caudally, posterior to the T1 vertebral body.

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14. Sectiona l Ana tomy of the Hea d & Neck

Transverse Sections of the Head (I): Cranial

Crista galli Dorsal Vitreous body nasal artery

Nasal branch of facial artery

Ethm oid air cells

Superior oblique Levator palpebrae superioris

Periorbital fat

Superior rectus Superficial temporal vein Temporalis Optic chiasm Third ventricle

Optic tract (CN II)

Cerebral peduncle

Red nucleus

Substantia nigra

Cerebral aqueduct Choroid plexus Cerebellum , verm is

Inferior sagit tal sinus Lateral ventricle, occipital horn

Superior sagit tal sinus

Fig. 14.13 Transve rse se ction throug h the uppe r level of the orbits Inferior view. The highest section in this series displays the m uscles in the upper level of the orbit (the orbit al levels are described on p. 236). The section cut s the bony crista galli in the anterior cranial fossa, anked on each side by cells of the ethm oid sinus. The sections of the optic chiasm and adjacent optic tract are part s of the diencephalon,

which surrounds the third ventricle at the center of the section. The red nucleus and subst antia nigra are visible in the m esencephalon. The pyram idal tract descends in the cerebral peduncles. The section passes through the posterior (occipital) horns of the lateral ventricles and barely cut s the verm is of the cerebellum in the m idline.

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Nasal cavit y Lens

Nasal septum

Vitreous body

Ethm oid air cells Medial rectus

Lacrim al gland

Lateral rectus

Optic nerve (CN II) Optic canal Internal carotid artery

Temporalis Pituitary gland (hypophysis)

Oculom otor nerve (CN III)

Dorsum sellae Basilar artery

Cavernous sinus

Interpeduncular fossa

Pons

Cerebellum , verm is

Tentorium cerebelli Inferior sagit tal sinus Lateral ventricle, occipital horn

Falx cerebri

Superior sagit tal sinus

Fig. 14.14 Transverse section through the optic nerve and pituitary Inferior view. The optic nerve is seen just before it s entry into the optic canal, indicating that the plane of section passes through the m iddle level of the orbit. Because the nerve com pletely lls the canal, growth disturbances of the bone at this level m ay cause pressure injury to the nerve. This plane cut s the ocular lenses and the cells of the ethm oid

labyrinth. The internal carotid artery can be identi ed in the m iddle cranial fossa, em bedded in the cavernous sinus. The section cut s the oculom otor nerve on either side, which courses in the lateral wall of the cavernous sinus. The pons and cerebellar verm is are also seen. The falx cerebri and tentorium cerebelli appear as thin lines that com e together at the straight sinus.

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Transverse Sections of the Head (II)

Vom er (bony part of nasal septum ) Nasal cavit y

Cartilaginous nasal septum Inferior oblique

Vitreous body Inferior rectus Periorbital fat

Inferior orbital fissure

Temporalis

Sphenoid bone, greater wing

Sphenoid sinus Cavernous sinus

Internal carotid artery

Trigem inal nerve (CN V)

Tem poral bone, petrous part

Clivus

Pons

Basilar artery Trigem inal nerve (CN V)

Cerebellum

Tentorium cerebelli Straight sinus Falx cerebri

Superior sagit tal sinus

Fig. 14.15 Transve rse se ction throug h the sphe noid sinus Inferior view. This section cut s the infratem poral fossa on the lateral aspect of the skull and the tem poralis m uscle that lies within it. The plane passes through the lower level of the orbit, which is continuous posteriorly with the inferior orbit al ssure. This section displays the anterior extension of the t wo greater wings of the sphenoid bone and the posterior extension of the t wo petrous part s of the tem poral

bones, which m ark the boundary bet ween the m iddle and posterior cranial fossae. The clivus is part of the posterior cranial fossa and lies in cont act with the basilar artery. The pontine origin of the trigem inal nerve is visible. Note: The trigem inal nerve passes superior to the petrous portion of the tem poral bone to enter the m iddle cranial fossa.

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Nasal cavit y

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Cartilaginous nasal septum

Buccal fat pad

Maxillary sinus Infraorbital nerve (from CN V2 ) in infraorbital canal

Zygom atic arch Body, sphenoid bone

Temporalis

Mandibular division (CN V3 )

Lateral pterygoid

Masseter Head (condyle), m andible Internal carotid artery

Superficial temporal artery and veins

Inferior petrosal sinus

Clivus Basilar artery Facial nerve (CN VII) Vestibulocochlear nerve (CN VIII)

Pontocerebellar cistern Cerebellum , verm is

Transverse sinus

Dentate nucleus

Cerebellum , posterior lobe Straight sinus

Falx cerebri Superior sagit tal sinus

Occipital lobe

Fig. 14.16 Transve rse se ction throug h the middle nasal concha Inferior view. This section below the orbit passes through the infraorbital nerve and canal. Medial to the infraorbit al nerve is the roof of the m axillary sinus. The zygom atic arch is visible in it s entiret y, with portions of the m uscles of m astication (m asseter, tem poralis, and lateral pterygoid) and the upper part of the head of the m andible. The m andibular division of the trigem inal nerve (CN V3 ) appears in cross section in it s bony canal, the foram en ovale. The body of the sphenoid bone

form s the bony center of the base of the skull. The facial and vestibulocochlear nerves (CNs VII and VIII) em erge from the brainstem and enter the internal acoustic m eatus. The dent ate nucleus lies within the white m at ter of the cerebellum . The space around the anterior part of the cerebellum , the pontocerebellar cistern, is lled with cerebro- spinal uid in the living individual. The transverse sinus is prom inent am ong the dural sinuses of the brain.

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Transverse Sections of the Head (III): Caudal

Naris

Alar cartilage, m edial crus

Cartilaginous nasal septum

Nasal cavit y Nasal septum Inferior nasal concha

Facial vein

Choana Medial pterygoid Masseter Long buccal nerve (of CN V3 )

Lateral pterygoid and pterygoid venous plexus

Pharyngot ympanic (auditory) tube

Masseteric nerve

CN V3 Nasopharynx

Auriculotem poral nerve and m axillary veins

Parotid gland Retrom andibular vein

Internal carotid artery

External auditory canal

Auricular cartilage

Facial nerve (CN VII)

Glossopharyngeal nerve (CN IX), vagus nerve (CN X), and accessory spinal nerve (CN XI)

Internal jugular vein Sigm oid sinus Vertebral venous plexus

Accessory nerve (CN XI), spinal root

Medulla oblongata

Vertebral artery

Diploic veins Transverse sinus

Falx cerebelli

Sem ispinalis capitis

Fig. 14.17 Transve rse se ction throug h the nasopharynx Inferior view. This section passes through the external nose and portions of the cartilaginous nasal skeleton. The nasal cavities com m unicate with the nasopharynx through the choanae. Cartilaginous portions of the pharyngot ym panic tube project into the nasopharynx. The internal jugular vein travels with the vagus nerve (CN X) and com m on carotid artery as a neurovascular bundle within the carotid sheath, a fascial covering that extends from the base of the skull to the arch of the aort a. The glossopharyngeal, accessory spinal, and hypo-

glossal nerves (CN IX, XI, and XII) also pierce the upper portion of the carotid sheath. However, these neurovascular structures do not all enter and exit the skull base together. The jugular foram en consist s of a neural and a venous portion. The neural portion conduct s the glossopharyngeal (CN IX), vagus (CN X), and accessory spinal (CN XI) nerves, and the venous portion cont ains the jugular bulb, which receives blood from the sigm oid sinus. (Note: The internal jugular vein begins at the inferior portion of the jugular foram en.) The internal carotid artery enters the carotid canal, and the hypoglossal (CN XII) nerve enters the hypo glossal canal.

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Soft palate (including tensor and levator veli palatini)

Maxilla

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Mucoperiosteum of the hard palate

Lateral pterygoid plate

Levator anguli oris Buccinator Masseter

Lingual nerve Medial pterygoid

Inferior alveolar nerve

Lateral pterygoid

Atlas (C1)

Ram us, m andible

Glossopharyngeal nerve (CN IX)

Maxillary artery Internal carotid artery

Internal jugular vein

Accessory spinal nerve (CN XI)

Facial nerve (CN VII) within parotid gland

Hypoglossal nerve (CN XII) Vagus nerve (CN X)

Occipital artery

Median atlantoaxial joint

Posterior condylar em issary vein

Dens of axis (C2)

Splenius capitis

Vertebral artery Transverse ligam ent of atlas

Occipital bone

Spinal Trapezius cord

Fig. 14.18 Transverse section through the median atlantoaxial joint Inferior view. The section at this level passes through the connective tissue sheet that stretches over the bone of the hard palate. Portions of the upper pharyngeal m uscles are sectioned close to their origin. The neurovascular structures in the carotid sheath are also well displayed. The dens of the axis articulates in the m edian atlantoaxial joint with the

Sem ispinalis capitis

facet for the dens on the posterior surface of the anterior arch of the atlas. The transverse ligam ent of the atlas that helps to st abilize this joint can also be identi ed. The vertebral artery and it s accom panying veins are displayed in cross section, as is the spinal cord. In the occipit al region, the section passes through the upper portion of the posterior neck m uscles.

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Transverse Sections of the Neck (I): Cranial

Arytenoid cartilage

Epiglot tic cartilage

Laryngeal vestibule

Plat ysm a

Om ohyoid Thyrohyoid

Piriform recess Superior thyroid vein

Thyroid cartilage

Com m on carotid artery, internal jugular vein, and vagus nerve (CN X) in carotid sheath

Sternocleidom astoid Laryngopharynx

C5 vertebra

Inferior pharyngeal constrictor

External jugular vein

Longus colli

Accessory spinal nerve (CN XI), external branch

C4 spinal nerve

Vertebral artery

C5 spinal nerve

C6, vertebral body

C6 spinal nerve

Longissim us capitis

Levator scapulae

Longissim us cervicis

Trapezius

Splenius cervicis

Splenius capitis

C7, spinous process

Fig. 14.19 Transve rse se ction at the level of the C5 ve rtebral body Inferior view. The internal jugular vein travels with the com m on carotid artery and vagus nerve in the carotid sheath. The accessory spinal nerve (CN XI) is m edial to the sternocleidom astoid; m ore proxim al to the skull base it will pierce the carotid sheath to enter the jugu-

Sem ispinalis cervicis

lar fora m en with the internal jugular vein, as well as CN IX and X. The elongated spinous process of the C7 vertebra (vertebra prom inens) is visible at this level, owing to the lordotic curvature of the neck. Note that the triangular shape of the arytenoid cartilage is clearly dem onstrated in the laryngeal cross section.

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Epiglot tic cartilage Laryngeal vestibule

Thyroid cartilage Piriform recess

Inferior pharyngeal constrictor

Thyroid gland Com m on carotid artery

Superior thyroid artery and vein

Vagus nerve (CN X) Internal jugular vein

Anterior scalene with phrenic nerve

External jugular vein C5 spinal nerve

Middle scalene

C6 spinal nerve

Posterior scalene

Vertebral artery

Longissim us capitis

C7 spinal nerve

Levator scapulae

C6 vertebra

Trapezius

Spinal cord

Serratus posterior superior Splenius cervicis

C7, vertebral arc

Nuchal ligam ent

Sem ispinalis cervicis

Rhom boid m inor

Fig. 14.20 Transve rse se ction throug h the C6 ve rtebral body Inferior view. The piriform recess can be identi ed at this level, and the vertebral artery is visible in it s course along the vertebral body. The vagus nerve (CN X) lies in a posterior angle bet ween the com m on carotid artery and internal jugular vein within the carotid sheath. The phrenic nerve, which arises from the anterior ram i of cervical spinal nerves C3– C5, lies on the anterior scalene m uscle on the left side.

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Transverse Sections of the Neck (II): Caudal

Arytenoid cartilage

Thyroid cartilage Sternohyoid

Superior thyroid vein

Thyrohyoid

Laryngopharynx

Om ohyoid

Com mon carotid artery, internal jugular vein, and vagus nerve (CN X) in carotid sheath

Thyroid gland Sternocleidom astoid

Longus colli

Anterior scalene with C5 spinal nerve

C4 spinal nerve

Vertebral vein Middle scalene C6 spinal nerve and C6 vertebra

Vertebral artery Posterior scalene

C7 spinal nerve and C7 vertebra Levator scapulae

T1, vertebral arch Trapezius

Fig. 14.21 Transve rse se ction at the level of the C6 ve rtebral body Inferior view. This cross section passes through the base of the arytenoid cartilage in the larynx. The hypopharynx appears as a narrow transverse cleft behind the larynx.

Sem ispinalis cervicis

Splenius cervicis

Thyroid cartilage Rim a glot tidis

Sternohyoid

Lam ina of cricoid cartilage

Thyrohyoid Superior thyroid artery

Laryngopharynx

Sternocleidom astoid

Com m on carotid artery, internal jugular vein, and vagus nerve (CN X)

Thyroid gland

C6 vertebra External jugular vein Vertebral artery and vein

C5 spinal nerve C6 spinal nerve

Middle scalene

C7 spinal nerve and C7 vertebra

Posterior scalene Levator scapulae

C8 spinal nerve Trapezius

T1, vertebral arch

Fig. 14.22 Transve rse se ction at the level of the C6/C7 ve rtebral junctio n Inferior view. This cross section passes through the larynx at the level of the vocal folds. The thyroid gland appears considerably sm aller at this level than in subsequent views.

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Superior thyroid vein

Sternohyoid

Cricoid cartilage

Sternothyroid

Superior thyroid artery

Thyroid gland

Internal jugular vein, vagus nerve (CN X), and comm on carotid artery

Sternocleidom astoid

Phrenic nerve with anterior scalene

Esophagus Thyrocervical trunk

External jugular vein

Inferior thyroid artery

Anterior ram i of

C6 spinal nerve

Vertebral artery and vein

C7 spinal nerve

Middle scalene

C8 spinal nerve Intervertebral disk

Posterior scalene

T1 vertebra and spinal nerve

Second rib T2, transverse process

Fig. 14.23 Transve rse se ction at the level of the C7/T1 ve rtebral junctio n Inferior view. This cross section clearly displays the anterior and m iddle scalenes and the interval bet ween them , which is traversed by

Sternocleidom astoid

the C6–C8 root s of the brachial plexus. Note the neurovascular structures (com m on carotid artery, internal jugular vein, vagus nerve) that lie within the carotid sheath bet ween the sternocleidom astoid, anterior scalene, and thyroid gland.

Anterior jugular vein

Arch of cricoid cartilage Trachea

Com m on carotid artery, internal jugular vein, and vagus nerve (CN X)

Thyroid gland

Esophagus

Anterior scalene

Thyrocervical trunk

Omohyoid

Anterior ram i of

C6 spinal nerve

External jugular vein

C7 spinal nerve

Transverse cervical artery

C8 spinal nerve

Middle scalene Longus colli and vertebral artery

First rib T1 vertebra

Posterior scalene Second rib

Pleural dom e of left lung

Spinal cord

Serratus anterior

Third rib

Levator scapulae

Fig. 14.24 Transve rse se ction at the level of the T1/T2 ve rtebral junctio n Inferior view. Due to the curvature of the neck in this specim en, the section also cut s the intervertebral disk bet ween T1 and T2. This section includes the C6–C8 nerve root s of the brachial plexus and a sm all

section of the left pleural dom e. The proxim it y of the pulm onary apex to the brachial plexus shows why the growth of an apical lung tum or m ay dam age the brachial plexus root s. Note also the thyroid gland and it s proxim it y to the trachea and neurovascular bundle in the carotid sheath.

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Transverse MRIs of the Head Superior rectus

Ethm oid air cells

Frontal sinus

Eyeball

Lacrim al gland

Ophthalm ic vein

Temporalis

Sphenoid bone

Optic nerve (CN II)

Temporoparietalis

Sphenoid sinus and pituitary gland (hypophysis)

Internal carotid artery Dorsum sellae

Middle cerebral artery Lateral ventricle, temporal horn

Basilar artery

Pons Fourth ventricle Verm is, cerebellum

Temporal bone

Confluence of the sinuses Occipital bone with internal occipital protuberance

A Ethm oid air cells

Nasal bone

Eyeball, anterior cham ber

Lens Zygom atic bone

Eyeball Medial, superior, and lateral rectus m uscles

Optic nerve (CN II) in periorbital fat

Temporalis Tem poral lobe

Temporoparietalis

CN V2 and CN V3 anterior to internal carotid artery

Sphenoid sinus Clivus

Basilar artery and pons

Cochlea with posterior sem icircular canal

Mastoid air cells Sigm oid sinus

Internal acoustic m eatus with facial (CN VII) and vestibulocochlear (CN VIII) nerves

Uvula of verm is

Fourth ventricle Verm is, cerebellum

B

Internal occipital protuberance

Fig. 14.25 Transve rse MRIs through the orbit and e thmoid air cells Inferior view. A Superior orbit. This section dem onstrates the relationship of the front al and sphenoid sinuses to the orbit and nasal cavit y. B Section through optic nerve (CN II). The divisions of the eye can be clearly seen along with the extraocular m uscles located in the peri-

orbit al fat. The sigm oid sinus is located posterior to the m astoid air cells and lateral to the cerebellum . This section clearly displays the inter nal acoustic m eatus, which conduct s the facial (CN VII) and vestibulocochlear (CN VIII) nerves.

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Orbicularis oris

Middle nasal concha

14. Sectiona l Ana tomy of the Hea d & Neck

Nasal septum

Nasal bone

Maxilla with infraorbital canal

Levator labii superioris

Nasolacrim al duct Maxillary sinus Temporalis Medial pterygoid bet ween m edial and lateral pterygoid plates

Masseter Lateral pterygoid

Pharyngeal recess

Head (condyle), m andible

Levator and tensor veli palatini

Mandibular and auriculotemporal nerves (from CN V3 )

Internal carotid artery

Internal jugular vein with CN IX, X, and XI

Longus capitis Mastoid air cells

Vertebral artery Sigm oid sinus

Medulla oblongata Cerebellum , posterior lobe

Falx cerebri around superior sagit tal sinus

Fig. 14.26 Transverse MRI through the orbit and nasolacrimal duct Inferior view. This sect ion clearly dem onst rates t he relat ionships of t he infraorbit al canal and nasolacrim al duct to t he m axillary sinus. The m edial and lateral pterygoid plates can be seen flanking t he m edial pterygoid. The pharyngeal recess is visible, anterior to t he lon-

Occipital bone

Fourth ventricle

gus capit is. The m andibular division of t he t rigem inal nerve (CN V3 ) is lateral to t he levator and tensor veli palat ini and m edial to t he lateral pterygoid. The glossopharyngeal, vagus, and accessory spinal nerves (CN IX, X, and XI) run just anterom edial to t he internal jugular vein.

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Transverse MRIs of the Oral Cavity Maxillary sinus

Nasal concha

Orbicularis oris

Zygom atic bone

Sphenoid bone

Sphenoid sinus

Temporalis Masseter

Articular disk

Trigem inal nerve (CN V) Head (condyle), m andible

Foram en lacerum

External acoustic m eatus

Vertebral artery

Internal carotid artery

Internal jugular vein Mastoid air cells

Medulla oblongata Fourth ventricle Falx cerebri Cerebellum , posterior lobe Occipital bone

Fig. 14.27 Transverse MRI through the temporomandibular joint (TMJ) Inferior view. Note: The plane of this section is slightly higher than Fig. 14.26. It has been included here in order to show the articular disk of the TMJ and the full extent of the m andible.

Maxilla alveolar process

Orbicularis oris Levator anguli oris

Hard palate, m axilla

Facial artery Lateral and m edial pterygoids

Buccinator Temporalis

Masseter Tensor and levator veli palatini

Ram us, m andible Internal carotid artery

Parotid gland

Internal jugular vein

Retrom andibular vein Medulla oblongata and interpeduncular cistern

Mastoid air cells

Vertebral artery Anterior condylar (hypoglossal) canal

Splenius capitis Cerebellum , tonsil

Sem ispinalis capitis

Cisterna m agna

Fig. 14.28 Transverse MRI through the hard and soft palates Inferior view. This section dem onstrates the relation of the ram us of the m andible to the m uscles of m astication in the infratem poral fossa.

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Occipital bone

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Orbicularis oris

Genioglossus

Depressor anguli oris

Uvula and oropharynx

Mandible, alveolar process

Longus colli and capitis

Facial artery External carotid artery

Hyoglossus Masseter Medial pterygoid Palatine tonsils and pharyngeal m uscles Internal jugular vein and com m on carotid artery

Retrom andibular vein in parotid gland

Digastric, posterior belly

Sternocleidom astoid

Levator scapulae Axis (C2), body Splenius capitis

Longissim us cervicis

Vertebral artery

A

Sem ispinalis capitis

Spinal cord

Obliquus capitis inferior

Trapezius

Mandible Mentalis

Genioglossus

Depressor anguli oris Oropharynx Mylohyoid Hyoglossus

Laryngopharynx

Subm andibular gland

Retrom andibular vein

St ylohyoid and digastric, posterior belly External carotid artery

Epiglot tis Palatopharyngeus and m iddle pharyngeal constrictor

External jugular vein

Internal carotid artery Vertebral artery

External jugular vein C3 vertebra, body and posterior arch

Levator scapulae

Sternocleidom astoid Deep cervical veins Splenius capitis

B

Sem ispinalis capitis

Nuchal ligam ent

Fig. 14.29 Transve rse MRIs throug h the mandible Inferior view. A Section through m andibular arch. This section dem onstrates the relationship of the oropharynx to the soft palate (uvula) and

Spinalis cervicis

Trapezius

prevertebral m uscles (longus colli and capitis). The vessels of the carotid sheath are clearly visible, along with the retrom andibular vein in the parotid gland. B Section through body of m andible and hypophyarynx.

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Transverse MRIs of the Neck

Thyrohyoid and sternohyoid Epiglot tic cartilage Laryngeal vestibule

Aryepiglot tic fold Subm andibular gland

Plat ysm a

Com m on carotid artery

Inferior pharyngeal constrictor

Internal jugular vein Longus colli and capitis Sternocleidom astoid

External jugular vein

Vertebral artery

Longissim us capitis

Middle scalene

Spinalis cervicis

Levator scapulae

Splenius cervicis

Splenius capitis

Trapezius

Sem ispinalis cervicis

Sem ispinalis capitis

Fig. 14.30 Transverse MRI through the C4 vertebral body Inferior view. This section dem onstrates the aryepiglot tic fold in the laryngeal vestibule. Note the proxim it y of the prevertebral m uscles to the pharyngeal constrictors.

Thyroid cartilage

Sternohyoid and thyrohyoid

Anterior jugular veins Plat ysm a

Sternothyroid

Larynx

Thyroid gland

Internal jugular vein Com m on carotid artery

Cricoid cartilage

Scalenes Sternocleidom astoid with external jugular vein Esophagus

Levator scapulae

Vertebral artery and vein

Spinalis cervicis Sem ispinalis cervicis

C7 spinal nerve root

Splenius capitis

C6 vertebral body, C7 posterior arch

C7 spinous process

Multifidus

Fig. 14.31 Transverse MRI through the C6 vertebral body Inferior view. This section dem onstrates the cricoid and thyroid cartilage of the larynx (note the change in shape of the larynx). Due to lordosis of the cervical spine, this section includes the C6 vertebral body and the C7 spinous process with posterior arch.

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Trapezius

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Sternohyoid and sternothyroid

Trachea

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Anterior jugular vein

Thyroid gland with inferior thyroid artery

Esophagus Com m on carotid artery

Sternocleidom astoid Longus colli with vertebral artery

Internal jugular vein

Anterior scalene

External jugular vein

Middle and posterior scalene Spinal cord with C8 spinal nerve root

First rib T1, transverse process Serratus posterior superior Levator scapulae

Sem ispinalis capitis

Sem ispinalis cervicis

Fig. 14.32 Transverse MRI through the C7 vertebra Inferior view. This section dem onstrates the relationship of the trachea to the esophagus. Note the position of the carotid sheath (cont aining the com m on carotid artery, internal jugular vein, and vagus nerve

Rhom boid m inor

Splenius capitis

Trapezius

[CN X]) with respect to the thyroid gland. The C8 spinal nerve root can be seen em erging from the spinal cord. Note the rst rib and transverse process of the thoracic vertebra.

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Sagittal Sections of the Head (I): Medial

Frontal sinus

Corpus callosum

Anterior cranial fossa Olfactory bulb (CN I) Pituitary Sphenoid sinus

Clivus Transverse sinus

Choana Foram en m agnum Nasal septum

Atlas (C1), anterior and posterior arches

Hard palate, m axilla (palatine process)

Nuchal ligam ent

Soft palate

Transverse ligam ent of atlas

Nasopharynx Median atlantoaxial joint

Uvula Mandible

Axis (C2), dens C3 vertebra

Oropharynx Geniohyoid Mylohyoid Vallecula Hyoid bone

Laryngeal cartilage

Fig. 14.33 Midsag ittal se ction through the nasal se ptum Left lateral view. The anatom ical struct ures at this level can be roughly assigned to the facial skeleton or neurocranium (cranial vault). The lowest level of t he facial skeleton, is form ed by the oral oor m uscles bet ween t he hyoid bone and m andible and the overlying skin. This section also passes through the epiglot tis and the larynx below it , which are considered part of the cervical viscera. Note: The vallecula, located in the oropharynx, is bounded by the root of the tongue and the epiglot t is. The hard and soft palate with the uvula de ne the

Epiglot tis

Laryngopharynx

boundary bet ween the oral and nasal cavit ies. Posterior to the uvula is the oropharynx. The section includes the nasal septum , which divides the nasal cavit y into t wo cavities (sectioned above and in front of the sept um ) t hat com m unicate with the nasopharynx through the choanae. Posterior to t he front al sinus is the anterior cranial fossa, which is part of the neurocranium . This sect ion passes through the m edial surface of the brain (the falx cerebri has been rem oved). The cut edge of the corpus callosum , the olfactory bulb, and the pituit ary gland are also shown.

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Internal capsule

Caudate nucleus, head

14. Sectiona l Ana tomy of the Hea d & Neck

Medial segm ent of globus pallidus

Uncus

Lateral ventricle Posterior thalam ic nuclei

Oculom otor nerve (CN III) Optic nerve (CN II)

Pontocerebellar cistern

Frontal sinus

Tentorium cerebelli

Ethm oid air cells

Cerebellum Pharyngot ympanic (auditory) tube

Sphenoid sinus Middle nasal concha

Vertebral artery

Inferior nasal concha

Rectus capitis posterior m inor

Maxilla, palatine process (palatine sulcus)

Sem ispinalis capitis

Maxilla

Rectus capitis posterior m ajor

Superior labial vestibule

C2 spinal nerve

Oral cavit y Palatopharyngeus

Obliquus capitis inferior

Inferior labial vestibule

Longus capitis

Intrinsic m uscles of tongue

Splenius capitis

Mandible

C3 spinal nerve

Lingual nerve and deep lingual veins

Spinalis cervicis

Digastric, anterior belly

C4 spinal nerve

Mylohyoid Hyoid bone Epiglot tic cartilage and vallecula

Laryngopharynx

Thyroid cartilage

Fig. 14.34 Sag ittal se ction throug h the me dial orbital w all Left lateral view. This section passes through the inferior and m iddle nasal conchae within the nasal cavit y. Above the m iddle nasal concha are the ethm oid air cells. The only part s of the nasopharynx visible in this section are a sm all lum inal area and the lateral wall, which bears

Vertebral artery

C5 spinal nerve

C6 spinal nerve

C7 spinal nerve

a section of the cartilaginous portion of the pharyngot ym panic tube. The sphenoid sinus is also displayed. In the region of the cervical spine, the section cut s the vertebral artery at m ultiple levels. The lateral sites where the spinal nerves em erge from the intervertebral foram ina are clearly displayed. Note: This section is lateral to the geniohyoid.

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14. Sectiona l Ana tomy of the Hea d & Neck

Sagittal Sections of the Head (II): Lateral

Extrem e capsule

External capsule

Claustrum

Putam en

Internal capsule Dentate gyrus

Amygdala Trigem inal ganglion (of CN V) Lateral rectus

Internal carotid artery

Superior rectus

Pharyngot ympanic (auditory) tube

Frontal sinus

Posterior m eningeal artery

CN II Procerus

CN IX, X, and XI

Inferior rectus Vitreous body CN V2 in pterygopalatine fossa

CN XII Transverse sinus

Sphenoid sinus

Condylar em issary vein

Lateral pterygoid Levator veli palatini

Rectus capitis posterior m ajor

Medial pterygoid

Sem ispinalis capitis Internal carotid artery

Maxillary sinus

Obliquus capitis inferior

Palatine tonsil Orbicularis oris

Greater occipital nerve (C2)

Palatopharyngeus

Vertebral artery C3 spinal nerve

Tongue

Trapezius

Genioglossus Mylohyoid

Splenius capitis

Digastric, anterior belly Hyoid bone, lesser horn

Retropharyngeal space Subm andibular gland

Hyoid bone, greater horn

Thyroid cartilage, left lam ina

Fig. 14.35 Sag ittal se ction throug h the inne r third of the orbit Left lateral view. This section passes through the m axillary and front al sinuses while displaying one ethm oid air cell and the peripheral part of the sphenoid sinus. It passes through the m edial portion of the internal carotid artery and subm andibular gland. The pharyngeal and m asticatory m uscles are grouped about the cartilaginous part of the pharyn-

Inferior pharyngeal constrictor

Prevertebral m uscles

got ym panic tube. The eyeball and optic nerve are cut peripherally by the section, which displays relatively long segm ent s of the superior and inferior rectus m uscles. Sectioned brain structures include the external and internal capsules and the intervening put am en. The amygdala can be identi ed near the base of the brain. A section of the trigem inal ganglion appears below the cerebrum .

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Temporal bone, petrous part

Internal carotid artery

14. Sectiona l Ana tomy of the Hea d & Neck

Foot of hippocampus

Internal auditory canal Choroid plexus

Lateral rectus

Facial nerve (CN VII)

Periorbital fat Levator palpebrae superioris Frontalis

Vestibulocochlear nerve (CN VIII)

Superior rectus Vitreous body Lens Inferior oblique Orbicularis oculi, orbital and palpebral parts Lateral pterygoid, superior and inferior part s

Transverse sinus

Temporalis

Cerebellum

Levator labii superioris

Sem ispinalis capitis

Maxillary sinus

St ylopharyngeus Obliquus capitis inferior Splenius cervicis

Medial pterygoid

Splenius capitis

Buccinator

St ylohyoid

Oral vestibule

Internal jugular vein Levator scapulae

Orbicularis oris Inferior alveolar nerve, artery, and vein in m andibular canal

Lymph node Mandible, body

Mylohyoid

Plat ysm a

Subm andibular gland

Fig. 14.36 Sag ittal se ction throug h the approximate ce nte r of the o rbit Left lateral view. Due to the obliquit y of this section, the dom inant structure in the oral oor region is the m andible, whereas the oral vestibule appears as a narrow slit. The buccal and m asticatory m uscles are prom inently displayed. Much of the orbit is occupied by the eyeball,

Com m on carotid artery

which appears in longitudinal section. Aside from a few sections of the extraocular m uscles, the orbit in this plane is lled with periorbital fat. Both the internal carotid artery and the internal jugular vein are dem onstrated. Except for the foot of the hippocampus, the only visible cerebral structures are the white m at ter and cortex. The facial nerve and vestibulocochlear nerve can be identi ed in the internal auditory canal.

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14. Sectiona l Ana tomy of the Hea d & Neck

Sagittal MRIs of the Head Pituitary gland (hypophysis)

Optic nerve (CN II)

Septum pellucidum

Superior sagit tal sinus

Ethm oid air cells and sphenoid sinus

Corpus callosum

Straight sinus Fourth ventricle

Confluence of the sinuses

Frontal sinus Nasal bone

Basilar artery

Nasopharynx

Rectus capitis posterior m inor Nuchal ligam ent

Hard palate

Dens of axis (C2) and anterior arch of atlas (C1)

Tongue

C2/C3 intervertebral disk

A

Mandible, body

Internal carotid artery, syphon

Uvula

Sem ispinalis capitis

Oropharynx

Caudate nucleus, head

Thalam us Corpus callosum Superior sagit tal sinus Tentorium cerebelli Frontal sinus Confluence of the sinuses Clivus

Ethm oid air cells and sphenoid sinus

Vertebral artery

Nasopharynx Atlas (C1), posterior arch

Inferior nasal concha Hard palate

Sem ispinalis capitis

B

Sublingual gland

Uvula

Fig. 14.37 Sag ittal se ctions throug h the nasal cavity Left lateral view. A Midsagit t al section through nasal septum . B Parasagit t al section through inferior and m iddle nasal conchae. These sections dem onstrate the relationship of the nasopharynx to the oro-

Oropharynx

Longus capitis

pharynx. The optic nerve (CN II) is visible as the optic chiasm in A. The pituit ary gland (hypophysis) can be seen inferior to it, just posterior to the sphenoid sinus. The syphon of the internal carotid artery is beautifully displayed in B.

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Sectiona l Ana tomy

Basal ganglia

Thalam us

14. Sectiona l Ana tomy of the Hea d & Neck

Precentral gyrus

Roof of orbit Lateral ventricle

Corpus callosum Superior rectus

Lam bdoid suture

Optic nerve (CN II)

Tentorium cerebelli Maxillary sinus

Transverse sinus Cerebellum , anterior and posterior lobes

Medial pterygoid and levator veli palatini

Splenius capitis Levator labii superioris

Rectus capitis posterior m ajor

Maxilla, aveolar process Orbicularis oris

Sem ispinalis capitis Obliquus capitis inferior Longus capitis

Mandible, aveolar process

Internal carotid artery

Mylohyoid

Digastric, anterior belly

Hyoglossus

Middle pharyngeal constrictor

Fig. 14.38 Parasag ittal se ction throug h the orbit Left lateral view. This view exposes the superior and inferior rectus m uscles within the periorbit al fat. The course of the optic nerve (CN II) within the orbit can be seen. Note the proxim it y of the m axillary teeth to the m axillary sinus. Root s of the m axillary teeth m ay erupt into the m axillary sinus.

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Sectiona l Ana tomy

14. Sectiona l Ana tomy of the Hea d & Neck

Sagittal MRIs of the Neck Middle nasal concha

Frontal sinus

Ethm oid air cells

Sphenoid sinus

Palatine tonsil

Superior pharyngeal constrictor

Longus colli

Axis (C2), dens Nasopharynx Atlas (C1), posterior arch Orbicularis oris Suboccipital fat Hard and soft palates Oropharynx Longitudinal m uscle of tongue

Ligam entum flavum

Genioglossus and lingual septum

Nuchal ligam ent Interspinalis m uscles

Mandible

C5, vertebral body Transverse m uscle of tongue

C7, spinous process

Geniohyoid and mylohyoid

Posterior longitudinal ligam ent Esophagus and anterior longitudinal ligam ent

Hyoid bone Epiglot tis Vestibular and vocal folds of the larynx

Lam ina of cricoid cartilage

Thyroid gland

Brachiocephalic artery

Fig. 14.39 Midsag ittal se ction Left lateral view. This section illustrates the relations bet ween the nasal cavit y and ethm oid air cells. The nasal cavit y com m unicates posteriorly (via the choanae) with the nasopharynx, which is separated from the oral cavit y by the soft palate and uvula. Inferior to the uvula, the nasopharynx and oral cavit y converge in the oropharynx. Air continues

Trachea

T2 vertebral body

m ore anteriorly into the laryngopharynx and ultim ately the trachea, whereas food passes into the esophagus, posterior to the lam ina of the larynx. Note how closely opposed the esophagus is to the anterior surface of the vertebral bodies. This section also reveals the cervical vertebrae and ligam ent s.

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Superior rectus

Inferior rectus

Lateral pterygoid

Medial pterygoid

14. Sectiona l Ana tomy of the Hea d & Neck

Internal carotid artery

Internal jugular vein

Atlas (C1), transverse process

Rectus capitis posterior m inor Optic nerve (CN II)

Rectus capitis posterior m ajor

Maxillary sinus Obliquus capitis Buccinator Sem ispinalis capitis St ylohyoid

Levator scapulae

Digastric, posterior belly

External carotid artery

Mandible

Sem ispinalis cervicis

Facial vein Splenius capitis

Subm andibular gland External jugular vein

Posterior scalene

Com m on carotid artery Internal jugular vein

Brachial plexus

Sternocleidom astoid

Trapezius

Middle scalene Rhom boids m ajor and m inor

Clavicle

Left subclavian vein

Left subclavian artery

Left lung

Interspinalis m uscle

Multifidus

Fig. 14.40 Sag ittal se ction throug h carotid bifurcation Left lateral view. This section shows the com m on and external carotid arteries, as well as the internal and external jugular veins. The cranio vertebral joint m uscles are visible along with the nuchal m uscles. Note the position of the brachial plexus bet ween the m edial and posterior scalenes. The extent of the subm andibular gland can be appreciated in this view.

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Rest of Body Anatomy 15

Re st o f Body Anatomy Upper Limb Clavicle & Scapula Humerus & Glenohumeral Joint Bones of Forearm, Wrist, & Hand Muscles of the Shoulder (I) Muscles of the Shoulder (II) & Arm Muscles of the Forearm Muscles of the Wrist & Hand Arteries & Veins of the Upper Limb Brachial Plexus Thorax Thoracic Skeleton Muscles & Neurovascular Topography of the Thoracic Wall Female Breast Diaphragm Neurovasculature of the Diaphragm Divisions of the Thoracic Cavit y & Lymphatics Thoracic Vasculature Nerves of the Thoracic Cavit y Mediastinum : Overview Mediastinum : Structures Heart: Surfaces & Chambers Heart: Valves, Arteries, & Veins

384 386 388 390 392 394 396 398 400

402 404 406 408 410 412 414 416 418 420 422 424

Heart: Conduction & Innervation Pre- & Postnatal Circulation Esophagus Pleura Lungs in situ Pulmonary Arteries & Veins Abdomen Surface Anatomy & Muscles of the Abdominal Wall Arteries of the Abdom inal Wall & Abdomen Divisions of the Abdominopelvic Cavit y Peritoneal Cavit y, Greater Sac, & Mesenteries (I) Stomach & Om ental Bursa Mesenteries (II) & Bowel Liver, Gallbladder, & Biliary Tract Abdominal Aorta & Celiac Trunk Superior & Inferior Mesenteric Arteries Veins of the Abdomen Interior Vena Cava & Inferior Mesenteric Veins Autonomic Plexuses & Sectional Anatomy of the Abdomen Pelvis Pelvic Girdle & Ligaments of the Pelvis Contents of the Pelvis Arteries & Veins of the Pelvis

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426 428 430 432 434 436

438 440 442 444 446 448 450 452 454 456 458 460

462 464 466

Rest of Body Ana tomy

15. Rest of Body Ana tomy

Clavicle & Scapula

Conoid tubercle

Acrom ial end

Sternal articular surface Shaft of clavicle

A

Sternal end

Sternal end

Acrom ial articular surface

Impression for costoclavicular ligam ent

Acrom ial end

B

Groove for subclavius m uscle

Conoid tubercle

Fig. 15.1 Clavicle Right clavicle. A Superior view; B inferior view. The S-shaped clavicle is visible and palpable along its entire length. Its medial end articulates with the sternum at the sternoclavicular joint. Its lateral end articulates with the scapula at the acromioclavicular joint. The clavicle and scapula connect the bones of the upper limb to the thoracic cage.

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Acrom ion

Coracoid process

Scapular notch

Superior border

15. Rest of Body Ana tomy

Superior angle Subscapular fossa

Supraglenoid tubercle Glenoid cavit y Acrom ion

Infraglenoid tubercle

Superior angle Neck

Coracoid process

Medial border

Lateral border

Supraglenoid tubercle

Glenoid cavit y

Infraglenoid tubercle

A

Lateral border

Inferior angle Posterior surface

Superior angle

Superior border

Scapular notch

Scapular spine

Costal surface

Coracoid process

Acrom ion Supraspinous fossa

B

Inferior angle

Acrom ial angle Glenoid cavit y Infraglenoid tubercle

Medial border

Infraspinous fossa

Lateral border

C

Fig. 15.2 Scapula Right scapula. A Anterior view; B right lateral view; C posterior view. In its normal anatomic position, the scapula extends from the 2nd to the 7th rib.

Inferior angle

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15. Rest of Body Ana tomy

Humerus & Glenohumeral Joint

Greater Intertubercular Lesser tubercle groove tubercle

Greater tubercle

Head of hum erus Head of hum erus

Anatom ic neck

Anatom ic neck

Surgical neck

Surgical neck Crest of lesser tubercle Crest of greater tubercle

Radial groove (for radial nerve)

Deltoid tuberosit y

Shaft of hum erus, posterior surface

Anterolateral surface

Medial border

Anterom edial surface

Lateral supracondylar ridge

Lateral supracondylar ridge

Medial supracondylar ridge

Medial supracondylar ridge Radial fossa

Coronoid fossa Medial epicondyle

Medial epicondyle

Ulnar groove (for ulnar nerve)

Lateral Capitullum Trochlea epicondyle A

Lateral border

Condyle of humerus

B

Fig. 15.3 Humerus Right humerus. A Anterior view. B Posterior view. The head of the humerus articulates with the scapula at the glenohu-

Olecranon Trochlea fossa

Lateral epicondyle

meral joint. The capitullum and trochlea of the humerus articulate with the radius and ulna, respectively, at the elbow (cubital) joint.

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Coracoid process

Supraglenoid tubercle

Clavicle

15. Rest of Body Ana tomy

Scapular notch

Acrom ion Head of hum erus Lesser tubercle Greater tubercle

Glenoid cavit y Intertubercular groove Infraglenoid tubercle

A

Lateral border of scapula Scapular notch

Scapular spine

Clavicle

Acrom ion Head of hum erus Greater tubercle

Anatom ic neck Infraspinous fossa

Hum erus

B

Fig. 15.4 Glenohumeral joint: Bony elements Right shoulder. A Anterior view. B Posterior view.

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15. Rest of Body Ana tomy

Bones of Forearm, Wrist, & Hand

Axis of pronation/ supination

Axis of pronation/ supination

Radial collateral ligam ent

Radial collateral ligam ent

Olecranon

Trochlear notch

Coronoid process

Articular fovea

Ulnar collateral ligam ent

Annular ligam ent

Ulnar tuberosit y

Radial tuberosit y

Annular lig.

Proxim al radioulnar joint

Neck of radius Radial tuberosit y

Ulnar tuberosit y

Oblique cord

Anterior border

Shaft of ulna Interosseous border of ulna Interosseous border of ulna

Interosseous border of radius

Interosseous border Interosseous m em brane

Interosseous m em brane

Lateral surface Posterior border Posterior surface

Dorsal radioulnar ligam ent

Head of ulna Palm ar radioulnar ligam ent A

St yloid process of radius

St yloid process of ulna

Dorsal tubercle

Head of ulna St yloid process of ulna B

Fig. 15.5 Radius and Ulna Right forearm, anterior view. A Supination. B Pronation.

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Distal radioulnar joint

Radius

Rest of Body Ana tomy

Fig. 15.6 Elbow (cubital) joint Right limb. The elbow consists of three articulations bet ween the humerus, ulna, and radius: the humeroulnar, humeroradial, and proximal radioulnar joints.

Hum erus

Radial tuberosit y

Radius

15. Rest of Body Ana tomy

Head of radius

Medial supracondylar ridge Capitellum Medial epicondyle Olecranon process

Ulna

Coronoid process

Trochlea Tuberosit y of distal phalanx Head Shaft

Middle phalanx

Base

Distal phalanx

Proxim al phalanx

Head Sesam oid bones Metacarpal

Shaft

Base Trapezoid

Hook of ham ate

Tubercle of trapezium

Pisiform Triquetrum

Capitate

Lunate

Ulna

Tubercle of scaphoid

St yloid process

St yloid process of radius

Head

Radius

Fig. 15.7 Hand Right hand, palmar view.

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15. Rest of Body Ana tomy

Muscles of the Shoulder (I)

Acrom ion

Coracoid process

Scapular Supra- Superior notch spinatus border Superior angle

Greater tubercle Lesser tubercle Intertubercular groove Medial border Crest of greater tubercle

Subscapularis

Crest of lesser tubercle

Supraspinatus

Shaft of humerus

Scapular spine

Coracoid process

Acrom ion

Superior angle A

Inferior angle

Greater tubercle

Medial border

Infraspinatus Lateral border B

Fig. 15.8 Serratus anterior Right shoulder. A Anterior view. B Posterior view. The rotator cuff consists of four muscles: supraspinatus, infraspinatus, teres minor, and subscapularis.

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Inferior angle

Teres m inor

Shaft of hum erus

Rest of Body Ana tomy

Clavicle

15. Rest of Body Ana tomy

1st rib

Acrom ion Coracoid process

Subclavius

Pectoralis minor

3rd through 5th ribs Coracoid process Acrom ion 1st rib Glenoid cavit y Medial border Scapula

Fig. 15.9 Subclavius and pectoralis minor Right side, anterior view.

Serratus anterior Inferior angle

9th rib

Fig. 15.10 Serratus anterior Right lateral view.

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15. Rest of Body Ana tomy

Muscles of the Shoulder (II) & Arm

Acrom ion

Pectoralis m ajor, clavicular part Clavicle

Coracoid process

Lesser tubercle Intertubercular groove

Pectoralis m ajor, sternocostal part

Crest of greater tubercle

Sternum

Coracobrachialis

Pectoralis m ajor, abdominal part Hum erus

Fig. 15.11 Pectoralis major and coracobrachialis Anterior view.

Acromion Scapular spine

Clavicle

Deltoid, clavicular part

Deltoid, acromial part Deltoid, spinal part Scapula

Shaft of hum erus

Fig. 15.12 Deltoid Right shoulder, right lateral view.

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Deltoid tuberosit y

Rest of Body Ana tomy

Supraglenoid tubercle

Coracoid process

15. Rest of Body Ana tomy

Scapula, anterior surface

Greater tubercle Lesser tubercle Intertubercular groove

Biceps brachii, long head

Biceps brachii, short head

Scapula, posterior surface

Scapular spine

Acrom ion

Greater tubercle

Biceps brachii

Infraglenoid tubercle

Brachialis

Shaft of hum erus Triceps brachii, m edial head

Lateral border Bicipital aponeurosis Radial tuberosit y, biceps brachii tendon of insertion

Triceps brachii, long head

Triceps brachii, lateral head

Ulnar tuberosit y, brachialis tendon of insertion

Fig. 15.13 Right shoulder, right lateral view. Right arm, anterior view.

Medial epicondyle

Lateral epicondyle

Olecranon

Anconeus

Ulna

Radius

Fig. 15.14 Triceps brachii and anconeus Right arm, posterior view.

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15. Rest of Body Ana tomy

Muscles of the Forearm

Humerus Brachioradialis

Lateral epicondyle

Medial epicondyle Olecranon

Extensor carpi radialis longus Ulna

Lateral epicondyle

Olecranon

Com m on head of extensor digitorum , extensor digiti m inim i, and extensor carpi ulnaris

Extensor carpi radialis brevis

Ulna

Extensor carpi ulnaris

Radius Interosseous m embrane

Base of 3rd m etacarpal

Lateral epicondyle

Ulnar groove

Olecranon

Extensor digitorum

Brachioradialis tendon of insertion St yloid process of radius

Medial epicondyle

Supinator Ulna

Extensor digiti m inim i

Posterior border of ulna

Radius

Base of 2nd metacarpal

Radius Abductor pollicis longus

Shaft of 2nd metacarpal

Extensor pollicis longus

A Base of 5th m etacarpal

Extensor pollicis brevis Extensor indicis

5th proxim al phalanx, base

Dorsal digital expansion, intertendinous connections 2nd m etacarpal

B

Dorsal tubercle Base of 1st m etacarpal 1st m etacarpal 1st proxim al phalanx, base 1st distal phalanx, base

Fig. 15.15 Muscles of the posterior compartment of the forearm Right forearm , posterior view. A, B Superficial extensors. C Deep extensors with supinator.

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C

Rest of Body Ana tomy

15. Rest of Body Ana tomy

Medial epicondyle

Medial epicondyle, com m on head of flexors

Coronoid process

Radial tuberosit y Pronator teres Flexor carpi radialis

Radial tuberosit y

Ulnar tuberosit y

Interosseous m em brane

Palm aris longus Flexor carpi ulnaris

Radius Flexor digitorum profundus

Flexor pollicis longus

Flexor digitorum superficialis Pronator quadratus Base of 2nd m etacarpal

Pisiform bone Hook of ham ate

Tubercle of trapezium Trapezium

Base of 5th m etacarpal

Pisiform bone Hook of ham ate

Palm ar aponeurosis

2nd through 5th m iddle phalanges

1st distal Base of phalanx

4th distal phalanx B

A

Fig. 15.16 Muscles of the anterior compartment of the forearm Right forearm, anterior view.

A Superficial and intermediate muscles. B Deep muscles.

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15. Rest of Body Ana tomy

Muscles of the Wrist & Hand

5th proxim al phalanx

1st proxim al phalanx Transverse head Oblique head

5th m etacarpal Abductor digiti m inim i

Adductor pollicis

Abductor pollicis brevis

Opponens digiti m inim i Hook of ham ate (under tendon) Pisiform (under tendon)

Capitate (under tendon) Trapezium (under tendon) Scaphoid

A

5th proxim al phalanx

Flexor digiti m inim i brevis Hook of ham ate (under tendon)

Fig. 15.17 Thenar and hypothenar muscles Right hand, palmar (anterior) view. A Removed: Flexor pollicis brevis, opponens pollicis, and flexor digiti minimi brevis. B Removed: Adductor pollicis, abductor pollicis brevis, abductor digiti minimi, and opponens digiti minim i.

1st proxim al phalanx Flexor pollicis brevis Opponens pollicis Capitate (under tendon) Trapezium (under tendon)

B

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15. Rest of Body Ana tomy

2nd distal phalanx, base

2nd proxim al phalanx

2nd m etacarpal 1st lum brical 2nd lum brical 3rd lum brical (often arises by t wo heads) 4th lum brical (often arises by t wo heads)

Hook of ham ate

Trapezoid

Pisiform

Radius

Ulna

A

2nd through 5th proxim al phalanges

3rd dorsal interosseus

2nd dorsal interosseus

4th dorsal interosseus

1st dorsal interosseus

2nd through 5th m etacarpals

1st m etacarpal

Flexor digitorum profundus tendons

B

1st palm ar interosseus 2nd palm ar interosseus 3rd palm ar interosseus 2nd through 5th m etacarpals

C

Fig. 15.18 Metacarpal muscles Right hand, palm ar (anterior) view. A Lum brical muscles. B Dorsal interosseus muscles. C Palmar interosseus m uscles.

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15. Rest of Body Ana tomy

Arteries & Veins of the Upper Limb

Subclavian artery Brachiocephalic trunk

Vertebral artery

Axillary artery Subclavian artery

Thyrocervical trunk

Suprascapular artery

Comm on carotid artery

Axillary artery Brachial artery

Thoracoacromial artery

Acromial branch

Left subclavian artery Brachiocephalic trunk

Deltoid branch Pectoral branch

Superior thoracic artery Thoracic aorta

Anterior and posterior circum flex hum eral arteries

Ulnar artery Radial artery

Internal thoracic artery Circum flex scapular artery

Deep artery of arm

Thoracodorsal artery

Brachial artery

Lateral thoracic artery Radial collateral artery

A

Middle collateral artery Radial recurrent artery

Superior and inferior ulnar collateral arteries Ulnar recurrent artery Com mon interosseous artery

Posterior interosseous artery

Radial artery

Anterior interosseous artery Ulnar artery Superficial palm ar branch (radial artery)

Deep palm ar arch Superficial palmar arch Com mon palmar digital arteries

Palm ar digital arteries

B

Fig. 15.19 Arteries of the upper limb Right limb, anterior view. A Main arterial segments. B Course of the arteries.

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Subscapular artery

Rest of Body Ana tomy

15. Rest of Body Ana tomy

Subclavian vein

Deltopectoral groove

Axillary vein

Cephalic vein

Thoracoepigastric vein

Basilic hiatus

Thoracodorsal vein

Basilic vein

Brachial veins

Median cubital vein Median antebrachial vein

Median basilic vein

Cephalic vein

Anterior interosseous veins

Perforator veins

Ulnar veins

Radial veins

Superficial palm ar venous arch

Deep palm ar venous arch Palm ar m etacarpal veins

Intercapitular veins

Palm ar digital veins A

B

Fig. 15.20 Veins of the upper limb Right lim b, anterior view. A Superficial veins. B Deep veins.

Cephalic vein

Median antebrachial vein

A

Basilic vein Median cephalic vein Median cubital vein Deep m edian cubital vein Basilic vein

Cephalic vein Accessory cephalic vein

Median cubital vein

Perforator vein

Median basilic vein

Median basilic vein

Cephalic vein

Basilic vein

Basilic vein

B

Median antebrachial vein

Median antebrachial vein

Median cephalic vein

C

Fig. 15.21 Veins of the cubital fossa Right lim b, anterior view. The subcutaneous veins of the cubital fossa have a highly variable course. A M-shaped. B With accessory cephalic vein. C Without median cubital vein.

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Brachial Plexus Alm ost all muscles in the upper lim b are innervated by the brachial plexus, which arises from spinal cord segm ents C5 to T1. The anterior ram i of the spinal nerves give off direct branches (supraclavicular part of the brachial plexus) and merge to form three trunks, six divisions

(three anterior and three posterior), and three cords. The infraclavicular part of the brachial plexus consists of short branches that arise directly from the cords and long (terminal) branches that traverse the limb.

Dorsal scapular nerve Suprascapular nerve

Ta ble 15.1 Nerves of the brachial plexus C5

Posterior cord Lateral cord

Supraclavicular part Direct branches from the anterior rami or plexus trunks

Medial cord

T1

Subscapular nerve

Phrenic nerve

Axillary artery Nerve to the subclavius

Axillary nerve

Long thoracic nerve Musculocutaneous nerve

Dorsal scapular n.

C4–C5

Suprascapular n.

C4–C6

N. to the subclavius

C5–C6

Long thoracic n.

C5–C7

Infraclavicular part Short and long branches from the plexus cords Lateral pectoral n. Lateral cord

Median n.

Medial brachial cutaneous nerve Medial and lateral pectoral nerves

Median nerve Radial nerve Radial nerve

Deep branch

Superficial branch

Musculocutaneous n.

Medial cord

Ulnar nerve Posterior cord

Medial brachial cutaneous n.

T1

Ulnar n.

C7–T1

Upper subscapular n.

C5–C6

Thoracodorsal n.

C6–C8

Lower subscapular n.

Radial n.

Fig. 15.22 Brachial plexus and its branches in the upper limb Right side, anterior view.

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C8–T1

Medial antebrachial cutaneous n.

Axillary n.

Anterior interosseous nerve

C6–C7

Medial root

Medial pectoral n.

Thoracodorsal nerve

400

Lateral root

C5–C7

C5–C6 C5–T1

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Posterior (dorsal) root

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Anterior (ventral) root

Posterior (dorsal) ram i

Lateral cord

C6

Upper trunk (C5–C6)

Medial cord

Axillary artery Musculocutaneous nerve

C5

Anterior (ventral) rami

Posterior cord

Lateral root Medial root

Axillary nerve

Median nerve

Ulnar nerve

C7

Middle trunk (C7) C8

Lower trunk (C8–T1)

Radial nerve

Median nerve

B T1 Anterior divisions of C5–C7

Posterior divisions of C5–T1

Lateral cord

Anterior division of C8–T1

Posterior cord Medial cord

Axillary nerve

Axillary artery C5 spinal nerve Ulnar nerve Union of m edian nerve roots

Musculocutaneous nerve Radial nerve

Middle scalene Dorsal scapular nerve

Median nerve

Phrenic nerve Anterior scalene

Upper trunk

A

Middle trunk Suprascapular nerve

Vertebra prom inens (C7) C8 spinal nerve

Lower trunk Interscalene space

T1 spinal nerve Com m on carotid artery

Posterior cord

Subclavian artery

Lateral cord

Brachiocephalic trunk

Subscapular nerve

Nerve to the subclavius

Medial cord

1st rib Long thoracic nerve

Axillary artery Axillary nerve

Intercostobrachial nerve

Posterior circum flex hum eral artery Musculocutaneous nerve

Medial brachial cutaneous nerve Medial pectoral nerve

Radial nerve Median nerve

C

Medial antebrachial cutaneous nerve

Ulnar nerve

Thoracodorsal Lateral nerve pectoral nerve

Fig. 15.23 Brachial plexus Right side, anterior view. A Structure of the brachial plexus. B Division of the cords into term inal branches. C Course of the brachial plexus, stretched for clarit y

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Thoracic Skeleton

Clavicular notch

Superior thoracic aperture Jugular notch Manubrium Sternal angle

Sternum

Body Xiphoid process

Costal cartilage

Costal m argin (arch)

1st rib Clavicular notch

Inferior thoracic aperture

A

T1 vertebral body Spinous process

Sternum

Intervertebral disk

T1 spinous process

Costal cartilage

Costal tubercle

Costal m argin (arch) B

Costal angle Transverse process Costotransverse joint

T12 spinous process C

12th rib

L1 spinous process

Fig. 15.24 Thoracic skeleton A Anterior view. B Left lateral view. C Posterior view.

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T12 vertebral body 12th rib L1 vertebral body

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Costal angle

Spinous process

Transverse process

Vertebral foram en

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Costal tubercle

Neck of rib Vertebral body

Head of rib

Body (shaft) of rib

Costal tubercle

Costal angle

Crest of neck Neck

Costal cartilage

Head Costal tubercle Crest of neck

Sternum

Fig. 15.25 Structure of a thoracic segment Superior view of 6th rib pair.

Head Tuberosit y for serratus anterior

Neck Costal angle

Head

2nd rib

Body (shaft)

11th rib

5th rib

Fig. 15.26 Ribs Right ribs, superior view.

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Muscles & Neurovascular Topography of the Thoracic Wall Atlas (C1)

Fig. 15.27 Muscles of the thoracic w all Anterior view. The external intercostal muscles are replaced anteriorly by the external intercostal mem brane. The internal intercostal muscles are replaced posteriorly by the internal intercostal membrane (removed in Fig. 15.28).

Axis (C2)

Anterior longitudinal ligam ent

Posterior scalene Middle scalene Anterior scalene

1st rib Manubrium

External intercostal m uscles

Radiate sternocostal ligam ents

External intercostal m em brane

Internal intercostal m uscles Sternum External intercostal m uscles

Costal cartilage

Anterior longitudinal ligam ent

Posterior scalene Middle scalene Anterior scalene Innerm ost intercostal m uscles Manubrium

Internal intercostal m uscles

External intercostal m uscles

Transversus thoracis

Internal intercostal m uscles

Xiphoid process Costal cartilage

Fig. 15.28 Transversus thoracis Anterior view with thoracic cage opened to expose posterior surface of anterior wall.

Subcostal m uscles Chondro-osseous junction

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Lateral thoracic artery and vein

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Cephalic vein Thoracoepigastric vein

Internal thoracic artery and vein Intercostal vein, artery, and nerve

Superior epigastric artery and vein Rectus sheath, posterior layer Internal oblique Rectus abdom inis Um bilicus

External oblique

Arcuate line

Transversus abdominis

Superficial epigastric vein

Inferior epigastric artery and vein

Inguinal ligament

Transversalis fascia Superficial circum flex iliac artery and vein

Superficial epigastric artery and vein Great saphenous vein

Fascia lata

Fig. 15.29 Neurovascular structures on the anterior side of the anterior trunk w all Anterior view. The superficial (subcutaneous) neurovascular structures are demonstrated on the left side of the trunk and the deep neurovascular structures on the right side. Removed on right side: pectoralis major and minor, external and internal

obliques (partially rem oved), rectus abdominus (partially rem oved or rendered transparent). The intercostal spaces have been exposed to display the course of the intercostal vessels and nerves. Note: The intercostal vessels run in the costal groove. From superior to inferior they are vein, artery, and nerve.

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Female Breast The female breast, a modified sweat gland in the subcutaneous tissue layer, consists of glandular tissue, fibrous stroma, and fat. The breast extends from the 2nd to the 6th rib and is loosely at tached to the pec-

toral, axillary, and superficial abdominal fascia by connective tissue. The breast is additionally supported by suspensory ligam ents. An extension of the breast tissue into the axilla, the axillary tail, is often present.

Nipple Areola Areolar glands

Fig. 15.30 Female breast Right breast, anterior view.

Subclavian artery and vein Axillary artery and vein

Fig. 15.31 Mammary ridges Rudimentary mammary glands form in both sexes along the mammary ridges. Occasionally, these may persist in humans to form accessory nipples (polythelia), although only the thoracic pair normally remains.

Internal thoracic artery and vein Lateral thoracic artery and vein Medial m amm ary branches

Perforating branches

Lateral m amm ary branches Mam m ary branches

Fig. 15.32 Blood supply to the breast Supraclavicular nerves

Intercostal nerves, m edial m am m ary branches Intercostal nerves, lateral m am m ary branches

Fig. 15.33 Sensory innervation of the breast

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Pectoral fascia

Suspensory (Cooper’s) ligam ent s Pectoralis m inor

Mam m ary lobes

Intercostal m uscles

Nipple Pectoralis m ajor Lactiferous sinus

Intercostal vein, artery, and nerve

Lactiferous duct

Superficial thoracic fascia

Interlobular connective tissue B

A

Mam m ary lobes

Lobules Level II

Lactiferous duct

Level I

Lactiferous sinus

Acini

C

Level III

Interpectoral axillary lymph node Parasternal lymph node

Term inal duct Term inal duct lobular unit (TDLU)

Fig. 15.34 Structures of the breast A Sagit tal section along midclavicular line. B Duct system and portions of a lobe, sagit tal section. In the nonlactating breast (shown here), the lobules contain clusters of rudim entary acini. C Terminal duct lobular unit (TDLU). The clustered acini composing the lobule empt y into a terminal ductule; these structures are collectively known as the TDLU. The glandular tissue is composed of 10 to 20 individual lobes, each with its own lactiferous duct. The gland ducts open on the elevated nipple at the center of the pigm ented areola. Just proximal to the duct opening is a dilated portion called the lactiferous sinus. Areolar elevations are the openings of the areolar glands (sebaceous). The glands and lactiferous ducts are surrounded by firm , fibrofat t y tissue with a rich blood supply. The most comm on t ype of breast cancer, invasive ductal carcinoma, arises from the lining of the lactiferous ducts. Typically it m etastasizes through lymphatic channels, m ost abundantly to axillary nodes, but it may also travel to supraclavicular nodes, the contralateral breast and the abdomen. Obstruction of the lymphatic drainage and fibrosis (shortening) of the suspensory ligaments can cause a leathery (peau d’ orange) and dimpled appearance of the skin. Because the intercostal veins that drain the breast communicate with the azygos system and through that the vertebral venous plexus, breast cancer can spread to the vertebrae, cranium and brain. Elevation of the breast with contraction of the pectoralis major m uscle suggests invasion of the retrom amm ary space.

Fig. 15.35 Lymphatic drainage of the breast The lymphatic vessels of the breast (not shown) are divided into three system s: superficial, subcutaneous, and deep. These drain prim arily into the axillary lymph nodes, which are classified based on their relationship to the pectoralis muscle as Levels I, II, and III. Level I is lateral to pectoralis major; Level II is along this muscle; Level III is m edial to it. The m edial portion of the breast is drained by the parasternal lymph nodes, which are associated with the internal thoracic vessels.

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Diaphragm

Clavicle

Scapula

Sternum Caval opening Central tendon Diaphragm , right dom e

Diaphragm , left dom e Xiphoid process

12th rib

L1, transverse process

10th rib

Lum bocostal triangle

Aortic hiatus Right crus

A

L1, transverse process

B

Left crus

Caval opening

Esophageal hiatus

Central tendon

Right dom e

Left dom e

Median arcuate ligam ent Right crus

Fig. 15.36 Diaphragm A Anterior view. B Posterior view. C Coronal section with diaphragm in intermediate position. The diaphragm , which separates the thorax from the abdomen, has t wo asymmetric dom es and three apertures (for the aorta, vena cava, and esophagus; see C).

Lateral arcuate ligam ent

Aortic hiatus

Quadratus lum borum

Transversus abdom inis

Psoas m ajor C

Psoas m inor

Medial arcuate ligam ent

Table 15.2 Diaphragm Muscle

Origin Costal part

Diaphragm

Lum bar part

Insertion

Action

Phrenic n. (C3–C5, cervical plexus)

Principal muscle of respiration (diaphragmatic and thoracic breathing); aids in compressing abdom inal viscera (abdominal press)

7th to 12th ribs (inner surface; lower m argin of costal arch) Medial part: L1–L3 vertebral bodies, intervertebral disks, and anterior longitudinal ligam ent as right and left crura

Central tendon

Lateral parts: lateral and medial arcuate ligam ent s Sternal part

Innervation

Xiphoid process (posterior surface)

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Right superior phrenic artery

Costal groove

Intercostal nerve, collateral branch

Latissim us dorsi

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Intrinsic back m uscles

Intercostal vein, posterior (dorsal) branch

External intercostal m uscles

Spinal cord (with spinal ganglion)

Internal intercostal m uscles

Intercostal nerves, anterior (ventral) ram i

Innerm ost intercostal m uscles

Posterior intercostal arteries and veins

Endothoracic fascia

Azygos vein Thoracic aorta

Central tendon

Esophagus

Serratus anterior

Inferior vena cava

Diaphragm

Phrenic nerve, pericardiacophrenic artery and vein Pericardium

Parietal pleura, costal part

Musculophrenic artery (from internal thoracic artery) Internal thoracic artery and vein

Intercostal nerve, lateral cutaneous branch

Anterior perforating branch Sternum

External oblique

Intercostal nerve, anterior cutaneous branch

Fig. 15.37 Thoracic section Transverse section, anterosuperior view.

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Neurovasculature of the Diaphragm

Inferior thyroid vein

Com m on carotid artery Left internal jugular vein Left external jugular vein Left subclavian artery and vein Left brachiocephalic vein Left phrenic nerve

Superior vena cava Internal thoracic artery

Posterior intercostal veins Azygos vein Pericardiacophrenic artery Hem iazygos vein Musculophrenic artery Left phrenic nerve

Superior phrenic arteries

Inferior phrenic arteries Celiac trunk

Inferior vena cava

Fig. 15.38 Neurovasculature of the diaphragm Anterior view of opened thoracic cage. C3 C4 C5 Anterior scalene

Left phrenic nerve

Rib From parietal pleura, mediastinal part Intercostal m uscles

Pericardial branches From parietal pleura, diaphragmatic part Intercostal nerves

Fig. 15.39 Innervation of the diaphragm Anterior view. The phrenic nerves lie on the lateral surfaces of the fibrous pericardium together with the pericardiacophrenic arteries and veins. Note: The phrenic nerves also innervate the pericardium.

Diaphragm

Efferent fibers

Afferent fibers

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Ta ble 15.3 Blood vessels of the diaphragm Artery

Origin

Vein

Drainage

Inferior phrenic aa. (chief blood supply)

Abdom inal aorta; occasionally from celiac trunk

Inferior phrenic vv.

Inferior vena cava

Superior phrenic aa.

Thoracic aorta

Superior phrenic vv.

Azygos v. (right side), hemiazygos v. (left side)

Pericardiacophrenic vv.

Internal thoracic vv. or brachiocephalic vv.

Musculophrenic vv.

Internal thoracic vv.

Pericardiacophrenic aa.

Internal thoracic aa.

Musculophrenic aa.

Spinal cord Thoracic aorta

Sym pathetic trunk

Hem iazygos vein Intercostal nerve Parietal pleura, costal part

Azygos vein

Parietal pleura, diaphragm atic part Left superior phrenic artery (from thoracic aorta)

Right superior phrenic artery

Parietal pleura, mediastinal part Inferior vena cava

Esophagus Phrenic nerve, pericardiacophrenic artery and vein

Parietal pleura, costal part

A

Pericardium

Musculophrenic artery (from internal thoracic artery)

Internal thoracic artery and veins Sternum

Rectus abdom inis

Diaphragm , central tendon

Diaphragm , costal part

Left phrenic nerve

Caval opening

Esophageal hiatus

Right phrenic nerve

Celiac trunk

Right inferior phrenic artery

Left inferior phrenic artery

Right superior suprarenal artery

Left superior suprarenal artery

Com m on hepatic artery

Splenic artery

External and internal oblique m uscles, tranversus abdom inis

Greater splanchnic nerve

Diaphragm , lum bar part

B

Left ascending lum bar vein Quadratus lum borum

Psoas m ajor

Abdom inal aorta

Spinal cord

Lum bar vertebra

Intrinsic back m uscles

Fig. 15.40 Arteries and nerves of the diaphragm A Superior view. B Inferior view. Removed: Parietal peritoneum. Note: The margins of the diaphragm receive sensory innervation from the lowest intercostal nerves.

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Divisions of the Thoracic Cavity & Lymphatics

Table 15.4 Major structures of the thoracic cavity Superior m ediastinum Right pleural cavit y (right lung)

Thymus, great vessels, trachea, esophagus, and thoracic duct

Superior m ediastinum

Left pleural cavit y (left lung)

Mediastinum

Inferior m ediastinum

Inferior m ediastinum

Anterior

Thymus (especially in children)

Middle

Heart, pericardium , and roots of great vessels

Posterior

Thoracic aorta, thoracic duct, esophagus, and azygos venous system

Diaphragm A

Pleural cavities

Com m on Thyroid gland, carotid artery right lobe

Thyroid cartilage

Right pleural cavit y

Right lung

Left pleural cavit y

Left lung

Left phrenic nerve

Internal jugular vein

Recurrent laryngeal nerve

Right phrenic nerve

Brachial plexus

Anterior scalene

Left vagus nerve

Trachea

Subclavian artery and vein

Right vagus nerve

Internal thoracic artery and vein

Brachiocephalic trunk

First rib Left brachiocephalic vein

Right brachiocephalic vein

Aortic arch

Superior vena cava

Left vagus nerve

Thymus

Left pulm onary artery

Pericardiacophrenic artery and vein, phrenic nerve

Parietal pleura, m ediastinal part

Left lung Right lung Fibrous pericardium

B

Pericardiacophrenic artery and vein, pericardial branches

Fig. 15.41 Thoracic cavity Coronal section, anterior view. A Divisions of the thoracic cavit y. The thoracic cavit y is divided into three large spaces, the mediastinum (p. 418) and the t wo pleural cavities (p. 432).

Phrenic nerve, pericardial branches

Parietal pleura (diaphragmatic part)

B Opened thoracic cavit y. Removed: Thoracic wall; connective tissue of anterior mediastinum

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Com m on carotid artery Internal jugular vein Jugular trunk

Jugular trunk

Subclavian artery

Thoracic duct

Right lym phatic duct Subclavian trunk Subclavian trunk Left subclavian vein

Right subclavian vein

Left brachiocephalic vein

Brachiocephalic trunk

Bronchom ediastinal trunk

Right brachiocephalic vein

Ascending aorta

Superior vena cava Bronchom ediastinal trunk

Thoracic aorta

Accessory hem iazygos vein Thoracic duct Intercostal lymphatics

Diaphragm

Azygos vein Hem iazygos vein

Aortic hiatus Celiac trunk Abdom inal aorta Cisterna chyli Left lum bar trunk Right lum bar trunk

Fig. 15.42 Lymphatic trunks in the thorax Anterior view of opened thorax. The body’s chief lymph vessel is the thoracic duct. Beginning in the abdomen at the level of L1 as the cisterna chyli, the thoracic duct empties into the junction of the left internal jugular and subclavian veins. The right lymphatic duct drains to the right junction of the internal jugular and subclavian veins.

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Thoracic Vasculature

Thyroid cartilage Right com m on carotid artery

Left com m on carotid artery

Anterior scalene

Trachea Thyrocervical trunk

Middle scalene Right vertebral artery

Left subclavian artery

Right subclavian artery

Esophagus

Internal thoracic artery

Aortic arch

1st rib Brachiocephalic trunk

Ascending aorta Bronchial artery

Right m ain bronchus Left m ain bronchus Esophageal branch Posterior intercostal arteries Descending aorta

Diaphragm

Inferior phrenic artery

Aortic hiatus

Celiac trunk Abdom inal aorta

Lum bar artery

Fig. 15.43 Thoracic aorta in situ Anterior view. Removed: Heart, lungs, and portions of the diaphragm .

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Ta ble 15.5 Thoracic tributaries of the superior vena cava Major vein

Tributaries

Region drained

Inferior thyroid v.

Esophagus, trachea, thyroid gland

Internal jugular vv. External jugular vv. Brachiocephalic vv.

Subclavian vv.

Head, neck, upper lim b

Suprem e intercostal vv. Pericardial vv. Left superior intercostal v.

Trachea, bronchi, esophagus

Visceral branches

Right internal jugular vein Right subclavian vein Right brachiocephalic vein Right pulm onary veins

Azygos system (left side: accessory hem iazygos v.; right side: azygos v.)

Left brachiocephalic vein

Posterior intercostal vv. Parietal branches

Superior phrenic vv.

Inner chest wall and diaphragm

Right superior intercostal v.

Superior vena cava

Thym ic vv.

Thymus

Left pulm onary veins

Mediastinal tributaries

Posterior m ediastinum

Anterior intercostal vv.

Anterior chest wall

Pericardiacophrenic v.

Pericardium

Musculophrenic v.

Diaphragm

Internal thoracic v.

Inferior vena cava

Note: Structures of the superior m ediastinum m ay also drain directly to the brachiocephalic veins via the tracheal, esophageal, and m ediastinal veins.

A

Right internal jugular vein

Inferior thyroid vein Left brachiocephalic vein

Right subclavian vein

Superior vena cava Azygos vein

Accessory hem iazygos vein

Posterior intercostal veins

Hem iazygos vein

Hepatic veins

Diaphragm

Left renal vein Right testicular/ ovarian vein*

Lum bar veins

Right ascending lum bar vein

Left ascending lum bar vein

Left com m on iliac vein B

Inferior vena cava

Fig. 15.44 Superior vena cava Anterior view. A Projection of venae cavae onto chest. B Veins of the thoracic cavit y.

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Nerves of the Thoracic Cavity

Right vagus nerve

Left vagus nerve

Sympathetic trunk, thoracic ganglion Right phrenic nerve

Left phrenic nerve

Posterior intercostal nerves

A Trachea Sym pathetic trunk, m iddle cervical ganglion

Esophagus, cervical part Left com m on carotid artery

Right subclavian artery

Brachial plexus

Right recurrent laryngeal nerve

Left subclavian artery

Right vagus nerve

1st rib

Brachiocephalic trunk

Left vagus nerve

Posterior intercostal artery

Left recurrent laryngeal nerve

Intercostal nerve

Aortic arch

Right m ain bronchus

Left m ain bronchus

Esophagus, thoracic part

Thoracic aorta

Sympathetic trunk Anterior vagal trunk with esophageal plexus

Sympathetic trunk

Greater splanchnic nerve Caval opening

Diaphragm

Anterior gastric plexus Stom ach

B

Fig. 15.45 Nerves in the thorax Anterior view of opened thorax. Thoracic innervation is mostly autonomic, arising from the paravertebral sympathetic trunks and parasympathetic vagus nerves. There are t wo exceptions: the phrenic nerves innervate the pericardium and diaphragm and the intercostal nerves innervate the thoracic wall.

A Thoracic innervation. B Nerves of the thorax in situ. Note: The recurrent laryngeal nerves have been slightly anteriorly retracted; normally, they occupy the groove bet ween the trachea and the esophagus, making them vulnerable during thyroid gland surgery.

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Parasympathetic nervous system

Sympathetic nervous system Superior cervical ganglion

Middle cervical ganglion

Stellate ganglion

T1

Vagus nerve (CN X)

T2 T3

Superior laryngeal nerve

Cervical cardiac nerves

T4

Larynx

T5 T6 T7 Pharyngeal plexus

T8 T9

External carotid plexus

T10 T11

Internal carotid plexus

T12

Recurrent laryngeal nerve

L1 L2

Com m on carotid plexus Esophageal plexus

Sympathetic trunk

Vertebral plexus

Greater and lesser splanchnic nerves

Subclavian plexus

Thoracic aortic plexus Pulm onary plexus Pulm onary plexus

Cardiac plexus

Cardiac branches Vagal trunks

Fig. 15.46 Sympathetic and parasympathetic nervous systems in the thorax The autonom ic nervous system innervates sm ooth muscle, cardiac muscle, and glands. It is subdivided into the sympathetic (red) and parasympathetic (blue) nervous systems, which together regulate blood flow, secretions, and organ function.

Ta ble 15.6 Peripheral sympathetic nervous system

Ta ble 15.7 Peripheral parasympathetic nervous system

Origin of preganglionic fibers*

Origin of preganglionic fibers

Ganglion cells

Course of postganglionic fibers Follow intercostal nn.

Spinal cord

Sympathetic trunk

Target

Course of preganglionic motor axons*

Blood vessels and glands in chest wall

Accompany intrathoracic aa.

Visceral targets

Gather in greater and lesser splanchnic nn.

Abdom en

* The axons of preganglionic neurons exit the spinal cord via the anterior root s and synapse with postganglionic neurons in the sympathetic ganglia.

Brainstem

Vagus n. (CN X)

Target

Cardiac branches

Cardiac plexus

Esophageal branches

Esophageal plexus

Tracheal branches

Trachea

Bronchial branches

Pulm onary plexus (bronchi, pulmonary vessels)

* The ganglion cells of the parasympathetic nervous system are scat tered in m icroscopic groups in their target organs. The vagus nerve thus carries the preganglionic m otor axons to these targets. CN, cranial nerve.

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Mediastinum: Overview The mediastinum is the space in the thorax bet ween the pleural sacs of the lungs. It is divided into t wo parts: superior and inferior. The inferior

mediastinum is further divided into anterior, middle, and posterior portions.

Ta ble 15.8 Contents of the mediastinum ● Superior mediastinum Esophagus (cervical part) Cervical part Thoracic part

Thoracic inlet Esophagus, thoracic part

A

● Middle

● Posterior

• Thym us

• Esophagus

Organs

• Heart • Pericardium

• Smaller vessels

• Ascending aorta • Pulm onary trunk and branches • Pericardiacophrenic aa.

• Thoracic aorta and branches

Arteries

• Aortic arch • Brachiocephalic trunk • Left common carotid a. • Left subclavian a.

Veins and lymph vessels

• Superior vena cava • Brachiocephalic vv. • Thoracic duct

• Smaller vessels, lymphatics, and lymph nodes

• • • •

• Azygos v. • Hemiazygos v. • Thoracic duct

• None

• Phrenic nn.

Nerves

• Vagus nn. • Left recurrent laryngeal n. • Cardiac nn. • Phrenic nn.

Superior m ediastinum Sternum

Posterior m ediastinum

● Anterior

• Thym us • Trachea • Esophagus

Trachea

Anterior m ediastinum Middle m ediastinum

Inferior mediastinum

Diaphragm

Esophageal inlet

Superior vena cava Azygos v. Pulm onary vv. Pericardiacophrenic vv.

• Vagus nn.

Thyroid cartilage

Esophagus, cervical part

Trachea Pretracheal layer Investing layer

Brachiocephalic lymph node Azygos vein

Deep cervical fascia

Left brachiocephalic vein

Left m ain bronchus, origin

Manubrium Tracheobronchial lymph node

Ascending aorta

Right pulm onary artery

Thym us (retrosternal fat pad)

Esophagus, thoracic part

Aortic valve

Left atrium

Sternum Pericardial cavit y

Superior phrenic lymph node Site of at tachm ent bet ween liver and diaphragm (bare area)

Diaphragm Liver

Xiphoid process

B

Fig. 15.47 Divisions of the mediastinum A Schematic. B Midsagit tal section, right lateral view.

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Thyroid gland, right lobe

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Thyroid cartilage

Anterior scalene Trachea Com m on carotid artery

Phrenic nerve

Vagus nerve (CN X) Left recurrent laryngeal nerve Internal thoracic artery

Inferior thyroid vein Thym us

Left vagus nerve Aorta

Superior vena cava Pericardiacophrenic artery and vein, phrenic nerve

Left recurrent laryngeal nerve Left pulm onary artery

Brachial plexus

Left internal jugular vein

Parietal pleura, m ediastinal part

Parietal pleura, diaphragm atic part

Left subclavian artery and vein

Left brachiocephalic vein

Parietal pleura, cervical part

Aortic arch Ligam entum arteriosum Left pulm onary artery Superior and inferior lobar bronchi Left pleural cavit y

Superior vena cava Diaphragm A

At tachm ent bet ween fibrous pericardium and diaphragm atic fascia

Fibrous pericardium

Right pulm onary veins Pulm onary trunk

Thoracic aorta Parietal pleura, m ediastinal part

Right pleural cavit y

Parietal pleura, diaphragm atic part

Inferior pharyngeal constrictor Left com m on carotid artery

Thyroid gland, right lobe Esophagus, cervical part

B

Pericardiacophrenic Caval Esophagus, Fibrous artery and vein, opening thoracic part pericardium phrenic nerve

Left internal jugular vein Left subclavian artery and vein Aortic arch

Superior vena cava Trachea Azygos vein Right m ain bronchus

Left pulm onary artery Fibrous pericardium , left atrium Left pulm onary veins

Right pulm onary artery Esophagus, thoracic part Right pulm onary veins

Thoracic aorta Fibrous pericardium , left ventricle Esophageal aperture C

Diaphragm

Fibrous pericardium , right atrium Inferior vena cava (in caval opening) Posterior intercostal arteries

Fig. 15.48 Contents of the mediastinum A Anterior view. The thymus, which lies on the fibrous pericardium surrounding the heart, extends into the inferior mediastinum and grows throughout childhood. At pubert y, high levels of circulating sex hormones cause the thym us to atrophy leaving the smaller adult thymus, which extends as shown only into the superior mediastinum . B Anterior view with heart, pericardium , and thymus removed. C Posterior view.

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Mediastinum: Structures

Clavicle 1st rib

Brachial plexus

Ram i com m unicantes

Right subclavian artery and vein

Intercostal artery, vein, and nerve

Brachiocephalic trunk Right brachiocephalic vein

Brachiocephalic lymph nodes Right vagus nerve

Left brachiocephalic vein

Azygos vein

Trachea

Sympathetic trunk, thoracic ganglion

Superior vena cava Right phrenic nerve

Superior lobar bronchus

Thym us (retrosternal fat pad) Fibrous pericardium

Right pulm onary artery Com mon trunk of m iddle and inferior lobar bronchi

Right pulm onary veins Phrenic nerve, pericardiacophrenic artery and vein

Esophagus Greater splanchnic nerve Parietal pleura, costal part

Posterior intercostal artery and vein, intercostal nerve

Diaphragm

Intercostal m uscles

A

Fig. 15.49 Mediastinum A Right lateral view, parasagit tal section. Note the m any structures passing bet ween the superior and inferior (m iddle and posterior) m ediastinum .

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Clavicle

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1st rib

Brachial plexus Left subclavian artery and vein Intercostal artery, vein, and nerve

Esophagus

Thoracic duct

Left superior intercostal vein

Aortic arch

Left vagus nerve Ligam entum arteriosum

Left recurrent laryngeal nerve

Left phrenic nerve Sympathetic trunk Left pulm onary artery

Accessory hem iazygos vein

Left pulm onary veins

Ram i com m unicantes Left m ain bronchus

Fibrous pericardium

Thoracic aorta (descending aorta)

Lateral pericardial lym ph node Left vagus nerve

Parietal pleura, costal part

Phrenic nerve, pericardiacophrenic artery and vein

Hem iazygos vein

Superior phrenic lymph node Intercostal m uscles Diaphragm

Posterior intercostal artery and vein, intercostal nerve

B

B Left lateral view, parasagit tal section. Removed: Left lung and parietal pleura. Revealed: Posterior m ediastinal structures.

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Heart: Surfaces & Chambers

Left subclavian artery Left com m on carotid artery

Aortic arch Ligam entum arteriosum

Brachiocephalic trunk

Left pulm onary artery

Right pulm onary artery

Left pulm onary veins

Superior vena cava

Pulm onary trunk

Ascending aorta

Left auricle

Right atrium

Pericardium (reflected edge)

Coronary sulcus

Anterior interventricular sulcus

Right ventricle

Inferior vena cava

A

Left com m on carotid artery Left subclavian artery

Left ventricle

Cardiac apex Right auricle

Brachiocephalic trunk Aortic arch

Left pulm onary artery

Superior vena cava

Left pulm onary veins

Right pulm onary artery

Left auricle Right pulm onary veins Left atrium

Right atrium

Left ventricle Pericardium (reflected edge) Aortic arch

B

Coronary sinus

Inferior vena cava

Superior vena cava Left pulm onary artery Left pulm onary veins

Right pulm onary artery Right pulm onary veins

Left atrium

Right atrium

Coronary sinus

Fig. 15.50 Surfaces of the heart A Anterior (sternocostal) surface. B Posterior surface (base). C Inferior (diaphragmatic) surface. Note the reflection of visceral serous pericardium to become the parietal serous pericardium.

Left ventricle

Cardiac apex C

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Right ventricle Posterior interventricular sulcus

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Aortic arch

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Ligam entum arteriosum Pulm onary trunk

Right pulm onary artery

Left pulm onary veins

Superior vena cava

Valve of pulm onary trunk

Conus arteriosus Supraventricular crest

Septal papillary m uscle

Right atrium

Left ventricle

Coronary sulcus Right atrioventricular valve, anterior cusp

Interventricular septum Trabeculae carneae

Inferior vena cava Chordae tendineae A

Anterior papillary m uscle

Cardiac apex Posterior Septom arginal papillary m uscle trabecula

Ascending aorta Superior vena cava

Pulm onary trunk

Right pulm onary artery

Right auricle Crista term inalis

Left atrium

Pectinate m uscles

Right pulm onary veins

Right ventricle

Interatrial septum

Right atrioventricular orifice with atrioventricular valve

Lim bus of fossa ovalis Fossa ovalis Inferior vena cava B

Left pulm onary artery

Valved orifice of inferior vena cava

Valved orifice of coronary sinus

Aortic arch

Pulm onary trunk Right pulm onary artery Left auricle

Pectinate m uscles

Left superior pulm onary vein Valve of fossa ovalis

Anterior papillary m uscle

Left atrium

Trabeculae carneae of interventricular septum

Interatrial septum

Chordae tendineae

Inferior vena cava

Cardiac apex C

Posterior Left atrioventricpapillary m uscle ular valve

Fig. 15.51 Chambers of the heart A Right ventricle, anterior view. Note the supraventricular crest, which marks the adult boundary bet ween the embryonic ventricle and the bulbus cordis (now the conus arteriosus). B Right atrium, right lateral view. C Left atrium and ventricle, left lateral view. Note the irregular trabeculae carneae characteristic of the ventricular wall.

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Heart: Valves, Arteries, & Veins The cardiac valves are divided into t wo groups: semilunar and atrioventricular. The t wo sem ilunar valves (aortic and pulm onary), located at the base of the t wo great arteries of the heart, regulate passage of

Pulm onary valve

Right cusp Anterior cusp

blood from the ventricles to the aorta and pulmonary trunk. The t wo atrioventricular valves (left and right) lie at the interface bet ween the atria and ventricles.

Left cusp Right cusp

Aortic valve

Posterior cusp

Left cusp

Right coronary artery Anterior cusp

Left coronary artery

Left atrioventricular (bicuspid or m itral) valve

Anterior cusp

Septal cusp

Posterior cusp

A

Posterior cusp

Right atrioventricular (tricuspid) valve

Coronary sinus

Pulm onary valve

Right cusp Anterior cusp

Left cusp Right cusp

Aortic valve

Posterior cusp

Left cusp

Right coronary artery Anterior cusp

Left coronary artery

Left atrioventricular valve

Anterior cusp

Septal cusp

Posterior cusp

Posterior cusp

B

Fig. 15.52 Cardiac valves Plane of cardiac valves, superior view. Removed: Atria and great arteries. A Ventricular diastole (relaxation of the ventricles). Closed: Semilunar

Right atrioventricular valve

Coronary sinus

valves. Open: Atrioventricular valves. B Ventricular systole (contraction of the ventricles). Closed: Atrioventricular valves. Open: Semilunar valves.

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Pulm onary Superior left valve pulm onary vein

Superior vena cava

Atrial branches

Ascending aorta with aortic sinus

Left auricle (atrial appendage) Left coronary artery

Branch to sinoatrial node

Circum flex branch

Right auricle (atrial appendage)

Left m arginal artery and vein

Right coronary artery

Great cardiac vein

Conus branch

Anterior interventricular artery (left anterior descending artery)

Atrial branch Sm all cardiac vein Right m arginal artery and vein

Lateral branch

Anterior veins of right ventricle

Oblique vein of left atrium

Left atrium

Atrial branches

A

Superior vena cava

Left pulm onary veins

Left ventricle

Right ventricle

Cardiac apex

Branch to sinoatrial node Right pulm onary veins

Circum flex branch Great cardiac vein

Right atrium Posterior left ventricular branch

Coronary sinus Inferior vena cava Right coronary artery

Left posterior ventricular vein

Sm all cardiac vein

Right posterolateral artery

Fig. 15.53 Coronary arteries and cardiac veins A Anterior view. B Posteroinferior view. Note: The right and left coronary arteries t ypically anastom ose posteriorly at the left atrium and ventricle.

Right ventricle

Posterior interventricular artery (posterior descending artery)

Left ventricle B

Middle cardiac vein

Ta ble 15.9 Branches of the coronary arteries

Ta ble 15.10 Divisions of the cardiac veins

Left coronary artery

Right coronary artery

Vein

Branch to SA node

Anterior cardiac vv. (not shown)

Circumflex branch • Atrial branch • Left m arginal a. • Posterior left ventricular branch Anterior interventricular branch (left anterior descending) • Conus branch • Lateral branch • Interventricular septal branches

Conus branch

Tributaries

Drainage to Right atrium

Anterior interventricular v.

Atrial branch

Great cardiac v.

Right m arginal a.

Left m arginal v. Oblique v. of left atrium

Posterior interventricular branch (posterior descending) • Interventricular septal branches

Left posterior ventricular v.

Branch to AV node

Small cardiac v.

Coronary sinus

Middle cardiac v. (posterior interventricular v.)

Right posterolateral a.

Anterior vv. of right ventricle Right marginal v.

Abbreviations: AV, atrioventricular; SA, sinoatrial.

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Heart: Conduction & Innervation Dorsal m otor nucleus

Superior, m iddle, and inferior cervical cardiac nerves

Vagus nerve (CN X)

Superior cervical ganglion Middle cervical ganglion

Superior and inferior cervical cardiac branches

T1 spinal cord segm ent Stellate ganglion

Cervical cardiac nerves Aortic arch with thoracic aortic plexus

Cardiac branches to cardiac plexus

Thoracic cardiac branches

Sym pathetic trunk

Sympathetic trunk, inferior cervical ganglion

Pulm onary artery and pulm onary veins with pulm onary plexus

Cardiac plexus

Cardiac plexus Sinoatrial (SA) node

Cardiac plexus (along the coronary arteries)

B

Atrioventricular (AV) node A

Myocardium Hyoid bone Superior laryngeal nerve

Thyroid cartilage Left vagus nerve

Right vagus nerve Sympathetic trunk, m iddle cervical ganglion

Thyroid gland Anterior scalene Left com m on carotid artery

Brachial plexus

Left recurrent laryngeal nerve

Subclavian artery Trachea

Brachiocephalic trunk Thoracic aortic plexus

Right recurrent laryngeal nerve

Left vagus nerve Sympathetic trunk, thoracic ganglion

Right vagus nerve Right phrenic nerve

Left phrenic nerve

Superior vena cava

Pulm onary plexus

Ascending aorta

Pulm onary trunk Cardiac plexus

Phrenic nerve (on diaphragm )

C

Fibrous Gastric plexus pericardium (opened)

Fig. 15.54 Autonomic innervation of the heart A Schematic. Sympathetic innervation: Preganglionic neurons from T1 to T6 spinal cord segm ents send fibers to synapse on postganglionic neurons in the cervical and upper thoracic sympathetic ganglia. The three cervical cardiac nerves and their thoracic cardiac branches contribute to the cardiac plexus. Parasympathetic innervation: Pregan-

glionic neurons and fibers reach the heart via cardiac branches, some of which also arise in the cervical region. They synapse on postganglionic neurons near the SA node and along the coronary arteries. B Autonomic plexuses of the heart, right lateral view. Note the continuit y bet ween the cardiac, aortic, and pulmonary plexuses. C Autonom ic nerves of the heart. Anterior view of opened thorax.

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Superior vena cava

Interatrial bundle

Aortic arch

Sinoatrial (SA) node

Atrioventricular bundle (of His)

Anterior, m iddle, and posterior internodal bundles

Left bundle branch

Purkinje fibers

Atrioventricular (AV) node

A

Right bundle branch

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Interventricular septum

Superior vena cava

Pulm onary trunk

Sinoatrial (SA) node

Interventricular septum

Left bundle branch

Right bundle branch

Right atrium

Right ventricle Septom arginal trabecula

Atrioventricular (AV) node

B

Atrioventricular bundle (of His)

Anterior papillary m uscle Purkinje fibers

Aortic arch Pulm onary trunk

Left atrium

Left bundle branch

Anterior fascicle

Interventricular septum

Middle fascicle Posterior fascicle Left ventricle

C

Cardiac apex

Purkinje fibers (subendocardial branches)

Fig. 15.55 Cardiac conduction system A Anterior view. Opened: All four chambers. B Right lateral view. Opened: Right atrium and ventricle. C Left lateral view. Opened: Left atrium and ventricle. Contraction of cardiac muscle is modulated by the cardiac conduction

system . This system of specialized myocardial cells (Purkinje fibers) generates and conducts excitatory impulses in the heart. The conduction system contains t wo nodes, both located in the atria: the sinoatrial (SA) node, known as the pacemaker, and the atrioventricular (AV) node.

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Pre - & Postnatal Circulation

Aortic arch Ductus arteriosus (patent)

Pulm onary arteries (very lit tle blood flow) Left pulm onary veins (very lit tle blood flow) Left atrium

Superior vena cava Oval foram en (patent)

Pulm onary trunk

Right atrium

Left ventricle Right ventricle

Hepatic veins Liver Ductus venosus

Anastom osis bet ween um bilical vein and portal vein

Portal vein

Abdom inal aorta

Um bilical vein

Inferior vena cava

Um bilical arteries

Com m on iliac artery Internal iliac artery

Um bilicus

Um bilical arteries

Placenta

Fig. 15.56 Prenatal circulation (after Fritsch and Kühnel) Oxygenated and nutrient-rich fetal blood from the placenta passes to the fetus via the umbilical vein. Approximately half of this blood bypasses the liver (via the ductus venosus) and enters the inferior vena cava. The remainder enters the portal vein to supply the liver with nutrients and oxygen. Blood entering the right atrium from the inferior vena cava bypasses the right ventricle (as the lungs are not yet functioning) to enter the

left atrium via the oval foramen, a right-to-left shunt. Blood from the superior vena cava enters the right atrium, passes to the right ventricle, and moves into the pulmonary trunk. Most of this blood enters the aorta via the ductus arteriosus, a right-to-left shunt. The partially oxygenated blood in the aorta returns to the placenta via the paired umbilical arteries that arise from the internal iliac arteries.

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Aortic arch

Ligam entum arteriosum (obliterated ductus arteriosus)

Pulm onary arteries (perfused) Left pulm onary veins (perfused) Left atrium

Superior vena cava Oval foram en (closed)

Pulm onary trunk

Right atrium

Left ventricle

Right ventricle Hepatic veins Liver Ligam entum venosum (obliterated ductus venosus)

Portal vein Round ligam ent of liver (obliterated um bilical vein) Abdom inal aorta Um bilical cord

Inferior vena cava

Upper body circulation

Um bilicus

Fig. 15.57 Postnatal circulation (after Fritsch and Kühnel) As pulmonary respiration begins at birth, pulmonary blood pressure falls, causing blood from the right pulmonary trunk to enter the pulmonary arteries. The oval foramen and ductus arteriosus close, eliminating the fetal right-to-left shunts. The pulmonary and systemic circulations in the heart are now separate. As the infant is separated from the placenta, the umbilical arteries occlude (except for the proximal portions), along with the umbilical vein and ductus venosus. Blood to be metabolized now passes through the liver.

Obliterated um bilical aa. (medial um bilical ligam ents) Pulm onary circulation Pulm onary vein Pulm onary artery Superior vena cava Ascending aorta Right atrium

Left atrium Aorta Left ventricle Right ventricle

Hepatic veins

Inferior vena cava

Portal vein

Portal circulation

Fig. 15.58 Circulation Oxygenated blood is shown in red; deoxygenated blood in blue. See Fig 15.56 for prenatal circulation.

Lower body circulation

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Esophagus The esophagus is divided into three parts: cervical (C6–T1), thoracic (T1 to the esophageal hiatus of the diaphragm), and abdom inal (the diaphragm to the cardiac orifice of the stomach). It descends slightly to

the right of the thoracic aorta and pierces the diaphragm slightly to the left, just below the xiphoid process of the sternum.

C6 Cricoid cartilage Cervical part

Upper esophageal (pharyngoesophageal) constriction

Esophageal inlet Trachea, thoracic part

Thoracic part Diaphragm

Abdom inal part

Sternum

T4

Middle esophageal (thoracic) constriction

A

Fig. 15.59 Esophagus: Location and constrictions A Projection of esophagus onto chest wall. Esophageal constrictions are indicated with arrows. B Esophageal constrictions, right lateral view.

Trachea, cervical part

Diaphragm

T10

Lower esophageal (phrenic) constriction B

Aorta

Esophagus, cervical part Left internal jugular vein

Brachial plexus

Left subclavian artery and vein

Anterior scalene Brachiocephalic trunk

Left brachiocephalic vein

Right brachiocephalic vein Parietal pleura, cervical part

Aortic arch Ligam entum arteriosum

Arch, azygos vein

Left pulm onary artery Left vagus nerve

Right pulm onary artery

Superior and inferior lobar bronchi

Right pulm onary veins Right vagus nerve

Thoracic aorta

Pulm onary trunk

Parietal pleura, m ediastinal part

Azygos vein Thoracic duct

Esophageal plexus

Parietal pleura, diaphragm atic part

Esophagus, thoracic part

Fibrous pericardium

Fig. 15.60 Esophagus in situ Anterior view.

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Mucosa, longitudinal folds Mediastinal part Muscularis

Circular layer

Diaphragm atic part

Parietal pleura

Longitudinal layer

Esophageal hiatus Junction of esophageal and gastric m ucosae (Z line) Pharyngeal raphe

Thyroid cartilage

Inferior pharyngeal constrictor, thyropharyngeal part

Killian’s (dehiscence) triangle

Gastric fundus

Parietal peritoneum Peritoneal cavit y B

Visceral peritoneum

Gastric cardia

Gastric folds (rugae)

Inferior pharyngeal constrictor, cricopharyngeal part

Cricoid cartilage

Muscular coat, circular layer

Trachea

Esophagus

Muscular coat, longitudinal layer

Muscular coat, circular layer Subm ucosa A

C

Mucosa

Fig. 15.61 Structure of the esophagus A Esophageal wall, oblique left posterior view. B Esophagogastric junction, anterior view. A true sphincter is not identifiable at this junction; instead, the diaphragmatic muscle of the

Inferior pharyngeal constrictor Zenker’s diverticulum Trachea

Parabronchial diverticulum Left m ain bronchus

Right m ain bronchus

Esophagus (thoracic part)

Epiphrenic diverticulum Diaphragm

esophageal hiatus functions as a sphincter. It is often referred to as the “Z line” because of its zigzag form. C Functional architecture of esophageal muscle.

Fig. 15.62 Esophageal diverticula Diverticula (abnormal outpouchings or sacs) generally develop at weak spots in the esophageal wall. There are three main t ypes of esophageal diverticula: —Hypopharyngeal (pharyngo -esophageal) diverticula: outpouchings occurring at the junction of the pharynx and the esophagus. These include Zenker’s diverticula (70% of cases). —“True” traction diverticula: protrusion of all wall layers, not t ypically occurring at characteristic weak spots. However, they generally result from an inflammatory process (e.g., lymphangitis) and are thus com m on at sites where the esophagus closely approaches the bronchi and bronchial lymph nodes (thoracic or parabronchial diverticula). —“False” pulsion diverticula: herniations of the m ucosa and subm ucosa through weak spots in the m uscular coat due to a rise in esophageal pressure (e.g., during normal swallowing). These include parahiatal and epiphrenic diverticula occurring above the esophageal aperture of the diaphragm (10% of cases).

Esophagus, abdom inal part

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Pleura

Cervical pleura (cupola)

Costomediastinal recesses

Parietal pleura

Parietal pleura

Right lung Left lung Inferior border of lung

Left lung

Right lung

Inferior border of lung

Costodiaphragm atic recesses of pleural cavities

Costodiaphragm atic recesses of pleural cavities

A

B

Fig. 15.63 Vertical reference lines of the thorax A Anterior view. B Right lateral view.

Right lung 8th rib

Cervical part

Intercostal vein, artery, and nerve

Visceral pleura Parietal pleura, diaphragm atic part Diaphragm

Parietal pleura, costal part

Costal part

Parietal peritoneum Visceral peritoneum Costodiaphragm atic recess

Mediastinal part Diaphragm atic part

Costal groove External intercostal

Fibrous pericardium

Internal intercostal A

B

Fig. 15.64 Parietal pleura A Parts of the parietal pleura. Opened: Right pleural cavit y, anterior view. B Costodiaphragmatic recess, coronal section, anterior view. Reflection of the diaphragmatic pleura onto the inner thoracic wall (becoming the costal pleura) forms the costodiaphragmatic recess. The pleural cavit y is bounded by t wo serous layers. The visceral (pulmonary) pleura covers the lungs, and the parietal pleura lines the inner surface of the thoracic cavit y. The four parts of the parietal pleura (costal, diaphragmatic, mediastinal, and cervical) are continuous.

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Endothoracic fascia Liver Innerm ost intercostal

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Internal thoracic artery and vein

Sternum

Right ventricle

Right lung, superior lobe

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Costom ediastinal recess Interventricular septum

Horizontal fissure of right lung

Left ventricle

Right atrium

Left lung, superior lobe

Right lung, m iddle lobe

Phrenic nerve (bet ween fibrous pericardium and parietal pleura, m ediastinal part)

Left atrium

Oblique fissure of left lung

Oblique fissure of right lung

Thoracic duct

Esophagus

Thoracic (descending) aorta Azygos vein

Right lung, inferior lobe

Left vagus nerve (anterior vagal trunk)

Sym pathetic trunks

Hem iazygos vein

Left lung, inferior lobe

Fig. 15.65 Thorax in transverse section Transverse section through T8, inferior view.

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Lungs in situ Mediastinum

Superior lobe

Right lung

Superior lobe

Horizontal fissure Middle lobe

Oblique fissure

Oblique fissure

Left lung

Inferior lobe Inferior lobe

A

Esophagus

Descending aorta

Left subclavian artery and vein Brachiocephalic trunk Left brachiocephalic vein Parietal pleura, cervical part

Aortic arch

Pulm onary apex Right lung, superior lobe Left pulm onary artery

Superior vena cava Right pulm onary artery

Superior and inferior lobar bronchi

Right pulm onary veins

Left lung, superior lobe

Right lung, horizontal fissure

Thoracic aorta

Pulm onary trunk Right lung , m iddle lobe

Parietal pleura, m ediastinal part

Right lung, oblique fissure

Left lung, oblique fissure Parietal pleura, costal part

Right lung, inferior lobe

Left lung, inferior lobe

Costodiaphragm atic recess B

Diaphragm

Parietal pleura, diaphragm atic part

Esophagus, thoracic part

Fig. 15.66 Lungs in situ The left and right lungs occupy the full volum e of the pleural cavit y. Note that the left lung is slightly smaller than the right due to the asym -

Fibrous pericardium

metrical position of the heart. A Topographical relations of the lungs, transverse section, inferior view. B Anterior view with lungs retracted.

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Apex

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Apex

Superior lobe Superior lobe

Anterior border Horizontal fissure

Costal surface

Middle lobe Inferior lobe

Anterior border

Oblique fissure

Costal surface Inferior lobe Lingula

Oblique fissure A

Inferior border

B

Inferior border

Apex

Apex Superior lobe

Branches of right pulm onary artery

Mediastinal surface

Superior lobe

Anterior border

Superior lobar bronchus

Mediastinal surface

Branches of left pulm onary artery

Oblique fissure

Hilum

Inferior and m iddle lobar bronchi (com m on origin)

Oblique fissure

Horizontal fissure

Branches of right pulm onary veins

Hilum

Anterior border

Costal surface, vertebral part Pulm onary ligam ent

Middle lobe

Branches of left pulm onary veins

Aortic impression

Inferior lobe Cardiac impression

Superior and inferior lobar bronchi

Cardiac impression

Inferior lobe

Cardiac notch

Costal surface (vertebral part) Inferior border

Lingula

Base C

Inferior border

D

Fig. 15.67 Gross anatomy of the lungs A Right lung, lateral view. B Left lung, lateral view. C Right lung, medial view. D Left lung, medial view. The oblique and horizontal fissures divide the right lung into three lobes: superior, middle, and inferior. The oblique fissure divides the

Pulm onary ligam ent

Base

left lung into t wo lobes: superior and inferior. The apex of each lung extends into the root of the neck. The hilum is the location at which the bronchi and neurovascular structures connect to the lung.

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Pulmonary Arteries & Veins

Trachea Right lung

Left lung

Superior lobe

Superior lobe Aortic arch

Right m ain bronchus

Left m ain bronchus

Right pulm onary artery

Left pulm onary artery

Superior right pulm onary vein

Superior left pulm onary vein

Inferior right pulm onary vein

Inferior left pulm onary vein

Superior vena cava Ascending aorta

Pulm onary trunk

Right atrium

Left ventricle

Middle lobe

Inferior lobe

Inferior vena cava

Right ventricle

Fig. 15.68 Pulmonary arteries and veins Anterior view. The pulmonary trunk arises from the right ventricle and divides into a left and right pulmonary artery for each lung. The paired pulmonary veins open into the left atrium on each side. The pulmonary arteries accompany and follow the branching of the bronchial tree, whereas the pulmonary veins do not, being located at the margins of the pulm onary lobules.

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Cardiac apex

Inferior lobe

Rest of Body Ana tomy

Left com m on carotid artery

Brachiocephalic trunk

15. Rest of Body Ana tomy

Left subclavian artery Aortic arch

Right pulm onary artery

Ligam entum arteriosum

Middle lobe artery

Left pulm onary artery

S

D A Right/left superior pulm onary vein

F G

Fig. 15.69 Pulmonary arteries Schematic.

Right/left inferior pulm onary vein

L K J

Pulm onary trunk

Ö Ä Y X CB

H

V

Fig. 15.70 Pulmonary veins Schematic.

Ta ble 15.11 Pulmonary arteries and their branches Right pulmonary artery

Ta ble 15.12 Pulmonary veins and their tributaries

Left pulmonary artery

Right pulmonary vein

Superior lobe arteries

Left pulmonary vein

Superior pulmonary veins

Apical segm ental a.

Apical v.

Posterior segm ental a.

Posterior v.

Anterior segm ental a.

Anterior v.

Anterior v.

Middle lobe v.

Lingular v.

Middle lobe arteries Lateral segm ental a. Medial segm ental a.

N

Apicoposterior v.

Inferior pulmonary veins

Lingular a.

Superior v. Com mon basal v.

Inferior lobe arteries Superior segmental a.

Inferior basal v.

Anterior basal segm ental a.

Superior basal v.

Lateral basal segmental a.

Anterior basal v.

Posterior basal segm ental a. Medial basal segmental a. Vagus nerve (CN X) Dorsal m otor nucleus

Middle cervical ganglion

Postganglionic fibers (to cardiac plexus)

Larynx, thyroid cartilage

Superior laryngeal nerve

Cervicothoracic ganglion

Recurrent laryngeal nerve

T1 spinal cord segm ent

Laryngopharyngeal branch

2nd through 5th thoracic ganglia

Autonom ic branches to trachea Pulm onary plexus

Greater splanchnic nerve (to abdom en)

Trachea

Bronchial branches in pulm onary plexus

Fig. 15.71 Autonomic innervation of the tracheobronchial tree Sympathetic innervation (red); parasympathetic innervation (blue).

Right m ain bronchus

Left m ain bronchus

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15. Rest of Body Ana tomy

Surface Anatomy & Muscles of the Abdominal Wall

Caval opening Esophageal hiatus

Central tendon

Median arcuate ligam ent

Diaphragm, costal part

Lateral arcuate ligament

Diaphragm , lum bar part, and left crus

Medial arcuate ligam ent

Aortic hiatus Transversus abdom inis

Quadratus lumborum

Psoas m ajor

Psoas m inor

Iliacus

Iliopsoas

Superior border of m anubrium

Fig. 15.72 Muscles of the posterior abdominal w all Coronal section with diaphragm in intermediate position.

Table 15.13 Transverse planes through the abdomen Transpyloric plane

Transverse plane m idway bet ween the superior borders of the pubic symphysis and the m anubrium

Subcostal plane

Plane at the lowest level of the costal m argin (the inferior margin of the tenth costal cartilage)

Supracrestal plane

Plane passing through the summ its of the iliac crest s

Transtubercular plane

Plane at the level of the iliac tubercles (the iliac tubercle lies ~ 5 cm posterolateral to the anterior superior iliac spine)

Interspinous plane

Plane at the level of the anterior superior iliac spine

Superior border of pubic sym physis

Fig. 15.73 Transverse planes through the abdomen Anterior view. See Table 15.13.

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Internal intercostals

Pectoralis m ajor (sternocostal part)

Costal cartilage Sternum

Sternum

Serratus anterior

External intercostals

Pectoralis m ajor (abdom inal part)

Rectus abdom inis

Xiphoid process

Linea alba External oblique

External oblique

External oblique aponeurosis Rectus sheath, anterior layer

Linea alba

Internal oblique

Um bilicus

Um bilicus Internal oblique aponeurosis Anterior superior iliac spine Inguinal ligam ent

Inguinal ligam ent

Rectus sheath, anterior layer Superficial inguinal ring

A

Sperm atic cord, crem aster m uscle

B Sperm atic cord, crem aster m uscle

Fundiform ligam ent of the penis

Fig. 15.74 Muscles of the abdominal w all Right side, anterior view. A Superficial abdominal wall m uscles. B Removed: External oblique, pectoralis major, and serratus anterior.

Rectus sheath, anterior layer

Linea alba

Rectus abdom inis

Superficial m em branous layer of the subcutaneous tissue Superficial fat t y layer (Scarpa's fascia) of the subcutaneous tissue (Cam per's fascia) External oblique aponeurosis

External oblique Internal oblique

Rectus sheath, posterior layer

Parietal peritoneum

Transversalis fascia Transversus abdom inis aponeurosis

Transversus abdom inis

Internal oblique aponeurosis

Fig. 15.75 Anterior abdominal w all and rectus sheath Transverse section, superior to the arcuate line. The rectus sheath is created by fusion of the aponeuroses of the transversus abdom inis and abdominal oblique muscles. The inferior edge of the posterior layer of the rectus sheath is called the arcuate line.

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15. Rest of Body Ana tomy

Arteries of the Abdominal Wall & Abdomen

Superior thoracic artery

Subclavian artery

Axillary artery Lateral thoracic artery

Internal thoracic artery

Thoracodorsal artery Celiac trunk (T12)

Superior m esenteric artery (L1) Inferior m esenteric artery (L3) Aortic bifurcation (L4)

Superior epigastric artery

Renal arteries (L1/L2)

Superficial epigastric artery

Inferior epigastric artery

Left com m on iliac artery

External iliac artery

Deep circum flex iliac artery Superficial circum flex iliac artery

Fem oral artery

Fig. 15.76 Abdominal aorta and major branches Anterior view. The abdominal aorta enters the abdomen at the T12 level through the aortic hiatus of the diaphragm . Before bifurcating at L4 into its terminal branches, the com mon iliac arteries, the abdom inal aorta gives off the renal arteries and three major trunks that supply the organs of the alim entary canal: Celiac trunk: supplies the structures of the foregut, the anterior portion of the alimentary canal. The foregut consists of the esophagus (abdominal 1.25 cm ), stom ach, duodenum (proximal half), liver, gallbladder, and pancreas (superior portion). Superior mesenteric artery: supplies the structures of the midgut: the duodenum (distal half), jejunum and ileum, cecum and appendix,

1R

S

1L

Left superior suprarenal artery

Common hepatic artery

Left gastric artery Splenic artery 3L

Proper hepatic artery

ascending colon, right colic flexure, and the proximal one half of the transverse colon. Inferior mesenteric artery: supplies the structures of the hindgut: the transverse colon (distal half), left colic flexure, descending and sigmoid colons, rectum, and anal canal (upper part).

Table 15.14 Branches of the abdominal aorta

Right superior suprarenal artery

Right gastric artery

Fig. 15.77 Arteries of the abdominal w all The superior and inferior epigastric arteries form a potential anastomosis, or bypass for blood, from the subclavian and femoral arteries. This effectively allows blood to bypass the abdominal aorta.

The abdominal aorta gives rise to three m ajor unpaired trunks (bold) and the unpaired m edian sacral artery, as well as six paired branches.

Branch from abdominal aorta 1R

1L

Inferior phrenic aa. (paired)

Branches Superior suprarenal aa. Left gastric a.

Gastroduodenal artery

Left inferior suprarenal artery

F

Splenic a.

S

5L

Celiac trunk

Proper hepatic a. Com mon hepatic a.

6R

Gastroduodenal a.

7L 3R

K

3L

F 9L

9R

Superior mesenteric a. 5L

Renal aa. (paired)

6R

6L

Lumbar aa. (1st through 4th, paired)

7R

7L

Testicular/ovarian aa. (paired)

K 9R

Anterior view. See Table 15.14.

Middle suprarenal aa. (paired)

5R

Ö Fig. 15.78 Branches of the abdominal aorta

Right gastric a.

Inferior suprarenal aa.

Inferior mesenteric a. 9L

Ö

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Com mon iliac aa. (paired) Median sacral a.

External iliac a. Internal iliac a.

Rest of Body Ana tomy

Com m on hepatic artery

15. Rest of Body Ana tomy

Abdom inal aorta Celiac trunk

Abdom inal aorta

Splenic artery Celiac trunk

Proper hepatic artery

Left gastroom ental artery

Right gastric artery Anterior/posterior superior pancreaticoduodenal artery Duodenal branches

Pancreatic branches Right gastroom ental artery Inferior pancreaticoduodenal artery

Artery of pancreatic tail Great pancreatic artery Inferior pancreatic artery Dorsal pancreatic artery

Gastroduodenal artery Posterior superior pancreaticoduodenal artery Anterior superior pancreaticoduodenal artery

Superior m esenteric artery A

Left gastric artery

Com mon hepatic artery

Left gastric artery

Gastroduodenal artery

Splenic artery with pancreatic branches

B

Inferior pancreaticoSuperior duodenal artery, mesenteric artery anterior branch

Fig. 15.79 Celiac trunk A Celiac trunk distribution. B Arterial supply to the pancreas. Fig. 15.80 Abdominal arterial anastomoses Celiac trunk The three major anastomoses provide overlap in the arterial supply to supplies: Esophagus abdominal areas to ensure adequate blood flow. These are bet ween Stomach the celiac trunk and the superior m esenteric artery via the pancreatiDuodenum coduodenal arteries, Liver the superior and inferior m esenteric arteries via the middle and left Spleen Gallbladder colic arteries, and Pancreas the inferior mesenteric and the internal iliac arteries via the superior Superior mesenteric and m iddle or inferior rectal arteries.

Pancreaticoduodenal arteries

1 2

artery supplies: Pancreas Duodenum Jejunum Ileum Cecum Ascending and transverse colon Inferior mesenteric artery supplies: Transverse and descending colon Sigmoid colon Rectum Anal canal

Inferior pancreaticoduodenal artery

Middle colic artery Left colic artery

3

Middle/inferior rectal artery Internal iliac artery supplies: reproductive organs Inferior Left colic m esenteric artery artery

Superior m esenteric artery

Superior rectal artery

Left colic flexure

Left colic flexure

Right colic artery Ileocolic artery

Middle colic artery

Jejunal and ileal arteries

Superior rectal artery

Appendicular artery

Sigm oid arteries

Fig. 15.81 Superior mesenteric artery

Fig. 15.82 Inferior mesenteric artery

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15. Rest of Body Ana tomy

Divisions of the Abdominopelvic Cavity Organs in the abdom inopelvic cavit y are classified by the presence of surrounding peritoneum (the serous mem brane lining the cavit y) and

a mesentery (a double layer of peritoneum that connects the organ to the abdominal wall) (see Table 15.15).

Lesser om entum Parietal peritoneum

Parietal peritoneum

Greater omentum

Mesentery

Peritoneal cavit y

Visceral peritoneum Parietal layer Visceral layer

A

B

Peritoneum

Intraperitoneal organ

Fig. 15.83 Peritoneal cavity A Midsagit tal section through the m ale abdominopelvic cavit y, viewed from the left. The peritoneum is shown in red. B An intraperitoneal organ, showing the mesentery and surrounding peritoneum. Arrows indicate location of blood vessels in the mesentery.

Table 15.15  Organs of the  abdominopelvic cavity classi e d by the ir relationship to the  pe ritone um Location

Organs

Intraperitoneal organs: These organs have a m esentery and are completely covered by the peritoneum.

Abdominal peritoneal

• Stomach • Small intestine (jejunum , ileum , som e of the superior part of the duodenum ) • Spleen • Liver

Pelvic peritoneal

• Uterus (fundus and body)

• Gallbladder • Cecum with verm iform appendix • Large intestine (transverse and sigm oid colons)

• Ovaries

• Uterine tubes

Extraperitoneal organs: These organs either have no mesentery or lost it during developm ent. Retroperitoneal

Prim arily

• Kidneys and ureters

Secondarily

• Duodenum (descending, horizontal, and ascending) • Pancreas

Infraperitoneal/subperitoneal

• Urinary bladder • Distal ureters • Prostate

• Suprarenal glands

• Sem inal vesicle • Uterine cervix

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• Uterine cervix

• Ascending and descending colon • Rectum (upper 2/3) • Vagina • Rectum (lower 1/3)

Rest of Body Ana tomy

15. Rest of Body Ana tomy

Esophagus

Sternum

Liver, bare area

Liver Om ental foram en Hepatogastric lig. (lesser om entum )

Celiac trunk

Om ental bursa (lesser sac)

Splenic artery and vein

Pancreas

Left renal artery

Stom ach

Superior m esenteric artery

Middle colic artery

Left renal vein

Transverse m esocolon

Pancreas, uncinate process Abdom inal aorta Duodenum , horizontal part

Transverse colon Greater om entum

Mesentery

Jejunum and ileum

L5 vertebra

Rectus abdom inis

Left com m on iliac artery and vein

Rectovesical pouch

Urinary bladder Ductus deferens, ampulla

Rectum Prostate Deep transverse perineal

Bulbospongiosus

Scrotum , septum

Fig. 15.84 Peritoneal relationships of the abdominopelvic organs Midsagit tal section through the m ale abdominopelvic cavit y, viewed from the left.

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15. Rest of Body Ana tomy

Peritoneal Cavity, Greater Sac, & Mesenteries (I) The peritoneal cavit y is divided into the large greater sac and small om ental bursa (lesser sac). The greater om entum is an apron-like fold of peritoneum suspended from the greater curvature of the stomach and covering the anterior surface of the transverse colon. The at tachment

Falciform ligam ent of liver

of the transverse mesocolon on the anterior surface of the descending part of the duodenum and the pancreas divides the peritoneal cavit y into a supracolic compartment (liver, gallbladder, and stomach) and an infracolic compartment (intestines).

Liver, left lobe

Round ligam ent of liver

Stom ach

Liver, right lobe

Left colic flexure

Gallbladder Transverse colon

Ascending colon

Greater om entum

Tenia coli

Ileum

Lateral um bilical fold (with inferior epigastric artery and vein)

Rectus abdom inis m uscle

Medial um bilical fold (with obliterated um bilical artery) A

Arcuate Median um bilical fold line (with obliterated urachus)

Greater om entum (reflected superiorly)

Transverse colon

Transverse m esocolon with m iddle colic artery and vein

Parietal peritoneum Jejunum (covered by visceral peritoneum )

Ascending colon Tenia coli

Fig. 15.85 Dissection of the peritoneal cavity Anterior view. A Greater sac. Retracted: Abdominal wall. B Infracolic compartm ent, the portion of the peritoneal cavit y below the at tachment of the transverse m esocolon. Retracted: Greater omentum and transverse colon. C Mesenteries and mesenteric recesses in the infracolic compartm ent. Retracted: Greater omentum, transverse colon, small intestines, and sigmoid colon.

Ileum

Lateral um bilical fold (with inferior epigastric artery and vein)

Rectus abdom inis m uscle

Medial um bilical fold (with obliterated um bilical artery) B

Arcuate Median um bilical fold line (with obliterated urachus)

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15. Rest of Body Ana tomy

Greater om entum (reflected superiorly) Transverse colon Round ligam ent of liver Parietal peritoneum Epiploic appendices Left colic flexure Transverse m esocolon

Superior duodenal recess

Inferior duodenal recess

Mesentery, root

Haustra of descending colon Sigm oid colon Sigm oid m esocolon

Inferior iliocecal recess

Intersigm oidal recess Transversus abdominis, internal and external obliques Retrocecal recess Lateral um bilical fold (with inferior epigastric artery and vein)

Rectus abdom inis Median um bilical fold (with obliterated urachus)

Medial um bilical fold (with obliterated um bilical artery)

C

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Stomach & Omental Bursa

Liver, right lobe

Falciform ligam ent of liver Round ligam ent of liver

Liver, left lobe

Esophagus

Parietal peritoneum Diaphragm

Stom ach, fundus Stom ach, cardia Hepatoesophageal ligam ent

Gallbladder

Hepatoduodenal ligam ent

Stom ach, body

Lesser om entum

Spleen Lesser curvature

Hepatogastric ligam ent Right kidney

Greater curvature

Right colic flexure

Descending colon

Ascending colon

Transversus abdom inis, internal and external obliques

Duodenum

Pyloric canal

Pyloric antrum

Greater om entum

Fig. 15.86 Stomach in situ Anterior view of the opened upper abdomen. Arrow indicates the omental foram en. Esophagus

Cardia

Duodenum Pyloric sphincter

Fig. 15.87 Stomach Anterior view. Removed: Anterior wall.

Pyloric orifice

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Angular notch

Body with longitudinal rugal folds

Rest of Body Ana tomy

Stom ach, greater curvature

15. Rest of Body Ana tomy

Gastrocolic ligam ent Stom ach, posterior surface

Gastrosplenic ligam ent Gallbladder Left gastric artery Left suprarenal gland Vestibule of om ental bursa

Left kidney, superior pole

Om ental foram en

Splenic artery Spleen

Com m on hepatic artery

Celiac trunk

Liver, right lobe

Phrenicocolic ligam ent Pancreas

Duodenum , descending part

Transverse m esocolon Middle colic artery and vein

Right colic flexure

Gastrocolic ligam ent Transverse colon

Ascending colon

Greater om entum

Descending colon

Fig. 15.88 Omental bursa Anterior view. Divided: Gastrocolic ligament. Retracted: Liver. Reflected: Stomach.

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15. Rest of Body Ana tomy

Mesenteries (II) & Bow el

Liver, right lobe

Round ligam ent of liver

Hepatogastric ligam ent (lesser om entum )

Liver, left lobe Cardiac orifice

Superior border

Gallbladder

Spleen

Gastric surface

Hepatoduodenal ligam ent (lesser om entum )

Gastrosplenic ligam ent

Om ental foram en

Pancreas

Duodenum , superior part

Transverse m esocolon, root

Stom ach, pyloric part

Left colic flexure

Greater om entum

Transverse colon

Right colic flexure

Duodenojejunal flexure

Transverse colon Duodenum , horizontal part Mesentery (cut)

Descending colon

Tenia coli

Transversus abdom inis, internal and external oblique m uscles

Ascending colon Ileum

Sigm oid m esocolon (cut)

Cecum Rectum

Lateral um bilical fold (with inferior epigastric artery and vein)

Rectus abdom inis

Medial um bilical fold (with obliterated um bilical artery)

Median um bilical fold (with obliterated urachus)

Fig. 15.89 Mesenteries and organs of the peritoneal cavity Anterior view. Divided: Stomach, jejunum, and ileum. Retracted: Liver.

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Rest of Body Ana tomy

Pyloric orifice

Com m on bile duct

15. Rest of Body Ana tomy

Pyloric sphincter

Duodenum , superior part Circular folds (valves of Kerckring) Accessory pancreatic duct

Pancreas

Minor duodenal papilla Duodenum , descending part

Duodenojejunal flexure

Main pancreatic duct Major duodenal papilla

Muscular coat

Superior m esenteric artery and vein

Longitudinal layer Circular layer

Jejunum Subm ucosa

Fig. 15.90 Duodenum Anterior view with the anterior wall opened. The small intestine consists of the duodenum, jejunum, and ileum. The duodenum is prim arily retroperitoneal and is divided into four parts: superior, descending, horizontal, and ascending.

Duodenum , horizontal part

Greater om entum (cut)

Haustra

Left colic (splenic) flexure

Transverse m esocolon

Right colic (hepatic) flexure

Descending colon

Tenia coli

Ascending colon

Transverse colon

Mesentery (with anterior cecal artery)

Tenia coli

Tenia coli

Ileocecal orifice Ileum , term inal part

Ileal papilla, frenulum

Haustra

Tenia coli

Sigm oid m esocolon

Sem ilunar folds

Iliocecal labrum , superior and inferior lips Epiploic appendices

Cecum

Fig. 15.91 Large intestine Anterior view. The ascending and descending colon are normally secondarily retroperitoneal, but som etimes they are suspended by a short mesentery from the posterior abdom inal wall. Note: In the clinical set ting, the left colic flexure is often referred to as the splenic flexure and the right colic flexure, as the hepatic flexure.

Verm iform appendix (with orifice)

Mesoappendix (with appendicular artery) Rectum (with peritoneal reflection)

Sigm oid colon

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15. Rest of Body Ana tomy

Liver, Gallbladder, & Biliary Tract

Right triangular ligam ent

Coronary ligam ent

Bare area (diaphragm atic surface of liver)

Fig. 15.92 Surfaces of the liver A Anterior view. B Inferior view. The liver is divided into four lobes by its ligaments: right, left, caudate, and quadrate. The falciform ligament, a double layer of parietal peritoneum that reflects off the anterior abdom inal wall and extends to the liver, spreading out over its surface as visceral peritoneum, divides the liver into right and left anatomic lobes. The round ligament of the liver is found in the free edge of the falciform ligament and contains the obliterated umbilical vein, which once extended from the umbilicus to the liver.

Left triangular ligam ent Fibrous appendix of liver Left lobe, diaphragm atic surface

Right lobe, diaphragm atic surface

Falciform ligam ent

Round ligam ent (ligam entum teres) of liver (rem nant um bilical vein) Inferior border

A

Gallbladder, fundus Caudate lobe

Fibrous appendix of liver

Inferior vena cava

Ligam ent of vena cava

Bare area

Caudate process Coronary ligam ent Right lobe, visceral surface

Left lobe, visceral surface

Portal vein Proper hepatic artery, right branch

Left hepatic duct Proper hepatic artery, left branch

Right hepatic duct

Proper hepatic artery Round ligam ent (ligam entum teres) of liver

B

Cystic artery

Quadrate lobe

Bile duct

Cystic duct

Gallbladder

Duodenum , m uscular coat Longitudinal layer

Duodenum wall Hepatopancreatic ampulla A

Circular layer

Bile duct

Sphincter of bile duct Sphincter of pancreatic duct Sphincter of hepatopancreatic ampulla

Sphincter of hepatopancreatic ampulla B

Fig. 15.93 Biliary sphincter system A Sphincters of the pancreatic and bile ducts. B Sphincter system in the duodenal wall.

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Longitudinal slips of duodenal m uscle on bile duct Pancreatic duct

Rest of Body Ana tomy

Right hepatic duct

15. Rest of Body Ana tomy

Left hepatic duct

Cystic duct

Com m on hepatic duct

Neck Infundibulum

Gallbladder

Duodenum , superior part Body Bile duct Fundus

Accessory pancreatic duct Pancreatic duct

Minor duodenal papilla Major duodenal papilla Duodenum , descending part

Duodenum , horizontal part

Fig. 15.95 Biliary tract in situ Anterior view. Removed: Stom ach, sm all intestine, transverse colon, and large portions of the liver. The gallbladder is intraperitoneal and covered by visceral peritoneum where it is not at tached to the liver.

Fig. 15.94 Extrahepatic bile ducts Anterior view. Opened: Gallbladder and duodenum. Inferior vena cava

Hepatic veins

Esophagus

Abdom inal aorta Spleen

Liver, right lobe Left suprarenal gland

Left hepatic duct Right hepatic duct

Celiac trunk

Comm on hepatic duct

Splenic artery

Cystic duct

Com m on hepatic artery

Proper hepatic artery Gallbladder

Left colic flexure

Bile duct

Pancreas Right colic flexure

Left kidney

Hepatopancreatic duct (opening on m ajor duodenal papilla)

Jejunum

Duodenum , descending part

Pancreatic duct

Duodenum , ascending part

Superior m esenteric artery and vein

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15. Rest of Body Ana tomy

Abdominal Aorta & Celiac Trunk

Esophagus Inferior vena cava

Left superior suprarenal arteries Left inferior phrenic artery

Aortic hiatus of diaphragm

Left m iddle suprarenal artery

Celiac trunk

Left inferior suprarenal artery

Superior m esenteric artery

Left renal artery Left 1st lum bar artery

Abdom inal aorta Inferior m esenteric artery

Left ovarian artery (testicular artery in m ales)

Right com m on iliac artery

Left ureter Median sacral artery Left iliolum bar artery Right internal iliac artery

Left superior gluteal artery

Right external iliac artery

Left lateral sacral artery

Right um bilical artery

Sacral plexus

Right obturator artery

Left deep circum flex iliac artery

Right inferior vesical artery

Left inferior epigastric artery

Fem oral artery and vein

Uterine artery

Right m iddle rectal artery

Obturator branch of right inferior epigastric artery

Right inferior gluteal artery

Right internal pudendal artery

Fig. 15.96 Abdominal aorta Anterior view of the female abdom en. Removed: All organs except the left kidney and suprarenal gland. The abdominal aorta is the distal continuation of the thoracic aorta (see Fig. 15.43, p. 414). It enters the abdomen at the T12 level and bifurcates into the common iliac arteries at L4.

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Proper hepatic artery, left branch Proper hepatic artery, right branch

Abdom inal aorta

Inferior vena cava

15. Rest of Body Ana tomy

Left gastric artery Lesser om entum

Liver

Stom ach

Gallbladder

Spleen

Cystic artery Proper hepatic artery Portal vein Celiac trunk Com m on hepatic artery Bile duct Right gastric artery Posterior superior pancreaticoduodenal artery Gastroduodenal artery

Duodenum

Right gastroom ental artery

Anterior superior pancreaticoduodenal artery

Splenic artery Pancreas

Left gastroom ental artery Greater om entum

Fig. 15.97 Celiac trunk: Stomach, liver, and gallbladder Anterior view. Opened: Lesser omentum. Incised: Greater om entum. The celiac trunk arises from the abdominal aorta at about the level of T12.

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Rest of Body Ana tomy

15. Rest of Body Ana tomy

Superior & Inferior Mesenteric Arteries

Portal vein Inferior vena cava

Proper hepatic artery

Left gastric artery

Right gastric artery

Com m on hepatic artery

Gastroduodenal artery

Splenic artery

Left renal vein

Left renal artery

Right gastroom ental artery

Superior m esenteric artery

Anterior superior pancreaticoduodenal artery

Middle colic artery (cut)

Inferior pancreaticoduodenal artery, anterior and posterior branches

Jejunal arteries Right colic artery Marginal artery Ileocolic artery

Ileal arteries

Ileocolic artery, colic branch Ileocolic artery, ileal branch Posterior cecal artery

Vasa recta

Anterior cecal artery

Fig. 15.98 Superior mesenteric artery Anterior view. Partially removed: Stomach, duodenum, and peritoneum . Reflected: Liver and gallbladder. Note: The middle colic artery has been truncated (see Fig. 15.99). The superior and inferior mesenteric arteries arise from the aorta opposite L2 and L3, respectively.

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Rest of Body Ana tomy

15. Rest of Body Ana tomy

Greater om entum

Transverse colon

Marginal artery Left colic (splenic) flexure Middle colic artery

Superior m esenteric artery (cut) Duodenum

Right colic artery

Abdom inal aorta

Marginal artery

Descending colon

Inferior vena cava

Inferior m esenteric artery

Ascending colon Marginal artery

Left colic artery

Right com m on iliac artery

Aortic bifurcation Sigm oid arteries

Ileocolic artery (cut) Ileocolic artery, colic branch

Superior rectal artery

Ileocolic artery, ileal branch Posterior cecal artery

Sigm oid colon

Anterior cecal artery

Fig. 15.99 Inferior mesenteric artery Anterior view. Removed: Jejunum and ileum . Reflected: Transverse colon.

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15. Rest of Body Ana tomy

Veins of the Abdomen

Hem iazygos vein

Azygos vein

1L

1R

S Inferior vena cava

Inferior vena cava 3R

Abdom inal aorta

L4 vertebra

3L

4L 4R

Com m on iliac vein

5L 6L

7R

7L

5R

6R

Fig. 15.100 Location of the inferior vena cava Anterior view.

Right inferior phrenic vein

L

Fig. 15.101 Tributaries of the inferior vena cava Schematic. See Table 15.16.

Left inferior phrenic vein

Anastom osis Inferior vena cava

Table 15.16 Tributaries of the inferior vena cava 1R

1L

S

Right suprarenal vein

Left suprarenal vein

Right renal vein

Left renal vein

Right testicular/ ovarian vein

Left testicular/ ovarian vein

8L

8R

Inferior phrenic vv. (paired) Hepatic vv. (3)

3R

3L

Suprarenal vv. (the right vein is a direct tributary)

4R

4L

Renal vv. (paired)

5R

5L

Testicular/ovarian vv. (the right vein is a direct tributary)

6R

6L

Ascending lumbar vv. (paired), not direct tributaries

7R

7L

Lumbar vv.

8R

8L

Com mon iliac vv. (paired)

L

Fig. 15.102 Tributaries of the renal veins Anterior view.

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Median sacral v.

Rest of Body Ana tomy

Left gastric vein (with esophageal veins)

To hepatic veins

Right gastric vein

15. Rest of Body Ana tomy

Short gastric veins

Splenic vein Cystic vein Pancreatic veins Left gastroom ental vein

Portal vein

Splenic vein Posterior superior pancreaticoInferior duodenal vein m esenteric vein Inferior pancreaticoL4 duodenal vein

Portal v. Superior m esenteric vein

Right gastroom ental vein Inferior m esenteric vein

Superior m esenteric vein

A

Middle colic vein Left colic vein

Right colic vein Ileocolic vein

Sigm oid veins

Appendicular vein

Ileal Jejunal veins veins

B

Right gastric vein

Left gastric vein

Subclavian vein Esophageal veins

Azygos/ hem iazygos vein Superior vena cava

A

Internal thoracic vein

Portal vein

Inferior vena cava

Paraum bilical veins

Superior epigastric vein

S

Com m on iliac vein

Superior m esenteric vein Perium bilical veins

S

Inferior m esenteric vein

D Colic veins

F

C

Superior rectal vein

Superior rectal vein

Fig. 15.103 Portal vein The portal vein drains venous blood from the abdom inopelvic organs supplied by the celiac trunk and superior and inferior mesenteric arteries. A Location, anterior view. B Portal vein distribution. C Collateral pathways bet ween the portal system and the heart. When the portal system is comprom ised, the portal vein can divert blood away from the liver back to its supplying veins, which return this nutrient-rich blood to the heart via the venae cavae. The red arrows indicate the flow reversal in the (1) esophageal veins, (2) paraumbilical veins, (3) colic veins, and (4) m iddle and inferior rectal veins.

Inferior epigastric vein Ascending lum bar vein

D Colic veins

Middle/inferior rectal vein

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15. Rest of Body Ana tomy

Inferior Vena Cava & Inferior Mesenteric Veins

Hepatic veins

Left inferior phrenic vein Esophagus

Inferior vena cava Celiac trunk Right suprarenal vein

Left suprarenal vein

Superior m esenteric artery

Left renal artery and vein Left ovarian artery and vein

Right renal vein

Ureter Right ovarian artery and vein Abdom inal aorta

Left ascending lum bar vein Left 3rd lum bar vein

Inferior m esenteric artery

Left com m on iliac artery and vein

Right com m on iliac vein

Deep circum flex iliac artery and vein Left lateral sacral vein

Right internal iliac vein

Left superior gluteal vein

Right external iliac vein Right obturator vein

Median sacral artery and vein

Right m iddle rectal vein Right inferior epigastric artery and vein

Rectum (and rectal venous plexus)

Right internal pudendal vein

Uterine venous plexus

Right inferior gluteal vein

Vesical venous plexus

Right uterine vein Right inferior vesical vein

Fem oral a. and v.

Vagina

Urethra

Fig. 15.104 Inferior vena cava Anterior view of the female abdom en. Removed: All organs except the left kidney and suprarenal gland.

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Portal vein

15. Rest of Body Ana tomy

Inferior vena cava

Left gastric artery and vein

Proper hepatic artery

Splenic artery and vein

Right gastric artery and vein

Left renal artery

Gastroduodenal artery

Inferior m esenteric vein

Right gastroom ental artery and vein

Middle colic artery and vein

Superior m esenteric artery and vein Right colic artery and vein

Left colic artery and vein

Ileocolic artery and vein

Jejunal/ileal arteries and veins (cut) Inferior m esenteric artery and vein Left com m on iliac artery and vein Sigm oid arteries and veins

Cecal veins

Posterior cecal artery

Anterior cecal artery

Superior rectal artery and vein

Fig. 15.105 Inferior mesenteric vein Anterior view. Partially removed: Stomach, duodenum, and peritoneum . Removed: Pancreas, greater omentum, transverse colon, and small intestine. Reflected: Liver and gallbladder. The inferior mesenteric vein is part of the portal system.

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15. Rest of Body Ana tomy

Autonomic Plexuses & Sectional Anatomy of the Abdomen

Posterior vagal trunk, celiac branch

Posterior vagal trunk

Anterior vagal trunk

Right greater splanchnic nerve Left greater splanchnic nerve

Right lesser splanchnic nerve

Left lesser splanchnic nerve

Celiac ganglion

Superior m esenteric ganglion

Suprarenal plexus Renal plexus

Aorticorenal ganglia Lum bar ganglia

Interm esenteric plexus Ureteral plexus

Interganglionic trunk

Inferior m esenteric ganglion

Sym pathetic trunk

Testicular/ ovarian plexus Hypogastric nerves

Superior hypogastric plexus

Sym pathetic trunk, sacral ganglia

Gray ram i com m unicantes

1st sacral nerve, anterior ram us

Pelvic splanchnic nerves

Left hypogastric nerve Sacral plexus

Ganglion impar

Fig. 15.106 Autonomic plexuses in the abdomen and pelvis Anterior view of the m ale abdomen and pelvis. Removed: Peritoneum, majorit y of the stomach, and all other abdominal organs except kidneys and suprarenal glands.

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Com m on bile duct

Internal Transverse thoracic artery colon and vein Duodenum

15. Rest of Body Ana tomy

Greater om entum

Pyloric part

Superior m esenteric artery and vein Gallbladder

Anterior wall

Liver, right lobe Inferior vena cava Intercostal artery, vein, and nerve

Stom ach

Posterior wall Om ental bursa

Interm ediate lumbar lymph nodes Right suprarenal gland

Splenic vein Pancreas Spleen

Kidney (with right renal artery)

Transverse colon Descending colon Abdom inal L1 vertebra aorta

A

Left colic flexure

Spinal cord Lateral lum bar Perirenal Left kidney (in vertebral canal) lymph node fat capsule

Vertebral venous plexus

Transverse colon

Pancreas, Superior m esenteric head artery and vein

Stom ach, body Jejunal artery Celiac lym ph nodes

Duodenum , descending part

Transverse m esocolon

Gallbladder

Jejunum

Liver

Duodenojejunal flexure

Right kidney Psoas m ajor

B

Inferior vena cava

Spinal cord

Abdom inal aorta

Ureter

Fig. 15.107 Transverse sections of the abdomen Inferior view. A Section through L1 vertebra. B Section through L2 vertebra.

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Pelvic Girdle & Ligaments of the Pelvis Fig. 15.108 Pelvic girdle Anterosuperior view. The pelvic girdle surrounds the pelvis, the region of the body inferior to the abdom en. It consists of the t wo hip bones and the sacrum that together connect the vertebral column to the femur. The stabilit y of the pelvic girdle is necessary for the transfer of trunk loads to the lower lim b, which occurs in norm al gait. Sacroiliac joint

Iliac crest Iliac fossa

Iliac tuberosit y

Anterior superior iliac spine

Auricular surface of ilium

Hip bone

Arcuate line Anterior inferior iliac spine

Pubic sym physis

Ischial spine

Acetabular rim Sacrum

Pectineal line

Acetabulum

Obturator foram en

A Iliac crest

Ischial tuberosit y

Symphyseal surface

Iliac tuberosit y

Iliac fossa

Posterior superior iliac spine

Anterior superior iliac spine

Auricular surface of ilium Posterior inferior iliac spine

Anterior inferior iliac spine Arcuate line

Ilium , body

Superior pubic ram us

Ischial spine

Pectineal line

Ischium , body

Pubic tubercle Pubis, body Symphyseal surface B

Inferior pubic ramus

Obturator foram en

Ischial ram us

Ischial tuberosit y

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Fig. 15.109 Hip bone Right hip bone (male). A Anterior view. B Medial view. The t wo hip bones are connected to each other at the cartilaginous pubic symphysis and to the sacrum via the sacroiliac joints, creasting the pelvic brim (seen in red in Fig 15.108).

Rest of Body Ana tomy

Sacral prom ontory

Anterior longitudinal ligam ent

15. Rest of Body Ana tomy

Iliolum bar ligam ent

Anterior sacroiliac ligam ent s Anterior superior iliac spine Inguinal ligam ent Sacrotuberous ligam ent Anterior inferior iliac spine

Sacrospinous ligam ent

Coccyx

Ischial spine

Pubic symphysis

A

Pubic tubercle

Obturator m em brane

L4 spinous process Iliac crest

Iliolum bar ligam ent

Iliac tubercle Ilium , gluteal surface Posterior superior iliac spine Interosseous sacroiliac ligam ents

Posterior inferior iliac spine

Greater sciatic foram en

Posterior sacroiliac ligam ent s

Sacrospinous ligam ent

Ischial spine Obturator m em brane

Lesser sciatic foram en

Coccyx

Sacrotuberous ligam ent

Ischial tuberosit y

B

Fig. 15.110 Ligaments of the pelvis Male pelvis. A Anterosuperior view. B Posterior view. Removed on the right side: some of the posterior sacroiliac ligaments to reveal the interosseous sacroiliac ligaments.

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15. Rest of Body Ana tomy

Contents of the Pelvis Right com m on iliac artery and vein

Sigm oid m esocolon Tenia coli

L5 vertebra

Sigm oid colon Parietal peritoneum

Right ductus deferens

Rectus abdom inis

Rectovesical pouch

Visceral peritoneum of bladder

Visceral peritoneum of rectum Rectum

Visceral pelvic fascia on bladder

Parietal pelvic fascia on rectum

Superior pubic ram us

Right ureter

Urinary bladder

Levator ani

Inferior pubic ram us

Right sem inal vesicle

Prostate

External anal sphincter

A

Perineal body

Rectum

Rectoprostatic fascia Rectovesical pouch

Rectovesical septum

Urinary bladder

Parietal peritoneum

Pubic symphysis Retropubic space

Am pulla of ductus deferens

Suspensory ligam ent of penis Penile fascia

Prostate

Corpus cavernosum of penis

Bulbourethral gland

Deep transverse perineal Corpus spongiosum of penis

Bulbospongiosus

Urethra Scrotal septum Prepuce

B

Fig. 15.111 Male pelvis A Parasagit tal section, viewed from the right side. B Midsagit tal section, viewed from the right side.

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Rest of Body Ana tomy

Right com m on iliac artery and vein

15. Rest of Body Ana tomy

Sigm oid m esocolon Tenia coli

L5 vertebra

Sigm oid colon Uterine tube

Ligam ent of ovary

Round ligam ent of uterus

Uterus

Vesicouterine pouch

Rectouterine pouch Visceral peritoneum of rectum

Visceral peritoneum on bladder

Rectum

Visceral pelvic fascia on bladder

Visceral pelvic fascia on rectum

Superior pubic ram us

Right ureter

Urinary bladder Levator ani

A

Inferior pubic ram us

External anal sphincter

Perineal body

Vagina

Left com m on iliac artery and vein

Suspensory ligam ent of ovary (with ovarian artery and vein )

L5 vertebra

Right uterine tube

Right ureter

Right external iliac artery and vein

Right ovary

Rectus abdom inis

Ligam ent of ovary Fundus of uterus Body of uterus

Round ligam ent of uterus

Rectouterine pouch

Parietal peritoneum Vesicouterine pouch

Rectum Cervix of uterus

Urinary bladder

Posterior vaginal fornix

Pubic symphysis

Anterior vaginal fornix

Vagina Crus of clitoris

Levator ani External anal sphincter

Sm ooth m uscle

B

Fig. 15.112 Female pelvis A Parasagit tal section, viewed from the right side. B Midsagit tal section, viewed from the right side.

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Rest of Body Ana tomy

15. Rest of Body Ana tomy

Arteries & Veins of the Pelvis

Right com m on iliac vein

Right com m on iliac artery

Right internal iliac vein Median sacral artery L5 vertebra

Right internal iliac artery Right external iliac artery

A

Superior vesical artery

S

D

F

A

L

Inferior rectal artery

H J

Deep dorsal penile vein

Artery of ductus deferens

K

Veins of penile bulb

A Deep penile veins

Inferior rectal veins Posterior scrotal veins

Inferior vena cava

Right com m on iliac artery

Abdom inal aorta

Right internal iliac artery

A

S

Right internal iliac vein

D

Uterine artery

A S

Uterine veins

Superior vesical artery

K

G

L H J

Obturator branch of inferior epigastric artery

S

F

Right external iliac vein

Piriform is

G

Um bilical artery, obliterated part

A

D

Inferior epigastric artery

Right external iliac artery

Inferior vena cava

G

F

H

K

L Vaginal artery

Right external iliac vein

J Vaginal branch of uterine artery

B

Fig. 15.113 Arteries of the pelvis A Male pelvis. B Female pelvis. See Table 15.17.

K J

D

H

F G

Ö

B

Fig. 15.114 Veins of the pelvis A Male pelvis. B Fem ale pelvis. See Table 15.18.

Table 15.17 Branches of the internal iliac artery

Table 15.18 Venous drainage of the pelvis

The internal iliac artery gives off five parietal (pelvic wall) and four visceral (pelvic organs) branches.* Parietal branches are shown in italics.

Tributaries

Branches

A

Superior gluteal v.

S

Lateral sacral v.

A

liolumbar a.

D

Obturator vv.

S

Superior gluteal a.

F

Vesical vv.

D

Lateral sacral a.

G

Vesical venous plexus

H

Middle rectal vv. (rectal venous plexus) (also superior and inferior rectal vv., not shown)

A. of ductus deferens

F

Um bilical a.

G

Obturator a.

J

Internal pudendal v.

H

Inferior vesical a.

K

Inferior gluteal vv.

J

Middle rectal a.

L

Prostatic venous plexus

K

Internal pudendal a.

Ö

Uterine and vaginal venous plexus

L

Inferior gluteal a.

Superior vesical a.

Inferior rectal a.

The m ale pelvis also contains veins draining the penis and scrotum .

* In the female pelvis, the uterine and vaginal arteries arise directly from the anterior division of the internal iliac artery.

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15. Rest of Body Ana tomy

Abdom inal aorta Inferior m esenteric artery Left com m on iliac artery and vein

Median sacral artery Right internal iliac artery and vein

Right um bilical artery

Right iliolum bar artery

Right ureter

Right lateral sacral vein

Right external iliac artery and vein

Right superior gluteal artery and vein

Right obturator artery and vein

Superior rectal artery and vein (from /to inferior m esenteric artery and vein)

Right superior vesical artery and vein

Right inferior vesical artery and vein

Right ductus deferens and artery

Right m iddle rectal artery and vein

Left ureter

Sem inal gland

Left superior and inferior vesical artery and vein

Left m iddle rectal artery and vein

Dorsal penile artery, deep dorsal penile vein Prostate

Left inferior rectal artery and vein

Sperm atic cord

Left internal pudendal artery and vein Posterior scrotal branches, posterior scrotal artery and vein

A

Right com m on iliac artery Right ovarian artery and vein (in ovarian suspensory ligam ent) Right um bilical artery Right ureter

Right internal iliac artery Median sacral artery Right iliolum bar artery Internal iliac artery and vein, anterior division Right uterine artery and vein Right inferior vesical artery, vesical vein

Right superior vesical artery

Superior rectal artery and vein

Right ovary and uterine tube

Right vaginal artery

Right obturator artery and vein

Right m iddle rectal artery and vein Uterine venous plexus

Right external iliac artery and vein Right round ligam ent of uterus

Left uterine artery and vein Vaginal venous plexus

Left superior vesical artery, vesical vein

Left m iddle rectal artery and vein

Left ureter

Left inferior vesical artery, vesical vein

Deep dorsal clitoral vein

Left inferior rectal artery and vein Left internal pudendal artery and vein

B

Fig. 15.115 Blood vessels of the pelvis Idealized right hemipelvis, left lateral view. A Male pelvis. B Fem ale pelvis.

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Appendices Appendix A Anatomy of Local Anesthesia for Dentistry Appendix B Factual Questions & Answer Explanations Appendix C Clinical Questions & Answer Explanations

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Appendix A

Ana tomy of Loca l Anesthesia for Dentistry

dentists try to maxim ize the duration of pulpal anesthesia and minimize the undesirable persistence of soft tissue anesthesia. The duration of pulpal anesthesia and the duration of soft tissue anesthesia of some of the main local anesthetic agents following m axillary infiltration and an inferior alveolar nerve block are listed in Table A.1.

General Principles of Local Anesthesia Physiology of Peripheral Nerve Depolarization

General Injection Technique

When a nerve is inactive (not generat ing act ion potent ials), there is a potential difference across it s m em brane, which is known as t he rest ing m em brane potent ial (RMP) and is m easured in m illivolt s (m V). Nerve cells have an RMP of −70 m V, which is est ablished by differences in pot assium and sodium ion concent rat ions across t he rest ing cell m em brane — high pot assium concent rat ion intercellularly and high sodium ion concent rat ion extracellularly. At rest , t he nerve cell is relatively resist ant to ion passage, but on e xcit at ion, volt age-gated sodium channels open, and t here is a slow influx of sodium ions into t he cell. When a t hreshold potent ial is reached, depolarizat ion occurs, and there is a fast influx of sodium ions into t he cell, causing t he po tent ial across the m em brane to becom e posit ive (+40m V). The sodium channels quickly close again, prevent ing further sodium influx. At t he sam e tim e, pot assium channels open, and t here is pot assium efflux from t he cell. This causes repolarization of the cell m em brane back to t he RMP. The depolarization of a nerve cell initiates a sequential series of depolarizations along the nerve fiber, thus propagating the impulse (action potential) along the fiber. In myelinated nerve fibers, the depolarizations “jump” from one node of Ranvier to the next (saltatory conduction). In unmyelinated fibers (which do not have nodes of Ranvier), the depolarization spreads to adjacent cells.

Mechanism of Action of Local Anesthetics

The fingers of the supporting hand retract the soft tissue around the injection site, enabling the dentist to visualize the target area. These fingers may also be used to provide stabilit y for the syringe and can act as reference points for some injections. When ready to inject, the needle is inserted gently and directly in one continuous m ovem ent to the target area. The dentist should then aspirate to ensure that the tip of the needle does not lie within a blood vessel. Most dental syringes are “self-aspirating,” m eaning that if the plunger of the syringe is slightly deployed, it bounces back, aspirating (sucking) as it does so. If the syringe is not self-aspirating, aspiration is perform ed by drawing back slightly on the plunger. The absence of blood in the local anesthetic cartridge suggest s that no vessel has been breached. If there is blood in the cartridge, the needle tip should be repositioned slightly and aspiration repeated. Following a negative aspiration result, the local anesthetic is injected slowly, exerting as little pressure as possible. Injection into the hard palate and interdental papillae are exceptions because the m ucosa is tightly adherent to the supporting periosteum in these areas, necessit ating that som e pressure is used.

Classification of Injection Techniques

Local anesthetics block the inner (cytoplasmic) gate of sodium channels in nerve cells, preventing sodium influx and action potential initiation and propagation. Term ination of action of the anesthetic at the site of injection is by diffusion of the active drug into the systemic circulation, followed by metabolism and elim ination

Infiltration

Duration of Anesthesia

Local anesthetic solution is deposited around the main nerve trunk and therefore anesthetizes all of the branches distal to this.

Local anesthetic solution is deposited at the level of the tooth apices and diffuses through alveolar bone to bathe the periapical nerves.

Nerve Blocks

Duration of dental local anesthesia can be defined in terms of duration of pulpal anesthesia versus the duration of soft tissue anesthesia. Usually,

Table A.1

Duration of anesthesia w ith some local anesthetic agents

Local anesthetic agent

Maxillary infiltration

Inferior alveolar nerve block

Duration of pulpal anesthesia (min)

Duration of soft tissue anesthesia (min)

Duration of pulpal anesthesia (min)

Duration of soft tissue anesthesia (min)

Lidocaine 2% with 1:100,000 epinephrine*

45−60

170

85

190

Articaine 4% with 1:100,000 epinephrine*

45−60

190

90

230

Bupivacaine 0.5% with 1:200,000 epinephrine*

90

340

240

440

Prilocaine 4% plain

20

105

55

190

Mepivacaine 3% plain

25

90

40

165

* The duration of action is prolonged when com bined with epinephrine, a vasoconstrictor. A “plain” solution contains no vasoconstrictive agent.

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Appendix A

Overview of Nerves Anesthetized Injections given within the oral cavit y anesthetize a branch or branches of either the maxillary or m andibular division of the trigeminal nerve (CN V2 or CN V3 , respectively) on the same side as the injection (Figs. A.1 and A.2).

Failure of Anesthesia Patient Variation

Ana tomy of Loca l Anesthesia for Dentistry

Allergic Reactions Allergy to local anesthetic is uncom m on but possible. It m ay be due to allergy to the drug, allergy to the additives for com pounding the drug, or latex allergy to the rubber bung located at one end of a local anesthetic cartridge. Allergy m anifest s as facial flushing, swelling, rash, itching, and wheezing. The patient should be sent for allergy testing to determ ine the precise cause. For m inor allergic reactions, provide reassurance, and antihistam ines if necessary. For severe (anaphylactic) reactions, urgently call for an am bulance, place the patient in a supine position, and give em ergency m edication as needed (e.g., intram uscular epinephrine, intravenous hydrocortisone, and oxygen by m ask).

A t ypical dose of local anesthetic profoundly anesthetizes som e patients and may not sufficiently anesthetize others. The dentist must try to ascertain whether failure is due to patient variation or improper injection technique. If due to the former, then m ore local anesthetic may be given to achieve adequate anesthesia. Likewise, differences occur bet ween patients in the duration of action of anesthetics. The best way to m itigate these differences is to begin treatm ent as soon as anesthesia is achieved: ~ 2 minutes after injection for an infiltration and ~ 5 minutes after injection for a block.

Cardiovascular Collapse

Acute Pulpitis or Apical Abscess

Hematomas

Acute pulpitis (pulpal inflamm ation) results in a hyperemic tooth (a tooth in which the pulpal blood vessels dilate causing a painful increase in pressure) that is difficult to adequately anesthetize. The pus of an apical abscess can prevent proper diffusion of the local anesthetic solution to the periapical nerves and vessels.

Small hematomas are of lit tle consequence. Larger hematom as can com promise the airway.

Intravascular Injection If all or part of an injection of local anesthetic is deposited intravascularly, then there m ay be lit tle or no anesthesia achieved.

Injection into Muscles or Their Fascia If the local anesthetic is deposited in a muscle or its fascia instead of into the bone near the teeth apices, then the distance the anesthetic has to diffuse to reach the apical nerves and vessels is increased, resulting in reduced anesthesia. Injection into a m uscle can also produce trismus (restricted mouth opening).

Com plications and Their Treatm ent Fainting This is the most comm on systemic complication and is likely at tributed to anxiet y over the procedure. It can be m inimized by administering local anesthetic with the patient supine. If fainting does occur, place the patient in a supine position, and recovery will occur rapidly.

Cardiovascular collapse may be precipitated by, or exacerbated by stress, excessive amounts of local anesthetic, and improper aspiration, leading to deposition of local anesthetic in a blood vessel. Epinephrine in the local anesthetic can act directly on the heart, which, if previously diseased, can cause arrhythmias. If this occurs, urgently call for an ambulance, place the patient in a supine position, and maintain airway and circulation.

No treatment is needed for small hematomas; large hematomas due to arterial bleeding, if they are not self-lim iting, may require ligation of the vessel.

Trismus Trismus is the inabilit y to open the mouth norm ally. It usually occurs after an inferior alveolar nerve block that is given too low, resulting in hematom a formation in the medial pterygoid. This may be accompanied by infection. Treatment includes reassurance, antibiotics, and encouragement to progressively try to open the mouth.

Facial Paralysis Facial paralysis (or palsy) may occur following an improperly placed inferior alveolar nerve block. If the needle is directed too far posteriorly, the tip may enter the superficial layer of deep cervical fascia that surrounds the parotid gland. Local anesthetic is therefore able to penetrate the gland and anesthetize the five branches of the facial nerve that are em bedded within it. This is manifested by the patient’s inabilit y to frown or blink and drooping of the mouth on the affected side. The facial paralysis is transient, normally lasting for ~ 1 hour. Treatment includes reassurance and a protective eye covering until the blink reflex returns.

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Appendix A

Ana tomy of Loca l Anesthesia for Dentistry

Trigem inal n. (CN V)

Maxillary division (CN V2 , via foram en rotundum )

Pterygopalatine ganglion

Posterior Middle Anterior

Superior alveolar nn.

Zygom atic n. Infraorbital n. (and foram en)

Mandibular division (CN V3 , via foram en ovale)

Long buccal n.

Auriculotem poral n.

Medial and lateral pterygoid nn. Masseteric n. Mylohyoid n. Lingual n.

Inferior alveolar n. (in m andibular canal) Inferior dental branches

Fig. A.1 Trigeminal nerve in the oral cavity Right lateral view.

Mental n. (and foram en)

Superior labial branches Anterior and m iddle superior alveolar branches

Nasopalatine n.

Posterior superior alveolar branches

Greater palatine n.

Long buccal n.

Lesser palatine n.

Fig. A.2 Innervation of the hard palate Inferior view.

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Ana tomy of Loca l Anesthesia for Dentistry

Appendix A

Maxillary Anesthesia

•

Maxillary Incisors and Canines

Clinical Considerations

Anatomy The incisors and canines and their associated periodontal ligam ents, buccal gingiva, mucosa, and supporting bone are innervated by the anterior superior alveolar nerves, which branch off the infraorbital nerve just before it em erges from the infraorbital foram en (Table A.2). These nerves anastomose over the midline. The palatal gingiva, mucosa, and supporting bone are innervated by the nasopalatine nerve, which em erges through the incisive foramen. The medial spread of local anesthetic m ay be hindered by the labial frenulum that anchors the lip to the at tached gingiva in the midline. The maxillary bone has a thin, porous lamina (layer) easily penetrated by an infiltration of local anesthetic solution.

Injection Technique •

•

Insert the needle in the m ucobuccal fold im mediately superior to the crown of the tooth being anesthetized and pass it axially toward the apex of the tooth (Fig. A.3A and B). The needle should be in close proxim it y to the bone to ensure that the local anesthetic solution has m inimal diffusion distance before it bathes the periapical nerves and vessels. Following a negative aspiration result, slowly inject 1.0 to 1.8 mL of local anesthetic.

For central incisors, the injection is best placed distally due to the close proximit y of the anterior nasal spine.

•

A m ucobuccal fold infiltration is sufficient for cavit y preparation and pulpal procedures.

•

Extractions will require supplementary anesthesia of the palatal gingiva, m ucosa, and supporting bone, either by local infiltration of the palate (p. 480) or by a nasopalatine block (p. 479).

•

Painful injection Ta ble A.2

Anesthesia of maxillary incisors and canine

Areas anesthetized* (see Fig. A.3C and D)

Nerve (Fig. A.3B)

Maxillary central, lateral incisor* and canine** and their associated periodontal ligam ent s, buccal gingiva, m ucosa, and supporting bone

Anterior superior alveolar nerve

Lateral aspect of the nose

External nasal branch fibers of the infraorbital nerve

Upper lip

Superior labial branch fibers of the infraorbital nerve

* This applies when the injection is placed superior to the maxillary lateral incisor. ** The root of the canine is longer, and the apical part of the root is often distally oriented; therefore, the maxillary right canine m ay not be sufficiently anesthetized for cavit y preparation from this injection alone.

Infraorbital nerve Anterior superior alveolar nerves

B

A

C Fig. A.3 Infiltration of the maxillary lateral incisor A Injection technique. B Nerves anesthetized, anterior view. C Areas anesthetized, right lateral view.

D

D Areas anesthetized, inferior view. Note the lips roughly extend to the first premolar region on each side; the cheeks are colored gray.

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Ana tomy of Loca l Anesthesia for Dentistry

Infraorbit al Nerve Block

•

Hematom a is rare with this injection, but there is potential for iatrogenic (accidental, clinician-induced) dam age to the patient’s eye.

Anatomy

•

To obtain complete anesthesia of the central incisor on the sam e side as the injection, it may be necessary to block anastomosing fibers from the anterior superior alveolar nerve on the contralateral side of the midline. This is achieved by placing a supplemental 0.5 mLof local anesthetic in the contralateral buccal fold, just distal to the central incisor.

The infraorbital nerve is a continuation of the maxillary nerve as it enters the infraorbital canal. The anterior superior alveolar nerve and middle superior alveolar nerve (when present) branch from this nerve just before it exits the infraorbital canal and are therefore also anesthetized by diffusion of local anesthetic from the injection site (Table A.3).

Injection Technique •

•

Table A.3

Palpate the center of the inferior margin of the orbit with the index finger of the supporting hand. At a point ~ 1 cm below the orbital margin, the infraorbital foram en can be palpated. Hold the index finger at that point, while retracting the upper lip with the thum b of the supporting hand. Insert the needle at the m ucobuccal fold imm ediately superior to the 1st maxillary prem olar, parallel to the long axis of the tooth, toward the tip of the index finger (Fig. A.4A and B). Following a negative aspiration result, slowly inject ~ 1 mL of local anesthetic.

Clinical Considerations •

•

To avoid having to give more than one injection, an infraorbital block may be used to anesthetize multiple teeth for cavit y preparation or pulpal procedures. It may also be used when infiltration has failed to achieve pulpal anesthesia or is contraindicated (e.g., infiltration would require an injection into an infected area).

Anesthesia follow ing an infraorbital nerve block

Areas anesthetized (Fig. A.4C and D)

Nerve (Fig. A.4B)

Incisors and canine and their associated periodontal ligam ent, buccal gingival, m ucosa, and supporting bone

Anterior superior alveolar nerve

Prem olars and possibly the m esiobuccal cusp of the 1st molar and their associated periodontal ligam ent, buccal gingival, m ucosa, and supporting bone

Middle superior alveolar nerve or fibers from the superior dental plexus

Lateral aspect of the nose

External nasal branches of the infraorbital nerve

Lower eyelid

Inferior palpebral branches of the infraorbital nerve

Upper lip and m ucosa

Superior labial branches of the infraorbital nerve

Extractions of any of the teeth anesthetized by an infraorbital block will require supplementary anesthesia of the palatal gingiva by a nasopalatine or greater palatine block or by local infiltration of the palate.

Inferior palpebral nerve Infraorbital nerve

External nasal nerve Anterior superior alveolar nerves

Middle superior alveolar nerves

B

Superior labial nerve

A

C Fig. A.4 Infraorbital nerve block A Injection technique. B Nerves anesthetized, right lateral view.

D

C Areas anesthetized, right lateral view. D Areas anesthetized, inferior view.

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Appendix A

Maxillary Prem olars

Clinical Considerations •

A m ucobuccal fold infiltration is sufficient for cavit y preparation and pulpal procedures.

•

Extractions will require supplementary anesthesia of the palatal gingiva, mucosa, and supporting bone, usually by one local infiltration injection of the palate bet ween the premolars.

Anatomy The prem olar area is innervated by the superior dental plexus, which is formed by convergent branches from the posterior superior alveolar nerve and the anterior superior alveolar nerve. Som etim es there is a middle superior alveolar nerve that, when present, innervates the premolars, their periodontal ligaments, buccal gingiva, and supporting bone, and often the mesiobuccal root of the first molar (Table A.4). The palatal gingiva, mucosa, and supporting bone adjacent to the prem olars is m ainly innervated by the greater palatine nerve, but the area of the first premolar m ay also be innervated by fibers of the nasopalatine nerve. Diffusion of local anesthetic deposited in the m ucobuccal fold is especially good in this area because the bone lam ina is thin, and the apices of the premolars lie very close to the lam ina. Consequently, small volum es of local anesthetic are required, and the palatal roots of the premolars are almost always anesthetized by this one injection.

Injection Technique The same infiltration technique is used as for the incisors and canines. Deposit 1.0 to 1.5 mL of local anesthetic solution around the apex of the prem olars (Fig. A.5A and B).

Anesthesia of maxillary premolars

Ta ble A.4

Area anesthetized* (Figs. A.5C and D)

Nerve (Fig. A.5B)

Both m axillary prem olars* and their associated periodontal ligament s, buccal gingival, m ucosa, and supporting bone

Middle superior alveolar nerve or branches of the superior dental plexus

Canine and the m esiobuccal cusp of the 1st molar** and their associated periodontal ligam ent s, buccal gingival, m ucosa, and supporting bone * This applies when the injection is placed bet ween the prem olars. ** These teeth, soft tissues, and bone m ay also be anesthetized to a lesser extent.

Superior dental plexus

B

A

C Fig. A.5 Infiltration of the maxillary premolars A Injection technique. B Nerves anesthetized, right lateral view.

D C Areas anesthetized, right lateral view. D Areas anesthetized, inferior view.

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Ana tomy of Loca l Anesthesia for Dentistry

Maxillary Molars

•

Extractions will require supplem entary anesthesia of the palatal gingiva, mucosa, and supporting bone by greater palatine block or by local infiltration.

Anatomy

•

For infiltration injections of the maxillary third molars, the patient should not be asked to open too widely; otherwise, the coronoid process of the m andible is moved anteriorly and can cover the injection site.

The molar region of the maxilla is innervated by the posterior superior alveolar nerve, which branches from the infraorbital nerve before it enters the infraorbital canal. These branches enter foramina on the infratem poral surface of the m axilla, where they enter to innervate the maxillary molars and their associated periodontal ligaments, buccal gingiva, mucosa, and supporting bone (Table A.5). The distance bet ween the mucobuccal fold and the apices of the maxillary molars varies from patient to patient. This distance may be increased by the lower margin of the zygomatic arch or when the maxillary sinus extends down bet ween the buccal and palatal roots. This can lead to failure of a buccal infiltration injection.

Injection Technique •

•

The same infiltration technique as for incisors and canines is used. Introduce the needle to the mucobuccal fold slightly mesially to the maxillary first molar (Fig. A.6A and B). A second injection m ay be given in the mucobuccal fold at the distal aspect of the maxillary first molar to ensure the tooth is adequately anesthetized.

Table A.5

Anesthesia of maxillary molars

Area anesthetized* (Fig. A.6C and D)

Nerve (Fig. A.6B)

Mesiobuccal cusp of the 1st m olar

Middle superior alveolar nerve (if present)

1st and 2nd molar* and their associated periodontal ligaments, buccal gingival, m ucosa, and supporting bone

Posterior superior alveolar nerve

Lateral aspect of the lip (may be very slight or absent)

Superior labial branches of the infraorbital nerve

* This applies when injection is placed m esially and distally to the 1st molar.

Following a negative aspiration result, slowly inject 1.0 to 1.8 mL of local anesthetic is.

Clinical Considerations •

A mucobuccal fold infiltration injected is usually sufficient for cavit y preparation and pulpal procedures. Rarely, it may be necessary to perform a palatal injection to achieve complete anesthesia of the palatal root.

Middle superior alveolar nerve Posterior superior alveolar nerve

B

A

C Fig. A.6 Infiltration of the maxillary molars A Injection technique. B Nerves anesthetized, right lateral view.

D

C Areas anesthetized, right lateral view. D Areas anesthetized, inferior view.

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Appendix A

Posterior Superior Alveolar Nerve Block Anatomy The posterior superior alveolar nerve is located in the infratemporal fossa and lies in close proxim it y to the pterygoid plexus of veins (Table A.6).

Injection Technique •

•

•

Instruct the patient to open his or her m outh and swing the mandible toward the same side to allow bet ter visualization of the injection site and more room to m aneuver. Insert the needle into the mucobuccal fold just superior to the maxillary second m olar, bet ween the medial border of the ramus of the m andible and the maxillary tuberosit y. Then advance the needle inward, backward, and upward 1.5 to 2.0 cm (Fig. A.7A and B). Following a negative aspiration result, slowly deposit 1.0 to 1.8 mL of local anesthetic .

Extractions will require supplementary anesthesia of the palatal gingiva, mucosa, and supporting bone by a greater palatine nerve block or by local infiltration.

Notes There is a significant risk of hematom a by introduction of the needle into the pterygoid plexus. Short needles and careful aspiration reduce this risk.

Ta ble A.6

Anesthesia follow ing a posterior superior alveolar nerve block

Areas anesthetized* (Fig. A.7C and D)

Nerve (Fig. A.7B)

Maxillary 1st,* 2nd, and 3rd m olars and their associated periodontal ligaments, buccal gingival, m ucosa, and supporting bone

Posterior superior alveolar nerve

* The mesiobuccal root of the 1st m olar may not be anesthetized and may therefore require supplem ental buccal infiltration anesthesia m esial to the 1st m olar (to anesthetize the middle superior alveolar nerve).

Clinical Considerations •

•

This injection is sufficient for cavit y preparation and pulpal procedures on all of the maxillary molars.

Pterygopalatine ganglion Posterior superior alveolar nerves

B A

C Fig. A.7 Posterior superior alveolar nerve block A Injection technique. B Nerves anesthetized, right lateral view.

D

C Areas anesthetized, right lateral view. D Areas anesthetized, inferior view.

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Ana tomy of Loca l Anesthesia for Dentistry

Maxillary Division Block

•

The needle should never be forced into the greater palatine foramen to avoid fracture of the wall of the greater palatine canal.

Anatomy

•

If the needle is placed too far superiorly, the anesthetic can be deposited in the eye, affecting vision.

•

Hematom a formation may occur due to rupture of the vessels that also run in the greater palatine canal.

The maxillary division block is an advanced local anesthetic technique. It uses the greater palatine canal to reach the pterygopalatine fossa and therefore enables the dentist to anesthetize all branches of the maxillary nerve (Table A.7). The canal is usually vertical, thus aiding this procedure.

Injection Technique

Table A.7

Anesthesia follow ing a maxillary division block

Areas anesthetized (Fig. A.8C and D)

Nerve (Fig. A.8B)

All m axillary teeth and their associated periodontal ligaments, buccal gingiva, m ucosa, and supporting bone

Anterior, m iddle (if present), and posterior superior alveolar nerves

•

Locate the greater palatine foram en with a cot ton swab applicator, which can be felt to sink slightly into the foramen. Inject a small amount of anesthetic. This lessens patient’s discomfort for the next part of the procedure.

•

Insert the needle into the greater palatine foram en ~ 28 to 30 mm. The needle tip should now be located in the pterygopalatine fossa (Fig. A.8A and B).

All palatal gingival, mucosa, and supporting bone

Nasopalatine nerve (anterior one-third) and greater palatine nerve (posterior t wo-thirds)

•

Following a negative aspiration result, slowly inject 1 to 2 mL of local anesthetic.

Lateral aspect of the nose

External nasal branches of the infraorbital nerve

Lower eyelid

Inferior palpebral branches of the infraorbital nerve

Upper lip

Superior labial branches of the infraorbital nerve

Clinical Considerations •

This injection is useful when extensive restorative dentistry and surgical procedures are needed.

External nasal nerve

Pterygopalatine ganglion

Lesser palatine nerves

B Greater palatine nerve

A

C

D

Fig. A.8 Maxillary division block A Injection technique, inferior view. B Nerves anesthetized, left lateral view of the right lateral nasal wall with the pterygopalatine ganglion exposed. .

C Areas anesthetized, right lateral view. D Areas anesthetized, inferior view.

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Appendix A

Nasopalatine Nerve Block

•

Anatomy The nasopalatine nerve is a branch of the m axillary nerve that passes through the pterygopalatine ganglion (Table A.8). It enters the nasal cavit y through the sphenopalatine foram en, passes across the roof of the nasal cavit y, then runs obliquely downward and forward in the nasal septum bet ween the supporting bone and mucous mem brane. It descends farther through the incisive canal and emerges into the anterior hard palate through the incisive foramen. Branches of the nasopalatine nerve anastomose with branches of the contralateral nasopalatine nerve and with the greater palatine nerve. Because the right and left nasopalatine nerves exit the incisive foram en in close proximit y, one injection anesthetizes both sides of the anterior one third of the hard palate.

Injection Technique •

Using a cot ton swab applicator, apply pressure close to the injection site to reduce the perception of pain. Insert the needle into the palatal m ucosa lateral to the incisive papilla until bone is contacted (Fig. A.9A and B).

After withdrawing the needle slightly and following a negative aspiration result, inject a very small volume of local anesthetic under m inimal pressure. The tissue will be seen to blanch due to the vasoconstrictor in the local anesthetic solution.

Clinical Considerations •

This injection is used to supplement buccal infiltration injections for extraction of any of the maxillary anterior teeth.

•

This injection is widely perceived to be the m ost painful variet y of dental injection. It is particularly painful because the mucosa of the hard palate is tightly bound to the periosteum of the palate, allowing lit tle space for the diffusion of local anesthetic. Ta ble A.8

Anesthesia follow ing a nasopalatine nerve block

Area anesthetized (Fig. A.9C)

Nerve (Fig. A.9B)

The maxillary gingiva, mucosa, and supporting bone from the right m axillary canine to the left m axillary canine

Nasopalatine nerve

Nasopalatine nerve Incisive foram en

A

B

C

Fig. A.9 Nasopalatine nerve block A Injection technique, inferior view. B Nerves anesthetized, inferior view. C Areas anesthetized, inferior view.

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Ana tomy of Loca l Anesthesia for Dentistry

Greater Palatine Nerve Block

Clinical Considerations •

This injection is used to supplement buccal infiltration, infraorbital, or posterior superior alveolar nerve blocks for extractions of the maxillary teeth. It is more comm only performed than a nasopalatine or greater palatine nerve block.

•

The injection is painful.

Anatomy The greater palatine nerve is a branch of the maxillary nerve that passes through the greater palatine ganglion (Table A.9). It runs from the pterygopalatine fossa, down through the greater palatine canal, and through the greater palatine foramen to reach the hard palate. It then runs forward in a groove to a point just distal to the canine tooth.

Injection Technique •

The greater palatine foramen lies ~ 0.5 to 1.0 cm mesial to the margin of the gingiva at the distal border of the maxillary second m olar (Fig. A.10A and B). It should be located by using a cot ton swab applicator, which can be felt to sink slightly into the foram en. With the cot ton swab applicator, apply pressure close to the injection site to reduce the perception of pain. Insert the needle until it contacts bone. Withdraw it slightly, then aspirate.

•

Following a negative aspiration result, slowly inject around 0.1 mL of local anesthetic.

Table A.10

Supplementary infiltration of the palate

Areas anesthetized

Nerve

Palatal gingival, mucosa, and supporting bone in the vicinit y of the injection site

Fibers of the nasopalatine nerve and/or greater palatine nerve

Clinical Considerations •

This injection is used to anesthetize palatal tissues for multiple extractions involving the m axillary premolars and molars on one side. It may also be useful for mucogingival surgical procedures.

•

Bone contact prior to injection is necessary to ensure that the needle is not in the soft palate.

•

The palate in the region of the greater palatine foramen is tightly bound to the supporting bone but less so than at the incisive foramen. Therefore, although still painful, this injection is less so than for the nasopalatine nerve block.

Table A.9

A Greater palatine nerve Greater palatine foram en

Anesthesia follow ing a greater palatine nerve block

Area anesthetized (Fig. A.10C)

Nerve (Fig. A.10B)

The m axillary gingiva, m ucosa, and supporting bone from the maxillary 1st prem olar to the posterior hard palate to the m idline of the hard palate

Greater palatine nerve

Supplem ent ary Infiltration of the Palate

B

Anatomy Supplementary infiltration of the palate may anesthetize fibers of the nasopalatine nerve and/or greater palatine nerve (depending on the site of the injection) (Table A.10).

Injection Technique •

Using a cot ton swab applicator, apply pressure close to the injection site to reduce the perception of pain. Insert the needle into the palatal mucosa ~ 1 cm from the neck of the tooth to be anesthetized, until bone is contacted.

•

Withdraw the needle slightly and aspirate.

•

Following a negative aspiration result, inject ~ 0.1 mL of local anesthetic. The m ucosa will be seen to blanch due to the vasoconstrictor in the local anesthetic.

C Fig. A.10 Greater palatine nerve block A Injection technique, inferior view. B Nerves anesthetized, inferior view. C Areas anesthetized, inferior view.

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Appendix A

Mandibular Anesthesia

Clinical Considerations •

A m ucobuccal fold injection is sufficient for cavit y preparation and pulpal procedures of the m andibular incisors.

Mandibular Incisors and Canines

•

Extractions require supplem ental anesthesia of the lingual gingiva, m ucosa, and supporting bone by sublingual infiltration (p. 487).

Anatomy The incisors and canines are innervated by the incisive nerve, a terminal branch of the inferior alveolar nerve (Table A.11). Its course lies within bone, but it m ay be anesthetized by infiltration because the bone lamina in this area of the m andible is thin and porous. Because the bone around the canine teeth in adults m ay be denser, infiltration anesthesia may fail. In this case, a mental nerve block or inferior alveolar nerve block can be used to ensure sufficient anesthesia of a canine tooth. The buccal soft tissues are innervated by the mental nerve, while the lingual gingiva and supporting bone are supplied by the sublingual nerve (a branch of the lingual nerve).

Ta ble A.11

Anesthesia of mandibular incisors and canine

Areas anesthetized* (Fig. A.11C)

Nerve (Fig. A.11B)

Mandibular central and lateral incisors and canine (to a lesser extent)*

Incisive nerve

Periodontal ligaments, buccal gingiva, m ucosa, and supporting bone associated with the incisors

Mental nerve

Lower lip Chin * This applies when the injection is placed at the m andibular lateral incisor.

Injection Technique The same infiltration technique is used as for the maxillary incisors and canines. Deposit around 1 mLof local anesthetic around the apices of the teeth (Fig. A.11A and B, Table A.11).

CN V3

CN V1 CN V2 Chorda t ympani Lingual nerve

Long buccal nerve Inferior alveolar nerve

A

B

C

Mental nerve (em erging from mental foram en)

Incisive nerve (within bone)

Fig. A.11 Infiltration of the mandibular incisors A Injection technique, anterior view. B Nerves anesthetized, anterior view. C Areas anesthetized, superior view.

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Ana tomy of Loca l Anesthesia for Dentistry

Ment al Nerve Block

•

For extractions of the mandibular first premolar, a supplem entary sublingual nerve infiltration is required. For extractions of the mandibular second premolar, an inferior alveolar nerve block is performed during which the lingual nerve is concurrently blocked.

Anatomy The mandibular first premolar is innervated by the mental nerve in the mandibular canal (Table A.12). The m andibular second premolar is mainly innervated by the inferior alveolar nerve. The periodontal ligaments, buccal gingiva, m ucosa, and supporting bone in the premolar area are innervated by the mental nerve, while the lingual gingiva is supplied by the sublingual nerve. The mental foramen lies bet ween and inferior to the apices of the mandibular premolar teeth. The t hick, com pact bone in t he m andibular prem olar region does not norm ally allow anesthesia of t hese teet h to be achieved by infilt rat ion anesthesia; therefore, a m ent al nerve block or inferior alveolar nerve block is used. The except ion to this is if art icaine is used; in t hat case, infilt rat ion anest hesia is effect ive (art icaine can achieve anest hesia of all m andibular teet h wit h the except ion of the second and third m o lars). The anatom ic direction of the canal that allows passage of the m ental nerve is medial→anterior→caudal. The needle should not be oriented in this direction to prevent dam age to the mental nerve and vessels within the canal. Table A.12

A CN V1

CN V2

Anesthesia follow ing a mental nerve block

Areas anesthetized* (Fig. A.12C)

Nerve (Fig. A.12B)

Mandibular 1st prem olar

Mental nerve

Mandibular 2nd premolar*

Inferior alveolar nerve and perhaps som e fibers from the m ental nerve

Canine, lateral, and central incisor

Incisive nerve**

All periodontal ligam ents, buccal gingiva, mucosa, and supporting bone from the 2nd prem olar to the central incisor

Mental nerve

Lower lip and chin

Mental nerve

Long buccal nerve

* Unreliably anesthetized, as sufficient anesthetic has to diffuse through the m ental foram en and spread distally to anesthetize fibers of the inferior alveolar nerve, which innervates this tooth. ** The incisive nerve is incidentally anesthetized by diffusion of local anesthetic during this block.

•

Locate the m ental foramen by palpation or by referring to a radiograph.

•

Insert the needle into the mucobuccal fold bet ween the first and second mandibular prem olar.

•

Advance the needle until it is at the level of the mental foram en (Fig. A.12A and B).

•

Following a negative aspiration result, slowly inject 1.0 to 1.5 mL of local anesthetic.

CN V3

Inferior alveolar nerve

B

Injection Technique

Lingual nerve

Mental nerve from m ental foramen

Clinical Considerations •

This injection is sufficient for cavit y preparation and pulpal procedures on the mandibular 1st prem olar. Cavit y preparation may be able to be performed on the m andibular second prem olar if anesthesia permits, but pulpal procedures and extensive cavit y preparations are likely to require an inferior alveolar nerve block to be performed for adequate anesthesia.

C Fig. A.12 Mental nerve block A Injection technique. B Nerves anesthetized, right lateral view. C Areas anesthetized, superior view.

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Incisive nerve

Appendix A

Inferior Alveolar Nerve Block

Clinical Considerations •

This injection is sufficient for cavit y preparations, pulpal procedures, and surgical procedures involving the lingual aspect of the m andibular teeth.

•

Extractions of the mandibular m olars require supplemental anesthesia of the long buccal nerve.

•

The patient may describe an “electric shock” if the tip of the needle directly touches the inferior alveolar nerve. In this case, the needle should be withdrawn slightly, as the nerve may be dam aged by intraneural injection, and the symptoms are often persistent.

•

The m andibular foramen is not at the same level in all patients; therefore, this technique has to be modified accordingly. In children, it is located closer to the posterior border of the mandible until more bone is produced. In edentulous patients, alveolar bone resorption has occurred, m aking the deepest part of the coronoid notch lower than normal. To avoid making the block too low, direct the needle higher than the deepest part of the coronoid notch.

•

In class II malocclusion, when the m andible is hypoplastic (underdeveloped), the m andibular foramen may be located more inferior than norm al.

•

In class III malocclusion, when the m andible is hyperplastic (overdeveloped) the mandibular foramen may be located more superior than norm al.

•

The medial pterygoid muscle is stretched and tense if the mouth is opened widely and may hinder proper placement of the needle. This can be overcome by slightly reducing mouth opening after the initial insertion of the needle.

•

If the needle is angled too far mesially, the bone of the temporal crest is contacted almost im mediately, and the needle should be repositioned laterally. If the needle is inserted too far posteriorly, then deposition of the local anesthetic solution may be m ade in the medial pterygoid m uscle, causing postoperative muscle pain and trismus (muscle spasm). If the needle continues farther posteriorly, then it m ay penetrate the capsule of the parotid gland. If local anesthetic is deposited within the capsule, it causes a transient facial paralysis (Bell’s palsy, see p. 471. Ensuring that the needle contacts bone at the appropriate depth ensures proper placement and mitigates the likelihood of any complications.

Anatomy All mandibular teeth are innervated by the inferior alveolar nerve (and its branches), which runs in the mandibular canal (Table A.13). The thick, compact bone in the mandibular molar region often does not allow for infiltration anesthesia. Anesthesia of the mandibular molars therefore requires blockade of the inferior alveolar nerve before it enters the mandibular canal. However, an infiltration injection of articaine has been shown to be effective in anesthetizing all m andibular teeth except the second and third molars.

Injection Technique •

Instruct the patient to open widely to ensure good visualization of the anatomic landmarks.

•

Palpate the coronoid notch of the mandible with the thumb of the supporting hand.

•

The deepest part of the coronoid notch (about halfway up the thum b) generally corresponds to the level of the mandibular foramen.

•

Move the thumb m edially to palpate the internal oblique ridge and then the pterygom andibular space, lateral to the pterygomandibular raphe. The index and m iddle fingers lie at the ramus and angle of the m andible to support the mandible.

•

Direct the needle from the contralateral premolar area into the pterygomandibular space at the level of the mandibular foram en, while keeping the needle parallel to the occlusal plane of the m andibular teeth on the injection side.

•

Insert the needle 20 to 25 mm until bone is contacted (Fig. A.13A and B).

•

Withdraw the needle slightly, then aspirate.

•

Following a negative aspiration result, slowly inject ~ 1.5 mL of local anesthetic into the pterygomandibular space.

•

The lingual nerve is concurrently blocked by withdrawing the needle about halfway (corresponding to the approximate level of the temporal crest), aspirating, and, if negative, slowly injecting the rem aining 0.5 mL of local anesthetic.

Ta ble A.13

Ana tomy of Loca l Anesthesia for Dentistry

Anesthesia follow ing an inferior alveolar nerve block

Areas anesthetized* (Fig. A.13C and D)

Nerve (Fig. A.13B)

All m andibular teeth

Inferior alveolar nerve

All buccal gingiva, m ucosa, and supporting bone from the 2nd premolar to the central incisor

Mental nerve

Lower lip and chin

Mental nerve

All lingual gingiva, m ucosa, and supporting bone

Lingual nerve (m olar region) and its sublingual branch (prem olar region to m idline)

Anterior t wo thirds of the tongue

Lingual nerve

* On the same side as the injection.

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Ana tomy of Loca l Anesthesia for Dentistry

CN V1 CN V2 CN V3 Chorda t ympani

Inferior alveolar nerve

Long buccal nerve

Mylohyoid nerve Lingual nerve

A

B

Medial pterygoid Inferior alveolar nerve, artery, and vein Lingual nerve Masseter Long buccal nerve Pterygomandibular raphe Buccinator

C

Fig. A.13 Inferior alveolar nerve block A Injection technique. B Nerves anesthetized, left lateral view. C Transverse section just above the occlusal plane of the mandibular teeth, superior view. D Areas anesthetized, superior view.

D

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Appendix A

Gow−Gates Block

•

Anatomy This block is a variation of the inferior alveolar nerve block. The aim is to anesthetize the inferior alveolar nerve at the level of the mandibular condyle but additional branches of CN V3 are also anesthetized by at injection given at this level (Table A.14).

Injection Technique

The rate of failure is lower and there are fewer aspiration issues than with the traditional inferior alveolar nerve block. Ta ble A.14

Anesthesia follow ing a Gow −Gates block

Area anesthetized* (Fig. A.14C)

Nerve (Fig. A.14B)

All m andibular teeth

Inferior alveolar nerve

All periodontal ligam ent s, buccal gingiva, m ucosa, and supporting alveolar bone from the 2nd prem olar to the 3rd molar

Long buccal nerve

Mental nerve

•

Instruct the patient to open as wide as possible.

•

Direct the needle from the contralateral premolars and insert the needle high into the mucosa at the level of the maxillary second molar, just distal to the mesiolingual cusp (Fig. A.14A and B).

All periodontal ligam ent s, buccal gingiva, m ucosa, and supporting alveolar bone from the 2nd prem olar to the central incisor

•

Use the intertragic notch of the ear as an extraoral landmark to help reach the neck of the mandibular condyle.

All lingual gingiva, supporting bone, and the mucosa of the floor of the m outh

Lingual nerve (m olar region) and its sublingual branch (prem olar to m idline)

•

When contact with the neck of the condyle is m ade, withdraw the needle slightly and aspirate.

Anterior t wo thirds of the tongue

Lingual nerve

Lower lip

Mental nerve

Following a negative aspiration result, slowly inject 1.0 to 1.8 mL of local anesthetic.

Skin in the temple region and the skin anterior to the ear

Auriculotemporal nerve

Posterior part of the cheek

Long buccal nerve

•

Clinical Considerations •

* On the same side as the injection.

This injection is useful for multiple procedures on mandibular teeth and buccal soft tissue.

CN V1 CN V2 CN V3 Chorda t ympani

Long buccal nerve

Inferior alveolar nerve Mylohyoid nerve Lingual nerve

A

B

C

Fig. A.14 Gow −Gates block A Injection technique. B Nerves anesthetized, left lateral view. C Areas anesthetized, superior view.

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Appendix A

Ana tomy of Loca l Anesthesia for Dentistry

Akinosi Block

Injection Technique •

Instruct the patient to close his or her mouth.

Anatomy

•

The Akinosi block is an alternative, closed-m outh m ethod of perform ing an inferior alveolar nerve block (Table A.15). It is useful when the patient has a lim ited abilit y to open the m outh, or when the patient has a strong gag reflex that is elicited by conventional inferior alveolar nerve block.

Insert the needle into the mucosa bet ween the medial border of the mandibular ram us and the m axillary tuberosit y at the level of the cervical margin of the m axillary m olars.

•

Advance the needle parallel to the maxillary occlusal plane ~ 20 to 25 mm . At this depth, the tip of the needle should be in the middle of the pterygom andibular space near the inferior alveolar and lingual nerves (Fig. A.15A and B).

•

Following a negative aspiration result, slowly inject the full cartridge of local anesthetic (1.8 m L).

Table A.15

Anesthesia follow ing an Akinosi block

Areas anesthetized* (Fig. A.15D)

Nerve (Fig. A.15B)

All m andibular teeth

Inferior alveolar nerve

All buccal gingiva, m ucosa, and supporting bone from the 2nd premolar to the central incisor

Mental nerve

All lingual gingiva, m ucosa, and supporting bone

Lingual nerve

Anterior t wo-thirds of the tongue

Lingual nerve

Lower lip

Mental nerve

Clinical Considerations •

This injection is sufficient for cavit y preparations, pulpal procedures, and surgical procedures involving the lingual aspect of the mandibular teeth.

•

Extractions of the mandibular molars require supplem ental anesthesia of the long buccal nerve.

* On the sam e side as the injection.

Chorda t ympani (CN VII) Long buccal nerve

Lingual nerve Inferior alveolar nerve Mylohyoid nerve

B A

Medial pterygoid Inferior alveolar nerve, artery, and vein Lingual nerve Long buccal nerve Masseter Pterygom andibular raphe Buccinator

Fig. A.15 Akinosi block A Injection technique. B Nerves anesthetized, left lateral view. C Transverse section just above the occlusal plane of the mandibular teeth, superior view. D Areas anesthetized, superior view.

D C

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Appendix A

Long Buccal Nerve Block

Clinical Considerations

Anatomy The long buccal nerve is a branch of the inferior alveolar nerve (Table A.16). It passes along the m edial side of the mandibular ram us anterior to the inferior alveolar nerve. It then crosses the anterior border of the m andibular ramus. Its branches innervate the buccal gingiva bet ween the mandibular second premolar and molars, as well as the retrom olar triangle Ta ble A.16

Ana tomy of Loca l Anesthesia for Dentistry

•

This injection is used to supplement a m ucobuccal fold infiltration or m ental nerve block for extractions of the mandibular incisors, canine, and prem olar teeth. It is not necessary for extraction of the m andibular molar teeth because the lingual nerve trunk is anesthetized as part of the inferior alveolar block given in these cases.

•

Hematoma formation may occur if the injection lacerates the vessels in the floor of the mouth.

Anesthesia follow ing a long buccal nerve block

Areas anesthetized* (Fig. A.16A)

Nerve (Fig. A.16B)

Buccal gingiva, m ucosa, and supporting bone from the m andibular 2nd prem olar to the last m olar and retromolar trigone

Long buccal nerve (from CN V3 )

Injection Technique •

Insert the needle into the buccal mucosa posterior to the last molar. It will only penetrate ~ 2 m m (Fig. A.16A and B).

•

Following a negative aspiration result, inject ~ 0.5 mL of local anesthetic.

A CN V3

Clinical Considerations •

Chorda t ympani (CN VII)

This injection is used to supplement an inferior alveolar nerve block for extractions or surgical procedures involving the mandibular second premolars to molars.

Supplem ent ary Sublingual Nerve Infiltration

Lingual nerve Long buccal nerve

Anatomy The lingual nerve passes downward together with the inferior alveolar nerve and com m unicates with the chorda t ym pani of the facial nerve just before reaching the m andibular foram en. This connection gives off secretory fibers to the subm andibular and sublingual glands via the subm andibular ganglion and t aste fibers to the anterior t wo-thirds of the tongue. The trunk of the lingual nerve gives off branches that innervate the lingual gingiva in the m olar region. The lingual gingiva and m ucosa of the floor of the m outh are innervated by the sublingual nerve, a branch of the lingual nerve (Table A.17). Ta ble A.17

Mylohyoid nerve

B

Supplementary sublingual nerve infiltration

Areas anesthetized*

Nerve

Lingual gingiva and supporting bone, and the m ucosa of the floor of the m outh in the vicinit y of the infiltration

Sublingual nerve

* On the same side as the injection.

C

Injection Technique •

Introduce the needle just below the at tached gingiva on the lingual side of the tooth requiring lingual anesthesia.

•

Following a negative aspiration result, slowly inject a sm all am ount of local anesthetic.

Fig. A.16 Long buccal nerve block A Injection technique. B Nerves anesthetized, superior view. C Areas anesthetized, superior view.

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Appendix B

Fa ctua l Questions & Answer Expla na tions

Factual Questions Chapter 1 Em bryology of the Head & Neck 1.

Maxillary prominence and m edial nasal prom inence Nasal septum and maxillary prom inence Maxillary prominence and lateral palatine processes Left and right lateral palatine processes Interm axillary segment

The interm axillary segm ent of the developing face provides the alveolar sockets for the A. B. C. D. E.

6.

Glossopharyngeal and vagus nerves Trigeminal and facial nerves Vagus and hypoglossal nerves Facial and glossopharyngeal nerves Trigeminal and glossopharyngeal nerves

Secondary cleft palate, without primary cleft palate or cleft lip, results from the failure of fusion of the A. B. C. D. E.

5.

Hard and soft palates Primary and secondary palates Lateral palatine processes Palatine and m axillary bones Medial nasal prom inences

The cranial nerves that carry sensory information from the part of the tongue derived from the hypopharyngeal eminence are the A. B. C. D. E.

4.

9.

The incisive foramen is an anatomical landm ark bet ween the A. B. C. D. E.

3.

Hyoid bone Nasal bone Palatine bone Stapes Occipital bone

Mandibular molars Maxillary canines Deciduous teeth Mandibular premolars Maxillary incisors

A child presents with a midline swelling at the base of of the tongue. Magnetic resonance imaging (MRI) shows a midsagit tal growth referred to as a lingual cyst by the radiologist. The em bryological origin of this lingual cyst is a A. B. C. D. E.

Persistent 1st pharyngeal groove Nonm igrating thyroid gland Laryngeotracheal diverticulum 2nd pharyngeal pouch Metastasis of the lingual tonsil

The anterom edial floor of the carotid canal in the petrous portion of the temporal bone is “open” to the nasopharynx through the A. B. C. D. E.

Foram en ovale Foram en lacerum Jugular foramen Foram en spinosum Mastoid foramen

10. The anterior cranial fossa is separated from the middle cranial fossa by the A. B. C. D. E.

Lateral pterygoid plate of the sphenoid bone Perpendicular plate of the ethm oid bone Lesser wing of the sphenoid bone Petrous part of the temporal bone Frontal crest of the frontal bone

11. What structure on the internal surface of the lateral wall of the cranial vault crosses over the area indicated by pterion? A. B. C. D. E.

Groove for the middle m eningeal artery Hypophyseal fossa Groove for the sigmoid sinus Internal acoustic meatus Crista galli of the ethmoid bone

12. The foram en rotundum exits the middle cranial fossa through which bone? A. B. C. D. E.

Petrous temporal Ethmoid Occipital Mandibular Sphenoid

13. The m ajorit y of the hard palate of the oral cavit y is formed from the union of the horizontal plate of the palatine bone with the A. B. C. D. E.

Medial pterygoid plate of the sphenoid bone Perpendicular plate of the ethm oid bone Palatine process of the maxilla Squam ous part of the temporal bone Alae of the vomer bone

14. The branch of the mandibular part of the maxillary artery that passes through the foramen spinosum is the

The hard palate has passages for branches of the maxillary division of the trigem inal nerve that include the incisive foram en for the nasopalatine nerve and the A. B. C. D. E.

Mental spine Pterygoid hamulus Coronoid process Lingula Condylar process

Chapter 3 Vasculature & Lymphatics of the Head & Neck

Chapter 2 Cranial Bones 7.

The m andibular foram en of the ramus is protected by the bony ________ in a superoanterior position. A. B. C. D. E.

The skeletal elem ents that develop within the 1st pharyngeal arch include the A. B. C. D. E.

2.

8.

Greater palatine foramen for the greater palatine nerve Infraorbital foram en for the infraorbital nerve Mental foramen for the m ental nerve Foramen rotundum for the maxillary nerve Sphenopalatine foramen for the nasopalatine nerve

A. B. C. D. E.

Middle meningeal artery Deep temporal artery Sphenopalatine artery Internal carotid artery Ophthalm ic artery

15. The inferior alveolar artery, supplying blood to the mandibular molars, is a branch of which artery? A. B. C. D. E.

Facial Maxillary Lingual Sphenopalatine Internal carotid

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Fa ctua l Questions & Answer Expla na tions

Appendix B

16. The vertebral artery is a branch of the A. B. C. D. E.

23. Which nerve innervates the middle ear m uscle that m odulates the motion of the stapes?

External carotid artery Comm on carotid artery Subclavian artery Arch of the aorta Brachiocephalic trunk

17. The danger zone (triangle) of the face deals with venous drainage from superficial veins into deep veins and intracranial venous sinuses. The direct com munication bet ween the angular (facial) vein and the cavernous sinus is via the A. B. C. D. E.

Pterygoid plexus Retromandibular vein Lingual vein Ophthalmic veins Brachiocephalic trunk

Comm on carotid External carotid Internal carotid Basilar Middle m eningeal

20. Normal venous drainage of the cavernous venous dural sinus is directly through the A. B. C. D. E.

Occipital Facial Nuchal Laryngeotracheal Deep cervical (jugular)

A. B. C. D. E.

Jugular foramen Internal auditory meatus Condylar canal Foramen magnum Foramen lacerum

26. The innervation for the hyoglossus muscle is the Ansa cervicalis Facial nerve Hypoglossal nerve Mylohyoid nerve Recurrent laryngeal nerve

27. The parasympathetic innervation to the parotid gland travels through the A. B. C. D. E.

Chorda t ympani Greater petrosal nerve Deep petrosal nerve Tympanic nerve Lingual nerve

28. The C8 spinal nerve exit s the vertebral canal Above the C7 vertebra Below the C7 vertebra Below the C8 vertebra Through the C8 transverse foramen Never because there is no C8 spinal nerve

29. During a routine physical, a patient comm ents to his primary care physician that he has tingling and a sensation of cold that is focused on the top of his right shoulder. The likely cause of this condition is A. B. C. D. E.

A. B. C. D. E.

22. The passageway in the skull through which the abducens nerve passes is the Superior orbital fissure Foramen rotundum Foramen ovale Infraorbital foram en Foramen spinosum

Lateral rectus Superior oblique Orbicularis oculi Rectus capitis lateralis Dilator pupillae

Osteophyte in the C1−C2 intervertebral foramen Compression of the axillary nerve C3−C4 slipped disk Referred pain from the spleen Avulsion of the C6 spinal nerve

30. The central nervous structure that develops from the em bryological myelencephalon is the

Chapter 4 Neuroanatomy & Innervation of the Head & Neck

A. B. C. D. E.

A. B. C. D. E.

A. B. C. D. E.

Straight sinus Petrosal sinuses External jugular vein Basilar vein Maxillary sinus

21. The superficial parotid (preauricular) lymph nodes drain directly into the ________ lymph nodes as the lymph drains back toward the cardiovascular system through either the lymphatic (right) or thoracic (left) ducts. A. B. C. D. E.

24. The extraocular muscle innervated by the trochlear nerve is the

A. B. C. D. E.

Brachiocephalic trunk Comm on carotid artery Thoracoacromial trunk Costocervical trunk Thyrocervical trunk

19. The m iddle cerebral artery is a direct branch of which artery? A. B. C. D. E.

Optic Oculomotor Vestibulocochlear Trigeminal Facial

25. The vagus nerve exits the posterior cranial fossa at the

18. While weightlifting, a 22-year-old m an at tempting a personal record on the parallel back squat drops the barbell across his upper back. The compression from the barbell ruptures his left dorsal scapular artery, and im mediately he starts to feel blood pooling deep to his trapezius and rhom boid m uscles. Compression to the ________ will stop the bleeding. A. B. C. D. E.

A. B. C. D. E.

Cerebral peduncle Thalamus Pons Medulla oblongata Tectum

31. The voluntary m otor cortex in the cerebral hem isphere is separated from the conscious body sensation cortex by the A. B. C. D. E.

Calcarine sulcus Parieto-occipital sulcus Sylvian (lateral) sulcus Longitudinal fissure Central sulcus

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Appendix B

Fa ctua l Questions & Answer Expla na tions

32. The flow of cerebrospinal fluid (CSF) in an individual with noncom municating hydrocephalus can be blocked by the choroid plexus in the A. B. C. D. E.

Cerebral aqueduct Pontom edullary cistern Cerebellomedullary cistern Confluence of sinuses Arachnoid granulations

41. The insertion (posterior at tachment) of the lateral pterygoid m uscle is the A. B. C. D. E.

Chapter 5 Face & Scalp

A. B. C. D. E.

Risorius Depressor labii inferioris Orbicularis oris Levator anguli oris Orbicularis oculi

34. Each of the following m uscles is innervated by a branch of the facial nerve passing through the parotid gland except the A. B. C. D. E.

Depressor anguli oris Buccinator Levator labii superioris Zygomaticus m inor Mentalis

Skin Connective tissue Epicranial aponeurosis Loose areolar connective tissue Pericranium

37. Which of the following arteries of the face is derived from the internal carotid artery? A. B. C. D. E.

Supraorbital Facial Lateral nasal Superficial temporal Transverse facial

Maxillary Transverse cervical Great auricular Greater occipital Facial

Anterior superior alveolar Buccal branch of the facial nerve Mental Supraorbital Infraorbital

A. B. C. D. E.

Protrude the mandible Tense the soft palate Depress the sphenoid bone Elevate the hyoid bone Retract the mandible

Masseter Sphenom andibular ligament Temporalis St ylomandibular ligam ent Pharyngeot ympanic tube

46. The nerve(s) that emerge from bet ween the t wo heads of the lateral pterygoid m uscle is/are the A. B. C. D. E.

A. B. C. D. E.

A. B. C. D. E.

Angular vein Anterior jugular vein External jugular vein Common facial vein Deep facial vein

40. Which nerve carries sensory inform ation from the upper lip? A. B. C. D. E.

A. B. C. D. E.

Inferior alveolar nerve Lingual nerve Deep temporal nerves Long buccal nerve Both A and B

Middle meningeal artery Inferior t ympanic artery Deep auricular artery Descending palatine artery Artery of the pterygoid canal

48. Sensation to the TMJ is provided by which of the following branches of the m andibular nerve?

39. The facial vein drains into the A. B. C. D. E.

44. The action of the lateral pterygoid muscle is to

47. Which of the following is not a branch of the maxillary artery?

38. The nerve that supplies the skin of the posterior scalp (occiput) is the A. B. C. D. E.

Masseter Medial pterygoid Temporalis Lateral pterygoid Mylohyoid

45. Which structure at taches to the lingula of the mandible?

36. Infections of the scalp are most likely to spread in which layer? A. B. C. D. E.

Mylohyoid muscle Sphenom andibular ligament Digastric muscle Pterygospinous ligam ent Buccinator

43. Which muscle of mastication is the prim ary retractor (retruder) of the mandible? A. B. C. D. E.

Plat ysm a Zygomaticus m ajor Posterior auricular Risorius Buccinator

35. A facial muscle at tached to the alveolar processes of the m andible and maxilla is the A. B. C. D. E.

Pterygoid rugosit y on the medial angle of the m andible Medial side of the coronoid process of the mandible Medial side of the zygomatic process of the temporal bone Pterygoid fovea and the condylar process of the m andible Inferior temporal line of the frontal, temporal, and parietal bones

42. Much of the weight of the m andible is supported by the

33. Which facial muscle can act as an oral sphincter? A. B. C. D. E.

Chapter 6 Temporal, Infratemporal, & Pterygopalatine Fossae

Inferior alveolar nerve Auriculotemporal nerve Lingual nerve Nerve to the lateral pterygoid Long buccal nerve

49. Through which opening does the pterygopalatine fossa comm unicate with the infratemporal fossa? A. B. C. D. E.

Greater palatine canal Pterygoid canal Sphenopalatine foramen Foram en rotundum Pterygom axillary fissure

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Fa ctua l Questions & Answer Expla na tions

Appendix B

50. The pterygopalatine ganglion receives preganglionic parasympathetic fibers traveling on which nerve? A. B. C. D. E.

Maxillary nerve Chorda t ympani Greater petrosal Lesser petrosal Deep petrosal

58. Which suprahyoid muscle is innervated by the facial nerve?

51. Which bone form s the superior boundary of the pterygopalatine fossa? A. B. C. D. E.

Sphenoid Maxilla Palatine Temporal Vom er

52. The nasal cavit y is enclosed by the ethmoid, vomer, m axillary, sphenoid, nasal, lacrimal, inferior nasal conchae, and which other bone? Palatine Zygom atic Mandibular Parietal Occipital

Inferior meatus Middle m eatus Superior m eatus Nasopharynx Sphenoethmoidal recess

Olfactory Anterior ethmoidal Greater palatine Nasopalatine Posterior superior alveolar

56. A patient comes to the dentist’s office complaining of pain from his left m axillary 2nd molar. The dentist exam ines the tooth and decides that it needs to be extracted. He knows that care needs to be taken to avoid introducing infection into the paranasal sinus just superior to the tooth. Which paranasal sinus can potentially be affected by this extraction? A. B. C. D. E.

Frontal Ethm oid Mastoid Sphenoid Maxillary

Frontal Ethm oid Mastoid Sphenoid Maxillary

A. B. C. D. E.

Tensor veli palatini Palatoglossus Palatopharyngeus Tensor t ympani Superior pharyngeal constrictor

A. B. C. D. E.

Tubal tonsil Lingual tonsil Pharyngeal tonsil Palatine tonsil Adenoid tonsil

A. B. C. D. E.

Periodontal ligament Cementum Pulp Dentine Alveolar bone

63. Which of the following perm anent teeth (secondary dentition) erupt at ~ 6 to 8 years of age? A. B. C. D. E.

Canine 1st prem olar 2nd prem olar 1st m olar 2nd m olar

64. The sublingual salivary glands receive postganglionic parasympathetic innervation from which ganglion? A. B. C. D. E.

Superior cervical Pterygopalatine Ciliary Otic Submandibular

65. The parotid gland produces which t ype of secretions?

57. A pituitary tumor (m acroadenoma) causing headache and loss of peripheral vision for an individual needs to be surgically treated. The surgeon decides to access the tumor, for removal, through which air sinus separating the pituitary gland from the nasal cavit y? A. B. C. D. E.

Ventral anterior Lateral dorsal Pulvinar Medial geniculate Ventral posterom edial

62. The tooth layer imm ediately deep to the enam el is the

Superior posterior alveolar Middle m eningeal Sphenopalatine Ascending pharyngeal Petrot ympanic

55. Innervation to the m ucosa covering the vom er bone is through which nerve? A. B. C. D. E.

A. B. C. D. E.

61. The part of Waldeyer’s (pharyngeal lymphatic) ring m ost closely associated with the epiglot tis is the

54. Kiesselbach’s area, the anastomosis of nasal septal arteries, links together branches of the superior labial, anterior ethm oidal, greater palatine, and ______ arteries. A. B. C. D. E.

Mylohyoid Hyoglossus Posterior digastric Geniohyoid St ylopharyngeus

60. Which m uscle of the soft palate is connected to the cartilaginous pharyngot ympanic tube?

53. The frontal air sinus comm unicates with the ________ of the respiratory system . A. B. C. D. E.

A. B. C. D. E.

59. Taste information from the posterior one-third of the tongue travels along the glossopharyngeal nerve via the petrosal (inferior) ganglion to the nucleus of the solitary tract (gustatory part) in the open m edullary part of the brainstem. From here it travels through the dorsal trigem inothalamic tract to reach the ________ nucleus of the thalamus. The final leg of the tract brings taste information to the insula and postcentral gyrus of the cerebral hem isphere.

Chapter 7 Nose & Nasal Cavit y

A. B. C. D. E.

Chapter 8 Oral Cavit y & Pharynx

A. Mucous B. Serous C. Mixed mucous and serous 66. Infections from which teeth can spread to the peripharyngeal fascial spaces? A. B. C. D. E.

Maxillary molars Maxillary canines Mandibular premolars Mandibular canines Mandibular incisors

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Appendix B

Fa ctua l Questions & Answer Expla na tions

67. Which potential space is located inferior to the mylohyoid line inferior and lateral to the mylohyoid m uscle? A. B. C. D. E.

Sublingual Submandibular Masticator Tonsillar Parotid

74. Taste fibers traveling through the m iddle ear cavit y are carried by a nerve that is a branch of the A. B. C. D. E.

Trigem inal nerve Facial nerve Vestibulocochlear nerve Glossopharyngeal nerve Vagus nerve

75. The m iddle ear ossicle that fits into the oval window of the inner ear is the

Chapter 9 Orbit & Eye 68. The artery running through the optic canal to supply blood to the orbit is a branch of the A. B. C. D. E.

Middle meningeal artery Deep temporal artery Sphenopalatine artery Internal carotid artery Ophthalmic artery

Anterior digastric Lateral rectus Inferior oblique Rectus capitis lateralis Superior oblique

Superior orbital fissure Foramen rotundum Foramen ovale Infraorbital foram en Foramen spinosum

71. The quickest impulse conduction through the retina links the rod or cone photoreceptors to the retinal ganglion cells through the A. B. C. D. E.

Horizontal cell Bipolar cell Am acrine cell Purkinje’s cell Müller’s cell

72. An individual complaining of tunnel vision (bitemporal hemianopia) asks her dentist to explain where the problem might be occurring. She also m entions that she is regularly experiencing headache, a change in her m enstrual cycle, and significant weight gain. The dentist explains that there is a chance of a pituitary tumor (m acroadenoma) creating pressure on the A. B. C. D. E.

Optic nerve Optic tract Optic chiasm Retrolenticular internal capsule Splenium of the corpus callosum

A. B. C. D. E.

Right posterior sem icircular canal Right lateral semicircular canal Left anterior sem icircular canal Left lateral semicircular canal Left posterior sem icircular canal

78. To detect sound, vibration of the hair cells is necessary. Movem ent at the oval window of the inner ear results in pressure waves that travel through the perilymph. Although the hair cells are not surrounded by perilymph, they are at tached to a flexible structure separating perilymph from endolymph called the A. B. C. D. E.

Basilar membrane Spiral ligam ent Vestibular mem brane Tectorial membrane Helicotrema

79. The part of the auditory system that is critical for the localization of sound is the A. B. C. D. E.

Vestibular nucleus Tensor t ympani Spiral ganglion Lateral geniculate nucleus Medial lemniscus

80. Which muscle draws the hyoid bone forward and is innervated by the anterior ramus of the C1 spinal nerve?

73. The blood supply to the external ear includes the posterior auricular artery and the Transverse facial artery Superficial temporal artery Sphenopalatine artery Internal carotid artery Occipital artery

Petrosal hiatus External acoustic meatus Mastoid canaliculus Internal acoustic meatus St ylomastoid foramen

Chapter 11 Bones, Ligam ents, & Muscles of the Neck

Chapter 10 Ear

A. B. C. D. E.

A. B. C. D. E.

77. The right anterior sem icircular canal of the vestibulocochlear apparatus of the petrous part of the temporal bone is at a parallel plane to the

70. Through which passageway in the skull does the superior branch of the oculomotor nerve pass? A. B. C. D. E.

Malleus Pisiform Stapes Navicular Incus

76. The vestibulocochlear nerve exits the posterior cranial fossa to reach the inner ear of the temporal bone through the

69. The extraocular muscle innervated by the trochlear nerve is the A. B. C. D. E.

A. B. C. D. E.

A. B. C. D. E.

Mylohyoid Geniohyoid St ylohyoid Omohyoid Sternohyoid

81. The muscle of the neck that rotates the head to the contralateral side is the A. B. C. D. E.

Rectus capitis posterior major Longissim us capitis Rectus capitis lateralis Splenius capitis Sternocleidomastoid

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Appendix B

82. The origin (proxim al at tachment) of which back muscle includes the spinous process of the T6 vertebra? A. B. C. D. E.

90. The external jugular vein collects blood directly from the posterior division of the retrom andibular vein, posterior auricular vein, and A. B. C. D. E.

Splenius cervicis Levator costarum longus Serratus posterior superior Iliocostalis thoracis Longus colli

Transverse cervical vein Inferior thyroid vein Pterygoid plexus Facial vein Lingual vein

83. What is the innervation to the geniohyoid muscle? A. B. C. D. E.

Mylohyoid nerve Facial nerve Anterior ram us of the C1 spinal nerve Inferior alveolar nerve Hypoglossal nerve

Chapter 13 Larynx & Thyroid Gland 91. The epiglot tic cartilage is at tached to the ________ cartilage of the respiratory system.

Chapter 12 Neurovascular Topography of the Neck 84. Which pharyngeal space lies posterior to the tongue and lateral to the m edian glossoepiglot tic fold? A. B. C. D. E.

Vallecula Piriform recess Rima glot tidis Foramen cecum Tonsillar fossa

85. The m iddle scalene m uscle originates on the C1 and C2 transverse processes and the C3−C7 posterior tubercles, and it inserts into the A. B. C. D. E.

Superom edial angle of the scapula 1st rib 2nd rib Basilar occipital bone Manubrium of the sternum

86. Nam e the neck triangle that provides the best access to the spinal accessory nerve. A. B. C. D. E.

Subm andibular Muscular Carotid Occipital Om oclavicular

Facial Glossopharyngeal Vagus Spinal accessory Hypoglossal

Cavernous sinus Lung Stom ach Mediastinum Subarachnoid space

Vagus nerve Hypoglossal nerve C3 anterior ram us C2 posterior ramus C1 anterior ram us

A. B. C. D. E.

Posterior cricoarytenoid Cricothyroid Lateral cricoarytenoid Transverse arytenoid Thyroarytenoid

93. The part of the thyroid gland that stretches anterior to the laryngeal prominence toward the foram en cecum of the tongue is the A. B. C. D. E.

Lateral lobe Isthm us Pyram idal lobe Superior parathyroid Inferior parathyroid

Chapter 15 Rest of Body Anatomy

A. B. C. D. E.

Infraspinatus Subclavius Teres major Rhomboid minor Deltoid

A. B. C. D. E.

Cephalic vein Axillary vein Brachiocephalic vein Internal jugular vein Subclavian vein

96. The insertion/distal at tachm ent of the biceps brachii is the

89. The superior root of the ansa cervicalis contains fibers from the A. B. C. D. E.

92. The only laryngeal m uscle that abducts the vocal cords and opens the rima glot tidis is the

95. The brachial vein drains into the ________ to return blood to the heart.

88. Bacterial infection of the oral cavit y m ay invade the parapharyngeal space and can easily spread inferiorly to the A. B. C. D. E.

Thyroid Cricoid Arytenoid Corniculate Tracheal

94. Impingement of the suprascapular nerve as it runs inferior to the superior transverse ligam ent of the scapula can result in paralysis of the

87. Which cranial nerve travels from the base of the skull to the mediastinum in the carotid sheath? A. B. C. D. E.

A. B. C. D. E.

A. B. C. D. E.

Lateral intertubercular groove of the humerus Coracoid process of the scapula Ulnar tuberosit y of the ulna Olecranon fossa of the humerus Radial tuberosit y of the radius

97. The left 8th posterior intercostal vein drains directly into the A. B. C. D. E.

Inferior vena cava Superior vena cava Hemiazygos vein Azygos vein Thoracic duct

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Fa ctua l Questions & Answer Expla na tions

98. The left (obtuse) m arginal artery of the heart are branches off the A. B. C. D. E.

Anterior interventricular (descending) artery Posterior interventricular artery Right coronary artery Circum flex artery Thebesian artery

100. During the administration of an inferior alveolar nerve block, the nee dle passes through which structure?

99. An elderly man presents in the em ergency department with sudden onset of breathlessness and chest pain along the superior posterolateral left chest wall. Im aging reveals a wedge-shaped opaque structure abutting the pleura, signifying a pulm onary infarction distal to a pulm onary embolism. The pulm onary lobe m ost likely affected is the A. B. C. D. E.

Appendix A Anatomy of Local Anesthesia for Dentistry

A. B. C. D. E.

Medial pterygoid Lateral pterygoid Buccinator Pterygom andibular raphe Parotid capsule

Apicoposterior segment of the superior lobe of the left lung Apical segment of the superior lobe of the right lung Lateral segm ent of the m iddle lobe of the right lung Superior lingular segment of the superior lobe of the left lung Superior segm ent of the inferior lobe of the left lung

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Appendix B

Answ er Explanations Chapter 1 Embryology of the Head & Neck 1.

C The palatine bone develops from the midline fusion of the maxillary prom inence of the 1st pharyngeal arch. A The lesser horn of the hyoid bone develops from the 2nd pharyngeal arch; the body and greater horn of the hyoid bone develop from the 3rd pharyngeal arch. B The nasal bones develop from the frontonasal prom inence, a structure that is developmentally distinct from the pharyngeal arches. D The stapes, the most m edial of the m iddle ear ossicles, develops from the posterior aspect of the 2nd pharyngeal arch. E The occipital bone develops from parachordal cartilage at the rostral end of the notochord and from occipital somites.

2.

5.

A, D The m andibular m olars and premolars are supported by the caudal part of the 1st pharyngeal arch specifically, the mandibular prominence. B The maxillary canines are supported by the maxillary prom inence, specifically, the lateral part of the lateral palatine processes. 6.

A The hypopharyngeal em inence, which arises in the floor of the pharynx bet ween the 3rd and 4th pharyngeal arches, gives rise to the posterior one-third of the tongue. It receives general (pain, touch) and special (taste) sensory innervation from both the glossopharyngeal and vagus cranial nerves (CN IX and X, respectively. The vagus nerve carries general and taste sensation from the root of the tongue and epiglot tis, while the glossopharyngeal nerve receives general and taste sensation from the majorit y of the posterior one-third of the tongue). B The trigeminal nerve receives general sensory innervation, and the facial nerve receives special sensory innervation from the anterior t wo-thirds of the tongue, which develops in the floor of the pharynx bet ween the 1st and 2nd pharyngeal arches. C Although the vagus nerve does carry sensory innervation from the region of the hypopharyngeal em inence, the hypoglossal nerve carries no sensory innervation. Instead, the hypoglossal nerve carries general som atic motor innervation to the tongue. D, E Although the facial, trigeminal, and glossopharyngeal nerves all carry sensory inform ation from the tongue, only the glossopharyngeal nerve carries inform ation from the hypopharyngeal eminence. The facial nerve carries special sensory information (taste) from the anterior t wo-thirds of the tongue; the trigem inal nerve carries general sensory inform ation from the anterior t wo-thirds of the tongue.

4.

Chapter 2 Cranial Bones 7.

A The greater palatine foramen of the palatine bone at the posterior margin of the hard palate allows for passage for the greater palatine nerve (and artery), a branch of the m axillary nerve (and artery). B The infraorbital foram en allows for passage of the infraorbital nerve (and artery), a branch of the m axillary division of the trigeminal nerve, although these vessels do not supply the hard palate. C The m ental foramen of the mandible allows passage for the terminal branches of the inferior alveolar nerve (and artery). The inferior alveolar nerve is a branch of the m andibular division of the trigem inal nerve, which innervates the inferior teeth. The inferior alveolar artery is a branch of the maxillary artery. D The foramen rotundum of the sphenoid bone is the passage for the unbranched (except middle m eningeal nerve) maxillary division of the trigem inal nerve to exit the middle cranial fossa. From this point, it enters the pterygopalatine fossa and branches extensively. Some branches will innervate the hard palate (as the nasopalatine and greater palatine), but there are many other branches that provide no innervation to the hard palate. E The sphenopalatine foramen allows passage of the sphenopalatine artery (of the maxillary) and the nasopalatine, m edial, and lateral posterior nasal nerves. Although the nasopalatine nerve innervates the hard palate, it enters the oral cavit y via the incisive foramen.

D Failure of fusion of the left and right lateral palatine processes results in secondary cleft palate. A Failure of fusion of the m axillary prominence with the m edial nasal prom inence will result in a cleft lip, with no effect on the secondary palate, although it m ay affect the prim ary palate. B Failure of fusion of the nasal septum with the maxillary prom inence will result in a persistent passage bet ween the left and right nasal cavities but will have no effect on the hard palate of the oral cavit y. C The lateral palatine processes are extensions of the maxillary prom inence and begin as a single rostral part of the 1st pharyngeal arch and therefore never undergo fusion. They rem ain as a single bony structure throughout life. E Failure of fusion of the interm axillary segm ent results from failure of fusion of the left and right medial nasal prominences. This would result in a midline cleft lip and a prim ary cleft palate.

B A nonmigrating thyroid gland would result in a lingual cyst presenting as a m idline swelling at the base of the tongue in the region of foramen cecum . During normal developm ent the thyroid gland passes from the oropharynx into the neck by invaginating the tongue through a path indicated by foramen cecum. A A persistent 1st pharyngeal groove would result in a deform ed auricle of the ear, a surface defect (depression) in the cheek, and an enlarged mouth (m acrostom ia). C The laryngeotracheal diverticulum is a norm al em bryological structure that gives rise to the connection bet ween the respiratory and digestive system s. This persists in the adult as the laryngeal inlet and the rim a glot tidis. D The 2nd pharyngeal pouch becomes the sinus of the palatine tonsil. It is laterally located in the oropharynx, and it norm ally persists in the adult. E Metastasis of the lingual tonsil may present as a midline swelling of the root of the tongue, but it likely would first involve the surface of the tongue, and it would migrate laterally as well as deeper into the structure of the tongue. It is unlikely to rem ain solely at the midline. Such a m etastasis would not be referred to as a lingual cyst.

B The incisive foram en is a landm ark bet ween the prim ary and secondary palates. A The landmark bet ween the hard and soft palates is the posterior edge of the horizontal plate of the palatine bone. C The landm ark bet ween the left and right lateral palatine processes is the interm axillary suture of the hard palate. D The landm ark bet ween the palatine and m axillary bones is the transverse palatine (palatom axillary) suture. E The landm ark bet ween the left and right m edial nasal prom inences is the nasal septum, the interm axillary segm ent of the upper lip, and the philtrum .

3.

E The maxillary incisors, both deciduous and secondary (therefore not answer choice C), are supported by the interm axillary segm ent of the upper jaw.

8.

D The m andibular foramen of the ramus is protected by the bony lingula in a superoanterior position. The lingula is an at tachment site for the sphenom andibular ligam ent. A The m ental spines (genial tubercles) are located in the internal genu of the m andible and are for the at tachment of the geniohyoid and genioglossus muscles. B The pterygoid ham ulus is part of the m edial pterygoid plate of the sphenoid bone and is used for a lever around which the tensor veli palatini m uscle changes orientation from it s vertical origin in the scaphoid fossa of the sphenoid bone to reach the horizontal palatine

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Fa ctua l Questions & Answer Expla na tions

aponeurosis. C The coronoid process of the mandible is located in the superoanterior ram us, but it is not associated with the mandibular foramen. Instead, it provides the at tachm ent site for the insertion for the temporalis muscle. E The condylar process of the mandible is located in the superoposterior ram us, but it is not associated with the mandibular foramen. Instead, it provides the m andibular articulation of the temporom andibular joint. 9.

B The anterom edial floor of the carotid canal in the petrous portion of the temporal bone is “open” to the nasopharynx through the foramen lacerum , although it is t ypically filled with cartilage after birth. A The foram en ovale of the sphenoid bone provides passage from the m iddle cranial fossa to the infratemporal fossa for the m andibular division of the trigeminal nerve (CN V3 ), the lesser petrosal nerve (CN IX), and the accessory meningeal artery. C The jugular foramen, located bet ween the temporal and occipital bones, provides passage from the posterior cranial fossa to the deep prevertebral neck for the internal jugular vein and the glossopharyngeal, vagus, and spinal accessory nerves. D The foramen spinosum of the sphenoid bone provides passage from the infratemporal fossa to the m iddle cranial fossa for the middle meningeal artery, a branch of the m axillary artery, and the recurrent meningeal nerve (nervus spinosus). E The m astoid foram en is an inconsistent passage for em issary veins to pass through the temporal bone. When present, it provides com munication bet ween the sigmoid sinus and occipital veins.

10. C The anterior cranial fossa is separated from the middle cranial fossa by the posterior border of the lesser wing of the sphenoid bone. A The lateral pterygoid plate provides muscular at tachm ent sites for both the medial and lateral pterygoid muscles of the infratemporal fossa. It is not located within the cranial vault. B The perpendicular plate of the ethmoid bone provides the superior half of the nasal septum and is in the nasal cavit y, not the cranial vault. D The petrous part of the temporal bone separates the m iddle and posterior cranial fossae. It provides at tachm ent for the cerebellar tentorium and houses the auditory and vestibular infrastructure. E The frontal crest of the frontal bone is in the anterior cranial fossa, but it provides an anterior anchor for the falx cerebri, in the m idline. It is not in a lateral position to allow for separation bet ween anterior and middle cranial fossae on both the right and left. 11. A The pterion, an H-shaped suture bet ween the frontal, sphenoid, temporal, and parietal bones, marks the location of the groove for the middle meningeal artery on the internal surface of the lateral wall of the cranial vault. B The hypophyseal fossa, the central part of the sella turcica of the sphenoid bone, is a midline structure in the middle cranial fossa. C The groove for the sigmoid sinus begins just posterior to the mastoid process of the temporal bone, at the location of the asterion. It is in the internal lateral wall of the cranial vault, but posterior to the pterion. D The internal acoustic meatus is centrally located in the petrous part of the temporal bone, in the posterior cranial fossa. E The crista galli is a centrally located structure in the floor of the anterior cranial fossa. 12. E The foramen rotundum , a passageway for the m axillary division of the trigeminal nerve (CN V2 ) to reach the pterygopalatine fossa, exit s the middle cranial fossa through the sphenoid bone. A The petrous part of the temporal bone provides a posterolateral passage for the facial (CN VII) and vestibulocochlear (CN VIII) nerves via the internal acoustic m eatus. It is located at the boundary bet ween the m iddle and posterior cranial fossae. B The ethm oid bone provides passage for the anterior and posterior ethmoidal branches of the ophthalmic division of the trigem inal nerve (CN V1 ) via the anterior and posterior ethmoidal foramina on the m edial wall of the orbit and passage of the olfactory nerves from the nasal cavit y through the cribriform plate.

C The occipital bone provides anterolateral passage for the hypoglossal nerve (CN XII) via the hypoglossal (anterior condylar) canal. The hypoglossal canal is located in the anterolateral wall of foram en m agnum of the posterior cranial fossa. D The m andible provides internal passage of the inferior alveolar branch of the mandibular division of the trigeminal nerve (CN V3 ) via the m andibular foramen and canal. 13. C The m ajorit y of the hard palate of the oral cavit y is formed from the union of the horizontal plate of the palatine bone with the palatine process of the m axilla. A The medial pterygoid plate of the sphenoid bone forms the posterior lateral wall of the choana of the nasal cavit y, superior to the hard palate. The pterygoid ham ulus, the inferior anterior part of the medial pterygoid plate, form s a very sm all part of the posterolateral hard palate. B The perpendicular plate of the ethm oid bone form s the superior half of the nasal septum, inside the nasal cavit y, above the hard palate. At no point does it touch the horizontal plate of the palatine bone, although posterolateral parts of the ethmoid bone will create suture joints with the vertical plates of the palatine bone. D The squamous part of the temporal bone is the lateral wall of the cranial vault. It is not associated with the hard palate in any way. E The alae of the vomer bone articulate with the horizontal plate of the palatine bone but do so in the floor of the nasal cavit y as part of the nasal septum. They are not located in the oral cavit y and do not contribute to the inferior surface of the hard palate.

Chapter 3 Vasculature & Lymphatics of the Head & Neck 14. A The middle meningeal artery is a branch of the mandibular part of the maxillary artery that enters the skull through the foram en spinosum of the sphenoid bone to supply blood to the lateral part of the internal cranial vault and meninges. B The deep temporal artery is a branch of the pterygoid part of the maxillary artery. It rem ains outside the skull bet ween the external lateral cranial vault and the temporalis muscle and therefore does not traverse a foramen. C The sphenopalatine artery is a terminal branch of the maxillary artery. From the pterygopalatine fossa, it passes through the sphenopalatine foramen to enter the nasal cavit y. D The internal carotid artery is not a branch of, and is substantially larger than, the maxillary artery. The internal carotid artery enters the skull through the carotid canal of the temporal bone to enter the middle cranial fossa. E The ophthalm ic artery branches from the internal carotid artery within the middle cranial fossa. It runs anterior from the m ost rostral end of the internal carotid artery, through the optic canal, to reach the orbit. 15. B The mandibular (bony/1st) part of the maxillary artery gives rise to the inferior alveolar artery. It enters the ramus of the mandible at the mandibular foram en and subsequently gives off small branches that supply blood to the mandibular molars, prem olars, canines, and incisors and ends on the face as the mental artery. A The facial artery is a direct branch of the external carotid artery, which wraps laterally around the body of the m andible but does not supply blood to any m andibular teeth. It does supply the cheeks, lips, nose, and anterior m edial orbit. C The lingual artery is a direct branch of the external carotid artery, which is positioned medially to the m andible and does not supply any mandibular teeth. It supplies the tongue and floor of the oral cavit y. D The sphenopalatine artery is a branch of the pterygopalatine part of the m axillary artery. It supplies the posterior superior nasal cavit y. Other branches of the pterygopalatine part of the maxillary artery are the posterior superior alveolar and infraorbital arteries. The posterior superior alveolar artery supplies the maxillary molars; the infraorbital artery gives off the middle superior alveolar artery to the

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Appendix B

m axillary premolars and the anterior superior alveolar artery to the m axillary incisors. E The internal carotid artery does not have any branches external to the skull. It supplies blood to the anterior t wo-thirds of the brain and augments the blood supply to the posterior orbit. 16. C The vertebral artery is a m ajor branch of the subclavian artery, along with the internal thoracic artery, thyrocervical trunk, and an inconsistent dorsal scapular artery and/or costocervical trunk. The vertebral artery supplies blood to the posterior one-third of the brain and the paravertebral m usculature of the neck. A The external carotid artery has eight branches that supply blood to the neck (superior thyroid), face (facial), tongue (lingual), upper and lower jaw (m axillary), lateral head (temporal), ear (posterior auricular), back of the head (occipital), and pharynx (ascending pharyngeal). It does not give rise to the vertebral artery. B The com mon carotid artery has t wo m ajor branches only, the internal and external carotid arteries. D, E The arch of the aorta (D) gives rise to the brachiocephalic trunk (E) on the right and the left comm on carotid and left subclavian arteries. The brachiocephalic trunk subdivides into the right subclavian artery and the right com mon carotid artery. The subclavian arteries on each side branch to give rise to the vertebral arteries. 17. D The ophthalm ic veins provide direct connections bet ween the angular veins and the cavernous sinus via the orbit through the superior orbital fissure. A The pterygoid plexus can serve as an intermediary bet ween the angular vein and the cavernous sinus. To reach the pterygoid plexus, blood must first travel through the deep facial vein or the infraorbital vein to the pterygoid plexus, and subsequently through sphenoidal em issary veins to reach the cavernous sinus. B The retromandibular vein has no direct connection to the cavernous sinus. It provides a connection bet ween the facial (angular) vein and the maxillary and superficial temporal veins, but to reach the cavernous sinus, blood would once again need first to enter the pterygoid plexus. C The lingual vein has no direct connection to the cavernous sinus. It drains into the retrom andibular vein, but infection would have to traverse m ultiple additional veins to reach the cavernous sinus. E The brachiocephalic trunk is an artery that supplies blood to the right side of the head and neck. Even the brachiocephalic vein, draining blood from the right (or left) side of the head and neck, does not provide direct a connection bet ween the angular vein and the cavernous sinus. 18. E The thyrocervical trunk has four major branches: the inferior thyroid, suprascapular, transverse cervical, and ascending cervical arteries. The deep branch of the transverse cervical artery (also called the dorsal scapular artery) runs deep to the rhomboid muscles. The superficial branch of the transverse cervical artery runs deep to the trapezius. A The brachiocephalic trunk is on the right side only. Compression of this structure, which is deep in the neck, is difficult; additionally, it would comprom ise the blood going to the right upper extrem it y, entire right side of the neck and face, and right side of the brain. B The com mon carotid artery has only t wo branches, the internal and external carotid arteries, which supply blood to the neck and head only. C The thoracoacromial trunk supplies blood in the anterior part of the shoulder. The four t ypical branches are the pectoral, deltoid, acrom ial, and clavicular branches. Although they may supply small amounts of blood to the superior edge of the trapezius, they do not run near the rhomboid muscles; therefore, compression will not arrest bleeding following this injury. D The costocervical trunk supplies blood to the intercostal m uscles bet ween the first t wo ribs, in a more lateral than posterior position. The plane of the injury is superficial to where this artery runs.

19. C The middle cerebral artery is a direct branch of the internal carotid artery. A The com mon carotid artery has only t wo m ajor branches, the external carotid and internal carotid arteries. B The external carotid artery has eight m ajor branches: the superior thyroid, facial, lingual, maxillary, superficial temporal, posterior auricular, occipital, and ascending pharyngeal. These arteries and m ost of their branches stay external to the skull and do not supply any central nervous structures. D The basilar artery form s from the union of the left and right vertebral arteries. It supplies blood to the brainstem and cerebellum. It terminally bifurcates into the t wo posterior cerebral arteries that supply blood to the inferior occipital lobe. E The middle meningeal artery is a branch of the maxillary artery in the infratemporal fossa. It pierces the skull at the foramen spinosum and supplies blood to the dura in the lateral part of the skull. 20. B The petrosal sinuses (both superior and inferior) drain the cavernous sinuses . The superior petrosal sinus then drains into the sigmoid sinus; the inferior petrosal sinus drains into the internal jugular vein. A The straight sinus drains the inferior sagit tal sinus and internal and great cerebral veins posteriorly to the confluence of sinuses. There is no direct connection bet ween the cavernous sinuses and the straight sinus. C The external jugular vein drains the occipital vein, retrom andibular vein (from the face and the lateral head via the superficial temporal), and posterior auricular veins. There is no direct connection bet ween the cavernous sinuses and the external jugular vein. D The basilar vein drains the inferior frontal lobe and infralateral diencephalon to the straight sinus. There is no direct connection bet ween the cavernous sinuses and the basilar veins. E The maxillary sinus is an air sinus, rather than a venous dural sinus. It is connected to the nasal cavit y via the m axillary hiatus of the middle (semilunar) m eatus. 21. E The deep cervical (jugular) lymph nodes drain lymph from the posterior (occipital), lateral (superficial parotid), and anterior (facial and subm andibular) lymph nodes down to the jugulosubclavian venous junction, where the thoracic/lymphatic duct joins the cardiovascular system. A The occipital lymph nodes drain lymph from the posterior head to the jugular (deep cervical) lymph nodes. They collect lymph from regions significantly posterior to the ear. B The facial lymph nodes drain lymph from the anterior head into the subm andibular lymph nodes. Subsequently, lymph drains into the jugular (deep cervical) nodes and from there to the cardiovascular system via the lymphatic/thoracic duct. C The nuchal lymph nodes drain lymph from the posterior neck and posteroinferior head to the jugular (deep cervical) nodes and from there into the cardiovascular system via the lymphatic/thoracic duct. D The laryngeotracheal lymph nodes drain lymph from the anterior neck and respiratory viscera to the jugular (deep cervical) nodes and from there to the cardiovascular system via the lymphatic/thoracic duct.

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Fa ctua l Questions & Answer Expla na tions

Chapter 4 Neuroanatomy & Innervation of the Head & Neck

E The recurrent laryngeal nerve, a branch of the vagus nerve (CN X), controls the intrinsic m uscles of the larynx, excluding the cricothyroid m uscle.

22. A The abducens nerve (CN VI) passes through the superior orbital fissure. B The foram en rotundum is for passage of the maxillary division of the trigem inal nerve (CN V2 ). C The foram en ovale is for passage of the m andibular division of the trigeminal nerve (CN V3 ). D The infraorbital foramen is for passage of the infraorbital nerve (the largest branch of the maxillary division of the trigem inal nerve, CN V2 ) to reach the surface of the face below the orbit. E The foramen spinosum is for passage of the middle meningeal artery to enter the middle cranial fossa of the skull. 23. E The facial nerve (CN VII) innervates the stapedius, the m iddle ear muscle that modulates the m otion of the stapes. A The optic nerve (CN II) carries sensory innervation from the neural retina to the lateral geniculate nucleus of the thalamus. B The oculom otor nerve (CN III) innervates the superior, medial, and inferior rectus m uscles, and the inferior oblique m uscle (extraocular muscles), the sphincter pupillae and ciliary muscles (intrinsic eye muscles), and levator palpebrae superioris m uscle of the eyelids. C The vestibulocochlear nerve (CN VIII) is responsible for transmit ting sensory inform ation for hearing and balance from the cochlea and vestibular apparatus, respectively, to the brain. It does not innervate any muscles. D The trigeminal nerve (CN V) innervates the tensor t ympani, the middle ear muscle that is at tached to the malleus, a 1st pharyngeal arch structure. Tensor t ympani acts to dampen sound. 24. B The trochlear nerve innervates the superior oblique extraocular muscle. A The lateral rectus is innervated by the abducens nerve (CN VI). C The orbicularis oculi is innervated by the facial nerve (CN VII). D The rectus capitis lateralis is innervated by the anterior ram us of the C1 spinal nerve. E The dilator pupillae is innervated by the sympathetic root and the sympathetic components of the short and long ciliary nerves. 25. A The vagus nerve (CN X) exits the posterior cranial fossa at the jugular foramen. B The internal acoustic m eatus is the posterior cranial fossa opening for the facial nerve (CN VII), vestibulocochlear nerve (CN VIII), and labyrinthine artery. C The condylar canal of the occipital bone is the posterior cranial fossa exit for an em issary vein connecting the sigmoid sinus to the occipital vein. D The foramen m agnum is the posterior cranial fossa entry for the vertebral arteries, spinal component of the spinal accessory nerve (CN XI), m edulla oblongata of the brainstem , and cranial meninges (pia, arachnoid, and dura). E The foramen lacerum is mostly closed by cartilage in a living body, but it is traversed by the internal carotid artery above and the pharyngot ympanic tube below. The only structures passing through the foram en lacerum are the autonom ics of the superior cervical ganglion that control vasoconstriction/vasodilation of the internal carotid artery. 26. C The hyoglossus is innervated by the hypoglossal nerve (CN XII), along with the genioglossus, st yloglossus, and all intrinsic muscles of the tongue. A The ansa cervicalis, emerging from the anterior rami of the C1−C3 spinal nerves, innervates the sternohyoid, sternothyroid, and omohyoid m uscles. B The facial nerve (CN VII) innervates the stapedius muscle of the middle ear, the st ylohyoid and posterior digastric muscles, and the muscles of facial expression. D The mylohyoid nerve, a branch of the mandibular division of the trigeminal nerve (CN V3 ), innervates the anterior digastric and mylohyoid muscles.

27. D Preganglionic parasympathetic fibers travel to the parotid gland travels via the t ympanic nerve, then the lesser petrosal nerves, both branches of the glossopharyngeal nerve (CN IX) to the otic ganglion. Postganglionic fibers then travel with the auriculotemporal nerve to the gland. A The chorda t ympani, a branch of the facial nerve (CN VII), carries preganglionic parasympathetic innervation to the submandibular ganglion and subsequently to the subm andibular and sublingual glands. It also carries taste innervation from the anterior t wo-thirds of the tongue. B The greater petrosal nerve, a branch of the facial nerve (CN VII), carries preganglionic parasympathetic innervation to the pterygopalatine ganglion . Branches of CN V2 subsequently distribute postgandlionic parasympathetic fibers to the lacrim al gland and small glands of the nasal cavit y, palate, and nasopharynx. C The deep petrosal nerve arises from the internal carotid plexus and carries postganglionic sympathetic innervation to the lacrimal and small nasal glands, nasopharynx, and palate via branches of CN V1 and CN V2 . E The lingual nerve, a branch of the m andibular division of the trigem inal nerve (CN V3 ), carries hitchhiking pre- and postganglionic parasympathetic innervation to the subm andibular and sublingual glands. It also carries hitchhiking taste innervation from the anterior t wo-thirds of the tongue to the chorda t ympani, as well as general som atic (touch, pain, and proprioception) innervation from the anterior tongue back to the trigeminal nerve. 28. B The C8 spinal nerve exits the vertebral canal through the intervertebral foram en below the C7 vertebra (therefore not E). A The C7 spinal nerve exit s the vertebral canal through the intervertebral foramen above the C7 vertebra. C, D There is no C8 vertebra in the human vertebral column and therefore no C8 transverse foramen. 29. C Slippage of the C3−C4 intervertebral disk to the right would result in compression of the C4 spinal nerve. This can present as changes in the C4 derm atom e at the top of the shoulder. A An osteophyte in the C1−C2 intervertebral foramen would start to compress the C2 spinal nerve, which has a dermatome that correlates to the back of the head. Tingling and num bness here would be indicative of a problem at that level. B Compression of the axillary nerve would present with the patient complaining of an inabilit y to abduct his arm and glenohum eral joint instabilit y. Any cutaneous effects would relate to the superior lateral arm , not the top of the shoulder. D Referred pain from the spleen can travel through the phrenic nerve (C3−C5), but it norm ally would present as deep, throbbing or burning pain, rather than tingling or num bness, over the left shoulder. E Avulsion of the C6 spinal nerve would result in the patient’s inabilit y to move or feel his thenar (thum b) region of the hand. 30. D The medulla oblongata develops from the myelencephalon, the caudal end of the rhombencephalon. A The cerebral peduncle, for passage of the corticospinal, corticopontine, and corticobulbar tracts, is part of the m esencephalon, one of the prim ary vesicles of the developing brain. B The thalam us, a relay nucleus for most cortical input from subcortical regions, is part of the diencephalon. The diencephalon contains the thalamic structures, including the hypothalamus, epithalam us (pineal), subthalamus, and thalam us proper. C The pons is a synaptic and decussation site for the corticopontocerebellar tract. It is part of the m etencephalon, which originally develops as the rostral end of the rhom bencephalon. E The tectum, m ade from the superior and inferior colliculi, is closely associated with visual tracking and hearing. It originally develops as part of the midbrain, or m esencephalon.

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Appendix B

31. E The central sulcus separates the voluntary motor cortex from the conscious body sensation cortex on the ipsilateral side. A The calcarine sulcus, located close to the cerebral falx, separates superior and inferior parts of the occipital lobe. This is the location of primary visual cortex. It is not associated with motor cortex. B The parieto-occipital sulcus separates the parietal lobe (conscious body sensation) from the occipital lobe (primary visual cortex). It is not associated with the m otor cortex. C The lateral sulcus separates the voluntary m otor cortex of the frontal lobe and the conscious body sensation cortex of the parietal lobe from the temporal lobe, which is the location of the prim ary auditory cortex and m emory formation components of the limbic system . D The longitudinal fissure separates the right and left cerebral hem ispheres. 32. A The cerebral aqueduct can be blocked by the choroid plexus of the 3rd ventricle; blockage results in noncomm unicating hydrocephalus in an individual. There are no alternate CSF flow passages bet ween the 3rd and 4th ventricles. B Blockage of CSF flow in the pontom edullary cistern in the subarachnoid space will not cause hydrocephalus. There are numerous alternate routes for the CSF to flow to reach the arachnoid granulations. For example, CSF could flow from the pontom edullary cistern to the cerebellom edullary cistern, then the vermian cistern, am bient cistern, and finally reach the arachnoid granulations. C Blockage of CSF flow in the cerebellom edullary cistern in the subarachnoid space will not cause hydrocephalus. There are numerous alternate routes for the CSF to flow to reach the arachnoid granulations. For example, CSF could flow from the cerebellom edullary cistern to the pontom edullary cistern, then the interpeduncular and chiasm atic (basal) cisterns, and finally reach the arachnoid granulations. D The confluence of sinuses is a dural venous sinus structure filled with deoxygenated blood. Blockage of this blood passage will not result in hydrocephalus. E The arachnoid granulations provide drainage of the CSF into the venous sinus system . Blockage here could result in a backup of CSF that may result in comm unicating hydrocephalus. However, all the internal CSF passages would remain open and unblocked.

upper lip. E The mentalis is at tached to the frenulum of the lower lip and the skin of the chin. 36. D Scalp infections can easily spread through the layer of loose areolar connective tissue. A−C, E Scalp infections are less likely to spread in the other four layers of the scalp. 37. A The supraorbital artery is a term inal branch of the ophthalm ic artery, which arises from the internal carotid artery. B The facial artery is a branch of the external carotid artery. C The lateral nasal artery is a branch of the facial artery, which arises from the external carotid artery. D The superficial temporal artery is a branch of the external carotid artery. E The transverse facial artery is a branch of the superficial temporal artery, which arises from the external carotid artery. 38. D The greater occipital nerve (posterior ram us of C2) is sensory to the occiput. A The m axillary nerve (CN V2 ) is sensory to the midface. B The transverse cervical nerve (anterior rami of C2−C3) is sensory to the anterior neck. C The great auricular nerve (anterior rami of C2−C3) is sensory to the lateral neck and earlobe. E The facial nerve (CN VII) is motor to muscles of facial expression stapedius, and posterior digastric and does not carry sensory information from the face or scalp. 39. D The facial vein joins the anterior division of the retrom andibular vein to form the comm on facial vein. A The angular vein drains into the facial vein. B The anterior jugular vein originates from superficial veins in the neck and drains to the term inal end of the external jugular vein or the subclavian vein. C The external jugular vein is form ed from the posterior division of the retromandibular vein and the posterior auricular vein and drains to the subclavian vein. E The deep facial vein connects the facial vein to the pterygoid plexus. 40. E Branches of the infraorbital nerve (a branch of the maxillary division of the trigem inal nerve) are sensory to the upper lip.

Chapter 5 Face & Scalp 33. C The orbicularis oris acts as an oral sphincter. A The risorius retracts the corner of the mouth, pulling it posteriorly during grimacing and smiling. B The depressor labii inferioris pulls the lower lip inferolaterally during pouting. D The levator anguli oris raises the angle of the mouth during sm irking and sm iling, increasing the nasolabial furrow. E The orbital portion of the orbicularis oculi acts as an orbital sphincter to close the eyelids voluntarily; the palpebral portion closes the eyes involuntarily. 34. C The posterior auricular m uscle is innervated by a branch of the posterior auricular nerve, which com es off the facial nerve before it enters the parotid gland. A The plat ysma is innervated by the cervical branch of the facial nerve. B The zygomaticus major is innervated by the zygomatic branch of the facial nerve. D, E The risorius and buccinator are innervated by the buccal branch of the facial nerve. 35. B The buccinator is at tached to the alveolar processes of the m andible and m axilla, the pterygom andibular raphe, and the lips. A The depressor anguli oris is at tached to the oblique line of the m andible and the skin at the corner of the m outh. C The levator labii superioris is at tached to the frontal process and infraorbital m argin of the maxilla and the skin of the upper lip. D The zygomaticus m inor is at tached to the zygomatic bone and the

A The anterior superior alveolar nerve (a branch of the infraorbital nerve [from CN V2 ]) is sensory to the maxillary incisors and canines B The buccal branch of the facial nerve is motor to som e of the m uscles of facial expression. C The m ental nerve (a branch of the mandibular division of the trigeminal nerve) is sensory to the lower lip and chin. D The supraorbital nerve (a branch of the ophthalm ic division of the trigeminal nerve [CN V1 ]) is sensory to the upper eyelid and skin of the forehead.

Chapter 6 Temporal, Infratemporal, & Pterygopalatine Fossae 41. D The insertion (posterior at tachment) of the lateral pterygoid m uscle is the pterygoid fovea and condylar process of the m andible and the temporomandibular joint (articular disk). A The m edial pterygoid muscle inserts (inferiorly at taches) to the pterygoid rugosit y of the m andible. B The temporalis m uscle inserts (inferoanteriorly at taches) to the coronoid process of the mandible. C The m asseter originates (superiorly at taches) from the body of the zygom atic bone and the zygomatic arch made from the temporal process of the zygom atic bone and the zygomatic process of the temporal bone. E The temporalis muscle originates (superiorly at taches) on the tem poral lines of the lateral cranial vault.

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42. B Much of the weight of the mandible is supported by the sphenomandibular ligam ent. A The mylohyoid muscle is located inferior to the mandible and is at tached to the body of the hyoid bone. It is not in a location where it can support the weight of the m andible in norm al anatom ical position. C The digastric muscle is located inferior to the m andible, but it is at tached posteriorly to the mastoid notch of the temporal bone. Only during extreme mandibular dislocation would the digastric m uscle play any role in supporting the weight of the m andible, after m any other structures have been comprom ised. D The pterygospinous ligament stretches bet ween the lateral pterygoid plate of the sphenoid bone and the spine of the sphenoid bone. The ligam ent, if it is present, spans the mandibular notch, but it does not at tach to the mandible at any point and therefore cannot support its weight. E The buccinator muscle is at tached to the alveolar processes of the mandible and m axilla. Its m ain function is to keep the cheek pressed against the teeth to avoid food accum ulation in the oral vestibule. The muscle fibers are oriented anteroposterior to facilitate that action, not resist the vertical pull of the weight of the mandible. 43. C The location of temporalis, bet ween the temporal lines of the frontal, parietal, and temporal bones and the coronoid process of the mandible places part of the muscle posterior to the temporomandibular joint (TMJ). This is the prim ary m asticator that can retrude the mandible. A The location of the m asseter muscle, bet ween the zygom atic arch and the lateral ramus of the m andible, places the entire m uscle anterior to the TMJ. It m ainly elevates the mandible, although it assists with protraction, side-to-side m otion, and some retraction (from its deep head). B The m edial pterygoid muscle, located vertically in the infratemporal fossa bet ween the m edial side of the lateral pterygoid plate and the medial ram us of the m andible, is placed anterior to the TMJ. It m ainly elevates the mandible. D The lateral pterygoid m uscle, located horizontally in the infratem poral fossa bet ween the lateral side of the lateral pterygoid plate and the neck and pterygoid fossa of the mandible, is placed anterior to the TMJ. Its m ain action is to protrude the mandible or assist in lateral motion for chewing. E The mylohyoid m uscle is located in the floor of the oral cavit y bet ween the mylohyoid line of the m andible and the body of the hyoid and the mylohyoid raphe. The m uscle is placed significantly anterior to the TMJ and is used to tighten the oral cavit y floor and protract the hyoid bone. 44. A The lateral pterygoid protrudes the m andible and pulls it laterally for chewing. B Tensing the soft palate is performed by the tensor veli palatini and levator veli palatini. C Depression of the sphenoid bone is not possible. D Elevation of the hyoid bone is perform ed by the suprahyoid muscles—the digastric, geniohyoid, st ylohyoid, and mylohyoid. The lateral pterygoid can only elevate the hyoid secondarily by first protruding the m andible. E Retraction of the m andible is perform ed by the temporalis m uscle, assisted by the m asseter. 45. B The sphenomandibular ligam ent runs bet ween the base of the sphenoid bone and the lingula of the mandible. It supports the weight of the mandible and helps to prevent overprotraction of the m andible. A The m asseter m uscle has superior at tachm ents on the body of the zygom atic bone and the anterior part of the zygomatic arch. The inferior at tachm ent is the lateral ramus and the angle of the m andible. C The temporalis has superior at tachment along the temporal lines of the frontal, parietal, and temporal bones and an inferior at tachment on the coronoid process of the m andible. D The st ylom andibular ligament runs bet ween the st yloid process of the temporal bone and the posterior ramus and angle of the m andible. Although it also prevents overprotraction, it does not at tach to the lingula. E The pharyngeot ympanic tube has both bony and cartilaginous

parts. The bony parts are supported within the petrous part of the temporal bone. The cartilaginous part is not supported by a bony structure within the nasopharynx but instead provides m uscle at tachment for some soft palate m uscles. 46. D The long buccal nerve, a branch of the m andibular nerve, em erges bet ween the t wo heads of the lateral pterygoid. A, B, E The inferior alveolar nerve and the lingual nerve emerge bet ween the m edial and lateral pterygoids. C The deep temporal nerves em erge superior to the superior head of the lateral pterygoid muscle. 47. B The inferior t ympanic artery is a branch of the ascending pharyngeal artery. A, C The m iddle m eningeal and deep auricular arteries are branches of the first (m andibular/bony) part of the m axillary artery. D, E The descending palatine artery and the artery of the pterygoid canal are branches of the third (pterygopalatine) part of the m axillary artery. 48. B The auriculotemporal nerve, along with the posterior deep temporal and the masseteric nerves, is sensory to the TMJ. A The inferior alveolar nerve is sensory to the m andibular teeth gingiva, and mucosa, as well as the chin and lower lip.. C The lingual nerve is sensory to the tongue, floor of the mouth, and mandibular lingual gingiva. D The nerve to the lateral pterygoid is motor to the lateral pterygoid muscle. E The long buccal nerve is sensory to the mucosa on the inside of the cheek and the buccal gingiva and mucosa of the mandibular molars. 49. E The pterygomaxillary fissure connects the pterygopalatine fossa with the infratemporal fossa laterally. The maxillary artery and the posterior superior alveolar neurovascular bundle traverse this fissure. A The greater palatine canal connects the pterygopalatine fossa with the oral cavit y inferiorly. B, D The pterygoid canal and foram en rotundum connect the pterygopalatine fossa with the m iddle cranial fossa posteriorly. C The sphenopalatine foramen connects the pterygopalatine fossa with the nasal cavit y m edially. 50. C The greater petrosal nerve is a branch of the facial nerve (CN VII) that carries preganglionic parasympathetic fibers to synapse in the pterygopalatine ganglion. Before reaching the ganglion, it joins with the deep petrosal nerve to form the nerve of the pterygoid canal (Vidian nerve). A The maxillary nerve (CN V2 ) contains sensory fibers. Branches of the m axillary nerve carry hitchhiking postganglionic parasympathetic fibers from the pterygopalatine ganglion. B The chorda t ympani is a branch of the facial nerve (CN VII) that carries preganglionic parasympathetic fibers to synapse in the submandibular ganglion. D The lesser petrosal nerve is a branch of the glossopharyngeal nerve (CN IX) that carries preganglionic parasympathetic fibers to synapse in the otic ganglion. E The deep petrosal nerve contains postsynaptic sympathetic fibers that join with the greater petrosal nerve to form the nerve of the pterygoid canal (vidian nerve). 51. A The greater wing of the sphenoid bone is the roof of the pterygopalatine fossa. B The posterior surface of the m axilla is the anterior wall of the pterygopalatine fossa. C The perpendicular plate of the palatine bone is the m edial wall of the pterygopalatine fossa. D, E The temporal bone and vomer do not form boundaries of the pterygopalatine fossa.

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Appendix B

Chapter 7 Nose & Nasal Cavit y 52. A The palatine bone m akes the posterior inferolateral walls and floor of the bony nasal cavit y. It helps to separate the oral cavit y from the nasal cavit y, just anterior to the soft palate. B The zygomatic bone forms the cheek and the lateral wall of the m axillary air sinus, inferior to the orbit. It is located too laterally to help form the nasal cavit y. C The m andible forms the lower jaw and the lateral walls of the oral cavit y. Although it is a m idline bone, it is too inferior to help form the nasal cavit y. D The parietal bone form s the posterolateral walls of the neurocranium , supporting the brain. The left and right parietal bones reach the midline to create the sagit tal suture but are not associated with the nasal cavit y. E The occipital bone form s the bony roof of the nasopharynx, but not the nasal cavit y. 53. B The m iddle m eatus of the nasal cavit y, superior to the inferior nasal concha, allows for drainage of the m axillary air sinus (via the semilunar hiatus), the anterior and m iddle ethmoid air cells, and the frontal sinus (via the frontonasal duct). A The inferior m eatus of the nasal cavit y, inferolateral to the inferior nasal concha, allows for drainage of the nasolacrim al duct from the orbit. C The superior m eatus of the nasal cavit y allows for drainage of the posterior ethm oid air cells. D The nasopharynx, posterior to the nasal cavit y, allows for drainage of the pharyngot ympanic tube from the middle ear. E The sphenoethmoidal recess, superior to the superior nasal concha, allows for drainage of the sphenoid air sinus into the most superior part of the nasal cavit y. 54. C The sphenopalatine artery has posterior septal branches that anastom ose with the anterior nasal septal arteries within Kiesselbach’s area. It is a large branch of the maxillary artery that is found in the infratemporal fossa. A The superior posterior alveolar artery supplies blood to the upper m olars, but it remains in a lateral position. It is a branch of the maxillary artery that stays within the maxillary bone. It does not anastom ose with the anterior nasal septal arteries B The m iddle m eningeal artery supplies blood to the lateral dura mater, inside the cranial vault. It is also a branch of the maxillary artery, but it does not supply the viscerocranium . D The ascending pharyngeal artery, a branch of the external carotid artery, supplies blood to the lateral pharynx and ascends toward the nasopharynx. It does not reach into the nasal cavit y, nor does it anastomose with the anterior nasal sepal arteries. E The petrot ympanic (anterior t ympanic) artery, also a branch of the m axillary artery, supplies blood to the anterior part of the m iddle ear. It anastomoses with the posterior t ympanic artery off the posterior auricular artery and pterygoid canal artery off the internal carotid artery. 55. D The nasopalatine nerve, a branch of the m axillary nerve (CN V2 ), innervates the posterior nasal septum, including the vomer. A The olfactory nerve pierces the cribriform plate of the ethm oid bone and innervates the olfactory epithelium at the roof of the nasal cavit y. B The anterior ethmoidal nerve, a branch of the ophthalm ic nerve (CN V1 ), innervates the anterior m edial and lateral walls of the nasal cavit y, including the anterior parts of the inferior nasal concha. C The greater palatine nerve, a branch of the maxillary nerve (CN V2 ), innervates the hard palate of the oral cavit y. It enters from a posterolateral position and runs anterior and m edial. E The posterior superior alveolar nerve, a branch of the m axillary nerve (CN V2 ), innervates the upper m olars inside the m axillary bone. It rem ains quite lateral and never reaches the nasal cavit y. 56. E The maxillary air sinus is located imm ediately superior to the upper m olars. Complications with tooth extraction of the molars can result in problem s within the maxillary air sinus.

A The frontal air sinus is located superior to and bet ween the orbit s. No teeth are closely associated with this sinus. B The ethm oid air sinus (cells) are located superior to and bet ween the orbits. This bone is not associated with any teeth. C The mastoid air sinus (cells) are located posterior and lateral to the middle ear. Although they are close to the temporomandibular joint, they are not closely associated with the superior m olars. D The sphenoid air sinus is located posterior to the ethmoid air cells on the midline of the skull. The molars are not associated with midline bones. 57. D The sphenoid air sinus separates the nasal cavit y from the hypophyseal fossa, the location of the pituitary gland. This route provides the most direct access to the m acroadenoma. A The frontal sinus separates the nasal cavit y from the cranial vault, but only for access to the frontal lobes of the cerebral hemispheres. The pituitary gland is located in the hypophyseal fossa (sella turcica) of the sphenoid bone, significantly posterior the frontal air sinus. B The ethm oid air sinus separates the nasal cavit y from the orbit and the anterior cranial fossa. Access to this space will still require access into the cranial vault via the optic canal or superior orbital fissure (of the sphenoid bone). C The mastoid air sinus is only connected to the nasal cavit y via the nasopharynx and pharyngot ympanic tube. It would provide access from the m iddle or external ear to the posterior cranial vault, but it is exclusively contained within the temporal bone. E The maxillary air sinus separates the nasal cavit y from the oral cavit y below and orbit above. Neither of these spaces will provide direct access to the pituitary gland.

Chapter 8 Oral Cavit y & Pharynx 58. C The posterior digastric is innervated by a sm all m uscular branch of the facial nerve, just after it exits the st ylomastoid foramen, before it enters the parotid gland to create the parotid plexus. A The mylohyoid is innervated by a branch of the mandibular division of the trigem inal nerve, specifically, the mylohyoid nerve. B The hyoglossus is innervated by a sm all muscular branch of the hypoglossal nerve. D The geniohyoid is innervated by a small contribution from the C1 anterior ram us that joins the hypoglossal nerve as it traverses the lateral neck. It breaks from the hypoglossal nerve as it approaches the posterior border of the mylohyoid. E The st ylopharyngeus is not a true suprahyoid muscle. Furthermore, it is innervated by the glossopharyngeal nerve via a small muscular branch that breaks from the nerve along the superior border of the inferior pharyngeal constrictor. 59. E The ventral posteromedial nucleus receives som atosensory and special visceral sensory input from the head and neck. Input travels through the trigem inothalam ic (central tegm ental: taste) tract, spinothalamic tract (pain/temperature), and medial lem niscus (face), and output goes to the postcentral gyrus. A The ventral anterior nucleus of the thalamus receives input from the globus pallidus and deep cerebellar nuclei and sends output to the precentral gyrus of the cerebral hemispheres. It is a motor relay nucleus and is not associated with taste. B The lateral dorsal nucleus of the thalamus is closely associated with mem ory form ation. It receives input from the hippocampus and sends output to the cingulate gyrus of the cerebral hem isphere. C The pulvinar nucleus of the thalamus receives input from the tem poral, parietal, and occipital lobes of the association cortex and sends output back to the sam e association cortex. It is an intercortical relay nucleus that is partially obsolete due to the telencephalic cortical connections of the splenium of the corpus callosum . D The medial geniculate nucleus deals with auditory inform ation as a relay bet ween the brainstem and the primary auditory cortex in the posterior superior temporal gyrus. Most of the input comes from the inferior colliculus, lateral lemniscus, or superior olivary nucleus, and the output goes through the acoustic radiations of the posterior lim b

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Appendix B

Fa ctua l Questions & Answer Expla na tions

of the internal capsule to the temporal lobe. 60. A The tensor veli palatini is connected to the anterolateral cartilaginous pharyngot ympanic tube and the palatine aponeurosis via the pterygoid hamulus. It flat tens the soft palate and opens the pharyngot ympanic tube. B The palatoglossus is connected to the palatine aponeurosis and the lateral dorsal tongue (intrinsic m uscles). It elevates the tongue and depresses the soft palate. It is not connected to the pharyngot ym panic tube. C The palatopharyngeus is connected to the palatine aponeurosis and the lateral pharynx and thyroid cartilage. It elevates the pharynx and depresses the soft palate. It is also not connected to the pharyngot ympanic tube. D The tensor t ympani is connected to the pharyngot ympanic tube within the petrous part of the temporal bone. It runs posterolaterally to insert into the malleus. It stiffens the t ympanic membrane to reduce the transmission of sound. It is not associated with the soft palate. E The superior pharyngeal constrictor has a variet y of at tachments, including both bony and fibrous, but no cartilaginous at tachm ents. It originates on the pterygoid ham ulus and mylohyoid line (bony) and the pterygomandibular raphe and lateral tongue (fibrous). It inserts into the pharyngeal tubercle of the basilar part of the occipital bone. It is not associated with the soft palate. 61. B The lingual tonsil is located on the dorsal root of the tongue, closely associated with the epiglot tis of the larynx. This midline tonsil com pletes the inferior extent of the pharyngeal lymphatic ring. A The tubal tonsils are associated with the pharyngot ympanic tube of the nasopharynx. They are located posterolateral within the space and are not closely related to the midline epiglot tis. C The pharyngeal tonsil is a midline structure located bet ween the right and left pharyngeot ympanic tubes of the nasopharynx. It is adjacent to the left and right tubal tonsils and completes the superior extent of the pharyngeal lymphatic ring, but it is not closely associated with the epiglot tis. D The palatine tonsils are located bet ween the palatoglossal (anterior) and palatopharyngeal (posterior) arches of the oropharynx. These t wo laterally located lymph structures are closely associated with the lateral tongue, close to but not im mediately adjacent to the epiglot tis. E The adenoid tonsil is another name for the pharyngeal tonsil of the nasopharynx. It is the superiorm ost part of the pharyngeal lymphatic ring. 62. D Dentine m akes up the m ajorit y of the tooth volume. It is deep to the enam el and cem entum and surrounds the pulp chamber. A The periodontal ligament connects the cem entum to the alveolar bone. B Cementum covers the roots of the teeth (enam el covers the crowns). The cem entum and enamel meet at the cem entoenam el junction, located at the cervical margin of the tooth. C The pulp is located in the pulp chamber at the center of the tooth. The pulp chamber is surrounded by dentine, enam el, and cem entum. E The roots of the teeth are embedded in the alveolar bone of the mandible and m axilla. 63. D The 1st molars erupt at 6 to 8 years of age and are comm only called the “6-year m olars.” A The canines erupt at 9 to 14 years of age. B The 1st premolars erupt at 9 to 13 years of age. C The 2nd prem olars erupt at 11 to 14 years of age. E The 2nd molars erupt at 10 to 14 years of age. 64. E The subm andibular ganglion provides postganglionic parasympathetic fibers for the submandibular and sublingual glands. A The superior cervical ganglion provides postganglionic sympathetic fibers (not parasympathetic) for the head. B The pterygopalatine ganglion provides postganglionic parasympathetic fibers for the palate, nasal m ucosa, and lacrimal glands. C The ciliary ganglion provides postganglionic parasympathetic fibers for the eye.

D The otic ganglion provides postganglionic parasympathetic fibers for the parotid gland. 65. B The parotid is a serous gland. A, C The parotid gland does not produce mucous secretions. The subm andibular gland produces both mucous and serous secretions. The sublingual gland is a m ixed gland with predominantly m ucous secretions. 66. A Infections from the m axillary and mandibular molars can spread to the peripharyngeal (retropharyngeal and parapharyngeal) spaces. They can also spread to the buccal space or submandibular, sublingual, or masticator spaces (mandibular molars only). B Infections from the maxillary canines can spread to the infraorbital space. C Infections from the mandibular premolars can spread to the buccal and sublingual spaces. D, E Infections from the m andibular canines and incisors can spread to the submental space. 67. B The subm andibular space is inferior to the mylohyoid line, superior to the hyoid bone, inferior and lateral to the mylohyoid, and medial to the superficial fascia and skin. A The sublingual space is inferior to the m ucosa of the oral floor, superior to the mylohyoid, lateral to the tongue, and m edial to the mandible. C The masticator space is anterior to the st ylom andibular ligament, medial to the cervical fascia, and inferior to the roof of the infratem poral fossa and the origin of the temporalis. D The tonsillar space is posterior to the palatoglossus, anterior to the palatopharyngeus, lateral to the mucosa of the oropharynx, and medial to the pharyngobasilar fascia. E The parotid space is posterior to the ram us of the mandible and st ylomandibular ligament, anterior to the sternocleidomastoid, lateral to the st yloid process and at taching m uscles, and m edial to the skin.

Chapter 9 Orbit & Eye 68. D The ophthalm ic artery (E) runs through the optic canal and supplies blood to the orbit; it is a branch of the internal carotid artery after it has entered the m iddle cranial fossa. A The middle meningeal artery is a superior branch of the mandibular (bony/1st) part of the maxillary artery that enters the skull through the foramen spinosum of the sphenoid bone to supply blood to the lateral part of the internal cranial vault. B The deep temporal artery stays outside the skull and runs bet ween the external lateral cranial vault and the temporalis m uscle. It is a branch of the pterygoid (m uscular/2nd) part of the maxillary artery that never runs through a foram en. C The sphenopalatine artery is the anterom edial term inal branch of the m axillary artery that enters the skull at the pterygomaxillary fissure to access the posterolateral nasal cavit y. It runs medially through the sphenopalatine foramen to reach the nasal cavit y. 69. E The superior oblique is innervated by the trochlear nerve. The muscle resides along the superior m edial wall of the orbit and runs through a small fascial pulley to insert into the superior aspect of the eyeball. A The anterior digastric is innervated by a nerve to the mylohyoid, a branch of the mandibular division of the trigeminal nerve. It is in the suprahyoid region of the neck, not the orbit. B The lateral rectus is innervated by the abducens nerve. It resides lateral to the eyeball, inside the bony orbit. C The inferior oblique is innervated by the inferior branch of the oculom otor nerve. The m uscle resides inferior to the eyeball, inside the bony orbit. D The rectus capitis lateralis is innervated by the anterior ramus of the C1 spinal nerve. It is in the paravertebral space, inferior to the skull, bet ween the occipital bone and the 1st cervical vertebra.

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Appendix B

70. A The superior orbital fissure is for the passage of the superior and inferior parts of the oculom otor nerve (CN III), in addition to all parts of the ophthalm ic division of the trigeminal nerve (CN V1 ), trochlear nerve (CN IV), abducens nerve (CN VI), and superior ophthalmic vein. B The foramen rotundum is for passage of the maxillary division of the trigem inal nerve (CN V2 ). C The foram en ovale is for passage of the mandibular division of the trigeminal nerve (CN V3 ). D The infraorbital foramen is for passage of the largest branch of the m axillary division of the trigeminal nerve (CN V2 ) to reach the surface of the skull in the upper jaw. E The foram en spinosum is for passage of the middle meningeal artery to enter the m iddle cranial fossa of the skull. 71. B The bipolar cell, located in the inner nuclear layer, is the intermediate neuron (sensory) bet ween the photoreceptor cells and the retinal ganglion cells. A The horizontal cell, located in the outer region of the inner nuclear layer, interconnects the photoreceptors to spread or collect visual signals. It does not connect to the retinal ganglion cells. C The amacrine cell, located in the inner region of the inner nuclear layer, interconnects the bipolar cells and the retinal ganglion cells to start to process visual signals. It does not connect to the photoreceptor cells. D The Purkinje cell, located in the cortical layer of the cerebellum , is the output neuron that connects the cerebellar cortex to the deep cerebellar nuclei. It is not associated with the retina. E The Müller’s cell, located in the inner nuclear layer, is the m ain glial support cell of the retina. Although it s cell body is located in this layer, it s peripheral and central processes make the inner and outer lim iting m embranes. It does not connect to either photoreceptor cells or retinal ganglion cells. 72. C The optic chiasm is where nasal retinal information (from the temporal field) from both eyes crosses to the contralateral side. It is located anterosuperior to the pituitary gland. A problem here would produce tunnel vision; it also can be associated with pituitary problem s such as weight gain and reproductive cycle changes. A The optic nerve sends inform ation from a single eyeball to both right and left lateral geniculate nuclei. A problem here would likely present with orbital problem s, such as blindness in one eye, paralysis of the extraocular muscles, and dry eye. It would not be associated with weight gain or a change in the menstrual cycle. B The optic track sends information from both eyes, from a single visual field (right or left) to the ipsilateral lateral geniculate nucleus. A problem here would present with blindness in either the right or left visual field (contralateral homonym us hem ianopia). It would not be associated with weight gain or a change in the menstrual cycle. D The retrolenticular lim b of the internal capsule is the location of the optic radiations that send inform ation from the lateral geniculate nucleus to the prim ary visual cortex (in the calcarine sulcus of the occipital lobe). A problem here would result in a modified form of hem ianopia that has a specific subquadrant missing from the patient’s visual space (contralateral hom onym us quadrantanopia). It would not be associated with weight gain or a change in the menstrual cycle. E The splenium of the corpus callosum interconnects the right and left posterior parietal, posterior temporal, and occipital lobes. It allows for cortical comm unication bet ween the t wo hem ispheres. Problems here would be auditory, visual, mem ory, and somatosensory. It would not be associated with weight gain or a change in the m enstrual cycle.

Chapter 10 Ear 73. B The superficial temporal artery has anterior auricular branches that supply blood to the anterior external ear. A The transverse facial artery runs anterior, im mediately inferior to the zygom atic arch. It supplies blood to the deep facial muscles and the lateral cheek. It does not run posteriorly toward the ear.

C The sphenopalatine artery is a terminal branch of the m axillary artery that supplies blood to the m edial and lateral part of the nasal cavit y. It does not run posteriorly or superficially toward the ear. D The internal carotid artery enters the skull through the carotid canal of the temporal bone to access the middle cranial fossa from below. It supplies blood to the anterior brain and has no branches that supply the external ear. E The occipital artery is a posterior branch of the external carotid artery. It runs deep to the sternocleidomastoid muscle and supplies blood to the posterior scalp and occipitalis muscle. 74. B The facial nerve carries taste fibers in its chorda t ympani branch. This branch of the facial nerve traverses the middle ear cavit y, just m edial to the neck of the malleus and the t ympanic m embrane. A The trigeminal nerve only carries hitchhiking taste fibers that originate in the facial nerve. The branch that carries these taste fibers is the lingual nerve, which is joined by the chorda t ympani inferior to the skull as they both approach the oral cavit y from a posterior direction. C The vestibulocochlear nerve does not carry any taste fibers. It carries other special somatic sensory fibers to the cochlea and vestibular apparatus, but these term inate at the inner ear and do not enter the middle ear cavit y. D The glossopharyngeal nerve carries taste fibers, but they reside within the pharyngeal branches that join the m ain trunk of the nerve and enter the skull through the jugular foramen. The t ympanic nerve, which also traverses the air space of the m iddle ear cavit y, is a branch of the glossopharyngeal nerve, but it only carries general somatic afferent (pain, touch, and proprioception) from the middle ear and viscerom otor fibers to the otic ganglion to drive secretion in the parotid gland. E The vagus nerve carries taste fibers from the root of the tongue, epiglot tis, and pharynx, but they reside in pharyngeal branches that join the m ain trunk of the nerve and enter the skull through the jugular foramen. 75. C The stapes of the middle ear cavit y has a footplate that fits neatly into the oval window of the medial wall of the middle ear cavit y. It is used to transmit sound waves, detected by the t ympanic m em brane, to the inner ear. A The m alleus of the middle ear cavit y is at tached to the t ympanic mem brane via its handle. Although it is in the m iddle ear cavit y, it is not physically at tached to the m edial wall or the inner ear. B The pisiform is a carpal bone located in the proximal anterom edial wrist, adjacent to the head of the ulna. It is not located in the m iddle ear region of the temporal bone of the skull. D The navicular bone of the foot supports the medial side of the talus and transm its forces into the three cuneiform bones of the foot. It is not located in the m iddle ear. E The incus of the middle ear cavit y is supported bet ween the malleus and stapes (and by other ligaments of the m iddle ear cavit y). It is not physically at tached to the m edial wall or the inner ear. 76. D The internal acoustic meatus provides a passage for the vestibulocochlear nerve to exit the posterior cranial fossa and reach the inner ear. The internal acoustic m eatus also transmits the facial nerve and the labyrinthine artery. A The greater petrosal hiatus provides a passage for the greater petrosal nerve (a branch of the facial nerve) and the superficial petrosal artery to exit the petrous part of the temporal bone and enter the middle cranial fossa as they course toward the foram en lacerum. B The external acoustic m eatus provides a passage for sound waves to enter the skull and reach the t ympanic mem brane, located within the temporal bone. It does not provide access to the posterior cranial fossa. C The m astoid canaliculus provides passage for the auricular branch of the vagus nerve to enter the external auditory canal from an inferior direction. It does not provide access to the posterior cranial fossa. E The st ylom astoid foramen provides passage for the facial nerve and st ylom astoid artery to exit the petrous part of the temporal bone on the inferior aspect of the skull.

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Fa ctua l Questions & Answer Expla na tions

77. E The left posterior semicircular canal aligns with a 45-degree plane offset from the median (posterior-anterior) axis of the head. It lies in a plane parallel to the right anterior sem icircular canal. A The right posterior sem icircular canal aligns with a 45-degree plane offset from the median (anterior-posterior) axis of the head. It lies in a plane parallel to the left anterior semicircular canal. B The right lateral sem icircular canal aligns with a 30-degree plane offset from the horizontal axis of the head. It lies in the exact sam e (parallel) plane as the left lateral sem icircular canal. C The left anterior sem icircular canal aligns with a 45-degree plane offset from the median (anterior-posterior) axis of the head. It lies in a plane parallel to the right posterior semicircular canal. D The left lateral semicircular canal aligns with a 30-degree plane offset from the horizontal axis of the head. It lies in the exact sam e (parallel) plane as the right lateral semicircular canal. 78. A The basilar mem brane stretches bet ween the m odiolus and spiral ligam ent and therefore lies bet ween the endolymph and perilymph. It physically supports the hair cells of the cochlear. B The spiral ligam ent underlies the stria vascularis of the cochlear duct. It supports the secretory stria, but it is not physically at tached to the hair cells and does not com e into contact with perilymph. C The vestibular mem brane stretches bet ween the m odiolus and the spiral ligament and also separates endolymph and perilymph. However, it is not a support structure of the hair cells and is not closely associated with sound detection. D The tectorial m embrane covers (supports) the stereocilia of the hair cells of the cochlear duct. It is completely enclosed within the cochlear duct and does not separate perilymph from endolymph. E The helicotrem a is a perilymphatic passage bet ween the scala vestibuli and scala t ympani. It does not separate endolymph from perilymph and is not associated with the hair cells. 79. C The spiral ganglion contains the cell bodies whose peripheral processes synapse with the inner hair cells and whose central processes are the m ain synaptic input for the cochlear nuclei. Without this input, no sound perception can be detected, so no sound could be localized. A The vestibular nuclei are critical for the perception of linear or angular acceleration changes of the head due to motion. None of these systems are critical for the localization of sound in auditory space (anterior, posterior, right, or left), which can be accomplished in a stationary head. B The tensor t ympani m uscle contracts to change the tuning of the t ympanic m embrane. Although it can be used to augment (or depress) the perception of sound, it is not used to localize sound. D The lateral geniculate nucleus is one of the synaptic targets of the optic tract. It deals exclusively with visual inform ation, which is not necessary for the localization of sound. E The m edial lem niscus is the midbrain tegm ental pathway connecting the posterior colum n nuclei (gracilis and cuneatus) to the ventroposterolateral and ventroposteromedial nuclei of the thalam us. This pathway is for perception of touch and conscious proprioception and is not necessary for the localization of sound.

Chapter 11 Bones, Ligam ents, & Muscles of the Neck 80. B The geniohyoid draws the hyoid bone anteriorly and is innervated by the anterior ramus of the C1 spinal nerve carried by the hypoglossal nerve. A The mylohyoid draws the hyoid bone anteriorly, but it is innervated by the mylohyoid nerve, a branch of the m andibular division of the trigeminal nerve (CN V3 ). C The st ylohyoid elevates the hyoid (and helps with posterior motion) and is innervated by the facial nerve (CN VII). D The omohyoid depresses the hyoid and fixes it in place. It is innervated by the ansa cervicalis, the C1−C3 anterior ram i that innervate most infrahyoid m uscles in the anterior neck. E The sternohyoid depresses the hyoid and fixes it in place. It is also

innervated by the ansa cervicalis, the C1−C3 anterior ram i. 81. E The sternocleidom astoid muscle of the neck rotates the head to the contralateral (opposite) side. A, B The rectus capitis posterior m ajor and longissim us capitis extend the head and rotate it to the ipsilateral (same) side. C The rectus capitis lateralis flexes the head at the atlanto-occipital joint anteriorly and laterally to the ipsilateral side. D The splenius capitis extends the cervical spine and head, as well as flexes and rotates the head to the ipsilateral side. 82. A The splenius cervicis originates (proximally at taches) to the spinous process of T3−T6. B The levator costarum longii muscles originate (inferiorly at tach) to the transverse processes of the C7−T11 vertebrae. C The serratus posterior superior originates (proxim ally at taches) on the nuchal ligament and the spines of the C7−T3 vertebrae. It does not extend as inferior as the T6 vertebra. D The iliocostalis thoracis originates (proximally at taches) on the iliac crest, sacrum , thoracolum bar fascia, and inferior ribs. E The longus colli originates (inferiorly at taches) to the anterior surfaces of the T1−T3 vertebrae in the prevertebral space. 83. C The geniohyoid m uscle of the suprahyoid group is innervated by the anterior ramus of the C1 spinal nerve. A The mylohyoid nerve, a branch of the m andibular division of the trigem inal nerve (CN V3 ), innervates the mylohyoid and anterior digastric muscles of the suprahyoid group, but it does not reach deeper than the mylohyoid. B The facial nerve (CN VII) innervates the m uscles of facial expression, the posterior digastric and st ylohyoid muscle of the suprahyoid group, and the stapedius muscle. The branches that reach far enough anterior (marginal m andibular and cervical) do not reach deeper than the thin facial m uscles. D The inferior alveolar nerve (of CN V3 ) is a purely sensory nerve that travels the length of the body of the mandible to reach the m ental foram en and provide sensory perception from the m andibular teeth and the m ental region of the face. It does not innervate any m uscles. E The hypoglossal nerve (CN XII) carries innervation to the intrinsic and most extrinsic m uscles of the tongue (genioglossus, hyoglossus, and st yloglossus, not palatoglossus). It provides a route for the ventral ram us of the C1 spinal nerve to reach the geniohyoid but does not innervate any of the suprahyoid muscles.

Chapter 12 Neurovascular Topography of the Neck 84. A The valleculae are the spaces bet ween the tongue and the epiglot tis that allow nursing infants to be able to breathe (through their nose) and nurse sim ultaneously. They are at the superior end of a gut ter that extends through the piriform recesses to reach the laryngopharynx and the esophagus. B The piriform recesses are lateral to the epiglot tis, superior and lateral to the cricoid cartilage. They are continuous with the valleculae superiorly and the esophagus inferiorly. C The rima glot tidis is the aperture bet ween the left and right vocal ligam ents and cords. This is a midline structure that lies posterior and inferior to the epiglot tis. D The foram en cecum is a small pit at the boundary of the anterior and posterior tongue that is the em bryological remnant of the thyroglossal duct. It is located on the midline, posterior to the vallate papilla. E The tonsillar fossa is occupied by the palatine tonsil, located bet ween the palatoglossal and palatopharyngeal arches. This lies anterior to the epiglot tis, lateral to the tongue.

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Appendix B

85. B The m iddle scalene muscle inserts (distally at taches) into the 1st rib posterior to the groove for the subclavian artery. A The superom edial angle of the scapula provides the insertion (distal at tachment) for the levator scapulae. Lateral to this position on the scapula, the om ohyoid muscle has an origin (proximal at tachm ent). The m iddle scalene is not connected to the scapula. C The 2nd rib provides the insertion (distal at tachm ent) for the posterior scalene muscle, which shares some of the sam e origin (proximal at tachm ent) as the m iddle scalene muscle, but the m uscle fibers run in a slightly different direction. The middle scalene is not connected to the 2nd rib. D The basilar occipital bone provides the insertion (distal at tachm ent) for a variet y of prevertebral m uscles, including the longus capitis, rectus capitis anterior, rectus capitis lateralis, and superior pharyngeal constrictor. Although som e of these muscles share the same origin (proxim al at tachment) as the middle scalene, they run in completely different directions. The middle scalene is not connected to the basal skull. E The m anubrium of the sternum is the origin (proxim al at tachment) of the sternocleidom astoid and pectoralis m ajor muscles. Although the sternocleidom astoid is very close and runs in a similar direction to the m iddle scalene, they have very different functions. The m iddle scalene is not at tached to the m anubrium. 86. D The occipital triangle provides the best access to the spinal accessory nerve as it travels superficial to the levator scapulae as it crosses the sternocleidomastoid and trapezius muscles in the posterior triangle of the neck. It also contains som e of the supraclavicular nerves and the occipital nerves of the neck. A The subm andibular triangle of the anterior neck contains the hypoglossal nerve, branches of the C1 anterior ram us, and branches of the mandibular division of the trigem inal nerve. It is located too far anterior to provide access to the spinal accessory nerve. B The m uscular triangle of the anterior neck contains laryngeal branches of the vagus nerve and most of the ansa cervicalis (C1−C3 anterior ram i). It is located too far anterior to provide access to the spinal accessory nerve. C The carotid triangle of the anterior neck lies just anterior to the m iddle part of the sternocleidomastoid. In this triangle, the ansa cervicalis and vagus nerves are the m ost prominent nervous structures. There are carotid branches of the glossopharyngeal nerve as well, but these are usually quite sm all. E The om oclavicular triangle, located in the posterior triangle of the neck, has no nervous structures located in it. Deep to the triangle, it is possible to access the brachial plexus, but not the spinal accessory nerve. 87. C The vagus nerve travels the entire length of the carotid sheath, running parallel to the com mon and internal carotid arteries and the internal jugular vein. A The facial nerve and its branches remain in the head for the m ost part. There is a cervical branch of the facial nerve that drops into the neck to innervate the plat ysma, superficial to the carotid sheath. No other branches come close to the carotid sheath. B, D, E The glossopharyngeal, spinal accessory, and hypoglossal nerves pass tangentially (anteroinferior) through the most superior part of the carotid sheath. The glossopharyngeal nerve contributes to the pharyngeal plexus and has branches innervating the st ylopharyngeus and the carotid body. The spinal accessory nerve innervates the sternocleidomastoid and trapezius muscles. The hypoglossal nerve innervates the intrinsic and extrinsic tongue muscles (except the palatoglossus). 88. D The parapharyngeal space will allow infections from the oral cavit y to drain, via gravitational abscess, into the mediastinum , causing m ediastinitis. A The cavernous sinus is accessible from the parapharyngeal space, but it lies superior to the parapharyngeal space associated with the oral cavit y. An inferior bacterial spread (gravitational abscess) would not m ove to this location. B The lung is som ewhat isolated from the parapharyngeal space due to the nature of the pleura of the thoracic cavit y. Bacterial infection

would need to traverse this barrier to spread to the lungs. C The stom ach is isolated from the parapharyngeal space due to the nature of the peritoneum of the abdominal cavit y. Bacterial infections would need to traverse this barrier to spread to the stomach. E The subarachnoid space is accessible from the parapharyngeal space, but it lies superior to the parapharyngeal space associated with the oral cavit y. An inferior bacterial spread (gravitational abscess) would not move to this location. 89. E The C1 anterior ram us is the m ain contributor to the superior root of the ansa cervicalis. It breaks away from the hypoglossal nerve, where it is temporarily carried, in such a way as it appears that the superior root of the ansa cervicalis is a large branch of the hypoglossal nerve. A The vagus nerve has branches that contribute to the pharyngeal plexus, superior laryngeal nerve, and recurrent laryngeal nerve. All of these branches are significantly deeper than the ansa cervicalis. B The hypoglossal nerve seems to have a large contribution to the superior root of the ansa cervicalis, but it is really just the anterior ram us of the C1 spinal nerve that breaks away to create the superior root. The branches of the hypoglossal nerve innervate the m uscles of the tongue only. C The C3 anterior ramus contributes to the inferior root of the ansa cervicalis, as well as the phrenic, supraclavicular, transverse cervical, and great auricular nerves. Most branches run either significantly inferior or posterior to the ansa cervicalis. D The C2 posterior ram us contributes to the innervation of the m uscles of the posterior cervical region and the greater occipital nerve. It is a posterior nerve that has no branches that run anteriorly toward the ansa cervicalis. 90. A The transverse cervical vein drains anteriorly in the occipital triangle to reach the external jugular vein. It collects blood from the retroauricular vein and occipital veins as it moves across the lateral neck. B The inferior thyroid vein drains inferiorly directly into to the brachiocephalic veins. It can be accompanied by a small thyroidea ima artery, but it is not associated with the external jugular vein. C The pterygoid plexus drains blood from the infratemporal fossa through the maxillary vein to reach the retromandibular vein. From here, blood can flow anterior into a com mon facial vein (facial and anterior division of the retrom andibular) or posteriorly into the external jugular vein. There are no direct connections bet ween the pterygoid plexus and the external jugular vein. D The facial vein drains posteroinferiorly along the body of the m andible and m eets the anterior division of the retromandibular vein. From here, blood drains through a common facial vein to reach the internal jugular vein. It is only through increased venous pressure that blood m ight flow superiorly through the retromandibular vein to the external jugular vein. E The lingual vein drains blood from the floor of the oral cavit y and meets the facial vein just prior to becoming the com mon facial vein. From here, blood t ypically drains into the internal jugular vein.

Chapter 13 Larynx & Thyroid Gland 91. A The base of the thyroid cartilage provides an at tachm ent for the midline of the epiglot tic cartilage via the thyroepiglot tic ligament. It is at the posterior union of the t wo thyroid plates that this ligament at taches. B The cricoid cartilage physically supports the t wo arytenoid cartilages and m aintains t wo cricothyroid joints in a posterolateral position with the inferior horn of the thyroid cartilage. There are no direct connections bet ween the cricoid cartilage and the epiglot tis. C The arytenoid cartilages rest on the arytenoid articular facets in a lateral position on the superior posterior surface of the cricoid cartilage. The arytenoid cartilages physically support the corniculate cartilages at their apex. D The corniculate cartilages rest on the superior m edial apex of the arytenoid cartilages, in a slightly lateral and posterior position within the larynx. The epiglot tis is at tached at an anterior inferior position, diagonally opposite the position of these cartilages.

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Appendix B

Fa ctua l Questions & Answer Expla na tions

E The tracheal cartilage rings occupy anterior and lateral positions inferior to the larynx. They reside inferior to the cricoid and thyroid cartilages, significantly inferior to the anterior m idline at tachment of the epiglot tic cartilage. 92. A The posterior cricoarytenoid rotates the arytenoid cartilage out ward and toward the side to abduct the vocal cords and open the rima glot tidis. B The cricothyroid changes the angle bet ween the thyroid and cricoid cartilages to increase tension on the vocal cords but does not necessarily change their position in the larynx. C The lateral cricoarytenoid rotates the arytenoid cartilage inward, which adducts the vocal cords and closes the rima glot tidis. D The transverse arytenoid moves the t wo arytenoid cartilages toward each other, adducts the vocal cords, and closes the rima glot tidis. E The thyroarytenoid and its inferior fibers (vocalis) rotate the arytenoid cartilage anteriorly, which relaxes (the vocalis tightens) the vocal cords and closes (or has no effect on) the rima glot tidis. 93. C The pyram idal lobe of the thyroid gland is the embryological remnant of the thyroglossal duct indicating the origin of the thyroid gland at the root of the tongue. It t ypically runs anterior to the laryngeal prominence of the thyroid cartilage. A The lateral lobes of the thyroid gland reside lateral to the cricoid cartilage and inferolateral to the thyroid cartilage. They do not approach the m idline (except at the isthmus) of the neck. B The isthmus of the thyroid gland joins the left and right lateral lobes, anterior to the anterior arch of the cricoid cartilage. It is a midline structure, but it is not as superiorly located as the laryngeal prominence. D The superior parathyroid gland, a separate embryological structure (4th pharyngeal pouch) from the thyroid gland (thyroid diverticulum), resides deep to the lateral lobe of the thyroid gland. It maintains this lateral position and does not shift toward the midline. E The inferior parathyroid gland, a separate em bryological structure (3rd pharyngeal pouch) from the thyroid gland (thyroid diverticulum), resides medial to the lateral lobe of the thyroid gland. It m aintains this lateral position and does not shift toward the midline.

Chapter 15 Rest of Body Anatomy 94. A The infraspinatus is innervated by the suprascapular nerve (C4−C6) after it passes through the suprascapular notch, covered by the superior transverse ligament of the scapula. B The subclavius is innervated by the nerve to the subclavius (C5− C6), which passes inferior to the medial end of the clavicle. The nerve to the subclavius does not approach the scapula. C The teres m ajor is innervated by the lower subscapular nerve (C5− C6), which passes anterior to the subscapularis m uscle in the axilla. The lower subscapular nerve reaches only the posterior lateral edge of the scapula, not in a superior position. D The rhom boid m inor is innervated by the dorsal scapular nerve (C4−C5), which passes posterior and medial to the m edial border of the scapula. The dorsal scapular nerve never reaches the superior lateral edge of the scapula, where the supra scapular notch is located. E The deltoid is innervated by the axillary nerve (C5−C6), which passes through the quadrangular space to reach the posterior undersurface of the deltoid. The axillary nerve passes anterior to the superior edge of the subscapularis, then passes posterior along the lateral edge of the scapula. 95. B The brachial (and cephalic) veins drain into the lateral (and medial) end of the axillary vein. From here, blood flows sequentially into the subclavian vein, brachiocephalic vein, and superior vena cava before reaching the heart. A The cephalic vein is not directly connected to the brachial vein. There are connections through the median cubital vein, but valves prevent back (peripheral) flow from the brachial vein to the cephalic vein.

C The brachiocephalic vein is not directly connected to the brachial vein. Bet ween the t wo are both the axillary vein and the subclavian vein. The brachiocephalic vein is necessary to drain brachial vein blood back to the heart. D The internal jugular vein is not directly connected to the brachial vein. Blood from the brachial vein eventually drains through the subclavian vein, which joins with the internal jugular vein, but there are valves in both the subclavian vein and the internal jugular vein that prevent back (peripheral) flow bet ween them . E The subclavian vein drains blood from the axillary vein and som e smaller veins, but it has no other major contributors from the arm. It runs inferior to the clavicle, whereas the brachial vein ends at the distal extent of the axilla. 96. E The radial tuberosit y of the radius is the insertion/distal at tachm ent of the biceps brachii tendon, which provides both forearm flexion and supination at the radioulnar joint. A The lateral intertubercular groove is the insertion of the pectoralis major. B The coracoid process of the scapula is the insertion of the pectoralis minor and the origin/proximal at tachm ent for the coracobrachialis and biceps brachii, short head. C The ulnar tuberosit y of the ulna is the insertion/distal at tachment for the brachialis, another flexor of the forearm . D The olecranon fossa of the humerus is the space in which the olecranon of the ulna fit s during forearm extension. No m uscles at tach in this space. 97. C The left 8th posterior intercostal vein drains into the hem iazygos vein. Com munications from this vein drain to the right to reach the azygos vein and subsequently the superior vena cava prior to returning blood to the heart. A The inferior vena cava is not directly connected to the posterior intercostal veins. To reach the inferior vena cava, blood would have to drain from the posterior intercostal veins to the azygos (right) or hemiazygos (left) veins and then drain inferiorly to reach the ascending lum bar veins. From here, blood could drain through the lumbar veins to reach the inferior vena cava. B The superior vena cava is not directly connected to the posterior intercostal veins. To reach the superior vena cava, blood would have to drain from the posterior intercostal veins to the hemiazygos (left) or azygos (right) veins. The hem iazygos vein drains to the azygos vein, which in turn drains to the superior vena cava. D The azygos vein drains the posterior intercostal veins on the right, not the left, side of the thorax. It collects blood from the hem iazygos and accessory hemiazygos veins and drains into the superior vena cava, but there are t ypically no direct connections bet ween the left posterior intercostal veins and the azygos vein. E The thoracic duct is a lymphatic passage that drains lymph from the lower extrem ities, pelvis, and abdom en. No veins drain directly into this lymphatic structure. 98. D The circumflex artery is one of t wo m ajor branches of the left coronary artery. It wraps around the heart from anterior to posterior in the left atrioventricular sulcus, giving rise to one or more obtuse (left) marginal arteries that supply blood to the left side of the left ventricle. It is paralleled by the great cardiac vein. A The anterior interventricular artery is a branch of the left coronary artery that descends bet ween the right and left ventricles on the anterior heart. Its branches are the diagonal (left) and septal (internal) branches that supply blood to the anterior left ventricle and interventricular septum . The anterior interventricular artery is paralleled by the great cardiac vein before it turns into the left atrioventricular sulcus and starts to parallel the circum flex artery. B The posterior interventricular vessels are t ypically terminal branches of the right coronary artery and the m iddle cardiac vein. These vessels run bet ween the right and left ventricles on the posterior aspect of the heart. Occasionally, the posterior interventricular vessels arise from the circumflex branch of the left coronary artery (left dominant heart). C The right coronary vessels follow the right atrioventricular sulcus from the anterior aspect of the heart to the posterior interventricular

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Appendix B

sulcus. The right coronary artery has the acute (right) marginal artery branches, but it does not supply blood to the left side of the heart. The sm all cardiac vein t ypically parallels the right coronary artery but still would not reach the left side of the heart before it drained into the coronary sinus. E Thebesian vessels are veins that drain blood from the right ventricle directly into the right atrium, bypassing the sm all cardiac vein and the coronary sinus. There are no thebesian arteries. Because these vessels are restricted to the right side of the heart, there is no way for these sm all vessels to reach the left (obtuse) margin of the heart. 99. A A pulmonary embolism in the apicoposterior segm ent of the superior lobe of the left lung would result in breathlessness and chest wall pain along the posterior superior lateral m argin of the left thorax. B A pulm onary em bolism in the apical segment of the superior lobe of the right lung would result in breathlessness and chest wall pain along the superior m argin of the right thorax. C A pulmonary em bolism in the lateral segment of the middle lobe of the right lung would result in breathlessness and chest wall pain along the lateral m argin of the right thorax. D A pulm onary em bolism in the superior lingular segment of the superior lobe of the left lung would result in breathlessness and chest wall pain along the m idlateral margin of the left thorax. E A pulm onary em bolism in the superior segment of the inferior lobe of the left lung would result in breathlessness and chest wall pain along the posterior and lateral margin of the left thorax.

Appendix A Anatomy of Local Anesthesia for Dentistry 100. C The needle passes through the buccinator m uscle during an inferior alveolar nerve block. The fact that the needle passes through muscle accounts for the particularly painful nature of this injection. A The needle passes into the pterygomandibular space lateral to the m edial pterygoid muscle during an inferior alveolar injection. If the needle is m istakenly aim ed too far m edially, the injection will be given into the m edial pterygoid muscle, causing failure of anesthesia and trimus (m uscle spasm) of this m uscle. B An inferior alveolar nerve block is given anteriorly to the lateral pterygoid muscle, so this muscle is not affected by this injection (intentionally or otherwise). D An inferior alveolar nerve block is given just laterally to the pterygomandibular raphe, a landm ark structure for this injection. E If an inferior alveolar nerve block is aim ed too posterolaterally, and bone is not contacted before the injection is given, then the needle is likely to have pierced the capsule of the parotid gland. This will cause anesthesia of the branches of the facial nerve that run through the gland, leading to a temporary facial paralysis (Bell’s palsy).

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Appendix C

Clinica l Questions & Answer Expla na tions

Clinical Questions For Questions 1 to 3: Mark has been experiencing a troubling series of symptom s involving his right upper limb. These symptoms have becom e exacerbated over the past few m onths. They include intermit tent periods of intense pain in various areas of the lim b and a tingling sensation (paresthesia) in others. He is also now experiencing various motor difficulties. He is sent for tests that include magnetic resonance im aging (MRI). It is discovered that he has a slipped disk that is impinging on spinal nerve C5. 1. To which of the following areas of the upper lim b would his pain and/or paresthesia be primarily localized? A. Superolateral aspect of the arm extending inferior to the lateral aspect of the m idpoint of the forearm B. Axillary fold extending into the m edial aspect of the arm C. Medial aspect of the arm and forearm D. Medial aspect of the forearm extending into the hypothenar eminence of the hand E. Lateral aspect of the forearm extending into the thenar em inence of the hand 2. Which of the following nerves would be totally dysfunctional as a result of a compression of C5? A. B. C. D. E.

Axillary Thoracodorsal Long thoracic Dorsal scapular Lateral pectoral

Abduction and adduction of the fingers Flexion at the elbow Abduction at the glenohumeral joint Lateral rotation at the glenohum eral joint Extension at the glenohum eral joint

Your friend William is walking down the street when he stares upward, then crumples to the ground. He lies there unconscious as you call for an ambulance. His wife arrives at the hospital, and after he becomes conscious, it is clear from his symptoms that he had an occlusion of the left m iddle cerebral artery. 4. One of the m ost obvious and prominent symptoms exhibited by William is alm ost total paralysis of his upper and lower lim bs on the right side of his body. This occurred because of lack of blood flow to which of the following parts of the brain? Left internal capsule Left putam en Right precentral gyrus Right prem otor cortex Left postcentral gyrus

5. Assuming that William is left brain dom inant, in addition to the difficult y m entioned previously, all of the following symptoms are consistent with an occlusion of the middle cerebral artery, except for A. Apraxia (inabilit y to perform a movem ent correctly in response to a verbal or writ ten request) B. Alexia (inabilit y to read) C. Agraphia (inabilit y to write) D. Right-sided paralysis E. Anosognosia (inabilit y to recognize disease or debilitation in oneself)

508

Posterior aspect of the superior temporal gyrus Supram arginal gyrus Lingual gyrus Inferior frontal cortex Inferior aspect of the precentral gyrus

7. If, for the sake of argum ent, the right m iddle cerebral artery was occluded rather than the left m iddle cerebral artery in a left brain−dominant individual, which of the following symptoms would be apparent? A. Inabilit y to move his right hand B. Inabilit y to move the muscles of facial expression on the right side of his face C. Inabilit y to appreciate tonalit y in speech or in m usic D. Inabilit y to calculate figures on a check during dinner E. Inabilit y to understand what is spoken to him and responding with clearly enunciated but nonsense sentences

Max is a 65-year-old patient of long standing, but you have not seen him for over a year. His prim ary complaint is that things “don’t feel right” when he chews, specifically, on the left side of his m outh. He has the sensation that he just cannot seem to put his teeth into the correct position. The initial exam ination reveals a carious lesion of the 2nd maxillary molar on the left side. Also, wear pat terns and abfraction (pathological loss of tooth structure at tributed to biom echanical forces or chemical degradation) on the left maxillary teeth are noted. 8. The initial thought was that Max was favoring his left side due to the pain associated with the carious tooth. To painlessly remove the decay, which of the following nerves need to be anesthetized?

For Questions 4 to 7:

A. B. C. D. E.

A. B. C. D. E.

For Questions 8 to 11:

3. Which of the following actions would be least affected as a result of compression of C5? A. B. C. D. E.

6. It is clear from William’s interactions with those around him that he understands what is being said about him and what is being asked of him . However, when he is asked to respond to a question or speak in general, he can only respond with grunts and garbled ut terances. It is clear that this is very frustrating to him . Based on this specific symptom, which of the following areas of his cerebrum is damaged?

A. B. C. D. E.

Posterior superior alveolar Long buccal nerve Middle superior alveolar Greater palatine Lesser palatine

9. Two weeks after the decay was removed, Max returns to the office with the same complaint. Now not only do things not “feel right,” but he is also in pain. The pain at tim es radiates throughout his entire m axillary arch. Before you can explore the region, Max states that he wants all of the teeth anesthetized. You explain that this is not necessary and that the procedure for anesthetizing the entire maxillary nerve is complex and potentially problematic. The most conventional form of this procedure would involve which of the following? A. Inserting a needle extraorally into the infratemporal fossa and the foramen ovale. Fluid would then enter into the m ost inferior aspect of the cranium at the point of exit of the m axillary nerve. B. Inserting a needle intraorally through the buccinator muscle into the infratemporal fossa, then placement of the needle adjacent to the foram en rotundum. Fluid would gain access to the inferior aspect of the cranium at the point of exit of the m axillary nerve. C. Inserting a needle extraorally into the infratemporal fossa and approximating the pterygom axillary fissure. Fluid would then gain access to the pterygopalatine fossa, and the maxillary nerve would be anesthetized. D. Inserting a needle intraorally into the greater palatine foram en. Fluid would then travel up the greater palatine canal into the pterygopalatine fossa, and the m axillary nerve would be anesthetized. E. Inserting a needle into the infraorbital foram en. Fluid would then be placed into the foram en and would travel posteriorly to the pterygopalatine fossa, and the maxillary nerve would be anesthetized.

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Appendix C

10. Max returns 3 weeks later. He is clearly agitated and states that things still do not “feel right.” You carefully palpate the external aspect of his jaw and infratemporal region and discover the muscles that elevate the m andible on the left side of his head seem to be slightly hypertrophied and spasm odic as compared with the sam e m uscles on the opposite side. The m uscles that you were able to palpate include the A. B. C. D. E.

Temporalis only Temporalis and m asseter Temporalis, masseter, and buccinator Temporalis, masseter, and zygomaticus major Temporalis, masseter, and lateral pterygoid

A. The m otor nucleus of cranial nerve (CN) V was dam aged on the right side of the brainstem. This would explain the abnormal activit y of the muscles of m astication on the right side of the jaw. B. The m esencephalic nucleus of CN V was damaged on the left side of the brainstem . This would explain the report of “things not feeling right,” as this nucleus is responsible for proprioception impulses that travel to nerves of the mandibular and maxillary m olars and sensory fibers associated with the temporom andibular joint (TMJ). C. The principal sensory nucleus of CN V was damaged on the left side of the brainstem. This would explain the intense pain experienced. D. The nucleus caudalis was damaged on the right side of the brainstem. This would explain the uneven wear pat terns seen, as this nucleus helps to control the coordination of m uscles of the TMJ on the left and right sides of the jaw. E. The nucleus interpolaris was dam aged on the right side of the brainstem . This would explain the uneven wear pat terns, as this nucleus is specifically responsible for fine touch and would com e into play when Max tries to approximate his maxillary teeth to his m andibular teeth.

For Questions 12 and 13: Your friend is lying in a hospital bed after being in a head-on automobile collision. Unfortunately, his classic car had neither seatbelts nor an airbag, so upon colliding with the other car, he catapulted forward, with his head violently hit ting the windshield. Upon awaking, it was discovered that he was suffering with both anosmia (loss of olfaction) and bilateral total anopsia (total blindness in both eyes). 12. His anosmia possibly resulted from damage to fibers that run through the Inferior orbital fissure Foramen rotundum Foramen ovale Cribriform plate Foramen spinosum

13. The bilateral anopsia possibly resulted from dam age to the optic chiasm because it was severed by which of the following broken shards of bone? A. B. C. D. E.

Ethm oid Frontal Lesser wing of the sphenoid bone Petrosal portion of the temporal bone Clivus

A restoration needs to be perform ed on a carious lesion on a m axillary 2nd molar. An anesthetic procedure takes place to num b the tooth. Unfortunately, sufficient care is not taken to ensure that the needle is sterile. In addition, when the needle is placed into the tissue, it is not withdrawn to discern whether or not it was inadvertently placed into a blood vessel. Three days after the procedure, the patient is rushed to an em ergency room with a fever of 104°F (40°C). The patient is dizzy, disoriented, and nauseated. He is also experiencing acute exophthalmia (marked protrusion of the eyeball) of his left eye and difficult y m oving his left eye laterally.

11. As a result of the previous examination, you suggest that Max use a bite splint at night. He does as requested, but 1 m onth later, rather enraged, he returns with the sam e complaint i.e., that things do not “feel right” when he chews. You now ask him if there was any m ajor health event or em ergency that occurred during the year before the first exam ination. He states that he had a m inor stroke from which he believes he has fully recovered. You contact the neurologist and discover that it was a brainstem stroke involving the pons. After a consultation with the neurologist, you tell Max that, unfortunately, there is very lit tle that you can do to ameliorate his discomfort. Your rationale for this statement is the following.

A. B. C. D. E.

For Questions 14 to 16:

14. The anesthetic procedure was to anesthetize which of the following nerves? A. B. C. D. E.

Middle superior alveolar Anterior superior alveolar Posterior superior alveolar Greater palatine Lesser palatine

15. The symptom s he is experiencing are a result of bacteria being introduced into the _______________, which then traveled into the ___________. A. B. C. D. E.

External carotid artery, m iddle m eningeal artery Ophthalmic vein, cavernous sinus Maxillary vein, retromandibular vein Pterygoid plexus, cavernous sinus Infraorbital vein, cavernous sinus

16. The difficult y the patient has in m oving his eye laterally is directly related to irritation of the __________ nerve, resulting in dysfunction of the ____________ m uscle. A. B. C. D. E.

Abducens, inferior oblique Oculomotor, superior rectus Oculomotor, inferior rectus Abducens, lateral rectus Trochlear, superior oblique

For question 17 to 20: Your patient has arrived with a carious lesion of his right 2nd mandibular molar. You at tempt an inferior alveolar nerve anesthetic procedure. Initially, all appears to be proceeding as planned. However, ~ 5 minutes after the injection, the patient reports no lower lip anesthesia and a symptom that is quite worrisom e. Based on this symptom, you realize that you have injected anesthetic fluid into the parotid capsule. 17. What is the symptom that is causing you concern? A. Difficult y depressing the mandible on the side of the injection B. Inabilit y to close the palpebral fissure on the side of the injection C. Inabilit y to open the palpebral fissure on the side opposite the injection D. Difficult y with swallowing E. Inabilit y to raise the m andible on the side opposite the injection 18. Which of these structures is found in the parotid space? A. B. C. D. E.

Retromandibular vein Internal carotid artery Internal jugular vein Masseteric branch of the m axillary artery Buccal branch of the m axillary artery

19. These symptom s probably occurred as a result of the needle placem ent that is A. B. C. D. E.

Too far superior and anterior Too far posterior and inferior Too far anterior and inferior Too far medial and inferior Too far medial and superior

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Clinica l Questions & Answer Expla na tions

20. A second injection was then perform ed to anesthetize the mandibular tooth. This did not provide the necessary anesthesia, and again it was assumed that the anesthetic fluid did not properly approxim ate the inferior alveolar nerve. However, the lack of anesthesia might not have been due to the procedure but because there are accessory sensory fibers that sometim es supply the roots of the mandibular molars. These fibers travel on or with the A. B. C. D. E.

Lingual nerve Long buccal nerve Nerve to the mylohyoid Marginal m andibular nerve Buccal branch of CN VII

For Questions 21 to 24:

21. Based on the symptom s, it is determ ined that he is suffering from Bell’s palsy Trigeminal neuralgia Geniculate neuralgia Glossopharyngeal neuralgia Temporal arteritis

22. A compression of which of the following nerves m ight be responsible for the aforem entioned syndrome and the symptoms described in the scenario? A. B. C. D. E.

Trigeminal Mandibular branch of the trigem inal Maxillary branch of the trigeminal Inferior alveolar nerve Lingual nerve

23. As stated, when asked to open his m outh, the patient experiences great difficult y as the muscles that oppose this action go into spasm. The muscles that are becoming spasm odic include the A. B. C. D. E.

Buccinator Lateral pterygoid Temporalis Mylohyoid Anterior digastric

24. In a person facing this degree of pain, it is som etimes necessary to take rather extrem e m easures. One of these measures is to ablate the ganglion involved with the transmission of pain impulses back to the central nervous system . This procedure is known as percutaneous needle rhizotomy. In this case, to alleviate the pain, the ganglion that would need to be ablated is the A. B. C. D. E.

Geniculate ganglion Sem ilunar ganglion Superior ganglion of CN IX Pterygopalatine ganglion Superior ganglion of CN X

A 25-year old male patient sits in your dental chair with an obvious disparit y in the appearance of the right and left sides of his face. The entire left side of his face is drooping. This includes his lips and the m uscles above and below his oral cavit y. He is also wearing an eye patch over his left eye. He tells you that the symptoms appeared “out of nowhere.” He went to bed one night feeling norm al and awoke the next m orning with the symptom s you are observing. He states that there was no other precipitating factor that would account for what occurred. He also states that there is apparently nothing else that ails him, and he is not experiencing muscle paralysis in any other area of his face or body. It is now 1 m onth to the day since the symptom s first manifested them selves. 25. Based on his appearance and the onset of his problem s, even before you discuss the m at ter with him , you conclude that he is suffering from

A 35-year old m an presents to the physician’s office with a report of shooting, excruciating pain on the left side of his face. This is episodic pain that is described as being jabbed by an electrified pin every 10 seconds or so. The pain radiates down the external aspect of the m andible and includes the skin over the mandible, the general area of the lower extent of the infratemporal fossa, and the m ucosa of the tongue and internal aspect of the mouth. The pain is only on the left side. In addition, when asked to open his mouth, the patient cannot fully do so without experiencing the sam e excruciating pain. Furthermore, as he opens his m outh, the m uscles that oppose this m otion becom e spasm odic.

A. B. C. D. E.

For Questions 25 to 28:

A. B. C. D. E.

A left-sided cerebral stroke A right-sided cerebral stroke Trigem inal neuralgia Bell’s palsy Glossopharyngeal neuralgia

26. On the other hand, it m ight be a compression of the facial nerve that is unrelated to any of the syndromes or diseases related above. Based on these symptoms, and these symptoms only, it could be a compression of the facial nerve A. As it travels through the parotid gland B. Just distal to the point at which it exits through the st ylom astoid foram en C. Just proxim al to the point at which it exits through the st ylomastoid foramen D. Just proxim al to the point at which the chorda t ympani branches E. Just distal to the point at which the chorda t ympani branches 27. Before you relate your thoughts to your patient, he tells you that he is also suffering from dim inished taste. He further inform s you that he is wearing the eye patch so that the fluid (artificial tears) he is placing onto his cornea will not escape. This is necessary because he is not lacrimating in his left eye. Finally, he tells you he is experiencing anesthesia of a portion of the skin on the external auditory meatus. Based on this additional inform ation, your analysis of where the compression of the facial nerve has occurred has now changed. You now believe that the compression of the facial nerve has occurred A. As it travels through the parotid gland B. Just proxim al to the point at which the chorda t ympani branches C. Just proxim al to the point at which the greater petrosal nerve branches D. Just distal to the point at which the greater petrosal nerve branches E. Just distal to the point at which the chorda t ympani branches 28. You ask your patient to briefly rem ove his eye patch and notice that the upper eyelid is abnorm ally elevated. This is because the ______ m uscle that is innervated by the _________ nerve is unopposed in it s action. A. B. C. D. E.

Orbicularis oculi, zygom atic branch of CN VII Orbicularis oculi, temporal branch of CN VII Levator palpebrae superioris, temporal branch of CN VII Levator palpebrae superioris, oculomotor nerve Corrugator supercilii and frontalis working as a unit, temporal branch of CN VII

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Appendix C

For Question 29: A patient presents him self to his physician with a persistent left-sided throat “tickle” and a nonproductive cough. He also says that as of late he has experienced an intermit tent hoarse voice. The initial treatment is palliative with a course of throat lozenges, inhalants, and basic antiinflam matory drugs that are purchased over the counter. However, the patient returns in 2 weeks with the same complaint, and an X-ray of the thorax is ordered. Even though the X-ray results are speculative at best, because of the persistence of the symptom s, a computed tomography (CT) scan with contrast is ordered. As a result of the CT scan, an aneurysm of the arch of the aorta is clearly visible. 29. Based on this, it is clear that the symptom s are a result of a compression of the A. B. C. D. E.

Left Left Left Left Left

vagus nerve external laryngeal nerve recurrent laryngeal nerve superior laryngeal nerve internal laryngeal nerve

30. Based on the patient’s clinical presentation, even before you proceed with a full set of X-rays and other clinical tests, you suspect that his pain is associated with which of the following? Trigeminal neuralgia Masseteric spasm s Maxillary sinusitis Middle ear infection Temporomandibular dysfunction

31. One of the difficulties in determ ining the exact location of pain em anating in the head is that there are many structures found in a confined area. All of these structures send neuronal impulses to the structure in the brain responsible for determ ining which impulses are originating from which area. This structure is the

A. B. C. D. E.

1st branchial arch 2nd branchial arch 3rd branchial arch 4th branchial arch 5th branchial arch

Postcentral gyrus Precentral gyrus Superior temporal gyrus Lingual gyrus Cingulate gyrus

Long buccal nerve Lingual nerve Deep temporal nerve Nerve to the lateral pterygoid Inferior alveolar nerve

For Questions 36 to 39: A 73-year-old m an complains that things are “tasting funny” and that this difficult y with taste has existed for the past few m onths. He says that he does not have a fever and has not suffered with a cold or virus in the past 3 months. He does not sm oke cigaret tes, a pipe, or cigars, nor does he chew tobacco. 36. You initially exam ine his tongue to discern whether there is any damage that might affect the taste buds on his tongue. You do this based on the knowledge that taste to the anterior t wo-thirds of the tongue initially runs in the A. B. C. D. E.

Glossopharyngeal nerve Inferior alveolar branch of the trigeminal nerve Chorda t ympani branch of the facial nerve Greater petrosal branch of the facial nerve Lesser petrosal branch of the glossopharyngeal nerve

37. Taste buds are prim arily associated with which of the following papillae of the tongue? A. B. C. D. E.

Superior colliculus Inferior colliculus Thalam us Hypothalamus Globus pallidus

32. Although the structure in question 31 is responsible for locating pain, the actual perception of pain is associated with a different area of the brain. This area is the A. B. C. D. E.

Medial and lateral pterygoids Medial pterygoid and m asseter Masseter and temporalis Temporalis and m edial pterygoid Temporalis and lateral pterygoid

34. From which branchial arch do the muscles of m astication develop?

A. B. C. D. E.

A 35-year-old m an presents with what he believes to be pain associated with “a left upper tooth.” The pain seems to be rather diffuse, so he cannot be m ore specific. After a full set of dental X-rays and a thorough intraoral examination, no lesion is found to be associated with any of his m axillary or mandibular teeth. Furthermore, the gingiva appears to be essentially norm al. Upon further questioning of the patient, he tells you the pain tends to recur and is worst during the spring and the fall.

A. B. C. D. E.

A. B. C. D. E.

35. Which of the following nerves is most likely to be initially displaced by this tumor?

For Questions 30 to 32:

A. B. C. D. E.

33. The insertions (distal at tachm ents) of what t wo m uscles of mastication may be displaced as this tum or continues to disrupt the angle of the mandible?

Filiform Fungiform Circumvallate Foliate Taste buds are found in abundance on all of the aforementioned papillae.

38. Another problem that can affect taste, especially in older individuals, is a decline in salivary fluid production. Parasympathetic fibers that stim ulate salivary output run with which of the following nerves? A. B. C. D. E.

Greater petrosal nerve Lesser petrosal nerve Deep petrosal nerve A and B only A, B, and C

39. Ganglia involved with fibers that stim ulate salivary output from the m ajor salivary glands include which of the following?

For Questions 33 to 35: A 58-year-old m an presents to the clinic complaining of pain that prevents him from fully opening his mouth. He has a lump over the angle of the mandible on the left side of his jaw that he says has been slowly get ting bigger over the past 18 months but that it has not hurt until recently, so he was not worried about it. Because the patient has a limited opening, you decide that a panoram ic radiograph is in order. Based on further testing and a biopsy, it is discovered that the lump is an am eloblastom a that originated within the m andible.

A. B. C. D. E.

Ciliary Superior cervical Middle cervical Submandibular Pterygopalatine

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Clinica l Questions & Answer Expla na tions

For Questions 40 to 42:

For Questions 46 to 48:

A m an is rushed into the em ergency room displaying exaggerated swelling in the subm andibular area. The patient is clearly having difficult y breathing, has a fever of 103°F (39.4°C), tachycardia, and tachypnea. He has a hard swelling in the floor of the mouth resulting in superoposterior displacement of the tongue, which is interfering with the airway. The patient is presum ed to be suffering with Ludwig’s angina. As treatm ent begins, the m edical staff works to m aintain the airway, administers antibiotics, and makes an external incision in the subm andibular area to begin drainage.

A 55-year-old male patient called your office with a complaint that his right rear lower tooth really hurt. You suggested he com e see you so that you could take a look at the tooth and the structures that surrounded it. Five days later, he called back happily proclaim ing that he was no longer in pain. You suggested that he should see you anyway. Your concern was that if it was an infection in the tooth, it could have now progressed from the tooth into a fascial space. Three days after his second call to you, the patient appears in an em ergency room with the following symptoms: • Temperature of 101.3°F (38.5°C)

40. The infection is found in which of the following spaces? A. B. C. D. E.

• Elevated white blood cell count

Submandibular only Sublingual only Submandibular and sublingual Submandibular and subm ental Submandibular, sublingual, and submental

• Reddened and flushed appearance on both sides of the neck • Pain upon movem ent of the neck • Great difficult y swallowing and breathing

41. The infection can originate from which of the following teeth? A. B. C. D. E.

Mandibular molars only Mandibular incisors, canines, and prem olars only Any mandibular tooth Maxillary molars Any maxillary tooth

46. In this case, it is irrelevant whether the infection is in the retropharyngeal space and/or danger space because the fascia bet ween the t wo has degenerated. This fascia is the

42. If it is necessary to insert an intraoral drain, the m ucosa of the floor of the m outh will need to be incised. Which of the following structures will be the first to be encountered? A. B. C. D. E.

Submandibular duct Lingual nerve Lingual artery Hypoglossal nerve Glossopharyngeal nerve

A. B. C. D. E.

A 50-year-old wom an arrives in your office with a painless mass in the floor of her m outh. She reports that the mass first appeared 2 years ago, but it rem ained small and painless, so she never bothered seeing a clinician. Recently, the m ass has begun to grow at a faster pace. The patient also reports a history of tobacco and alcohol use, including sm oking four packs of cigaret tes a week since her early 20s. Upon exam ination you find a nonulcerated, red-purple m ass in the floor of her mouth just lingual to the patient’s right mandibular posterior teeth. External palpation of the submandibular triangle reveals an enlarged, slightly tender submandibular gland that feels fixated to the surrounding tissue. A CT scan confirms an enlarged submandibular gland. You decide to perform an excisional biopsy. 43. When performing the extraoral excisional biopsy, one must be careful when resecting the submandibular gland not to dam age the following structure that runs through the gland? Facial vein Facial artery Lingual artery Hypoglossal nerve Anterior division of the retromandibular vein

44. Likewise, during resection one m ust be very careful not to dam age the following structure that runs on the superficial surface of the gland? A. B. C. D. E.

A. B. C. D. E.

Prevertebral fascia Pretracheal fascia Buccopharyngeal fascia Medial aspect of the carotid sheath Alar fascia

47. One of the prim ary concerns of infections that gain access to the retropharyngeal space is that they can then spread to the

For Questions 43 to 45:

A. B. C. D. E.

Dental exam ination and subsequent X-rays revealed that the apparent infection probably em anated in the second m andibular molar and spread to the retropharyngeal space and the danger space.

Maxillary sinus Cavernous sinus Mediastinum Peritoneal cavit y Orbit

48. Because of the marked difficult y in breathing, it is decided that an em ergency tracheostomy must be performed. Sometimes, in performing a tracheostomy, the thyroid gland m ust be cut vertically at its isthmus. Why is this not a problem with respect to the health of the patient? A. As hum ans age, the thyroid gland m arkedly regresses, and by the age of 55, it has lit tle or no functional significance. B. The thyroid gland is an exocrine gland, and its ducts are located inferolaterally. Thus, a vertical incision through the m idline of the gland will not affect its abilit y to send substances to the remainder of the body. C. The thyroid is an exocrine gland, and it s ducts are located superolaterally. Thus, a vertical incision through the midline of the gland will not affect its abilit y to send substances to the rem ainder of the body. D. The thyroid is an endocrine gland that secretes copious amounts of angiogenic factors. Thus, even with dam age to the midline venous and arterial structures, once it is placed back into position, additional arteries and veins grow to take their place. E. The thyroid is an endocrine gland, and it s hormones are secreted into veins that are found on the lateral aspect of the gland. These veins are norm ally not harm ed when a midline vertical incision is performed.

Cervical branch of the facial nerve Marginal m andibular branch of the facial nerve Mental branch of the trigeminal nerve Inferior fibers of the long buccal branch of the trigem inal nerve Inferior fibers of the buccal branch of the facial nerve

45. Once the gland is exposed, it is clear that a portion of the submandibular gland wraps around the A. B. C. D. E.

Hyoglossus Anterior belly of the digastric Posterior belly of the digastric Genioglossus Mylohyoid

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Appendix C

For Questions 49 to 51: Tim Brody, a quarterback for the champion Northwest Coffee Grinders, is viciously slamm ed to the ground in the semifinals. The training staff rushes onto the field, where he lies semiconscious. They im mediately shine a light in his left eye, and as they do so, they check the response of the pupils in the left and right eyes. Based on what they see, they are relatively pleased, and as Tim begins to become alert, they raise him to his feet. He staggers to the sidelines, where the trainers sit him down for further assessment.

54. As stated previously, when asked to stick out her tongue, what occurred is what is shown in the photo below. Based on this, which of the following muscles is not functioning properly? A. B. C. D. E.

Right hyoglossus Left hyoglossus Right genioglossus Left genioglossus Neither the left genioglossus nor the left hyoglossus is properly functioning.

49. By shining the light in one eye, then looking at both eyes, the training staff is testing for which of the following reflexes? A. B. C. D. E.

Corneal Pupillary dilator Vestibulo-ocular Consensual light Accomm odation

50. All of the following structures are involved in the aforem entioned reflex, except for the A. B. C. D. E.

Medial geniculate body Ciliary ganglion Edinger−Westphal nucleus Posterior commissure Optic nerve

51. This test is perform ed, at least in part, to try to determ ine if which of the following occurred? A. B. C. D. E.

Tear of the lining of the lateral ventricle Epidural hematoma Subdural hem atoma Occlusion of the anterior cerebral artery Occlusion of the posterior cerebral artery

For Questions 55 to 58:

For Questions 52 to 54: A middle-aged female dental patient returned for a prosthodontic evaluation after undergoing a radical neck dissection, m andibular reconstruction, and bone grafting following removal of a tumor on the right side of her neck and face. The evaluation occurred 8 weeks after the operation, and the healing was for all intents and purposes complete. The patient experienced difficult y rotating her head. It was necessary for her to rotate her trunk to face the assistant. The patient also experienced difficult y elevating her shoulder on her right side. She reported sporadically experiencing muscle spasm s and pain in the neck. Additionally, when asked to protrude her tongue, it was noted that the patient’s tongue deviated to the right (see photograph). 52. The dim inished abilit y to rotate her head is m ost likely due to A. Idiopathic spasmodic torticollis (abnormal wrenching of the neck) B. Dam age to the accessory nerve on the right side as a result of a surgical complication C. Dam age to the vagus nerve on the right side as a result of a surgical complication D. Dam age to the ansa cervicalis on the right side as a result of a surgical complication E. Dam age to the phrenic nerve on the right side as a result of a surgical complication 53. Based on the m ovement of the tongue seen in the patient, which of the following nerves was probably damaged while surgically removing the tum or in the mandible? A. B. C. D. E.

Inferior alveolar Chorda t ympani Hypoglossal Mandibular Glossopharyngeal

A.J., a 35-year-old female patient, tells you that she has been diagnosed with breast cancer and is considering a modified radical m astectomy. She has had extensive discussions with her primary physician and an oncologist. It is feared that the cancer is in the first stages of possibly spreading through her lymphatic system to the axillary nodes. 55. All of the following are considered to be part of the axillary nodes except for the A. B. C. D. E.

Pectoral nodes Lateral nodes Subscapular nodes Infraclavicular nodes Apical nodes

56. A m odified radical mastectomy is being considered rather than a full radical m astectomy. In a m odified radical mastectomy, the pectoralis major is spared. This not only provides mass on the anterior chest wall, thus aiding with a possible breast reconstruction procedure, but also spares which of the following motions performed by the pectoralis major? A. B. C. D. E.

Inferior rotation of the scapula Superior rotation of the scapula Medial rotation of the humerus Abduction of the hum erus Extension of the humerus

57. In a radical m astectomy, the lymph nodes and adipose tissue in the area of the chest and axilla are removed. Because of its placem ent on the superficial surface of the m uscle that it innervates, as well as its proximit y to the axilla, one of the following nerves is som etimes severed in the procedure. This nerve is the A. B. C. D. E.

Long thoracic Medial pectoral Lateral pectoral Thoracodorsal Axillary

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Clinica l Questions & Answer Expla na tions

58. When the nerve mentioned in question 56 is severed, the muscles that retract the scapulae are basically unopposed in their action, resulting in “winged scapulae.” Muscles that retract the scapulae include the A. B. C. D. E.

Rhomboid major Teres major Teres minor Latissim us dorsi Longissimus

For Questions 59 to 63: A 55-year-old rock star is preparing for a concert at the Palladium in London when he experiences intense m idsternal pain. He is rushed to the hospital and subm it ted to a series of blood tests and an electrocardiogram (ECG). Neither the blood tests nor the ECG indicate he has had a heart at tack. He feels som ewhat relieved with the news, but the chest pains, though not as pronounced, still remain. Because of the unrelenting pain, it is decided that he should undergo an angiography. The results of the angiography are also negative. 59. The arteries that were visualized using the angiography, as well as with the arteries from which they branch, are the A. Left coronary artery that branches from the arch of the aorta B. Anterior interventricular artery that branches from the right coronary artery C. Sinoatrial artery that branches from the right coronary artery D. Posterior interventricular artery that branches from the left coronary E. Right m arginal artery that branches from the anterior interventricular artery 60. Pain from the heart can be referred to areas other than the m idsternal region. These areas normally include all of the following except for the A. B. C. D. E.

Left shoulder Posterior neck Midline of the m andible Anterior aspect of the neck Right hypogastrium

A 25-year-old woman is riding her bicycle on a busy street in Boston. As she rides past a row of cars, one of the drivers opens the door without looking. She does not have tim e to stop and catapults over the door. As she lands, she at tempts to break her fall by throwing her right hand forward. The palm of her hand hits the ground, with the force of the fall being sent up through her wrist, forearm, and arm. Initially, her hand and wrist are sore, but over the next couple of hours, the soreness seem s to subside. However, upon looking at her wrist, she sees a pronounced black-and-blue mark forming over the ventral aspect of her wrist and the extreme distal portion of her forearm. She goes to her prim ary physician, who expresses some alarm and inform s her that her wrist m ay be broken and that she m ay be suffering from anterior compartm ent syndrom e. Her physician makes an imm ediate appointment for her to see an orthopedist specializing in the upper limb. The orthopedist takes im mediate action to drain the blood from the anterior compartment and repair the fracture. 63. Which of the following nerves is found in the anterior compartm ent of the forearm and also passes through the carpal tunnel with the long digital flexor tendons? A. B. C. D. E.

Deep branch of the radial Superficial branch of the radial Lateral cutaneous nerve of the forearm Ulnar Median

64. If left unabated, the accum ulation of blood could compress the nerve and cause perm anent dysfunction of which of the following muscles? A. B. C. D. E.

Flexor pollicis longus Flexor pollicis brevis Flexor digitorum superficialis Flexor carpi radialis All of the above

65. If this compression did occur, which of the following actions would be most affected?

61. The pain could be referred from areas or organs other than the heart. These organs include the A. B. C. D. E.

For Questions 63 to 65:

A. B. C. D. E.

Fine m otor movem ents of the thumb Adduction of the thumb Flexion of the fingers Extension at the carpom etacarpal joints All of the above

Esophagus Stom ach Pancreas A and B only A, B, and C

62. After further testing, it is determined that the star is suffering with pericarditis, and an appropriate treatment is begun. One of the necessary steps is to drain excess pericardial fluid from the pericardial space. This space is found bet ween which of the following t wo layers? A. Fibrous pericardium and outer pericardial fat B. Fibrous pericardium and the parietal layer of the serous pericardium C. Parietal layer of the serous pericardium and the visceral layer of the serous pericardium D. Serous layer of the visceral pericardium and the myocardium E. Myocardium and endocardium

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Appendix C

Answ er Explanations 1. A The dermatomal distribution for C5 is the superolateral aspect of the arm extending inferior to the lateral aspect of the midpoint of the forearm; therefore, pain and/or paresthesia would be localized to these areas. B The axillary fold extending into the m edial aspect of the arm is the dermatomal distribution for T1 or T2. C The m edial aspect of the arm and forearm is the derm atom al distribution that encompasses portions of T1 and C8. D The m edial aspect of the forearm extending into the hypothenar em inence is the dermatom al distribution for C8. E The lateral aspect of the forearm extending into the thenar eminence of the hand is the dermatomal distribution for C6. 2. D The dorsal scapular nerve contains fibers from C5 only, so it would be totally dysfunctional. A The axillary nerve contains fibers from both C5 and C6, so it would not be totally dysfunctional. B The thoracodorsal nerve contains fibers from both C6–C8, so it would be completely functional. C, E The long thoracic and lateral pectoral nerves contains fibers from C5–C7, so they would not be totally dysfunctional. 3. A Abduction and adduction of the fingers are accomplished through the actions of the interossei, which are innervated by the ulnar nerve. The ulnar nerve is composed of fibers from C7 to T1, so it would be totally unaffected by compression of C5. B Flexion at the elbow is prim arily, although not exclusively, accom plished through the action of the brachialis and biceps brachii. These m uscles are innervated by the musculocutaneous nerve, which contains neuronal fibers from C5 to C7. There would be a slight diminishm ent in this action. It should be rem em bered that the brachioradialis also participates in flexion at the elbow. The brachioradialis is innervated by the radial nerve, which receives neuronal fibers from C5 to T1. The radial nerve would probably be almost thoroughly functional, as would the brachioradialis. C Abduction at the glenohum eral joint is accomplished through the actions of the supraspinatus and medial fibers of the deltoid. The supraspinatus is innervated by the suprascapular nerve, which receives neuronal fibers from C5 and C6. The deltoid is innervated by the axillary nerve, which receives fibers from C5 and C6. Thus, these nerves, m uscles, and actions would be affected as a result of compression of C5. D Lateral rotation at the glenohumeral joint is accomplished through the actions of the teres minor, infraspinatus, and posterior fibers of the deltoid muscle. The teres minor and deltoid are innervated by the axillary nerve (described in answer explanation C). The infraspinatus is innervated by the suprascapular nerve (described in answer explanation C). E Extension at the glenohumeral joint is accomplished through the actions of the posterior fibers of the deltoid, teres m ajor, and latissim us dorsi. The teres m ajor is innervated by the lower subscapular nerve, which receives fibers from C5 and C6. The posterior fibers of the deltoid are innervated by the axillary nerve, which receives fibers from C5 and C6. The latissim us dorsi is innervated by the thoracodorsal nerve, which receives fibers from C6 through C8. 4. A Motor fibers that synapse on anterior horn cells of the spinal cord originate in the contralateral motor and premotor cortices as part of the pyram idal tract, specifically, the corticospinal tracts (lateral and anterior). Prior to decussating, these fibers travel in the internal capsule. Thus, dam age to the left internal capsule, which is supplied via branches of the middle cerebral artery (specifically, the lenticulostriate branches), would result in contralateral paralysis. Therefore, in William, dam age to the left internal capsule would result in paralysis of the right upper and lower limbs.

B The putamen, left or right, is involved in modulation, not initiation, of motion. Damage to the putam en, such as in Huntington’s disease, would result in a multiplicit y of m otor symptom s, including ballismus, but not paralysis. C, D Motor fibers that originate in the m otor and premotor cortices travel to contralateral anterior horn cells. Thus, damage to the right precentral gyrus and/or right premotor cortices would result in paralysis of the left lim bs, not the right. E The postcentral gyrus is involved with interpretation of sensory input, not m otor output. 5. E Anosognosia is associated with damage to the right cerebral hemisphere in a left brain−dominant individual. A−C Apraxia, alexia, and agraphia are associated with dam age to the left cerebral hemisphere of a left brain−dominant individual. D Right-sided paralysis will occur because the left precentral gyrus and premotor cortex are supplied by branches of the left middle cerebral artery. Also, the left lenticulostriate artery is a branch of the left middle cerebral artery, and lack of blood flow to the lenticulostriate artery can result in damage to the left internal capsule, left putamen, left globus pallidus, and left caudate nucleus. This will also result in paralysis of the right side of the body. 6. D The inferior frontal cortex contains Broca’s area. It is in this area that motor impulses from the precentral gyrus and premotor cortices, am ong other areas, cascade. These are then coordinated so the m uscle groups needed to articulate speech can work as a unit. Damage to Broca’s area results in William’s symptoms. A Wernicke’s area is found in the posterior aspect of the superior temporal gyrus. Dam age to this area results in an individual who is often fluent in language, but the conversation makes no sense in context. B Damage to the supram arginal gyrus can result in anomia (a problem with word finding or recall) or alexia (inabilit y to read), am ong other problems. However, it does not result in the symptom s associated with William. C The lingual gyrus, located in the occipital lobe, is involved with sight, not speech. E The precentral gyrus is involved with sensory perception and coordination of sensory information from various areas of the cerebrum . Damage to the precentral gyrus produces num erous sensory deficits but not the symptom listed above. 7. C Prosody, or the abilit y to recognize tonalit y in speech or music, is associated with the right cerebral hem isphere of a left brain−dominant individual. Thus, this would be affected in an individual with an occlusion of the right m iddle cerebral artery. A Occlusion of the middle cerebral artery results in contralateral, not ipsilateral, paralysis of the trunk and lim bs. B Occlusion of the m iddle cerebral artery results in contralateral paralysis of the muscles of facial expression inferior to the zygom atic arch, not total ipsilateral paralysis of the m uscles of facial expression. D Acalculia, or the inabilit y to perform mathematical calculations, is associated with the left cerebral hem isphere of a left brain−dominant individual. It would be unaffected in an occlusion of the right m iddle cerebral artery. E Inabilit y to speak sentences that m ake sense in response to a verbal or writ ten request is associated with dam age to Wernicke’s area, which is found in the left cerebral hem isphere of a left brain− dom inant individual. This would not occur in an individual with an occlusion of the right middle cerebral artery.

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Clinica l Questions & Answer Expla na tions

8. A The posterior superior alveolar nerve on each side innervates the maxillary molars and their associated buccal gingiva, mucosa, and periosteum. B The long buccal nerve on each side innervates the m ucosa of the cheek and the gingiva bet ween the m andibular 2nd prem olar and molars, as well as the retrom olar triangle. It does not innervate any teeth. C The m iddle superior alveolar nerve on each side (when present) innervates the roots of the 1st and 2nd premolars and the m esiobuccal root of the 1st molar. D The greater palatine nerve innervates the palatal gingiva, m ucosa, and periosteum from the m axillary 1st premolar to the posterior hard palate to the midline of the hard palate on the same side as the injection, that is, the posterior t wo-thirds of the hard palate. The anterior t wo-thirds of the hard palate is supplied by the nasopalatine nerve. E The lesser palatine nerve supplies the mucosa of the soft palate. 9. D The greater palatine foram en and canal are sufficiently large so that a small-bore needle can be placed within the foramen and fluid expressed that can gain access to the pterygopalatine fossa. The m axillary nerve lies within the fossa. A, B Under no circumstances would anesthetic fluid, by any direction or m eans, be intentionally placed into the cranial vault. This could have disastrous effects on the brain. C Under extrem e circumstances, fluid could be injected into the pterygopalatine fossa via the extraoral route. However, this is extrem ely dangerous, as the needle could damage any number of structures in the infratemporal fossa, including the mandibular nerve and its t wo major branches (inferior alveolar and lingual), m axillary artery, and pterygoid plexus of veins. Also, bacteria from the skin or superficial fascia could enter the fossa via this route. E In theory, anesthetic fluid could be placed into the infraorbital foramen and expressed through the canal into the pterygopalatine canal. However, because of the force needed, there are several side effects that could occur, including temporary paralysis of the extraocular muscles and temporary blindness. These side effects are a result of anesthetic fluid traveling from the infraorbital canal into the orbit. 10. B Both the temporalis and masseter elevate the m andible, and both can be externally palpated (therefore not answer choice A). The temporalis participates in elevation, retrusion, and lateral excursion of the m andible. The masseter participates in elevation, protrusion, retrusion, and lateral excursion of the m andible. C The buccinator does not elevate the mandible; rather, it presses the cheek against the m olar teeth, working with the tongue to keep food bet ween the occlusal surfaces and out of the oral vestibule. D The zygom aticus major does not elevate the mandible but rather pulls the corner of the m outh superiorly and laterally. E The lateral pterygoid functions in depressing, protruding, and medially excursing the m andible (inferior head). It also functions in stabilizing the mandible during retrusion (superior head). In addition, this muscle cannot be palpated externally. 11. B The mesencephalic nucleus of CN V is specifically associated with proprioception from the TMJ, the muscles that act upon it, and the teeth that directly surround it. Damage to the ipsilateral mesencephalic nucleus of CN V would result in the symptom s described. A Dam age to the motor nucleus of CN V, and or hyperactivit y associated with the m otor nucleus of V, could result in the hyperactivit y associated with m uscles, but the damage would need to be ipsilateral to the effect. Thus, it is the left motor nucleus of CN V that would need to be damaged, not the right. C The principal sensory nucleus of CN V is responsible for proprioception in the m ajorit y of the areas of the head and fine touch. However, the specific areas described in the question are served by the mesencephalic nucleus of CN V. D The nucleus caudalis of the spinal nucleus of CN V is involved with pain, temperature, pressure, and crude touch. It is not involved with coordinating muscle activit y. E The function of the nucleus interpolaris is still a mat ter of conjecture, but it is definitely not involved with fine touch. Also, if it were to be involved, it would need to be located on the left side of the

brainstem , not the right. 12. D Fibers of the olfactory nerve travel through the cribriform plate of the ethm oid bone. The force of the collision as it was transmit ted posteriorly could break through this rather tenuous bone. A The infraorbital nerve and vessels travel through the inferior orbital fissure. B The m axillary branch of the trigem inal nerve (CN V) travels through the foramen rotundum . C The mandibular branch of the trigeminal nerve and the lesser petrosal branch of the glossopharyngeal nerve travel through the foram en ovale. E The middle meningeal artery and nerve (nervus spinosus) travel through the foramen spinosum . 13. C The force of his head hit ting the windshield during the collision was transmit ted back through the frontal bone to the suture bet ween the frontal bone and lesser wing of the sphenoid bone, causing breakage of the lesser wing and a severing of the optic chiasm . A As stated in Q12, fibers of the olfactory, not the optic, nerve travel through the cribriform plate of the ethm oid bone. B The frontal bone is sufficiently massive, so that it probably would not break and cause the dam age as described. D, E The petrosal portion of the temporal bone and the clivus lie posterior to all of the structures listed in the scenario. 14. C The posterior superior alveolar nerve carries sensory fibers to the maxillary molars, a portion of the mucosa of the m axillary sinus, a portion of the buccal gingiva of the m axillary m olars, and a portion of the cheek. It is the nerve that is anesthetized in this procedure. A The middle superior alveolar nerve carries sensory fibers to the prem olar teeth and associated buccal gingiva and possibly the mesiobuccal root of the 1st molar. B The anterior superior alveolar nerve carries sensory fibers to the central and lateral incisors, the canines, the m ucosa of the m axillary sinus, the labial gingiva associated with the incisors and m axillary canines, and various nasal branches to the mucosa of a portion of the nasal septum , wall, and floor of the nasal cavit y. D The greater palatine nerve supplies the palatine gingiva and mucosa from the maxillary prem olars posteriorly. E The lesser palatine nerve supplies sensory innervation to the mucosa of the soft palate. 15. Overall, the symptoms described are indicative of a cavernous sinus thrombosis. The m ost comm on organism introduced into the sinus to cause the thrombosis is Staphylococcus aureus, with streptococci and pneum ococci being less comm on (Andreoli et al., Cecil Essentials of Medicine, 6th ed. Elsevier, 2004). This question relates to the manner by which the organisms were introduced into the sinus.

D Small tributaries of the pterygoid plexus can be punctured in an at tempt to anesthetize the posterior superior alveolar nerve. The pterygoid plexus com municates with the cavernous sinus via a system of emissary veins. A The middle meningeal artery is a branch of the external carotid artery, but neither connects to the cavernous sinus. B The ophthalmic vein does drain into the cavernous sinus. However, in a procedure to anesthetize the m axillary m olars, the needle should not be in the vicinit y of the ophthalm ic vein. C The maxillary vein does drain into the retromandibular vein. However, the retromandibular vein does not drain into the cavernous sinus. E The infraorbital vein drains into the pterygoid plexus. However, in a procedure to anesthetize the m axillary molars, the needle should not be in the vicinit y of the infraorbital vein.

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Appendix C

16. D The oculom otor, trochlear, and abducens nerves all travel through the cavernous sinus. However, the oculomotor and trochlear nerves travel in its lateral aspect and are wrapped in, and protected by, the dura mater. In contrast, the abducens nerve runs through the center of the sinus and is unprotected. Thus, in a cavernous sinus throm bosis, symptoms involving the abducens nerve are seen before those associated with either the trochlear or oculomotor nerve. The lateral rectus m uscle, innervated by the abducens nerve, moves the eyeball laterally. A The inferior oblique primarily acts in elevation of the eyeball. It is innervated via fibers of the oculomotor, not the abducens, nerve. B The superior rectus is innervated via fibers of the oculomotor nerve, but its primary action is elevation of the eyeball. It plays a m inor role in adduction of the eyeball. C The inferior rectus is innervated via fibers of the oculom otor nerve, but its prim ary action is depression of the eyeball. It plays a m inor role in adduction of the eyeball. E The superior oblique m uscle primarily acts in depression of the eyeball. It is innervated via branches of the trochlear nerve. It plays a minor role in abduction of the eyeball, but dam age to it, in and of itself, would not cause major difficult y in m oving the eyeball laterally. 17. B Lowering the eyelid is achieved via the orbicularis oculi, which is innervated by branches of the facial nerve (CN VII). The facial nerve runs through the parotid space and thus would be anesthetized on the side of the injection as a result of the procedure described. A Depressing the mandible is accomplished through the action of the lateral pterygoid, suprahyoid, and infrahyoid m uscles. The lateral pterygoid, mylohyoid, and anterior digastric m uscles are innervated by branches of the m andibular division of the trigeminal nerve (CN V3 ). The posterior digastric and st ylohyoid are innervated by branches of the facial nerve (CN VII). The geniohyoid and thyrohyoid are innervated by fibers of C1, and the rem ainder of the infrahyoid m uscles are innervated by branches of the ansa cervicalis. None of these nerves run through the parotid space. C Raising the upper eyelid is achieved via the levator palpebrae superioris, which is innervated by the oculom otor nerve. This also would be unaffected, as it is on the opposite side of the injection. D Swallowing is achieved via branches of the glossopharyngeal (CN IX), vagus (CN X), and accessory (CN XI) nerves. E Raising the mandible is accomplished via the temporalis, masseter, and m edial pterygoid muscles, which are innervated by branches of the mandibular division of the trigem inal nerve (CN V3 ). They would also be unaffected on the opposite side of the injection. 18. A The retrom andibular vein runs through the parotid space. B, C The internal carotid artery and the internal jugular vein travel m edial to the parotid space. D The m asseteric branch of the m axillary artery branches from the m axillary artery medial and internal to the parotid space. E The buccal branch of the maxillary artery branches from the m axillary artery m edial and internal to the parotid space. 19. B If the injection was too far posterior and inferior, there would be penetration into the parotid space with probable anesthesia of branches of the facial nerve. There would be no anesthesia of the inferior alveolar nerve, as evidenced by failure to numb the lower lip (no lower lip sign). A, C, E If the injection was too far superior and anterior, too far anterior and inferior, or too far m edial and superior, there would only be anesthesia at the injection site and no anesthesia of the inferior alveolar nerve, as evidenced by failure to num b the lower lip (no lower lip sign). There also would be no penetration into the parotid space. D If the injection was too far m edial and inferior, there would be possible anesthesia of the lingual nerve. More likely, there would only be anesthesia at the injection site and no anesthesia of the inferior alveolar nerve, as evidenced by failure to num b the lower lip (no lower lip sign). There also would be no penetration into the parotid space.

20. C There are sensory fibers that sometim es travel on the nerve to the mylohyoid. These sensory fibers may provide innervation to the m andibular teeth. A The lingual nerve carries sensory fibers to the anterior t wo-thirds of the tongue and the lingual gingiva of the mandibular molars, but not to the teeth them selves. B The long buccal nerve provides sensory fibers to the m ucosa and skin of the cheek and to the buccal gingiva of the mandibular molars, but not to the teeth themselves. D The marginal m andibular nerve is a motor branch of the facial nerve. E The buccal branch of CN VII is a m otor branch of the facial nerve. 21. B Trigeminal neuralgia affects the branches of the trigeminal nerve, t ypically in the following order: V2 > V3 > V1 . More often than not, it only affects the maxillary nerve and mandibular nerve and their branches. As described in this scenario, it is affecting branches of the m andibular nerve, with the associated pat tern of pain. A Bell’s palsy affects the facial nerve and the m uscles of facial expression, not the muscles of m astication. C Geniculate neuralgia involves similar pain pat terns as trigem inal neuralgia but deals with the pain areas of the facial, not the trigeminal, nerve. This may include pain associated with the external auditory m eatus or even pain felt deep within the ear. It is som etimes associated with herpes zoster and can result in vesicular eruptions on the eardrum and external auditory canal. D Glossopharyngeal neuralgia involves similar pain pat terns as trigeminal neuralgia but deals with the pain areas of the glossopharyngeal, not the trigeminal, nerve. This m ay include pain associated with the tongue, pharynx, throat, ear, and tonsils. E Temporal arteritis is pain associated with areas overlying, or adjacent to, the superior temporal artery, although it can be other arteries in the head. Severe headaches can result from temporal arteritis. 22. B The areas of pain associated with the scenario include regions of the inferior alveolar nerve (the mandible, skin over the m andible, and skin over the inferior aspect of the infratemporal fossa, as well as a portion of the internal aspect of the mouth) and the lingual nerve (mucosa of the anterior t wo-thirds of the tongue and a portion of the internal aspect of the m outh). A Pain associated with the trigeminal nerve would be all of the pain dom ains of the ophthalm ic, m axillary, and m andibular branches, which include the entire side of the face from the upper frontal regions down to the neck. This is not what occurred in the scenario. C The sensory distribution areas of the maxillary nerve are the m ore superior aspect of the infratemporal fossa, the skin overlying the maxilla and a portion of the nasal area, the maxillary teeth, and the mucosa and gingiva of the m axillary region. Pain was not described in these regions. D Areas of pain associated with the inferior alveolar nerve were reported, but pain associated with areas of the lingual nerve was also reported. E Areas of pain associated with the lingual nerve were reported, but pain associated with areas of the inferior alveolar nerve was also reported. 23. C The temporalis is one of the major elevators of the mandible. The other t wo are the m asseter and m edial pterygoid. A The buccinator is a m uscle of facial expression and does not move the m andible. B Actions of the lateral pterygoid include protrusion, depression, and medial excursion of the mandible. The upper head of the lateral pterygoid also stabilizes the m andibular condyle during retrusion. The lateral pterygoid does not function in elevation of the m andible. D, E The mylohyoid and anterior digastric play a role in depression of the m andible.

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Appendix C

Clinica l Questions & Answer Expla na tions

24. B The semilunar ganglion, otherwise known as the gasserian or trigem inal ganglion, would be ablated in this procedure. A The geniculate ganglion is associated with the facial nerve (CN VII). As previously stated, the facial nerve would not be involved in this syndrom e. C The inferior (not superior) ganglion of CN IX is the general sensory ganglion of the glossopharyngeal nerve and thus would not be involved with pain pat terns associated with the trigeminal nerve (CN V). D The pterygopalatine ganglion is one of the parasympathetic motor ganglia of the head. It is associated with the facial nerve. E The superior ganglion of CN X is the general sensory ganglion of the vagus nerve and thus would not be involved with pain pat terns associated with the trigem inal nerve. 25. D Bell’s palsy involves dysfunction of the facial nerve. This is norm ally of unknown etiology. It can involve all of the functions associated with the facial nerve but m ost often involves only ipsilateral paralysis of all of the muscles of facial expression. A A left-sided cerebral stroke produces paralysis of all of the muscles of the right side of the body, not just the face. B A right-sided cerebral stroke produces paralysis of all of the m uscles on the left side of the body, not just the face. C, E Trigem inal neuralgia and glossopharyngeal neuralgia produce tremendous pain, but not muscle paralysis. 26. A As initially stated, the symptoms involve only the muscles of facial expression. This is consistent with damage to the facial nerve at a spot where only branchial efferent impulses are carried. This spot is either just proxim al to or within the parotid gland. B There are m otor fibers of the facial nerve that supply the occipitalis and small muscles of the skin around the ear (auriculares). These muscles would be affected if the dam age to the facial nerve was just distal to its exit from the st ylom astoid foram en. In addition, the st ylohyoid and posterior belly of the digastric would be denervated. C The same caveat as for answer choice B applies for this answer. In addition, depending on where the compression occurred, there may be disruption of sensory impulses to the auricular branch of CN VII. D If the compression was just proximal to the branching of the chorda t ympani, not only would all of the aforementioned symptom s occur, but symptom s involving the chorda t ympani would also be witnessed. These include difficulties with taste and a possible perception of lessened salivation. E If the compression was just distal to the branching of the chorda t ympani, the symptom s would be the sam e as described in answer choice C. 27. C If the compression was just proximal to the point at which the greater petrosal nerve branches, the symptom s would include ipsilateral paralysis of the muscles of facial expression and the occipitalis and small m uscles of the external ear. In addition, the st ylohyoid and posterior belly of the digastric would also be denervated. Symptoms would include a lack of sensation associated with the auricular branch of CN VII, dim inished taste, and a possible perception of lessened salivation. Functions associated with the greater petrosal nerve would be disrupted, including loss of parasympathetic output from the pterygopalatine ganglion to glands in the nasal cavit y, pharynx, and mucosa of the palate, as well as to the lacrimal gland, resulting in lack of lacrim ation. In addition, there would be lack of taste from scat tered taste buds on the soft palate, although this would be barely perceptible by the patient. Finally, there might be a perception of increased “noise” on the side of the injury due to lack of function of the nerve to the stapedius. A Only the m uscles of facial expression, ipsilateral to the dam age, would be affected as a result of compression of the facial nerve as it travels through the parotid gland. B If the compression was just proximal to the branching of the chorda t ympani, the symptom s would include ipsilateral paralysis of the muscles of facial expression, the occipitalis, and sm all m uscles of the external ear. In addition, the st ylohyoid and posterior belly of the digastric would be denervated. Symptoms would include a lack of sensation associated with the auricular branch of CN VII, dim inished taste, and a possible perception of lessened salivation. D The symptom s would include all those stated in answer choice

B if the compression was just distal to where the greater petrosal nerve branches. In addition, there m ight be a perception of increased “noise” on the side of the injury due to a lack of function of the nerve to the stapedius. E If the compression was just distal to the point at which the chorda t ympani branches, symptoms would include ipsilateral paralysis of the m uscles of facial expression, ipsilateral paralysis of the small muscles of the external ear and occipitalis, denervation of the st ylohyoid and posterior belly of the digastric, and loss of sensation associated with the auricular branch of CN VII. 28. D The levator palpebrae superioris is innervated by the oculom otor nerve and acts in elevating the eyelid. It is unopposed in facial nerve (CN VII) paralysis, causing the eyelid to be abnorm ally elevated. A, B The orbicularis oculi is innervated by the zygom atic and tem poral branches of CN VII. However, these nerves act to depress the eyelid, not elevate it. C The levator palpebrae superioris does elevate the eyelid. However, it is innervated by a branch of the oculom otor nerve, not the temporal branch of CN VII. E The corrugator supercilii and frontalis are innervated by branches of the temporal branch of CN VII. However, neither acts to elevate the eyelid. 29. C Fibers of the left recurrent laryngeal nerve supply the majorit y of intrinsic m uscles of the larynx. They also supply the m ucosa of the larynx from the vocal folds and below. It is this nerve that would be constricted as it loops around the arch of the aorta. A Symptom s due to damage to the vagus nerve, depending on the location of the dam age, would include those described for all of the nerves listed in the question. In addition, there m ight be changes in heart rate and in m uscle tone associated with the gastrointestinal tract. B Fibers from the external laryngeal nerve innervate only the cricothyroid m uscle of the larynx and sometimes the cricopharyngeus muscle of the pharynx. The symptoms described above would not result from compression of this nerve, nor does it loop around the aorta. D The external and internal laryngeal nerves are branches of the superior laryngeal nerve. The function of the external laryngeal nerve has already been described. E The internal laryngeal nerve supplies sensory fibers to the mucosa of the larynx above the vocal folds. This might produce some of the sam e symptoms; however, because the nerve does not loop around the aorta, it would not be constricted in this scenario. 30. C Maxillary sinusitis can be interpreted as pain associated with the maxillary m olars. In m any patients, this pain is exacerbated because of allergies associated with flowering plants in the spring and rot ting leaves in the fall. A Pain associated with trigeminal neuralgia is episodic and extreme. It also does not occur on a seasonal basis. B, D, E Masseteric spasms, m iddle ear infection, and temporom andibular dysfunction can be interpreted as pain associated with the m axillary molars. However, the pain would not occur on a seasonal basis. 31. C Sensory impulses to the cerebrum are relayed through the thalamus. The thalam us is involved in localizing sensory impulses to areas in the body. A The superior colliculus is involved with sight and the coordination of the m uscles that move the eyeballs. B The inferior colliculus is involved with hearing. D The hypothalamus, am ong other things, is involved with hunger, thirst, m emory, and sexualit y. It is not involved with the localization of sensory impulses. E The globus pallidus is part of the basal ganglia. It s prim ary function is m odulation of m otor impulses.

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Appendix C

32. A Perception of pain, along with perception of m ost other sensations, is associated with the postcentral gyrus of the parietal lobe. B Initiation of motor impulses is associated with the precentral gyrus of the frontal lobe. C The superior temporal gyrus is associated with hearing, both perception and m emory. D The lingual gyrus of the occipital lobe is involved with sight. E The cingulate gyrus is involved with m em ory, primarily long-term retrograde. 33. B The m edial pterygoid inserts on the internal aspect of the angle of the m andible, and the masseter inserts on the external aspect of the angle of the mandible. These t wo form the pterygomasseteric sling. A The medial pterygoid inserts on the internal aspect of the angle of the mandible; the lateral pterygoid inserts onto the condyle of the m andible, the meniscus, and the pterygoid fovea of the mandible. C The m asseter inserts on the external aspect of the angle of the m andible; the temporalis inserts on the coronoid process of the mandible and the internal aspect of the superior portion of the ram us of the mandible. D, E The insertions of the temporalis, medial pterygoid, and lateral pterygoid have already been described. 34. A The muscles of m astication, anterior digastric, mylohyoid, tensor t ym pani, and tensor veli palatini develop from the 1st branchial arch. B The m uscles of facial expression, occipitalis, auricular muscles, posterior digastric, st ylohyoid, and stapedius develop from the 2nd branchial arch. C The st ylopharyngeus develops from the 3rd branchial arch. D Muscles of the soft palate, pharynx, and larynx develop from the 4th branchial arch. E The 5th branchial arch degenerates; nothing develops from it. 35. E The ameloblastom a develops within the mandible. It can break out from the mandible, but it would first affect nerves that travel through the mandible, and the only nerve listed that fulfills that criterion is the inferior alveolar nerve. The inferior alveolar nerve originates in the infratemporal fossa and travels through the mandibular foram en to gain access to the internal aspect of the mandible. A The long buccal nerve runs on the lateral aspect of the maxilla down to the external aspect of the mandible and the gingiva of the internal aspect of the mandible. B The lingual nerve originates in the infratemporal fossa and enters into the oral cavit y deep to the mylohyoid and hyoglossus. C The deep temporal nerve originates in the infratemporal fossa and travels to the temporal fossa to innervate the temporalis. D The nerve to the lateral pterygoid originates in the infratemporal fossa and term inates in the deep aspect of the t wo heads of the lateral pterygoid. 36. C The chorda t ympani carries taste fibers from the facial nerve. These taste fibers then travel from the chorda t ympani to the lingual nerve. A Taste does hitchhike in the lingual branch of the trigem inal nerve to the anterior t wo-thirds of the tongue, but not initially. B The inferior alveolar branch of the trigem inal nerve carries branchial efferent fibers and general sensory fibers, not taste fibers. D The greater petrosal branch of the facial nerve carries parasympathetic and taste fibers. However, the taste fibers go to scat tered taste buds associated with the soft palate, not the tongue. Also, there are so few taste buds associated with these fibers, that their dysfunction would be barely noticeable. E The lesser petrosal branch of the glossopharyngeal nerve carries preganglionic parasympathetic fibers that synapse in the otic ganglion. 37. C The m ajorit y of taste buds are found on the circumvallate papillae. A There are no taste buds on filiform papillae. B There are a minim al num ber of taste buds on fungiform papillae. D There are a few scat tered taste buds associated with the foliate papillae. E Taste buds are primarily associated with the circumvallate (vallate) papillae.

38. D The greater and lesser petrosal nerves both contain fibers that stim ulate salivation (therefore not A or B alone). The greater petrosal nerve carries preganglionic parasympathetic fibers from the facial nerve that synapse in the pterygopalatine ganglion. Som e postganglionic parasym pathetic fibers travel to scat tered salivary glands in the m ucosa of the soft palate. The lesser petrosal nerve carries preganglionic parasympathetic fibers from the glossopharyngeal nerve that synapse in the otic ganglion. Postganglionic parasympathetic fibers travel in the auriculotemporal nerve to the parotid salivary gland. C The deep petrosal nerve carries postganglionic sympathetic fibers that originate in the superior cervical ganglion. These fibers are not involved with stim ulation of salivation. Salivation is predom inantly under parasympathetic control but sympathetic stim ulation m ay result in a sm all flow of saliva that is rich in protein. E Incorrect. 39. D Preganglionic parasympathetic fibers originate in the facial nerve, travel to the chorda t ympani, and synapse in the submandibular ganglion. Postganglionic fibers travel to the submandibular and sublingual glands and sm all salivary groups found in the tongue and oral mucosa. A The ciliary ganglion is a parasympathetic ganglion associated with the oculom otor nerve (CN III). Postganglionic fibers from the ganglion carry impulses that cause constriction of the pupil as they innervate the pupillary constrictor muscle and accom modation via ciliary muscle contraction. B The superior cervical ganglion is a sympathetic ganglion that provides postganglionic fibers for the head and neck. C The m iddle cervical ganglion is a sympathetic ganglion that provides postganglionic fibers to the heart and thyroid gland. E Preganglionic parasympathetic fibers originate in the facial nerve, travel to the greater petrosal nerve and the nerve of the pterygoid canal, then synapse in the pterygopalatine ganglion. Postganglionic fibers go to very minor salivary glands found in the soft palate and mucosa of the oral cavit y. They also travel to the lacrimal gland. 40. E In Ludwig’s angina, infection is found bilaterally in the submandibular and sublingual spaces and in the subm ental space. A−D In Ludwig’s angina, infection is found in these spaces, but not exclusively. 41. C Ludwig’s angina results from an infection of a root of a tooth that im pinges into either the submandibular or the sublingual space; therefore, it can em anate from any of the m andibular teeth. A The inferior aspects of the m andibular m olars are found in the subm andibular space, but they do not exclusively lead to Ludwig’s angina. B The inferior aspects of the roots of the mandibular incisors and canines are found in the sublingual space, but they do not exclusively lead to Ludwig’s angina. . D, E Roots of the maxillary teeth do not gain access to the subm andibular or sublingual spaces. 42. A Because the m ost superior structure is the submandibular duct, it will be encountered first. B The lingual nerve is found just inferior to the subm andibular duct. C The lingual artery is the most inferior of the structures listed. D The hypoglossal nerve runs bet ween the lingual nerve and the lingual artery. E The glossopharyngeal nerve is not found in the floor of the oral cavit y. It enters the tongue on its posterior aspect. 43. B The facial artery runs through the subm andibular gland. A The facial vein runs superficial to the submandibular gland. C The lingual artery runs deep to the submandibular gland. D The hypoglossal nerve runs deep to the subm andibular gland. E The anterior division of the retrom andibular vein runs superior to the submandibular gland.

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Clinica l Questions & Answer Expla na tions

44. B The marginal m andibular branch of the facial nerve runs on the superficial surface of the subm andibular gland. A The cervical branch of the facial nerve runs posterior to the submandibular gland. C The m ental branch of the trigeminal nerve runs on the anteromedial surface of the mandible and is superior and anterior to the submandibular gland. D The fibers of the long buccal branch of the trigeminal nerve run on the superficial aspect of the cheek and into the gingiva of the mandible, not onto the subm andibular gland. E The inferior fibers of the buccal branch of the facial nerve travel on the lateral aspect of the cheek and are superior to the submandibular gland. 45. E The subm andibular gland sits on the anterior surface of the mylohyoid muscle, and a portion of the posterior aspect of the gland, as well as the submandibular duct, wraps around the muscle to its inferior aspect. A The hyoglossus is deep to both the subm andibular gland and the mylohyoid m uscle. B The anterior belly of the digastric is the anterior border of the submandibular triangle, and the submandibular gland sits within the triangle. The submandibular gland is posterior, and superficial, to much of the anterior belly. It does not wrap around it. C The posterior belly of the digastric is the posterior border of the submandibular triangle. The submandibular gland sits anterior to the posterior digastric. D The genioglossus muscle essentially sit s within the oral cavit y and is deep to the submandibular triangle. It is also anterior to the submandibular gland. 46. E The alar fascia (anterior layer of the prevertebral fascia) is the border bet ween the danger space and the retropharyngeal space. A The posterior layer of the prevertebral fascia is the posterior border of the danger space. B The pretracheal fascia is the anterior border of the retropharyngeal space. C In this case, the buccopharyngeal fascia is synonym ous with the pretracheal fascial; that is, they are continuous. D The medial aspect of the carotid sheath is the lateral border of the retropharyngeal space. 47. C Infections from the retropharyngeal space and/or danger space travel into the mediastinum and can then spread to the heart, resulting in pericarditis (inflam mation of the pericardium [outer layer] of the heart). A Infections from the roots of the m axillary teeth, nasal cavit y, or orbit m ay travel into the maxillary sinus with a resulting maxillary sinus infection. B Infections from the periorbital and infraorbital space, the supraorbital area, and the veins of the face, specifically, the pterygoid plexus of veins, may travel into the cavernous sinus. This can result in a cavernous sinus infection and/or throm bosis, which can be fatal in a mat ter of days. D Infections from the head normally do not gain access to the peritoneal cavit y. E Infections from the supraorbital and infraorbital areas, as well as the nasal cavit y and maxillary sinus, can gain access to the orbit. Symptom s associated with infections in the orbit include exophthalmos (bulging eyes) and diplopia (double vision). 48. E The thyroid gland is an endocrine gland and secretes into veins that are located on its lateral aspect. A vertical midline incision does not harm these vessels. A The thym us regresses as we age, not the thyroid gland. B, C The thyroid gland is an endocrine not an exocrine, gland. D The thyroid gland does not secrete angiogenic factors. Vessels cannot grow back to the thyroid gland once they are severed.

49. D The consensual light reflex occurs when a light is shined in one pupil, resulting in both pupils constricting. A The corneal reflex involves brushing the cornea and watching for the eyelid to shut. B The pupillary dilator reflex is an involuntary reflex involving dilation of the pupil. C The vestibulo-ocular reflex occurs when the head is m oved, but the im age viewed remains in a constant point on the retina. E The accom modation reflex is the adjustm ent of the shape of the lens to keep objects in focus when focal lengths change. This was not being tested. 50. A The medial geniculate body is involved with hearing. It is part of the auditory pathway. Fibers from the inferior colliculus travel to, and synapse in, the m edial geniculate body. Fibers from the m edial geniculate body travel to the auditory cortex of the temporal lobe. It is therefore not involved in the consensual light reflex. B−E In the consensual light reflex, sensory impulses from the retina travel to the pretectal nuclei via the optic nerve (E). Fibers from the pretectal nuclei comm unicate with each other via the posterior com missure (D). Fibers from the pretectal nuclei travel to the Edinger− Westphal nucleus. Preganglionic fibers from the Edinger−Westphal (C) nucleus travel to the ciliary ganglion (B). Postganglionic fibers from the ciliary ganglion travel to the pupillary constrictor m uscle and cause the pupil to constrict. 51. B The middle m eningeal artery is found in the epidural space. A sudden tear of the artery would enlarge the space and potentially compress structures found on the dorsal aspect of the midbrain, including the pretectal nucleus and posterior com missure. This could result in disruption of the consensual light reflex. A A tear of the lining of a ventricle could cause leakage of cerebrospinal fluid (CSF). However, this could not be tested through the consensual light reflex. A small tear of the ventricle would gradually leak CSF, but under m ost circumstances, there is no way to directly test for this. C Meningeal and cerebral veins are found in the subdural space; in som e rare cases, when they rip, pooling of blood can compress neuronal structures. However, in m ost cases, these tears result in a slow bleed that is not detected for a m at ter of hours or days, whereas the testing was to determ ine if a neuronal difficult y had occurred im mediately. Testing for tears of these veins would only occur after symptoms, such as dizziness or sem iconsciousness, had m anifested them selves. The testing would involve CT scans or MRI with contrast. D, E An occlusion of a cerebral artery would not be tested via the consensual light reflex. An angiography of the cerebral vessels would determine if this occlusion occurred. 52. B The accessory nerve can be dam aged in a radical neck dissection. The accessory nerve innervates the sternocleidom astoid, which participates in rotation of the head. It also innervates the trapezius, which participates in elevation of the shoulder (scapula). A Idiopathic spasmodic torticollis is normally inherited and not due to acute damage to a nerve. C The vagus nerve lies in the carotid sheath and is norm ally not dam aged in a radical neck dissection. D Branches of the ansa cervicalis could be injured in a radical neck dissection, but the m uscles it innervates (inferior belly of the omohyoid, superior belly of the om ohyoid, sternohyoid, and sternothyroid) are not involved in rotation of the head. E The phrenic nerve could conceivably be damaged in a radical neck dissection; however, it does not innervate muscles involved with rotation of the head, but rather innervates the diaphragm.

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Appendix C

53. C The hypoglossal nerve (CN XII) innervates all of the intrinsic m uscles of the tongue and all extrinsic muscles of the tongue (genioglossus, hyoglossus, and st yloglossus) except the palatoglossus, which is innervated by the vagus nerve (CN X). A The inferior alveolar nerve supplies sensory fibers to the m andibular teeth and the skin overlying a portion of the m andible. B The chorda t ympani carries preganglionic parasympathetic fibers and taste fibers. D The m andibular branch of the trigem inal nerve supplies sensory fibers to the m ajorit y of the head and motor fibers to the m uscles of m astication, the mylohyoid, the anterior digastric, the tensor t ym pani, and the tensor veli palatini. E The glossopharyngeal nerve supplies taste to the posterior onethird of the tongue, sensory from the upper portion of the pharynx, general sensory to the posterior one-third of the tongue, sensory from the external auditory m eatus, and motor to the st ylopharyngeus. It does not supply m uscles of the tongue. 54. C Dam age to the right hypoglossal nerve results in the right genioglossus not working properly. The right genioglossus protrudes the tongue toward the left. Thus, the left genioglossus would work unopposed, and the tongue, upon protrusion, deviates to the right. That is what is demonstrated in the photo. A, B The hyoglossus depresses and retrudes the tongue. Protrusion is demonstrated in the photo. B, D Damage to the left genioglossus results in the tongue deviating toward the left. E Dam age to the left genioglossus results in the tongue deviating toward the left. Damage to the left hyoglossus results in difficulties with depressing and retruding the tongue. 55. D The infraclavicular nodes are not part of the axillary group of nodes. Lymph from the axillary group drains to the infraclavicular and supraclavicular nodes. A The pectoral nodes are part of the axillary group of nodes. Lymph from the anterior chest wall and m am mary glands drains to the pectoral nodes. B The lateral nodes are part of the axillary group of nodes. Lymph from the upper limb drains to the lateral nodes. C The subscapular nodes are part of the axillary group of nodes. Lymph from the neck, back, and posterior aspect of the thoracic wall drains to the subscapular nodes. E The apical nodes are part of the axillary group of nodes. Lymph from the lateral nodes drains to the apical nodes. 56. C Medial rotation of the humerus is accomplished through the actions of the pectoralis major, teres m ajor, latissimus dorsi, and subscapularis. A Inferior rotation of the scapula is accomplished through the actions of the rhom boid m ajor, rhomboid minor, levator scapulae, and pectoralis m inor. B Superior rotation of the scapula is accomplished through the actions of the trapezius and serratus anterior. D Abduction of the humerus is accomplished through the action of the medial fibers of the deltoid, supraspinatus and serratus anterior. E Extension of the hum erus is accomplished through the actions of the latissim us dorsi and posterior fibers of the deltoid. 57. A The long thoracic nerve is found on the lateral chest wall. A portion of it is found within the confines of the axilla. As the long thoracic nerve travels on the superficial aspect of the serratus anterior, fibers from the nerve gain access to individual parts of the muscle. Because of its placem ent on the superficial aspect of the muscle, it is sometim es dam aged as lymph and adipose tissue are rem oved during a radical mastectomy. B The m edial pectoral nerve innervates the pectoralis minor, but fibers from the nerve enter it from its deep aspect. The nerve then travels to the deep surface of the pectoralis m ajor, which it also innervates. C The lateral pectoral nerve innervates the pectoralis major muscle. It gains access to the m uscle from its deep aspect. D The thoracodorsal nerve innervates the latissimus dorsi and gains access to it from its deep aspect. E The axillary nerve innervates the deltoid and teres m inor. In both cases, as it travels through the quadrangular space, it gains access to the deep aspects of the m uscles.

58. A The rhomboid major participates in retraction, elevation, and inferior rotation of the scapulae. B The teres m ajor participates in m edial rotation, extension, and adduction of the humerus. C The teres m inor participates in lateral rotation of the humerus. D The latissim us dorsi participates in medial rotation, extension, and adduction of the humerus. E The longissim us participates in extension and stabilization of the vertebral colum n. 59. C The sinoatrial artery is a branch of the right coronary artery. A The left coronary artery branches at the m ost proxim al portion of the ascending portion of the aorta. B The anterior ventricular artery is a branch of the left coronary artery. D The posterior interventricular artery is a branch of the right coronary artery. E The right marginal artery branches from the right coronary artery. 60. E Referred pain from the heart is norm ally not referred to the right hypogastrium. Som e of the structures found in the right hypogastrium are the cecum , appendix, and ascending colon. A−D Pain associated with angina is classically referred to the left shoulder and left upper lim b (A). It can also be referred to the posterior shoulder and back, although the pain associated with aortic dissection is m ore com monly felt in the back bet ween the shoulder blades. (B), to the m idline of the mandible (C), and to the anterior aspect of the neck (D). 61. E Referred pain from the esophagus, as in esophagitis or gastric reflux, can be referred to the m idsternal region (A), as can pain from the stom ach (B) and the pancreas, as in pancreatitis or pancreatic cancer (C). D Not applicable. 62. C The pericardial space (or cavit y), with pericardial fluid, is found bet ween the parietal layers of the serous pericardium and the visceral layer of the serous pericardium. Fluid is drained from the pericardial space by needle aspiration in a procedure known as pericardiocentesis. A The pericardial fat lies on the superficial aspect of the fibrous pericardium . There is no discernible space bet ween the t wo layers. B There is a small bit of nonspecific lymphatic-t ype fluid bet ween the parietal layer of the serous pericardium and fibrous pericardium , but there is no discernible space. D The serous layer of the pericardium is superficial to the myocardium ; there is no potential, or actual, space bet ween them. E The myocardium is superficial to the endocardium ; there is no potential, or actual, space bet ween them. 63. E The median nerve is found in the forearm and runs deep to the flexor retinaculum of the wrist and travels through the carpal tunnel. A The deep branch of the radial nerve is found in the posterior com partm ent of the forearm . B The superficial branch of the radial nerve is found in the superficial fascia of the posterior compartm ent. C The lateral cutaneous nerve of the forearm is found in the superficial fascia of the anterolateral aspect of the forearm . D The ulnar nerve is found in the proximal portion of the anterior compartment of the forearm but is superficial to the investing fascia in the distal portion of the forearm and superficial to the flexor retinaculum of the wrist. The ulnar nerve does not run through the carpal tunnel. 64. B The flexor pollicis brevis is innervated by the recurrent branch of the median nerve. If the median nerve was compressed in the distal aspect of the forearm or in the carpal tunnel, the recurrent branch would be dysfunctional. A, C, D The flexor pollicis longus, flexor digitorum superficialis, and flexor carpi radialis are innervated by the median nerve, but the nerve enters into these m uscles in the proximal portion of the forearm and thus should not be affected in the scenario presented. E Not applicable.

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Appendix C

Clinica l Questions & Answer Expla na tions

65. A Fine m otor movem ents of the thum b are achieved through the action of the flexor pollicis brevis, abductor pollicis brevis, and opponens brevis. All of these muscles are innervated by the recurrent branch of the m edian nerve, which m ay be affected in anterior compartm ent syndrom e. B Adduction of the thumb is via the adductor pollicis, which is innervated by the ulnar nerve. C Flexion of the fingers is accomplished via the flexor digitorum superficialis, which is innervated by the median nerve, but the m edian nerve enters the muscle proximal to where the blood would pool. The flexor digitorum profundus is innervated by the median nerve (sam e caveat applies) and the ulnar nerve. D Extension at the carpometacarpal joints is accomplished through the action of the extensor digitorum and extensor indicis. Both muscles are innervated by the radial nerve. E Not applicable.

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Index

Index Note: Speci c arteries, bones, glands, m uscles, nerves, and veins are listed by nam e or region under those m ain headings. Sectional anatomy and clinical applications are found under these m ain headings. Page num bers followed by f and t indicate gures and tables, respectively.

A Abdom en – anterior view of, 453–455, 453f–455f, 458–459, 458f–459f, 460, 460f – autonom ic plexuses in, 460, 460f – fem ale, anterior view of, 452, 452f, 458, 458f – m ale, anterior view of, 460, 460f – sectional anatomy of, 439, 439f, 461, 461f – transverse planes through, 438f, 438t – transverse sections of, 439, 439f, 461, 461f – veins of, 456–457, 456f–457f Abdom inal wall – anterior, 439, 439f – transverse section, 439, 439f – anterior view of, 439, 439f – arteries of, 440–441, 440f–441f – muscles of, 439, 439f – posterior, 438, 438f – super cial, 439, 439f – posterior, m uscles of, 438, 438f – subcutaneous tissue – super cial fat t y layer of, 439f – super cial m em branous layer of, 439f – surface anatomy of, 438, 438f Abdom inopelvic cavit y – divisions of, 442–443 – m idsagit tal section, 442f–443f – organs of, 442–443, 442f, 442t, 443f – extraperitoneal, 442t – intraperitoneal, 442t Abducent nerve palsy, 120t, 235, 235f, 235t Abscess(es) – apical, spread of infection from, potential routes for, 227, 227f, 227t – gravitation, 334 – retropharyngeal, 321 – spread of infection from , potential routes for, 321 Acetabular rim , 462f Acet ylcholine (ACh), 110 Acini (sing., acinus), of breast, 407, 407f Acoustic neurom a, 134, 134f, 271 Acoustic radiation, 276f “Adam ’s apple,” 336–337, 337f Additus laryngis. See Laryngeal inlet Adenohypophysis, 84f Adenoids, 217 Adrenoceptors, 110 Ageusia, 208 Air cells – ethm oid, 35, 35f, 163f, 174f–175f, 230f, 348, 348f–350f, 352f–353f, 360f–361f, 370f, 377, 377f, 378, 378f, 380f, 382, 382f – anterior, 174f, 231t, 354f – drainage of, 176, 176f, 176t – arterial supply to, 61t – m iddle, 175, 175f – drainage of, 176, 176f, 176t – posterior, 174f, 231t

– drainage of, 176t – ori ces of, 176f – venous drainage of, 64t, 176, 176f, 176t – m astoid, 32, 32f, 266, 266f–267f, 370, 370f–372f – arteries of, 272, 272f, 272t Ala (pl., alae), nasal, 172f Alcoholism , 87 Allantois, 6f Allocortex, 80, 82, 82f Alveolar bone, 190, 190f, 192, 192f, 193, 193f – in children, 198 – resorption of, 42 Alveolar crest, 193f Alveolar-gingival bers, 193f Alveolar m ucosa, 184f, 193f Alveolar plexus, superior, 126f, 127t Alveolar ostitis, 190 Alveolar wall, 193f Alveoli (tooth sockets), 40f, 42, 190, 190f Alzheim er disease, 78, 82, 95 Am acrine cells, retinal, 253, 253f Am aurosis, 256 Am bient gyrus, 118f, 182, 182f Am nion, 2, 2f Am niotic cavit y, 2, 2f Ampulla (pl., ampullae) – of ductus deferens, 464f – hepatopancreatic, 450f – sphincter of, 450f – of sem icircular canals, 280 – posterior, 271f – structure of, 278, 278f Ampullary crest(s), 270f, 278f, 280, 280f – structure of, 278, 278f Amygdala, 80f, 83, 83f, 83t, 107f, 118, 118f, 182, 182f, 378, 378f – dysfunction of, 83 Amygdaloid bodies, 107 Amylase, salivary, 212 Anal canal, blood supply to, 440, 440f–441f Anal sphincter, external, 464f–465f Anastom osis (pl., anastom oses) – arterial – abdom inal, 441, 441f – in auricle of ear, 264, 264f – carotid – external, 59, 59f – internal, 59, 59f – lacrim al, 56f, 231t – m iddle m eningeal, with lacrim al artery, 56f – facial nerve, 326f–327f – Galen’s, 342f – venous, m edullary, 99f Anem ia, 241 Anesthesia – epidural, 75, 75f – lum bar, 75, 75f – regional, 470-487 Aneurysm (s) – aortic, 341, 343f, 343t – berry, 97 – cerebral, rupture of, 103, 103f – internal carotid artery, 120t, 238 Angle – Bennet t, 166, 166f – cerebellopontine, acoustic neurom a in, 134, 134f – cham ber, 244, 244f, 250f, 251, 251f – obstruction of, 251, 251f

– costal, 402f–403f – m andibular, 40, 40f–41f, 43f, 162f, 223f, 355f – age-related changes in, 42 – on dental panoram ic tom ogram (DPT), 200f – of m outh, 184, 184f – scapular – acrom ial, 385f – inferior, 385f, 390f–391f – superior, 385f, 390f – sternal, 402f Anhydrosis, 329 Anisocoria, 250 Ankyloglossia, 10 Anopias, 256, 256f. See also Hem ianopia; Quadrantanopia Anorexia, hypothalamic lesion and, 87t Anosm ia, 208 Ansa cervicalis, 189f, 312t, 313, 316, 316f–317f, 322, 328, 328f–329f – root s of – inferior, 189f, 316, 316f–317f, 322, 328, 328f – superior, 189f, 316, 316f–317f, 322, 322f, 328, 328f Anterior com m issure, 82f, 84f Anterior perforated substance, 118f, 182, 182f Anterolateral sulcus, 89f Antihelix, 264f – crura of, 264f Antitragus, 264f Anulus brosus, 290f Anxiet y, 83 Aorta, 357f, 419f, 429f–430f – abdom inal, 299f, 411f, 411t, 413f–414f, 429f, 440, 440f–441f, 443f, 451f, 452, 452f–453f, 455f–456f, 458f, 461f, 466f–467f – branch(es), 440, 440f, 440t – in prenatal circulation, 428f – ascending, 413f–414f, 418f, 418t, 422f–423f, 425f–426f, 429f, 436f – descending, 414f, 421f, 433f–434f – dorsal, 2f – em bryology of, 3f – em bryonic – dorsal, 8, 8f – ventral, 8, 8f – thoracic, 398f, 409f, 411f, 411t–412t, 413f, 416f, 418t, 419f, 421f, 430f, 433f–434f – anterior view of, 414, 414f Aortic arch(es), 48, 100f, 139f, 225f, 333f, 341f, 356f, 412f, 414f, 416f, 418t, 419f, 421f–423f, 427f, 429f–430f, 434f, 436f–437f – developm ent of, 8, 8f – em bryonic, 8, 8f – innervation of, 138t, 139f – in prenatal circulation, 428f – throm botic m aterial on, 100f Aortic bifurcation, 440, 440f, 455f Aortic hiatus, in diaphragm , 408f, 413f–414f, 438f, 452f Aortic sinus, 425f Aortic valve, 418f – cusp, 424f – posterior, 424f Aphasia, 101, 101f Aponeurosis – bicipital, 393f

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– epicranial, 144f, 145, 145f–146f, 150f, 151, 151f – external oblique, 439f – internal oblique, 439f – lingual, 202f, 204f – palatine, 214f–215f, 215t – palm ar, 395f – st ylopharyngeal, 334, 334f – transversus abdom inis, 439f Appendix (pl., appendices) – epiploic, 445f, 449f – brous, of liver, 450f – verm iform, 442t, 449f – blood supply to, 440, 440f Aqueduct – cerebral, 84f, 88f, 90f, 91, 94f, 95, 95f, 120f, 261, 261f, 360f – cochlear, 266f, 270, 270f, 273f – vestibular, 33f, 271f, 273f Aqueous hum or, 244 – norm al drainage of, 251, 251f – pupillary resistance and, 251 – trabecular resistance and, 251 – trabecular route, 251 – uveoscleral route, 251 – obstruction of, 251, 251f Arachnoid granulations, 24f, 25, 25f, 102, 102f, 151f Arachnoid m ater, 102, 102f – spinal, 74f–75f Arachnoid villi, 102f Arch(es) – aortic. See Aortic arch(es) – azygos vein, 430f – costal, 402f – of cricoid cartilage, 337f–339f, 369f – dental, 184 – jugular venous, 315f, 322f – palatoglossal, 184f–185f, 202f, 203t, 215t – palatopharyngeal, 178f, 184f–185f, 202f, 216f–217f, 221t – palm ar – deep, 398f – super cial, 398f – palmar venous – deep, 399f – super cial, 399f – pharyngeal (branchial), 3, 3f, 8f, 13f – arrangem ent of, 7, 7f – artery, 6, 6f – cartilage, 6, 6f – cranial bones form ed from , 16f, 16t – derivatives of, 7, 7f, 7t, 11 – muscular, 7, 7f, 7t – neural, 7, 7f, 7t – skeletal and ligam entous, 7, 7f, 7t – developm ent of, 6, 6f – rst (m andibular), 7, 7f, 7t – fourth, 7, 7f, 7t – nerves, 6, 6f, 7, 7f, 7t – second (hyoid), 7, 7f, 7t – sixth, 7, 7f, 7t – structure of, 6, 6f – third, 7, 7f, 7t – tissues, m igration of, 11, 11f – superciliary, 21f – vertebral (neural arch), 284–285, 285f, 287f, 293f, 299f – atlas (C1) – anterior, 178f, 185f, 287f, 293f, 295f, 365, 376f, 380f

Index

– posterior, 286f–287f, 289f, 293f, 294, 294f–295f, 303f, 309f, 359f, 376f, 380f, 382f – C3, posterior, 373f – T1, 368f – vertebra prom inens (C7), 367f, 374, 374f – zygom atic, 19f, 27f, 30, 151, 155f, 156, 156f–157f, 157t, 161f, 163f, 201, 201f, 349f–350f, 363, 363f – displacem ent of, 36, 36f Archicortex, 82f Arcuate em inence, 262f Area dorsalis, 87f Area lateralis, 87f Area medialis, 87f Area postrem a, 88f Areola, 406f, 407 Areolar glands, 406f Argyll-Robertson pupil, 258 Arm . See also Lim b (upper) – m uscles of, 392–393, 392f–393f – anterior view of, 393f – posterior view of, 393f Artery(ies) (nam ed) – angular, 48f, 50f, 53, 53f, 53t, 59f, 150f, 153f, 240f – anterior cerebral, 51t, 61f, 96, 100f, 351f – distribution area of, 96f – occlusion of, 101, 101f – postcom m unicating part, segm ent A2, 96f – precom m unicating part, segm ent A1, 96f – appendicular, 441f, 449f – auricular, 314t – anterior, 58t, 264, 264f – deep, 56f, 57t, 272f, 272t, 273f – posterior, 48f, 50f, 51t, 54, 54f–56f, 186f, 264, 264f, 272t, 314t – branch(es), 55, 55f, 55t – auricular, 55f, 55t – m uscular, 55t – occipital, 55t – parotid, 55f, 55t – course, 55 – axillary, 49, 398f, 400f–401f, 406f, 440f – basilar, 49, 49f, 60f, 61, 61f, 96, 96f, 180f, 272, 272t, 273, 331, 361f, 362, 362f–363f, 370f, 380f – brachial, 398f – brachiocephalic, 382f – bronchial, 414f – buccal, 56f, 57t, 158f–159f, 186f – caroticot ympanic, 51t, 272f, 272t – carotid – com m on, 48, 48f–49f, 50, 50f, 52f–54f, 61f, 100f, 225f, 299f, 314, 314f, 320t, 322f, 323, 323f–324f, 325, 325f, 329, 329f, 332, 333f, 341f, 343f, 346f, 356f–357f, 364, 366, 366f–367f, 367, 368f, 369, 369f, 373f–374f, 375, 375f, 379f, 383, 383f, 398f, 401f, 410f, 412f–414f, 416f, 418t, 419f, 422f, 426f, 437f – external, 48, 48f, 50, 50f, 52f, 54f–55f, 58f–60f, 152–153, 153f, 207t, 213t, 224f, 264, 264f, 314, 314f, 314t, 328, 328f, 329, 329f, 332f, 334f, 347f, 356f, 373f, 383, 383f – anastom oses, 59, 59f – branch(es), 50, 50f, 51t, 52, 52f, 52t, 54, 54f, 55t, 153, 153f, 181, 181f, 272, 272f, 314, 314f, 314t – cricothyroid, 314f, 314t – glandular, 314f – infrahyoid, 314f, 314t – term inal, 56, 56f, 58, 58f

–

–

–

– –

–

– –

– –

– –

–

– linguofacial trunk of, 324, 324f – thyrolingual trunk of, 324, 324f – thyrolinguofacial trunk of, 324, 324f – internal, 32f, 33, 44f, 45t, 48, 48f, 50, 50f, 52f–54f, 60, 60f, 61, 61f, 96, 96f, 100, 100f, 102f, 121f, 133f, 153, 153f, 174f–175f, 224f, 232, 232f, 234f, 237, 237f, 238, 238f–239f, 266f–267f, 269f, 271f–272f, 272t, 314, 314f, 320t, 328, 328f, 329, 329f, 332, 332f, 334f, 347f, 351, 351f, 356f–357f, 361, 361f–363f, 364, 364f–365f, 370f–373f, 378, 378f, 379, 379f–381f, 383f – anastom oses, 59, 59f – aneurysm s of, 120t – intracavernous, 238 – atherosclerosis, 314 – branch(es), 50, 50f, 51t, 181, 181f, 224, 272 – anterior m eningeal, 51t – basal tentorial, 60f – cavernous sinus, 51t, 60f – ganglionic, 51t – marginal tentorial, 60f – m eningeal, 60f – neural, 60f – trigem inal ganglion, 60f – cavernous part, 60, 60f, 351 – cerebral part, 60, 60f – cervical part, 60, 60f – passage through skull, 32–33 – petrous part, 60, 60f – subdivisions, 60, 60f – variant s, 324, 324f – variants, 324, 324f cecal – anterior, 449f, 454f–455f, 459f – posterior, 454f–455f, 459f central retinal, 236f, 236t, 237, 244f, 247, 247f, 253f – ophthalm oscopic exam ination of, 247, 247f cervical – ascending, 49f, 314f, 314t, 324f–325f, 329f – deep, 49t, 314t, 325, 359f – super cial, 326f – transverse, 49f, 49t, 314f, 314t, 323f–324f, 325, 325f, 327f, 369f choroidal, anterior, 51t, 60f, 96, 96f ciliary – anterior, 61t, 247, 247f – posterior, 236t, 247, 247f – long, 61t, 237f, 247, 247f – short, 61t, 124f, 237f, 239f, 247, 247f circum ex hum eral – anterior, 398f – posterior, 398f, 401f circum ex scapular, 398f cochlear – com m on, 273f – proper, 273f colic, 441f, 443f–444f, 447f, 454, 454f–455f, 459f com m unicating – anterior, 61f, 96f – posterior, 51t, 60f–61f, 96f conjunctival, anterior, 247f coronary – branch(es), 425t – atrial, 425f, 425t – circum ex, 425f, 425t – conus, 425f, 425t – lateral, 425f, 425t – posterior left ventricular, 425f, 425t – to sinoatrial node, 425f, 425t crural

– – –

– –

– – –

–

– – – – –

–

–

– –

– –

–

–

– anterior, 272f – posterior, 272f cystic, 450f, 453f deep, of arm , 398f descending (coronary) – anterior, 425f, 425t – posterior, 425f, 425t of ductus deferens, 466f, 466t, 467f epigastric – inferior, 405f, 440, 440f, 444f–445f, 458f, 466f – obturator branch of, 452f, 466f – super cial, 405f, 440f superior, 405f, 440, 440f esophageal, 314t ethm oidal – anterior, 44f, 45t, 61t, 124f, 180f–181f, 231t, 237f, 239f – anterior septal branches, 59, 181f – posterior, 44f, 45t, 60f, 61t, 124f, 180f–181f, 231t, 237f, 239f facial, 48f, 50, 50f, 51t, 53, 53f–54f, 56f, 59, 59f, 113t, 150f, 153, 153f, 158f–159f, 180, 186, 186f, 207t, 212f, 240, 240f, 314t, 328f–329f, 355f–356f, 372f–373f – branch(es), 53, 53f, 53t – glandular, 53, 53f, 53t, 213t, 314t – inferior labial, 186 – nasal, 360f – superior labial, 186 – course, 53f, 53t – transverse, 58f, 58t, 150f, 152f–153f, 231t, 264f fem oral, 440, 440f, 452f, 458f gastric, 440f, 441f, 447f, 453f–454f, 459f gastroduodenal, 440f, 440t, 441f, 453f–454f, 459f gastro-om ental, 441f, 453f–454f, 459f gluteal – inferior, 452f, 466f, 466t – superior, 452f, 466f, 466t, 467f greater palatine, 44f, 45t, 57t, 59f, 169t, 170f, 170t, 180f–181f, 188f, 214, 214f, 214t, 348f – nasal branch, 181f hepatic – com m on, 411f, 440f, 440t, 441f, 447f, 451f, 453f–454f – proper, 440f, 440t, 441f, 450f–451f, 453f–454f, 459f – branch(es), 450f, 453f hyaloid, 245 hypophyseal – inferior, 51t, 60f – superior, 51t, 60f ileal, 441f, 454f, 459f ileocolic, 441f, 454f–455f, 459f – branch(es) – colic, 454f–455f – ileal, 454f–455f iliac – circum ex – deep, 440f, 452f, 458f – super cial, 405f, 440f – com m on, 440, 440f, 440t, 443f, 452, 452f, 455f, 457f, 459f, 464f–467f – in prenatal circulation, 428f – external, 440f, 440t, 452f, 465f–467f – internal, 440f, 440t, 441f, 452f, 466f–467f – branch(es), 466, 466f – parietal, 466, 466f – in prenatal circulation, 428, 428f – visceral, parietal, 466, 466f iliolum bar, 452f, 466f, 466t, 467f

– inferior alveolar, 53f, 56f, 57t, 153f, 155f, 158, 158f–159f, 186f, 197t, 211, 227f, 334f, 348f–350f, 379f – branch(es) – incisive, 57t, 197t – lingual, 57t – m ental, 56f, 57t – mylohyoid, 56f, 57t – inferior cerebellar – anterior, 96, 96f, 273 – posterior, 49t, 96, 96f – infraorbital, 53f, 56f, 57t, 59, 59f, 150f, 159f, 169t–170t, 186f, 231t, 236t, 238, 240, 240f, 353f – intercostal, suprem e, 49t, 314f, 314t, 325 – internal auditory, 272f, 272t – internal pudendal, 452f, 466f, 466t, 467f – interosseous (forearm ) – anterior, 398f – com m on, 398f – posterior, 398f – interventricular – anterior, 425f, 425t – posterior, 425f, 425t – jejunal, 441f, 454f, 459f, 461f – labial – inferior, 48f, 53, 53f, 53t, 59f, 150f, 153f – superior, 48f, 53, 53f, 53t, 59f, 153f – septal branches, 180f–181f – labyrinthine, 44f, 45t, 271–272, 272f, 272t, 273, 273f – lacrim al, 61t, 124f, 231t, 236t, 237f, 239f–240f – branch(es) – anastom otic, 231t – recurrent laryngeal, 231t – laryngeal – inferior, 218t, 314t, 341, 341f – superior, 48f, 52, 52f, 52t, 218t, 225f, 314f, 314t, 322f, 333f, 335f, 341, 341f–342f – foram en for, in thyrohyoid m em brane, 336f – lenticulostriate, 97, 97f – lesser palatine, 44f, 45t, 57t, 59f, 169t, 170f, 170t, 180f–181f, 188f, 214, 214f, 215t – lingual, 48f, 50f, 51t, 52, 52f–54f, 56f, 186, 186f, 206, 206f, 207t, 211, 211f–212f, 314f, 314t, 328f – branch(es), 52, 52f, 52t, 207t – dorsal lingual, 52f, 52t – suprahyoid, 52f, 52t – terminal, 207t – deep, 52f, 52t, 206, 206f, 207t, 314t, 350f, 352, 352f – dorsal, 206, 206f, 207t, 314t – lingular (pulm onary), 437f, 437t – lum bar, 414f, 440f, 440t – rst, 452f – m arginal (abdom inal), 454f–455f – m arginal (cardiac), 425f, 425t – m asseteric, 56f, 57t, 186f – m astoid, 272f, 314t – m axillary, 48f, 50f, 51t, 53f–54f, 55–56, 56f, 58f, 153, 153f, 158f, 159, 159f, 170f, 180, 181f, 186, 186f, 214, 236t, 272t, 314t, 356f–357f, 365f – branch(es), 57t, 159 – m andibular, 158, 158t, 186, 186f – m ental, 186f – mylohyoid, 186f – pterygoid (m uscular), 56f, 158, 158t, 186, 186f – pterygopalatine, 186, 186f – in pterygopalatine fossa, 170t

524

ERRNVPHGLFRVRUJ

Index

–

– –

–

– – –

– –

–

– –

– –

–

–

– course of, 56, 56f, 186, 186f – left lateral view of, 186, 186f – m andibular part, 56, 56f, 57t – pterygoid part, 56, 56f, 57t – pterygopalatine part, 56, 56f, 57t, 59, 169t–170t meningeal, 61t, 314t – accessory, 44f, 45t, 57t – m iddle, 25, 44f, 45t, 56, 56f, 57t, 159, 159f, 237f, 272t – branch(es) – anastom otic, with lacrim al artery, 56f – frontal, 56f – parietal, 56f – groove for, 33f – petrous, 56f – rupture of, 103, 103f – posterior, 44f, 45t, 52f, 52t, 378f mental, 59f, 150f, 153f mesenteric – inferior, 440, 440f, 440t, 441f, 452f, 454–455, 455f, 457, 458f–459f, 467f – anterior view of, 455, 455f – superior, 440, 440f, 440t, 441f, 443f, 449f, 451f–452f, 454, 454f–455f, 457, 458f–459f, 461f – anterior view of, 454, 454f middle cerebral, 51t, 61f, 96, 97f, 100, 100f, 102f, 370f – distribution area of, 96f – insular part, segm ent M2, 96f – occlusion of, 101, 101f – sphenoidal part, segm ent M1, 96f middle collateral (arm ), 398f musculophrenic, 409f–411f, 411t nasal – dorsal, 50f, 53f, 53t, 59, 59f–60f, 61t, 150f, 153f, 231t, 237f, 240f, 360f – lateral, 53, 53t, 59f, 150f, 240f – alar branches of, 181, 181f – posterior, 57t obturator, 452f, 466f, 466t, 467f occipital, 48f, 50f, 51t, 55f–56f, 152f–154f, 186f, 224f–225f, 272t, 314t, 330, 330f, 331, 332f–333f, 365f – branch(es), 54, 54f, 55t – auricular, 55t – descending, 54f, 55t – m astoid, 55t – m eningeal, 55t – m uscular, 55t – occipital, 54f, 55t – posterior, 54f – sternocleidom astoid, 55t – lateral, segment P3, 96f – m edial, segm ent P4, 96f ophthalm ic, 44f, 45t, 50, 50f, 51t, 59–60, 60f, 61t, 180, 181f, 231t, 236t, 237, 237f, 238, 238f–239f, 247, 247f, 352, 352f, 353, 353f – branch(es), 237, 237f ovarian, 440f, 440t, 452f, 457f–458f, 465f, 467f palatine, 314t – ascending, 53, 53f, 53t, 215t, 314t – descending, 45t, 57t, 59f, 170t, 180f–181f palm ar digital, 398f – com m on, 398f palpebral – lateral, 59f – medial, 59f, 61t, 237f pancreatic – dorsal, 441f – great, 441f – inferior, 441f pancreaticoduodenal – inferior, 441f

– – –

– –

–

–

– –

– – – –

– –

– – – –

– –

– –

– branch(es), 454f – superior, anterior/posterior, 441f of pancreatic tail, 441f penile, dorsal, 467f pericardiophrenic, 409f, 410, 410f–411f, 411t, 412f, 418t, 419f–421f – pericardial branches of, 412f perineal, 467f petrosal, super cial, 45t, 272f, 272t – branch(es) – ascending, 272f – descending, 272f pharyngeal, 57t, 169t, 314t – ascending, 48f, 50f, 51t, 52, 52f–54f, 56f, 207t, 224f, 272t, 314f, 314t, 332f – branch(es), 52t – palatine, 215t – pharyngeal, 52f, 52t – tonsillar, 335f – variants, 332, 332f phrenic – inferior, 411f, 411t, 414f, 440f, 440t, 452f superior, 409f, 411f, 411t posterior cerebral, 61f, 96 – distribution area of, 96f – occlusion of, 101, 101f – postcom m unicating part, segm ent P2, 96f – precomm unicating part, segm ent P1, 96f posterior nasal, lateral, 59f, 170t, 180f–181f posterolateral (coronary), right, 425f, 425t prevertebral, 314t pterygoid – lateral, 57t – m edial, 57t of pterygoid canal, 51t, 57t, 59f, 60, 60f, 169t–170t, 272t pulm onary, 412f, 418,419f, 421f, 423f, 429, 430f, 434f–435f, 436, 436f–437f, 437t – anterior basal segmental a., 437f, 437t – anterior segm ental a., 437f, 437t – apical segm ental a., 437f, 437t – branch(es), 437f, 437t – inferior lobe, 412f, 418,419f, 421f, 423f, 430f, 434f–435f, 436, 436f–437f, 437t – lateral basal segm ental a., 437f, 437t – lateral segm ental a., 437f, 437t – lingular a., 437f, 437t – m edial basal segm ental a., 437f, 437t – m edial segm ental a., 437f, 437t – m iddle lobe, 437f, 437t – posterior basal segm ental a., 437f, 437t – posterior segm ental a., 437f, 437t – superior lobe a., 437f, 437t – superior segm ental a., 437f, 437t radial, 398f – super cial palm ar branch, 398f radial collateral, 398f radial recurrent, 398f rectal – inferior, 441f, 466f, 466t, 467f – m iddle, 441f, 452f, 466f, 466t – superior, 441f, 455f, 459f, 467f renal, 440, 440f, 440t, 443f, 452f, 454f, 458f–459f, 461f sacral, 452f – lateral, 466f, 466t – m edian, 440f, 440t, 452f, 458f, 466f–467f scapular, descending (dorsal), 49t, 314t scrotal, posterior, 467f

– sigm oid, 441f, 455f, 459f – sphenopalatine, 56f, 57t, 59, 59f, 159f, 169t–170t, 181f, 186f, 214t – posterior septal branches, 57t, 59, 59f, 170t, 180f–181f – spinal, 314t – anterior, 44f, 45t, 49t, 74f, 96, 96f – posterior, 44f, 45t, 49t, 96 – splenic, 411f, 440f, 440t, 441f, 443f, 447f, 451f, 453f–454f, 459f – stapedial, 273f – sternocleidom astoid, 314t, 328f – st ylom astoid, 44f, 45t, 55t, 269f, 272f, 272t, 273f, 314t – posterior t ympanic branch, 272f – subarcuate, 272f – subclavian, 48f, 49, 49f, 60f, 139f, 225f, 314, 314f, 314t, 323, 323f, 324, 324f, 325, 325f, 329, 333f, 341f, 347f, 356f–357f, 383f, 398f, 401f, 406f, 410f, 412f–414f, 416f, 418t, 419f–422f, 426f, 430f, 434f, 437f, 440, 440f – branch(es), 49, 49f, 49t, 314, 314f, 314t – sublingual, 52f, 52t, 206, 206f, 207t, 211, 314t – glandular branches, 213t – subm ental, 53, 53f, 53t, 153f, 206f, 207t, 211, 314t – subscapular, 398f – superior alveolar – anterior, 56f, 57t, 59f, 170t, 186f, 195t – m iddle, 56f, 57t, 170t, 186f, 195t – posterior, 56f, 57t, 159f, 169t–170t, 186f, 195t – superior cerebellar, 96, 96f – superior pancreaticoduodenal – anterior, 453f–454f – posterior, 453f – suprahyoid, 314t – supraorbital, 59, 59f–60f, 61t, 124f, 153f, 231t, 236t, 237f, 239f, 240, 240f – suprarenal – inferior, 440f, 440t, 452f – middle, 440t, 452f – superior, 411f, 440f, 440t, 452f – suprascapular, 49f, 49t, 314f, 314t, 324f, 325, 325f, 327f, 398f – supratrochlear, 59f–60f, 61t, 124f, 231t, 237f, 239f–240f – temporal – deep, 56f, 57t, 155f, 157f, 157t, 158f, 186f – m iddle, 58f, 58t, 153f – super cial, 48f, 50f, 51t, 53f, 54, 54f, 55–56, 56f, 58, 58f, 59, 59f, 150f, 152f, 153, 153f, 155f, 157t, 158f–159f, 186f, 213t, 264, 264f, 314t, 363f – branch(es), 58, 58f, 58t – frontal (anterior), 58f, 58t, 59f, 152f – parietal (posterior), 58f, 58t, 152f, 154f – temporal, 154f – testicular, 440f, 440t – thoracic – internal, 49t, 324f–325f, 398f, 405f–406f, 409f–411f, 411t, 412f, 414f, 419f, 433f, 440f, 461f – branch(es), 406f – anterior perforating, 409f – lateral, 398f, 405f–406f, 440f – superior, 398f, 440f – thoracoacrom ial, 398f – branch(es) – acrom ial, 398f – deltoid, 398f – pectoral, 398f

525

ERRNVPHGLFRVRUJ

– thoracodorsal, 398f, 440f – thyroid – inferior, 49f, 49t, 225f, 314f, 314t, 324f, 325, 325f, 329, 329f, 333f, 335f, 341, 341f–342f, 346f, 347, 347f, 369f, 375f – superior, 48f, 50f, 51t, 52, 52f–54f, 56f, 60f, 186f, 224f, 314f, 314t, 322, 322f–323f, 328f, 329, 329f, 332f, 341, 341f, 346f, 347, 347f, 367f–369f – branch(es), 52t – cricothyroid, 52f, 52t – glandular, 52f, 52t – infrahyoid, 52f, 52t – m uscular, 52t – sternocleidom astoid, 52f, 52t – thyroid ima, 52f, 347 – tonsillar, 53, 53f, 53t, 207t, 314t – tracheal, 314t – tubal, 272f, 272t – t ympanic – anterior, 44f, 45t, 56f, 57t, 164, 269f, 272t, 273, 273f – inferior, 52f, 52t, 272f, 272t, 273f, 314t – posterior, 55f, 269f, 272f, 272t, 273f – superior, 44f, 45t, 272f, 272t, 273f – ulnar, 398f – ulnar collateral – inferior, 398f – superior, 398f – ulnar recurrent, 398f – um bilical, 428, 428f, 452f, 466f, 466t, 467f – obliterated part, 466f – uterine, 452f, 466f–467f – vaginal branch, 466f – vaginal, 466f–467f – vertebral, 44f, 45t, 48f, 49, 49f, 49t, 50f, 60f, 61, 61f, 96, 96f, 225f, 286, 289, 289f, 292f, 314, 314f, 314t, 324f, 325, 325f, 329f, 331, 333f–334f, 357f, 359f, 364f–365f, 365, 366f–367f, 367, 368f–369f, 371f–375f, 377, 377f–378f, 380f, 398f, 414f – m eningeal branches, 49t – vesical – inferior, 452f, 466f, 466t, 467f – superior, 466f, 466t, 467f – vestibular, 273f – vestibulocochlear, 273f – zygom aticofacial, 36 – zygom atico-orbital, 58f, 58t, 152f–153f, 231t – zygom aticotemporal, 36 Artery(ies) (of region or organ) – of abdom inal wall, 440–441, 440f–441f – auricular, 264, 264f – at base of brain, 96, 96f – cerebral, 49, 96, 96f – distribution areas of, 96, 96f – coronary – anterior view of, 425, 425f – branch(es), 425t – posteroinferior view of, 425, 425f – of diaphragm , 411f, 411t – of ear, 272, 272f, 272t, 273, 273f – of hard palate, 188, 188f – of head, 48, 48f, 50, 50f – super cial, 152, 152f, 153, 153f – intercostal, 405f, 407f, 420f–421f, 432f, 461f – posterior, 409f, 414f, 416f, 419f–421f – laryngeal, 341, 341f – of lateral nasal wall, 181, 181f – of m astoid air cells, 272, 272f, 272t – m ediastinal, 418t – nasal septal, 181, 181f – of neck, 48, 48f, 314, 314f, 314t

Index

– – – – –

of optic nerve, 247, 247f of oral cavit y, 186, 186f of ossicular chain, 273, 273f pelvic, 466–467, 466f–467f, 466t phrenic – inferior, 410f – superior, 410f – pontine, 96f – of pterygopalatine fossa, 170, 170f, 170t – pulm onary, 436, 436f – of t ympanic cavit y, 272, 272f, 272t – of t ympanic m em brane, 273, 273f – um bilical, 429f – in postnatal circulation, 429, 429f – of upper lim b, 398, 398f – vertebral, 75f Arytenoid cartilage. See Cartilage, arytenoid Arytenoid swelling, 10f, 10t Ascending tract s, 104, 104f Association area(s), 88, 88f Asterion, 17f, 19f, 23f Astigm atism, 245 Astrocyte(s), functions of, 73t Atherom a, 100 Atherosclerosis, 50, 314 Atlas (C1). See Vertebra/Vertebrae, cervical Atrioventricular (AV) bundle (of His), 427f Atrioventricular (AV) node, 426f, 427, 427f Atrioventricular (AV) ori ce, right, 423f Atrioventricular (AV) valve(s), 424, 424f – left (bicuspid, m itral), 423f–424f – anterior cusp of, 424f – posterior cusp of, 424f – right (tricuspid), 423f – anterior cusp of, 423f–424f – posterior cusp of, 424f – septal cusp of, 424f Atrium (pl., atria) , 422f–423f, 425f, 425t, 427f, 429f, 433f, 436f – lateral view of, 423, 423f – opened, 427f – in prenatal circulation, 428, 428f – throm botic m aterial in, 100f Auditory apparatus, 262, 262f, 270, 274, 274f – sound conduction apparatus of, 262 Auditory canal(s). See External auditory canal; Internal auditory canal Auditory cortex, 81, 81f – prim ary, 276 Auditory ossicles, 262, 266, 266f, 268, 268f. See also Ossicular chain Auditory pathway, 276, 276f – tonotopic organization of, 274, 276 Auditory tube. See Pharyngot ympanic (auditory/ Eustachian) tube Auricle – cardiac, 422f–423f, 425f – of ear, 264–265, 264f–266f – anterior, venous drainage of, 64t–65t – arteries of, 264, 264f – anastom oses, 264, 264f – perforating branches, 264f – blood supply to, 264, 264f – cartilage of, 264, 264f – developm ent of, 13, 13f, 13t – frostbite of, 264 – lym phatic drainage of, 70, 70f, 265, 265f – m uscles of, 264, 264f – posterior, venous drainage of, 65t – sensory innervation of, 265, 265f – venous drainage of, 272 Auricular cartilage. See Cartilage, auricular Auricular hillocks, 13

Autonom ic dysfunction, 87t Autonom ic nervous system , 110, 110f, 417, 417f. See also Parasympathetic nervous system ; Sympathetic nervous system Axis (C2). See Vertebra/Vertebrae, cervical Axis (pl., axes) – condylar-hinge, of m andible, 164, 166 – of lens, 249, 249f – optical, of eye, 245, 245f – oral, 344, 344f – orbital, of eye, 245, 245f – pharyngeal, 344, 344f – of pronation/supination, of radius, 388f – tracheal, 344, 344f Axon(s), 73, 73f – a erent (sensory), 4, 4f – e erent (m otor), 4, 4f – myelinated, 73, 73f – in olfactory tract, 183 Axon hillock, 73f

B Back, m uscles of, 298–299, 298f–299f – extrinsic, 298, 300, 300f – innervation of, 298 – intrinsic, 3, 3f, 36f–37f, 46f–47f, 296t, 298, 299f, 300–307, 300f–307f, 304t, 306t, 320t, 330, 409f, 411f – innervation of, 298, 300, 330 – posterior view of, 300f–301f Balance. See also Vestibular apparatus; Vestibular pathway – organ of, 262 – regulation of, 280, 280f – vestibular nuclei and, 281, 281f Baroreceptor re ex, 329 Basal cell(s) – olfactory, 183 – of tongue, 209f Basal lam ina, 193, 193f Basal layer, 193f Basilic hiatus, 399f Bell palsy, 131, 131f, 146 Bennet t angle, 166, 166f Berger space, 245f Bifurcation, aortic, 440, 440f, 455f Bifurcation, carotid, 48, 48f, 60f, 100f, 329f – atherom atous m aterial at, 100f Bile duct(s), 450f, 453f – com m on, 449f, 461f – extrahepatic, 451, 451f – sphincter of, 450f Biliary sphincter system , 450f Biliary tract, anterior view of, 451, 451f Bipolar cells, retinal, 253, 253f, 254, 254f, 258 – and pupillary light re ex, 259 Bladder. See Urinary bladder Blindness, 247, 251, 256, 256f – unilateral, 259 Blind spot. See Optic disk Blink re ex. See Corneal (blink) re ex Bone(s). See also speci c bone – of calvaria, 24f – compact, 193f – cranial – anterior view of, 20f–21f – developm ent of, 16–17, 16t – left lateral view of, 16f, 18f–19f – ossi cation of, 16f, 16t – posterior view of, 22f–23f – synostosis of, 17f – of hard palate, 39f – of skull base, 26f, 27, 27f, 28, 28f – spongy, 193f Botulinum toxin (Botox™), 144

Bouton(s), 73, 73f Bowm an gland, 183f Brachial plexus, 72f, 299f, 323f, 324, 324f, 325, 325f, 326, 327f, 329, 329f, 359f, 369, 383, 383f, 412f, 416f, 419f–421f, 426f, 430f – anterior view of, 400f–401f – branch(es), 400, 400t – cord(s) of, 400, 400f, 400t – lateral, 400, 400f, 400t, 401f – medial, 400, 400f, 400t, 401f – posterior, 400, 400f, 400t, 401f – term inal branches of, 401, 401f – course of, 401, 401f – infraclavicular part, 400, 400t – nerves of, 400, 400f, 400t, 401f – structure of, 401, 401f – supraclavicular part, 400, 400t – trunk(s) of, 400 – lower, 401f – m iddle, 401f – upper, 401f Brachiocephalic trunk, 48, 49f, 139f, 225f, 323f, 325f, 333f, 341f, 356f–357f, 398f, 401f, 412f–414f, 416f, 418t, 420f, 422f, 426f, 430f, 434f, 437f Brain, 72, 72f – blood supply to, 61, 61f, 325 – developm ent of, 5, 5f, 5t – gyri of, 81, 81f. See also Gyrus (pl., gyri) – hem ispheres of, 78, 78f. See also Hem isphere(s) – herniation of, 103, 103f – axial, 103, 103f – bilateral uncal, 103 – lateral, 103, 103f – tonsillar, 103 – inferior view of, 118, 118f, 119, 119f – lobes of, 81, 81f – sulci of, 81, 81f. See also Sulcus (pl., sulci) – venous drainage of, 66 Brain death, 257 Brainstem , 5t, 72, 78, 84, 84f–85f, 417t – adult, cranial nerve nuclei, topographic arrangem ent of, 116, 116f – anterior view of, 89f, 120f, 130f, 136f – and balance, 281, 281f – em bryology of, 116, 116f – external structure of, 88–89, 88f–89f – functional organization of, 88 – infarction of, 103 – left lateral view of, 89f – left posterolateral view of, 119, 119f – lesions of, 88, 343f, 343t – levels of, 88, 88f – organization of, 88–89, 88f–89f – parasympathetic nuclei in, 84, 85f – posterior view of, 89f, 140f – in sensorim otor system , 109, 109f Brainstem re ex(es), 257, 257f Breast, fem ale, 406–407, 406f–407f – anterior view of, 406, 406f – blood supply to, 406, 406f – connective tissue of, 407f – duct system of, 407, 407f – lobes of, 407, 407f – lobules of, 407, 407f – lymphatic drainage of, 407, 407f – sagit tal section, 407, 407f – sensory innervation of, 406, 406f – structures of, 407, 407f – term inal duct lobular unit of, 407, 407f Breast cancer, 407 Bregm a, 17f, 25f Bridging veins, 98, 102f – rupture of, 103, 103f Brodm ann areas, 81, 81f, 254, 276 – 28. See Prepiriform area

Bronchial carcinom a, 343f, 343t Bronchomediastinal trunk, 71t, 413f Bronchus (pl., bronchi) – lobar – inferior, 419f–420f, 430f, 434f–435f – m iddle, 420f, 435f – superior, 419f–420f, 430f, 434f–435f – m ain, 414f, 416f, 418f, 421f, 419f, 431f, 436f–437f – venous drainage of, 415t Bruxism , 161 Buccal fat pad, 144f, 227f, 350, 350f, 363f Buccal frenulum , 184f Buccal gland(s), innervation of, 128, 133, 136t Buccal m ucosa, lym phatic drainage of, 71t Buccal space, 226f, 226t, 227f, 227t Buccal vestibule – inferior, 348f – superior, 348f Bulbourethral gland(s), 464f Bulbus cordis, 423 Bundle, – atrioventricular (AV) (of His), 427f – branch, 427f – interatrial, 427f – internodal, 427f – m edial forebrain bundle, 182 – olivocochlear, 277, 277f Burning m outh syndrom e, 106

C Calcorine sulcus, 81f Caldwell-Luc procedure, 177, 177f Caloric testing, 270 Calvaria, 103f, 151f – anterior view of, 146f – bones of, 24f – diploë of, 24f, 151f – external surface of, 25, 25f – inner table of, 24f, 151f – sensitivit y to traum a, 24f – internal surface of, 25, 25f – layers of, 24f – outer table of, 24f, 151f Canal(s) – anal. See Anal canal – auditory. See External auditory canal; Internal auditory canal – carotid, 27f, 33, 33f, 164f, 215f, 221f, 364 – neurovascular pathways through, 44f, 45t – central, of spinal cord. See Central canal – cochlear, compartm ents of, 274, 274f – condylar, 34 – anterior, 34f, 141f – neurovascular pathways through, 44f – posterior, 27f, 34f – neurovascular pathways through, 45t – ethm oidal – anterior, 231t – posterior, 231t – external auditory. See External auditory canal – facial, 131, 267, 267f – hiatus of, 29f – prom inence of, 266f – greater palatine, 39f, 168t, 169f, 169t – greater petrosal, 131 – hiatus of, 131f – neurovascular pathways through, 45t – hyaloid, 245, 245f – hypoglossal, 29f, 34, 34f, 293f, 364, 372f

526

ERRNVPHGLFRVRUJ

Index

– neurovascular pathways through, 44f, 45t – venous plexus of, 44f, 45t, 67f – incisive, 23f, 27f, 39, 39f, 172f–173f, 178f, 180f – neurovascular pathways through, 44f, 45t – infraorbital, 228, 228f–230f, 238, 238f, 348, 348f, 352–353, 363, 363f, 371, 371f – internal auditory. See Internal auditory canal – lesser petrosal, 133 – hiatus of, neurovascular pathways through, 44f, 45t – m andibular, 40, 158, 163f, 188f, 348, 349f–350f, 379f – on dental panoram ic tomogram (DPT), 200f – nasolacrim al, 176t, 231t, 242f – developm ent of, 12 – opening of, 176f – optic, 29f, 30, 31f, 39f, 119, 119f, 121, 124f, 228, 229f–230f, 231t, 232, 234, 237f, 353, 361, 361f – neurovascular pathways through, 44f, 45t – neurovasculature in, 238, 238f – palatovaginal (pharyngeal), 168t, 169f, 169t – pharyngeal, 27f – pterygoid (vidian), 31f, 39f, 133f, 168t, 169f, 169t – pyloric, 446f – root. See Tooth, root canal(s) of – sacral, 285f – of Schlem m , 244, 244f, 248f, 250f, 251, 251f – sem icircular. See Sem icircular canal(s) – vertebral, 284, 289, 289f, 294 – vom erovaginal, 27f – zygom aticofacial, 231t – zygom aticotemporal, 231t Canaliculus (pl., canaliculi) – lacrim al – com m on, 243, 243f – inferior, 242, 242f–243f – superior, 242, 242f–243f – mastoid, 33f – t ympanic, 27f, 33f, 137f, 266f, 267, 267f Canine(s), 41f, 190, 190f – deciduous, 198, 198f – mandibular, 194 – m orphology of, 196, 196f, 197t – maxillary, m orphology of, 194, 194f, 195t Canine space, 226f, 226t, 227f, 227t Canthomeatal plane, 270f Canthus – lateral canthus, 241f – medial, 241f – lymphatic drainage of, 71t Capitate, 389f, 396f Cardiac conduction system , 427, 427f Cardiac prom inence, 3, 3f, 6, 6f, 12-14f Cardiac valves, 424, 424f Caries – on bitewing radiograph, 201, 201f – detection of, on radiograph, 201, 201f Carotid bifurcation, 48, 48f, 60f, 100f, 329f – atherom atous m aterial at, 100f Carotid body, 48, 48f, 136t, 137f, 137t, 139t, 224f, 328f–329f, 332f Carotid bruit, 50 Carotid sheath, 158t, 299, 299f, 314–315, 320f, 320t, 321, 321f, 329, 332, 334,

346, 346f, 364–366, 366f, 367, 368f, 369, 373 Carotid siphon, 351, 357f, 380 Carotid sinus, 136t, 137f, 137t, 329, 329f – m assage of, 329 Carotid triangle, 318f, 318t, 319f, 328, 328f – lateral view of, 328, 328f Cartilage – alar, 146f, 364f – m ajor, 172f – lateral crus, 172, 172f – m edial crus, 172, 172f–173f – m inor, 172f – arytenoid, 7t, 336, 336f, 337, 337f, 355, 355f, 366, 366f, 368, 368f – anterolateral surface of, 337, 337f – apex, 337, 337f – colliculus, 337f – m edial surface of, 337, 337f – m uscular process, 337, 337f–338f – posterior surface of, 337, 337f – vocal process, 336f, 337, 337f–339f – auricular, 264, 264f, 364f – corniculate, 7t, 336, 336f, 337, 337f – costal, 402f–404f, 439f – cricoid, 7f, 7t, 185f, 219f, 336f, 337, 337f, 340f, 345f, 354, 354f, 369f, 374, 374f, 430f–431f – arch of, 337f–339f, 369f – articular facet s, 337f – lam ina of, 338f, 368f, 382f – posterior, 337f – cuneiform , 7t – epiglot tic, 219f, 336, 336f, 337, 337f–338f, 340f, 366f–367f, 374f, 377f – laryngeal, 336f, 376f – Meckel’s, 7f, 7t – nasal, 172, 172f – lateral, 172, 172f – septal, 172, 172f, 173, 173f – posterior process, 173f – thyrohyoid, 354f–355f, 355 – thyroid, 7f, 7t, 11f, 219f, 313f, 322f–324f, 336, 336f, 337, 337f, 340f, 345f–347f, 366f–368f, 374, 374f, 377f, 412f, 414f, 418f–419f, 426f, 431f, 437f – inferior horn, 336f–338f – inferior thyroid tubercle, 337f – lam inae of, 337, 337f, 342f, 378f – oblique line, 336f–338f – superior horn, 336f–337f – superior thyroid tubercle, 337f – tracheal, 336f, 340f Cataract s, 249 Cauda equina, 72f, 74, 74f, 75, 75f Cavit y(ies) – abdom inopelvic. See Abdom inopelvic cavit y – am niotic, 2, 2f – dental. See Caries – infraglot tic, 340f, 340t, 354f – laryngeal – divisions of, 340, 340t – interm ediate, 340f, 340t – nasal. See Nasal cavit y – oral. See Oral cavit y – pericardial, 418f – peritoneal. See Peritoneal cavit y – pleural. See Pleural cavit y(ies) – thoracic. See Thoracic cavit y – t ym panic. See Tympanic cavit y C cells, 9t, 11 Cecum , 442t, 449f – blood supply to, 440, 440f–441f Celiac plexus, 139t Celiac trunk, 410f–411f, 411t, 413f–414f, 440, 440f, 440t, 441, 441f, 443f, 447f, 451f–452f, 453, 453f, 458f

– distribution of, 441, 441f Cem entoenam el junction, 192f, 192t, 198 Cem entum , 192, 192f, 192t, 193, 193f Central canal, 93, 93f–95f Central descending analgesic system , 107, 107f Central gray substance, 120f Central nervous system (CNS), 72, 72f – cells of, 73t – em bryology of, 4, 4f Central sulcus, 78f, 81f Central sympathetic tract, 90f–93f Central tegmental tract, 79f, 90f, 91, 91f Central venous catheterization, 62 Cerebellar cortex, 5t Cerebellar peduncle(s), 5t, 79, 79f, 89 – inferior, 79, 79f, 89, 89f, 92, 92f, 281f – m iddle, 79, 79f, 89, 89f – superior, 79, 79f, 89, 89f, 90, 90f–91f Cerebellopontine angle, acoustic neurom a in, 134, 134f Cerebellum , 5t, 72f, 78, 84f, 86t, 88f, 103, 103f, 360, 360f–362f, 363, 363f, 370, 370f, 372f, 377f, 379f – anterior view of, 79f – and balance, 281, 281f – developm ent of, 5, 5f – ssures of, 79 – horizontal, 79f – posterolateral, 79, 79f – prim ary, 79, 79f – occulus of, 134f – hem isphere(s) of, 79, 79f – herniation of, 79 – lobes of, 79 – anterior, 79, 79f, 381f – occonodular, 79, 79f, 280, 280f – posterior, 79, 79f, 363f, 371f–372f, 381f – lobules of – central, 79f – quadrangular, 79f – sem ilunar – inferior, 79f – superior, 79f – simple, 79f – in sensorim otor system , 109, 109f – superior view of, 79f Cerebral aqueduct, 84f, 88f, 90f, 91, 94f, 95, 95f, 120f, 261, 261f, 360f Cerebral cortex, 5t, 80, 80f, 86, 86f – arterial supply to, 96f – ascending tract s to, 86f – descending tract s from , 86, 86f – functional organization of, 81 – in sensorim otor system , 109, 109f – venous drainage of, 98, 98f Cerebral edem a, 78, 101, 103 Cerebral em boli, 100 Cerebral ischem ia, 100 Cerebral peduncle(s), 5t, 84, 84f, 89f, 99f, 120f, 360, 360f – com pression of, 103, 103f Cerebral venous throm bosis, 100–101, 101f Cerebrospinal uid (CSF) – excess, 95 – ow of, 94, 94f – obstruction of, 95 – leakage, from nose, 29, 35, 118 – production of, 94 – spaces, 94, 94f – volum e of, 94 Cerebrovascular disease, 100, 100f Cerebrum, 72f, 348f–350f, 351 – arteries of, 96, 96f – developm ent of, 5, 5f – functions of, 78t – gyri of, 78, 78f. See also Gyrus (pl., gyri)

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ERRNVPHGLFRVRUJ

– lobes of, 78, 78f – sensory pathways in, arrangem ent of, 105, 105f – sulcus/sulci of, 78, 78f. See also Sulcus (pl., sulci) – central, 78f, 81f – lateral, 78f, 81f, 276f – ventricular system and, 95 Cerum en, 263, 263f – im paction of, 263 Cerum en glands, of ear, 263, 263f Cervical exure, 5f Cervical region(s) (triangles), 318, 318f, 318t – anterior, 318, 318f, 318t, 322, 322f, 329 – lateral, 318f, 318t – deep, 329, 329f – posterior, 318, 318f, 318t, 319f, 326, 326f–327f, 329 – sternocleidom astoid, 318, 318f, 318t, 319f, 329 Cervical sinus, 8, 8f, 9t – ductal portions, rem nants of, 11, 11f Cervicofacial trunk, 154f Cervix, uterine, 442t, 465f Cham ber(s) (cardiac). See Atrium (pl., atria); Heart, cham bers of; Ventricle(s), cardiac Cham ber(s) (ocular) – anterior, 244, 244f, 248, 248f, 250, 250f, 251, 251f – posterior, 244f, 248, 248f, 250, 250f, 251, 251f Cham ber angle, 244, 244f, 250f, 251, 251f – obstruction of, 251, 251f Cheek(s) – developm ent of, 12, 12f, 12t – lymphatic drainage of, 71t Chem oreceptor(s) – of carotid body, 136t–137t, 139t – of para-aortic body, 138t, 139f Chest wall. See also Thoracic wall; Trunk wall – anterior, venous drainage of, 415t – inner, venous drainage of, 415t Chin – lym phatic drainage of, 71t – venous drainage of, 64t–65t Choana (pl., choanae), 39, 39f, 168f, 173, 173f, 177, 177f, 178, 178f–180f, 185f, 216f, 225f, 333f, 364, 364f, 376, 376f, 382 – blockage by enlarged tonsil, 217, 217f – developm ent of, 13, 13f Chondrocranium , bones of, developm ent of, 16f Chondro-osseous junction, 404f Chordae tendineae, 423f Chorda t ympani, 32, 32f, 33, 44f, 45t, 112t, 123t, 128, 128f, 129t, 130, 130t, 131, 131f, 133, 133f, 146, 159t, 164, 189f, 206–207, 207f, 208, 208f, 213t, 266f, 267, 267f, 269, 269f, 273f–274f – injury to, 269 Choroid (eyeball), 244, 244f, 247f, 248, 248f, 250, 250f, 253f Choroid plexus, 84f–85f, 92f, 94, 94f, 98f, 360f, 379f – cells of, functions of, 73t Cilia, olfactory, 183, 183f Ciliary body, 241f, 244, 244f, 250, 250f–251f, 252, 252f – pars plana, 248, 248f – pars plicata, 248, 248f – pigm ent epithelium of, 244, 244f – posterior view of, 248, 248f Ciliary gland(s), 241, 241f

Index

Ciliary process(es), 248, 248f Cingulate gyrus, 78f, 82f–83f, 83t, 86t, 108t, 353, 353f Circle of Willis, 49, 61, 61f Circle of Zinn and von Haller, 246f, 247, 247f Circular bers, 193f Circulation, 429, 429f – lower body, 429f – portal, 429f – postnatal, 429, 429f – prenatal, 428, 428f – pulm onary, 429, 429f – system ic, 429, 429f – upper body, 429f Cistern – am bient, 94f – basal, 94f – cerebellom edullary, 94f, 293f – chiasm atic, 94f – interhem ispheric, 94f – interpeduncular, 94f, 372f – of lamina term inalis, 94f – pontocerebellar, 363, 363f, 377f – pontom edullary, 94f – verm ian, 94f Cisterna chyli, 413, 413f Cisterna m agna, 94f, 372f Claustrum , 80f, 97f, 378f – arterial supply to, 96f Clavicle, 298f, 319, 319f, 321f, 323f, 326f, 355f, 383f, 387f, 391f–392f, 408f, 420f–421f – acrom ial end, 384f – articular surface of – acrom ial, 384f – sternal, 384f – conoid tubercle of, 384f – groove for subclavius m uscle, 384f – impression for costoclavicular ligam ent, 384f – inferior view of, 384, 384f – shaft of, 384f – sternal end, 384f – superior view of, 384, 384f Clavicular notch, 402f Cleidocranial dysostosis, 16t Clinical applications – abducent nerve palsy, 120t, 235, 235f, 235t – abducting nystagm us, 261, 261f – accessory nerve lesions, 140, 140f, 140t, 326 – acoustic neurom a, 134, 134f, 271 – acute m axillary sinusitis, 174 – adenoids, 217 – ageusia, 208 – alcoholism , 87 – alveolar bone resorption, 42 – alveolar ostitis, 190 – Alzheim er disease, 78, 82, 95 – am aurosis, 256 – amygdala dysfunction, 83 – anem ia, 241 – anhydrosis, 329 – anisocoria, 250 – ankyloglossia, 10 – anopias, 256, 256f – anorexia, hypothalam ic lesion and, 87t – anosm ia, 208 – anterior cerebral artery occlusion, 101, 101f – anxiet y, 83 – aortic aneurysm , 341, 343f, 343t – aphasia, 101, 101f – Argyll-Robertson pupil, 258 – arterioarterial em boli, 100, 100f – astigm atism, 245 – atheroma, 100

– atherosclerosis, 50, 314 – autonomic dysfunction, hypothalam ic lesion and, 87t – basal skull fractures, 136t – berry aneurysm s, 97 – bim anual exam ination of salivary glands, 213, 213f – bim anual palpation of m uscles of m astication, 163 – bladder dysfunction, 101, 101f – blindness, 247, 251, 256, 256f – unilateral, 259 – botulinum toxin (Botox™), 144 – brain death, 257 – brain herniation, 103, 103f – brainstem infarction, 103 – brainstem lesion, 88 – breast cancer, 407 – bruxism , 161 – burning m outh syndrom e, 106 – Caldwell-Luc procedure, 177, 177f – caloric testing, 270 – cardiac em boli, 100, 100f – carotid bruit, 50 – carotid sinus m assage, 329 – cataract s, 249 – cavernous sinus throm bosis, 63, 66t, 120t, 238 – central hypotherm ia, hypothalam ic lesion and, 87t – central lesions involving pain pathways, 106 – central venous catheterization, 62 – cerebellar herniation, 79 – cerebral edem a, 78, 101, 103 – cerebral em boli, 100 – cerebral hem orrhage in internal capsule, 105 – cerebral ischem ia, 100 – cerebral venous throm bosis, 100–101, 101f – cerebrospinal uid (CSF) leakage, 118 – from the nose, 29, 35 – cerebrospinal uid (CSF) sam pling, in infant, 17f – cerebrovascular disease, 100, 100f – cerum en impaction, 263 – cervical lymphadenopathy, 68–69, 69f – cervical spine injury, 288–289 – chorda t ym pani injury, 269 – chronic sinusitis, 176 – cleft lip, 15, 15f – cleft palate, 9, 15, 15f, 39 – cleidocranial dysostosis, 16f – cochlear implant, 276 – conductive deafness, 268 – confrontation test, 255, 255f – conjunctivitis (pink eye), 241 – corneal (blink) re ex, 146, 241, 241f, 249 – corneal transplant, 249 – cranial infections, venous anastom oses as portals of, 66t – cribriform plate fracture, 29, 35 – cricothyrotomy, 342, 342f, 344 – cyanosis, 184 – cysts and stulas in neck, 11, 11f – depression, 83 – deviations of nasal septum , 173 – diabetes insipidus, hypothalam ic lesion and, 87t – diabetic reinopathy, 247 – diplopia, 36, 120t, 232, 235, 235t – disease spread into and out of orbit s, 230 – dislocation of temporom andibular joint (TMJ), 165, 165f – dissection of face, 144 – dizziness, 131, 262

– – – – – – – –

drusen, 247 dry eye, 242 dysarthria, 227t dysphagia, 227t, 347 dysphonia, 347 dyspnea, 138t, 227t, 347 ectopic thyroid, 11, 347, 347f em aciation, hypothalam ic lesion and, 87t – endoscopic surgery of m axillary sinus, uncinate process as landm ark for, 35 – endotracheal intubation, 344, 344f, 345, 345f – enlarged cervical lymph nodes, 68 – enophthalm os, 329 – epidural anesthesia, 75, 75f – epidural hem atom a, 56, 103, 103f – esophageal diverticula, 431, 431f – extracerebral hem orrhages, 97, 103, 103f – facial clefts, 15, 15f – facial infections, 240 – facial lacerations, 144 – facial nerve lesions, 130t, 207 – facial nerve paralysis (Bell palsy), 131, 131f, 146 – facial paralysis, 132, 132f, 241, 243 – facial swelling, 144 – fetal head in childbirth, posterior fontanelle as reference point for, 17f – frostbite of auricle, 264 – gaze deviations, 235, 235f, 235t – Gillies technique, 36 – glaucom a, 250t, 251, 251f – globe rupture, 244 – glossopharyngeal nerve lesions, 136t, 217 – goiter, 323, 346 – head injury, 35 – frontal, 29 – hearing loss, 131, 263, 271 – hem ianopia, 101, 101f, 256, 256f – bitemporal, 256, 256f – hem iparesis, 101, 101f, 103 – hem isensory de cit, 101, 101f – hippocam pal lesions, 82 – hoarseness, 138t – Horner syndrom e, 250t, 329 – hydrocephalus, 22f, 95 – hyperacusis, 131 – hyperopia (farsightedness), 245, 245f – hypertension, 97 – hypoglossal nerve lesions, 141, 141f, 141t – hypoglossal nerve palsy, unilateral, 205, 205f – hyponatrem ia, hypothalam ic lesion and, 87t – hypothalam ic lesions, 87, 87t – hypotherm ia, hypothalam ic lesion and, 87t – inadvertent parathyroid gland rem oval, 346 – increased intracranial pressure, 79, 94, 103 – indirect laryngoscopy – technique for, 339f – and vocal fold position, 339f – inferior alveolar nerve block, 214 – inner table of calvaria, sensitivit y to traum a, 24f – internal carotid artery aneurysm , 120t, 238 – internuclear ophthalm oplegia, 261, 261f – intracerebral hem orrhage, 97, 256 – intracranial hypertension, 247 – keratoconjunctivitis sicca, 242 – Korsako syndrom e, 87

– kyphosis, 284 – laryngeal edem a, 340 – lateral approach to pterygopalatine fossa, 168, 168f – Le Fort classi cation of m idfacial fractures, 20f – lingual thyroid, 11, 347, 347f – lordosis, 284 – loss of pupillary light response, 259 – loss of vision, 119 – lower denture design, 40 – Ludwig’s angina, 227t – lum bar anesthesia, 75, 75f – lum bar puncture, 74–75, 75f, 103 – lupus, 242 – m acular degeneration, 247 – m am m illary body lesions, 87 – m andibular fracture, 43, 43f – m andibular traum a, 164 – m axillary artery ligation, 59 – m axillary sinus endoscopy, 177, 177f – m ediastinitis, 334 – m em ory loss, 82 – in Korsako syndrom e, 87 – m eningitis, 29, 32, 63, 102, 120t, 151, 331, 334 – m etastatic cancer, lymph node involvem ent in, 69–70 – m icrocephaly, 22f – m iddle cerebral artery occlusion, 101, 101f – m igraine, 102, 250t – m iosis, 250, 250f, 329 – m iotic agent s, 250t – m ultiple sclerosis, 232, 261 – m umps, 322 – mydriasis, 113t, 120t, 235, 235f, 235t, 250, 250f – mydriatic agent s, 250t – myopia (nearsightedness), 245, 245f – nasal bone fractures, 37 – nasopharyngeal bleeding, 59 – neck dissection, 68 – newborn hearing screening, 277 – nosebleed, 181 – obesit y, hypothalam ic lesion and, 87t – obstruction of lacrim al drainage, 243, 243f – oculomotor palsy, 120t, 232–233, 235, 235f, 235t, 241, 250t – ophthalm oscopic exam ination, 247, 247f – optic nerve lesions, 119, 361 – optokinetic nystagm us, 257 – oral cancer, 185, 185f – oral dysesthesia, 106 – orbital fractures, 230 – oro-antral stula, 174 – otitis m edia, 269 – otoacoustic em issions, 277 – otoscopy, 263, 263f – palpation of cervical lymph nodes, 69, 69f – palpation of occipital nerves, 331, 331f – papilledem a of optic disk, 247 – Parkinson disease, 80 – parotid duct m alignancy, 212 – parotid gland swelling, 322 – perim etry, 255 – periodontitis, 193 – persistent thyroglossal duct, 346 – phobias, 83 – Pierre-Robin syndrom e, 9 – plasmacytom a, 24f – polythelia, 406 – posterior cerebral artery occlusion, 101, 101f – post-traum atic stress disorder, 83

528

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Index

– prem ature closure of cranial sutures, 22f – ptosis, 120t, 235t, 241, 329 – “punched-out lesions” in skull, 24f – quadrantanopia, 256, 256f – recurrent laryngeal nerve injury, 416 – recurrent laryngeal nerve palsy, 138t, 338t, 341, 347 – retinal detachm ent, 247, 253 – rheum atoid arthritis, 242 – rhinoscopy, 179, 179f – root canal infection, 201, 201f – ruptured cerebral aneurysm , 103, 103f – salivary gland tum ors, 212 – scalp infections, 151 – scalp lacerations, 151 – scoliosis, 284 – scotom as, 256, 256f – sensorineural deafness, 270 – sensory ataxia, 109 – sentinel node, 69 – sepsis, 63 – sinusitis, 174–177 – skull base fractures, 28f – spina bi da, 4 – spinal cord lesions, e ect s of, 77, 77f – spread of dental infections, 226, 226f – route of, from source, 227, 227f, 227t – spread of infections – peripharyngeal space and, 334, 334f – potential routes for, 320–321 – spread of nasopharyngeal infections, 266 – squam ous cell carcinom a of vocal folds, 343 – stapedius paralysis, 131 – stapedius re ex test, 269, 277 – sternocleidom astoid paralysis, 140t – stroke, 97, 100–101, 101f, 314 – subarachnoid hem orrhage, 97, 103, 103f – subdural hem atom a, 98, 103, 103f – subdural hem orrhage, 120t – swelling of neck veins, 328, 328f – syphilis, 258 – temporal arteritis, 58 – temporal bone fractures, 130t, 131 – tetany, 346 – thalam ic lesions, 86 – thyroidectomy, 347 – thyroid gland enlargem ent, 346 – tonsillectomy, 217, 335 – tonsillitis, 217 – tori, 39 – torticollis, 140, 140f, 140t – congenital, 297 – torus m andibularis, 39 – torus palatinus, 39 – tracheostomy, 344 – tracheotomy – high, 342, 342f – low, 342, 342f – transient ischem ic at tacks, 314 – transnasal surgical procedures on pituitary, 175 – trapezius paralysis, 140t – traum atic spondylolisthesis, 288 – Treacher Collins syndrome, 9 – trigem inal nerve lesions, 207 – trigem inal neuralgia, 122t – trism us, 36, 43, 161, 227t – trochlear nerve palsy, 120t, 235, 235f, 235t – tuberculous osteomyelitis of cervical spine, 321 – tum ors of pterygopalatine fossa, 168 – vagus nerve lesions, 138t, 343, 343f, 343t – venous catheterization, 62

– vertigo, 270, 281 – vestibular nystagm us, 270 – vestibular schwannom a, 134, 134f, 271 – vestibulocochlear nerve lesions, 135t – visual eld defect s, 256, 256f – visual eld exam ination, 255, 255f – visual pathway lesions, 256, 256f – vitam in B1 (thiam ine) de ciency, 87 – vitrectomy, 245 – vocal fold pathology, 343, 343t – wasting diseases, 350 – watery eye, 242 – whiplash injury, 288 – xerostom ia, 242 – zygomatic arch displacem ent, 36f – zygom atic (m alar) bone fracture, 36 – zygom atic fractures, 36 Clinoid process – anterior, 29f, 30, 31f, 39f – posterior, 29f, 31f Clitoris, crus of, 465f Clivus, 29f, 178f, 232f, 362, 362f–363f, 370f, 376f, 380f Coccyx, 284f, 463f Cochlea, 134f, 262f, 266f, 270, 270f, 274f, 277f, 370f. See also Modiolus – location of, 274, 274f – structure of, 274, 274f – traveling wave in, form ation of, 275, 275f Cochlear aqueduct, 266f, 270, 270f, 273f Cochlear canal, 274, 274f Cochlear duct, 270, 270f, 274, 274f, 276, 276f Cochlear implant, 276 Cochlear labyrinth, 270 Colic exure – left (splenic), 441f, 444f–445f, 448f, 449, 449f, 451f, 455f, 461f – blood supply to, 440, 440f – right (hepatic), 446f–448f, 449, 449f, 451f – blood supply to, 440, 440f Colliculus (pl., colliculi) – facial, 89f – inferior, 84f, 89, 89f – brachium of, 85f, 89f–90f – comm issure of, 276f – quadrigem inal plate, 89f – superior, 84f, 89, 89f, 119f – brachium of, 89f – quadrigem inal plate, 89f – in visual pathway, 257, 257f Colon, 448f – ascending, 442t, 444f, 446f–448f, 449, 449f, 455f – blood supply to, 440, 440f–441f – autonom ic innervation of, 110f – descending, 442t, 445f–448f, 449, 449f, 455f, 461f – blood supply to, 440, 440f–441f – sigmoid, 442t, 445f, 449f, 455f, 464f–465f – blood supply to, 440, 440f–441f – transverse, 442t, 443f, 444, 444f–445f, 447f–449f, 455f, 461f – blood supply to, 440, 440f–441f Com m on tendinous ring, 121, 121f, 232, 232f, 234, 234f, 235t, 238, 238f Concha – of auricle, 264f – nasal. See Nasal concha (pl., conchae) Cones, 119, 253–254, 254f Confrontation test, 255, 255f Conjunctiva, 251f – anatomy of, 241, 241f – arterial supply to, 61t – fornical, 241, 241f – goblet cell distribution in, 243, 243f

– in am m ation of (conjunctivitis), 241 – ocular, 241, 241f, 244f, 248f, 250f – palpebral, 241, 241f – tarsal, 241, 241f – venous drainage of, 64t Conjunctival fornix – inferior, 241, 241f – superior, 241, 241f Conjunctival sac, 241 Connecting stalk, 3f, 6f Conus arteriosus, 423, 423f Conus elasticus, 337f–338f, 340f, 343f Conus m edullaris, 74f, 75, 75f Copula, 10, 10f, 10t Cornea, 244, 244f–245f, 247f, 250, 250f–251f – basem ent m em brane of, 249, 249f – endothelium of, 249, 249f – epithelium of, 249, 249f – position of, 248, 248f – refractive power of, 249 – strom a of, 249, 249f – structure of, 249, 249f – transplantation of, 249 Corneal (blink) re ex, 146, 241, 241f, 249 – neural pathway for, 257, 257f Corneoscleral lim bus, 244, 244f Corniculate cartilage. See Cartilage, corniculate Corniculate tubercle, 216f, 225f, 333f, 335f, 338f–340f, 345f Coronal sutures. See Sutures, coronal Corpus callosum , 78f, 82, 82f–83f, 84, 84f–85f, 95f, 97f, 351f, 376, 376f, 380f–381f – arterial supply to, 96f – venous drainage of, 98 Coronary sinus, 422f, 424f–425f, 425t – valved ori ce of, 423f Coronary sulcus, 422f–423f Corpus striatum , 80, 80f Cortical areas, 81, 81f Cortical elds, 81, 81f Corticobulbar bers, 140f–141f Corticonuclear bers, 108f, 108t, 109, 109f, 261f Corticopontine tract, 90f Corticoreticular bers, 108t Corticospinal bers, 108f, 108t, 109 Corticospinal tract(s), 109, 261f – anterior, 108f, 108t, 109f – lateral, 108f, 108t, 109f Corti organ. See Organ of Corti Corti tunnel, 274f Costal angle, 402f–403f Costal cartilage. See Cartilage, costal Costal m argin, 402f Costal tubercle, 402f–403f Costocervical trunk, 49t, 314f, 314t, 325, 325f Costodiaphragm atic recess, 432f, 434f – coronal section, anterior view of, 432, 432f Costom ediastinal recess(es), 432f–433f Cranial arteritis. See Temporal arteritis Cranial exure, 5f Cranial nerves. See Nerves, cranial Cranial sutures. See Sutures, cranial Craniosynostosis (pl., craniosynostoses), 17f, 22f. See also Suture(s), cranial Cranium . See also Skull – left lateral view of, 18f–19f Crest(s) – alveolar, 193f – ampullary, 270f, 278f, 280, 280f – structure of, 278, 278f – frontal, 25, 25f, 29f – iliac, 298f, 301f, 305f, 462f–463f – infratemporal, 27f

529

ERRNVPHGLFRVRUJ

– lacrim al – anterior, 146f, 229f – posterior, 146f, 229f – nasal, 173f – nasal (palatine bone), 39f – neural, 2, 2f, 2t – cranial bones form ed from , 16t – derivatives of, 13 – developm ent of, 4, 4f – occipital – external, 23f, 34f, 294f – internal, 29f, 34f, 292f – sacral, 284f–285f, 285t – sphenoid, 31f, 173f – supramastoid, 156f, 157t – supraventricular (cardiac), 423, 423f Cribriform layer, 193f Cricoid cartilage. See Cartilage, cricoid Cricothyrotomy, 342, 342f, 344 Crista galli. See Ethm oid bone, crista galli Crista term inalis, 423f Crossbite, 195 Crown. See Tooth, crown of Cruciform em inence, 34, 34f Culm en, 79f Cuneiform cartilage. See Cartilage, cuneiform Cuneiform tubercle, 216f, 225f, 333f, 335f, 338f–340f Cuneocerebellar tract(s), 104, 104f Cupula, 278, 278f, 432f Cyanosis, 184 Cym ba conchae, 264f Cyst(s), in neck, 11, 11f Cystic duct, 450f–451f Cytoarchitectonics, 81

D Dark cell(s) – olfactory, 183f – taste, 209, 209f Deafness. See also Hearing loss – conductive, 268 – sensorineural, 270 Deltoid tuberosit y, 386f, 392f Dendrite(s), 73, 73f – apical, in olfactory bulb, 183, 183f Dental panoram ic tom ogram (DPT), 200, 200f Dentate gyrus, 82, 378f Dentine, 192, 192f, 192t, 193f – intratubular, 192t – peritubular, 192t Dentition. See also Teeth – rst, 199, 199t – second, 199, 199t Dentogingival bers, 193, 193f Denture(s), lower, design of, 40 Depression, 83 Derm atom e(s), 3, 3f, 77, 77f – of posterior neck, 331, 331f Derm is, 3f Desmocranium , bones of, developm ent of, 16f Developm ent, 3-16. See also speci c structures Diabetes insipidus, 87t Diabetic retinopathy, 247 Diagonal band of Broca, 83t Diaphragm , 409f, 412f–416f, 418f–421f, 430f–432f, 434f, 446f – action of, 408t – anterior view of, 408, 408f, 410f – apertures in, 408 – arteries of, 411f, 411t – blood vessels of, 411f, 411t – caval opening in, 408, 408f, 411f, 416f, 419f, 438f

Index

– – – – – – –

central tendon of, 408f–409f, 411f, 438f on coronal section, 408, 408f costal part, 408f, 408t, 411f, 438f crus of, 408f, 438f dom es of, 408, 408f inferior view of, 411f innervation of, 316, 324–326, 410, 410f–411f, 416 – lumbar part, 408f, 408t, 411f, 438f – nerves of, 411f – neurovasculature of, 410, 410f – posterior view of, 408, 408f – sternal part, 408f, 408t – superior view of, 411f – venous drainage of, 415t Diaphragma sellae, 102, 102f Diastole, ventricular, 424f Diencephalic sulcus, ventral, 84f Diencephalon, 5, 5f, 5t, 72, 78, 80f, 84, 84f–85f, 86, 88, 88f, 89, 360. See also Hypothalam us; Thalam us; Epithalam us; Subthalam us – functions of, 85t – internal structure of, 85f – somatom otor zone of, 85t – structures of, 85t – venous drainage of, 98 – ventricular system and, 95 Diplopia, 36, 120t, 232, 235, 235t Diverticulum (pl., diverticula) epiphrenic (esophageal), 431, 431f – esophageal, 431, 431f – “false” pulsion (esophageal), 431, 431f – hypopharyngeal (pharyngoesophageal), 431, 431f – parabronchial (esophageal), 431, 431f – “true” traction (esophageal), 431, 431f – Zenker’s, 431, 431f Dizziness, 131, 135t, 262. See also Vertigo Dorsal longitudinal fasciculus, 90, 90f Dorsal root ganglion, 3, 3f Dorsal trigem inothalam ic tract, 208, 208f Dorsum sellae, 28, 28f, 31f, 174f, 178f, 361f, 370f Double vision. See Diplopia DPT. See Dental panoram ic tom ogram (DPT) Drusen, 247 Ductus arteriosus, 428, 428f – in postnatal circulation, 429, 429f Ductus deferens, 443f, 464f, 467f – ampulla of, 464f Ductus reuniens, 270, 270f, 278f Ductus venosus, 428, 428f – in postnatal circulation, 429, 429f Duodenal recess – inferior, 445f – superior, 445f Duodenojejunal exure, 448f–449f, 461f Duodenum , 442t, 443f, 446f, 449, 449f, 453f–454f, 461f – anterior view of, 449, 449f – ascending part, 449, 451f – blood supply to, 440, 440f–441f – circular folds of, 449f – descending part, 447f, 449, 449f, 451f, 461f – horizontal part, 442t, 443f, 448f, 449, 449f, 451f – m uscular coat of – circular layer, 449f–450f – longitudinal layer, 449f–450f – opened, 449, 449f, 451, 451f – subm ucosa of, 449f – superior part, 448f, 449, 449f, 451f – wall of, sphincter system of, 450f Dural septa, 102, 102f Dura m ater, 24f, 102, 102f–103f, 163f, 270f–271f

– endosteal layer of, 24f – m eningeal layer of, 24f, 151f – periosteal layer of, 151f – spinal, 74f–75f Dysarthria, 227t Dysphagia, 217, 227t, 347 Dysphonia, 347 Dyspnea, 138t, 227t, 347

E Ear(s) – developm ent of, 13, 13f, 13t – em bryology of, 3f – external, 262, 262f, 264–265, 264f–265f, 266, 266f – venous drainage of, 272 – inner, 262, 262f, 266, 266f, 270, 270f. See also Vestibular apparatus – anterior view of, 273, 273f – arteries of, 272, 272t, 273, 273f – m uscles of, 269, 269f – projection onto bony skull, 270, 270f – sound conduction to, 275, 275f – veins of, 272–273, 273f – vestibule of, 262f, 266f, 270f – lymphatic drainage of, 70, 70f, 71t, 265, 265f – anterior zone of, 70, 70f – lower zone of, 70, 70f – posterior zone of, 70, 70f – m iddle, 262, 262f, 266, 266f, 268, 268f – arteries of, 272–273, 272f–273f, 272t – lymphatic drainage of, 71t – sound conduction in, to inner ear, 275, 275f Earlobe, 264f Ectoderm , 2, 2f, 6, 6f – derivatives of, 2t, 9t, 13t – neural crest cell, derivatives of, 13t – surface, 2f, 2t, 3f – derivatives of, 13t Ectopic thyroid, 11 Edem a – cerebral, 78, 101, 103 – laryngeal, 340 – subglot tic, 343f Em aciation, hypothalam ic lesion and, 87t Em bolus (pl., em boli), 100, 100f – arterioarterial, 100, 100f – cardiac, 100, 100f – cerebral, 100 Em bryo, 2, 2f – 5-week-old, 3, 6, 6f Em bryonic disk, 2 Em issary vein(s), 24f, 33, 44f, 45t, 63f, 66f, 66t, 67, 67f, 151f, 158t – condylar, 44f, 45t, 66f, 66t, 67f, 378f – posterior, 365f – foram en for, 37f – m astoid, 45t, 66f, 66t, 67f – occipital, 66f, 66t, 67f – parietal, 66f, 66t, 67f – sphenoidal, 63f, 67, 67f, 187f Enamel, 192, 192f, 192t, 193f Endoderm , 2, 2f, 6, 6f – derivatives of, 2t, 9t, 13t Endolym ph, 270, 274, 278 Endolym phatic duct, 270, 270f, 278f Endolymphatic sac, 266f, 270, 270f–271f, 278f Endolymphatic space, 270, 274 Endoneural space, 94f Endothelium , corneal, 249, 249f Endotracheal intubation, 344, 344f, 345, 345f – equipm ent for, 344, 344f – head positioning for, 344, 344f Endotracheal tube(s), 344, 344f

– cu , 345, 345f Enophthalm os, 329 Ependym a, 95 Ependym al cells, functions of, 73t Epicranial aponeurosis, 144f, 145, 145f, 150f, 151, 151f Epiderm is, 3f Epidural anesthesia, 75, 75f Epidural hem atom a, 56, 103, 103f Epidural space, spinal, 75, 75f Epiglot tic cartilage. See Cartilage, epiglot tic Epiglot tic tubercle, 339f Epiglot tis, 10f, 178f, 185f, 202f, 203t, 208f–209f, 216f–217f, 225f, 333f, 335f–336f, 339, 339f, 340, 340f, 342f, 344f, 351, 351f, 355, 373f, 376, 376f, 382f – innervation of, 208 – laryngoscopic view of, 345, 345f – stalk of, 337f – swelling of, 10f, 10t – taste bers, 133 Epipharynx, 216t Epiphysis, 84f Episcleral space, 236, 236f Epistaxis, 36–37 Epithalam us, 5t, 84 – functions of, 85t – structures of, 85t Epithelium – alveolar, 193, 193f – of ciliary body, 244, 248f – corneal, 249, 249f – gingival, 193, 193f – of iris, 244 – junctional, gingival, 193, 193f – of lens, 248–249, 249f – lingual, 202, 202f – olfactory, 13 – pigm ent(ed) – of ciliary body, 244, 244f – of iris, 251, 251f – retinal, 244, 252, 252f, 253, 253f – pseudostrati ed ciliated (“respiratory”), 179, 179f – respiratory, ciliated, 343f – retinal, 252, 252f – pigm ent(ed), 244, 252, 252f, 253, 253f – squamous, strati ed nonkeratinized, 343f – sulcular, 193f – of tongue, 209f Epit ympanum , 269, 269f Erb’s point, 317f, 326, 326f Erythroplakia, 185 Esophageal diverticula, 431, 431f Esophageal hiatus, in diaphragm , 408f, 411f, 431, 431f, 438f Esophageal inlet, 418f, 430f Esophageal plexus, 111t, 139t, 416f–417f, 430f – anterior, 139f Esophageal wall, 431, 431f Esophagogastric junction, 431, 431f Esophagus, 185f, 216f, 218f, 220f, 224f, 299f, 320t, 321, 325f, 332f, 335f, 340, 340f, 342f, 344f–345f, 358f, 369f, 374f, 375, 375f, 382, 382f, 409f, 411f, 412t, 414f, 418f, 418t, 420f–421f, 433f–434f, 443f, 446f, 451f–452f, 458f – abdom inal part, 430, 430f–431f – anterior view of, 430, 430f – blood supply to, 440, 440f–441f – cervical part, 416f, 418f–419f, 430, 430f – circular m uscle bers of, 223f – constrictions of, 430, 430f

– – – –

em bryology of, 8f location of, 430, 430f lymphatic drainage of, 71t m ucosa of, 431f – longitudinal folds, 431f – m uscle of, functional architecture of, 431f – m uscular coat of – circular layer, 223f, 431f – longitudinal layer, 431f – pharyngeal com m unication, 216t – structure of, 431, 431f – subm ucosa of, 431f – thoracic part, 416f, 418f–419f, 430, 430f–431f, 434f – venous drainage of, 415t Ethm oid bone, 18f–21f, 28f, 37f–38f, 168f, 172, 172f, 175, 175f, 228, 230f – canal, – anterior, 231t – posterior, 231t – cribriform plate, 29, 29f, 35, 35f, 118, 118f, 124f, 126f, 173f, 175, 175f–176f, 180f, 181, 181f, 183, 183f, 239f – fracture of, 29, 35 – neurovascular pathways through, 44f, 45t – crista galli, 29f, 35, 35f, 102f, 173f–176f, 230f, 349f, 360, 360f – developm ent of, 16t – isolated – anterior view of, 35, 35f – left lateral view of, 35, 35f – posterior view of, 35, 35f – superior view of, 35, 35f – m iddle concha, 35f – orbital plate, 35, 35f, 175, 175f, 228f, 230f, 348, 348f, 353f – perpendicular plate, 21f, 35, 35f, 39f, 172f–175f, 230f, 348f – position in facial skeleton, 35, 35f – position in interior skull base, 35, 35f – superior concha, 35, 35f – superior m eatus, 35f – uncinate process, 35, 35f, 175, 175f–176f, 179f – as landm ark for endoscopic surgery of m axillary sinus, 35 Ethm oid bulla, 35f, 174f, 175, 176f Ethm oid infundibulum , 177f Eustachian tube. See Pharyngot ympanic (auditory/Eustachian) tube External acoustic opening, 33f External auditory canal, 262, 262f, 264f, 266f, 364f – bony part, 263, 263f – cartilaginous part, 263, 263f – coronal section, anterior view of, 263, 263f – curvature of, 263, 263f – developm ent of, 11, 11f – innervation of, 138t, 139f – lym phatic drainage of, 70, 70f, 265, 265f External basal layer, 193f External capsule, 80f, 378, 378f Extrapyram idal m otor system , 108f, 108t Extrem e capsule, 80f, 378f Eye(s) – anterior view of, 232, 232f, 240–241, 240f–241f, 242, 242f – autonom ic innervation of, 110, 110f – axes of, 258, 258f – blood supply of, 61t – cham bers of. See Cham ber(s) (ocular) – color of, determ ination of, 251 – developm ent of, 13, 13f, 13t – dry (xerophthalm ia), 242 – embryology of, 3f, 5f

530

ERRNVPHGLFRVRUJ

Index

– fundus of, ophthalm oscopic exam ination of, 247, 247f – globe rupture, 244 – lateral view of, 232, 232f, 234, 234f – light refraction in, 245, 245f – norm al (em m etropic), 245f – optical axis of, 245, 245f – orbital axis of, 245, 245f – reference lines on, 245, 245f – sagit tal section of, 249, 249f, 252, 252f – surface anatomy of, 241, 241f – transverse section, 248, 248f – at level of optic nerve, 247f – superior view of, 250, 250f – venous drainage of, 64, 64f, 64t–65t – watery, 242 Eyeball, 236, 236f, 239f, 244–245, 244f–245f, 352f, 370f, 378, 378f, 379 – arterial supply to, 61t – equator of, 245, 245f – layers of, 244, 244f – m eridians of, 245, 245f – sagit tal section of, 252, 252f – transverse section, superior view of, 244, 244f, 245, 245f – venous drainage of, 64t Eyebrow, 241f Eyelid(s) – arterial supply to, 61t – inner layer, 241, 241f – innervation of, 241 – lateral canthus, 241f – lower, 241f–242f – m edial canthus, 241f – lymphatic drainage of, 71t – outer layer, 241, 241f – structure of, 241, 241f – upper, 241f–242f – venous drainage of, 64t Eye m ovem ent(s) – conjugate – coordination of, 260, 260f, 261 – loss of, 261, 261f – coordination of, 260, 260f – physiological, 257 – saccadic, 260 – supranuclear organization of, 260, 260f

F Face – anterior, super cal layer, neurovasculature of, 150, 150f – blood supply of, 61t – developm ent of, 12, 12f, 12t – dissection of, 144 – lacerations of, 144 – lateral, neurovasculature of – deep layer, 155, 155f – super cal layer, 152, 152f, 153, 153f – lymphatic drainage of, 71t – muscles of, super cial – anterior view of, 144, 144f – lateral view of, 145, 145f – neurovasculature of, 150, 150f, 152–155, 152f–155f – orbital com m unications with, 228, 231t – swelling of, 144 – veins of, 67, 67f – venous “danger zone” in, 151, 151f – venous drainage of, 64, 64f, 64t, 65, 65f, 65t Facet joint capsule, 290, 290f, 290t, 291f Facial nerve. See Nerves, nam ed Facial artery plexus, 111t, 139t, 416f–417f, 430f – anterior, 139f Facial paralysis, 132, 132f, 241, 243 – central (supranuclear), 132, 132f

– peripheral (infranuclear), 132, 132f Falx cerebelli, 102, 364f Falx cerebri, 24f, 25, 35, 102, 102f–103f, 151f, 163f, 349f–350f, 351, 351f–352f, 353, 353f, 361, 361f–363f, 371f–372f Fascia (pl., fasciae) – buccopharyngeal, 320f, 321, 321f, 334 – bulbar, 236, 236f – Camper’s, 439f – cervical, 320, 320f, 320t – super cial, 320t, 321 – superior, 315 – clavipectoral, 321, 321f, 322 – deep cervical, 296f, 297, 298f–299f, 322 – investing layer of, 418f – pretracheal layer of, 346, 346f, 418f – prevertebral layer of, 320t – super cial layer of, 299, 320f, 320t, 321, 321f, 322, 322f, 326, 326f, 328, 334, 334f, 346f – lam ina of – anterior, 326, 326f – deep, 322 – posterior, 322, 322f, 326, 326f – endothoracic, 409f, 432f – lata, 405f – nuchal, 299 – deep, 299, 299f, 300, 300f, 320t, 321f, 330 – prevertebral layer of, 320f – super cial, 299f, 320f, 320t, 321, 321f, 330 – super cial layer of, 330, 330f – super cial layer of, 299, 299f – parotid, 70f, 265f – pectoral, 407f – pelvic – parietal, 464f – visceral, 464f–465f – penile, 464f – pharyngobasilar, 220f, 221, 221f–222f, 224f, 332f – pretracheal, 320t, 321, 326, 326f, 334, 334f – m uscular, 299, 299f, 320f, 320t, 321, 321f, 322, 322f, 334 – posterior, 334 – visceral, 299, 299f, 320f, 320t, 321, 321f, 322 – prevertebral, 299, 299f, 320f, 320t, 326, 326f–327f, 330, 334, 334f – anterior (alar) layer of, 321, 321f, 334 – “danger space” bet ween layers of, 321, 321f, 334, 334f – posterior layer of, 321, 321f – rectoprostatic, 464f – renal – anterior layer of, 299f – posterior layer of, 299f – retrovisceral, 321, 321f – Scarpa’s, 439f – super cial thoracic, 407f – temporal, 157t – deep, 163f – super cial, 163f – thoracolum bar, 299, 299f, 321 – deep layer of, 299f, 301f – super cial layer of, 298f, 299, 299f, 300, 300f – transversalis, 299f, 405f, 439f Fascicle(s) – cardiac – anterior, 427f – m iddle, 427f – posterior, 427f – longitudinal, 293f, 294, 294f, 295, 295f Fasciculus (pl., fasciculi) – dorsal longitudinal, 90, 90f

– m am m illothalam ic, 85f – m edial longitudinal, 90f–93f, 260, 260f, 280, 280f, 281, 281f – course of, in brainstem , 261, 261f – lesion of, 261, 261f – rostral interstitial nucleus of, 260, 260f – of spinal cord – dorsal longitudinal, 182f – interfascicular, 76f – longitudinal, of posterior colum n, 76f – septom arginal, 76f – sulcom arginal, 76f – uncinate, 280f Fasciculus cuneatus, 93f, 105t Fasciculus gracilis, 93f, 105t Fasciculus proprius, lateral, of spinal cord, 76f Faucial (oropharyngeal) isthm us, 184f – posterior border, 216f Fenestra cochleae. See Round window Fenestra vestibuli. See Oval window Filling(s), on radiographs, 201, 201f Filum term inale, 75, 75f Fissure(s) – anterior m edian, 89f – cerebellar, 79 – horizontal, 79f – posterolateral, 79, 79f – prim ary, 79, 79f – horizontal, of right lung, 433f–434f – labial, 144f – longitudinal cerebral, 78, 78f – oblique, of lungs, 433f–434f, 435, 435f – oral, 184, 184f – orbital – inferior, 27f, 39f, 156, 156f, 168f, 168t, 169f, 169t, 170f–171f, 228, 228f–230f, 231t, 232f, 247, 349, 349f, 362, 362f – neurovasculature in, 238 – superior, 30, 31f, 39f, 119f, 120t, 121, 124, 124f, 228, 229f–230f, 231t, 232, 232f, 234, 237, 237f, 247 – com munications of, 230 – neurovascular pathways through, 44f, 45t – neurovasculature in, 238, 238f – palpebral, 144f, 241f – muscles of, 146–147, 146f–147f, 147t – norm al width, 241, 241f – petro-occipital, 29f – petrot ympanic, 27f, 33, 33f, 131f, 133, 164, 164f, 165, 269f – neurovascular pathways through, 44f, 45t – pterygom axillary, 156, 156f, 158, 168t–169t, 170, 170f, 228, 228f–229f, 231t – pterygopalatine, 168 – t ympanom astoid, 19f, 33f, 265 – t ympanosquamosal, 164, 164f Fistula(s), 201, 201f – in neck, 11, 11f Flocculus, 79f – peduncle of, 79f Fold(s). See also Vocal fold(s) – aryepiglot tic, 216f, 335f, 338f–339f, 340, 340f, 345f, 374, 374f – glossoepiglot tic, 203t – lateral, 209f, 355f – m edian, 209f, 339f, 344f–345f, 355f – laryngoscopic view of, 345, 345f – m alleolar – anterior, 263f – posterior, 263f – superior, 269f – m ucobuccal, 184f

531

ERRNVPHGLFRVRUJ

– neural, 2f, 4, 4f – salpingopharyngeal, 178f, 185f, 216f – lateral bands on, 185f, 217, 217f – sem ilunar, in colon, 449f – sublingual, 184f, 206f, 210f–211f, 212, 212f – um bilical – lateral, 444f–445f, 448f – m edial, 444f–445f, 448f – m edian, 444f–445f, 448f – vestibular, 185f, 339f, 340, 340f, 340t, 343f, 345f, 354, 354f, 382f Fontana spaces, 251, 251f Fontanelle – anterior, 17f – as access point for CSF sampling in infant, 17f – closure, 17t – m astoid (posterolateral), 17f – closure, 17t – posterior, 17f – closure, 17t – as reference point for fetal head in childbirth, 17f – sphenoid (anterolateral), 17f – closure, 17t Foram en (pl., foramina) – alveolar, posterior superior, 38f – apical, 192f, 192t – ethm oid – anterior, 35f, 228, 229f – posterior, 35f, 228, 229f – greater palatine, 27f, 39f, 188f, 214, 214f – neurovascular pathways through, 44f, 45t – greater sciatic, 463f – incisive, 23f, 39, 39f, 188f, 214, 293f – opening of, 27f, 39f, 180f – infraorbital, 19f, 21f, 38f, 128f, 188f, 229f, 242f – intervertebral, 284f, 286, 286f, 289, 289f–291f, 294f, 377 – jugular, 27f, 29f, 34, 136f, 140f, 164f, 343f, 364, 366 – neural part, 364 – neurovascular pathways through, 44f, 45t – venous part, 364 – lesser palatine, 27f, 39f, 188f – neurovascular pathways through, 44f, 45t – lesser sciatic, 463f – m andibular, 23f, 40, 40f–41f, 164f–165f, 313f – m astoid, 19f, 23f, 27f, 33, 33f – neurovascular pathways through, 44f, 45t – m ental, 19f, 21f, 40, 40f, 43f, 128f, 150f, 188f – position of, age-related changes in, 42 – nutrient, 291f – obturator, 462f – om ental, 443f, 446, 446f–448f – parietal, 23f, 25, 25f – sacral, 284f – sphenoidal, 27f – sphenopalatine, 126f, 156f, 168f, 168t, 169f, 169t, 181f, 232f – st ylom astoid, 27f, 29, 33, 33f, 128f, 130f, 130t, 131, 131f, 132, 133f, 164f – neurovascular pathways through, 44f, 45t – supraorbital, 19f, 21f, 229f, 231t, 242f – transverse, 49f, 286f – of cervical vertebrae, 314 – vertebral, 75, 285, 285f, 285t, 286f, 403f

Index

– zygom aticofacial, 36, 36f – zygom atico-orbital, 229f – zygom aticotemporal, 36 Foram en cecum , 10, 10f, 11, 11f, 194, 202f, 203t, 209f, 335f, 347, 347f Foram en lacerum , 27f, 29f, 221f, 372f – neurovascular pathways through, 44f, 45t Foram en m agnum, 26f, 28f–29f, 34, 34f, 103, 103f, 140f–141f, 156f, 289, 289f, 294, 294f, 359, 359f, 376f – neurovascular pathways through, 44f, 45t – venous plexus around, 67f Foram en ovale, 27f, 29f, 30, 31f, 39f, 128f, 156, 156f, 164f, 168f, 221f, 232f, 363 – neurovascular pathways through, 44f, 45t – in postnatal circulation, 429, 429f – in prenatal circulation, 428, 428f – venous plexus of, 66f Foram en rotundum , 30, 31f, 128f, 168t, 169f, 169t, 232f – neurovascular pathways through, 44f, 45t Foram en spinosum, 27f, 29f, 30, 31f, 39f, 156, 156f, 159, 164f, 168f, 232f – neurovascular pathways through, 44f, 45t Forceps m ajor, 80f Forearm – anterior compartm ent, m uscles of, 395f – anterior view of, 388, 388f – bones of, 388f – m uscles of, 394f–395f – anterior view of, 395f – deep, 395f – deep extensors, 394f – interm ediate, 395f – posterior view of, 394f – super cial, 395f – super cial extensors, 394f – posterior compartm ent, m uscles of, 394f – pronation of, 388f – supination of, 388f Forebrain, 5t – basal, 182 Foregut, blood supply to, 440, 440f Forehead – arterial supply to, 61t – developm ent of, 12f, 12t – venous drainage of, 64t Fornix, 78f, 82, 82f–83f, 83t, 84f, 87f, 95f – colum n of, 82f Fossa (pl., fossae) – cerebellar, 29f – cerebral, 29f – cranial, 28, 28f, 29 – anterior, 28, 28f, 29–30, 35, 173f, 175f–176f, 228f, 230f, 238f, 348, 348f, 349, 360, 376, 376f – arterial supply to, 61t – neurovascular structures in, 45t – superior view of, 238, 238f – venous drainage of, 64t – m iddle, 28, 28f, 29–30, 128f, 159, 173f, 230f, 231t, 238f, 351, 351f, 361–362 – arterial supply to, 61t – com m unication with pterygopalatine fossa, 169f, 169t – neurovascular structures in, 45t – superior view of, 238, 238f – posterior, 28, 28f, 29, 362 – dura of, innervation of, 138t, 139f – neurovascular structures in, 45t – digastric, 23f, 40f – hyaloid, 244f, 248

– hypophyseal, 29f, 30, 31f, 173f, 176f, 178f, 351 – incisive, 27f, 39f, 180f, 190f, 214f – infratemporal, 133, 156, 156f, 228, 231t, 349, 362, 372 – borders of, 156, 156f, 158t – com m unication with pterygopalatine fossa, 169t – content s of, 158, 158f, 158t – deep dissection of, 159, 159f – inferior view of, 168, 168f – left lateral view of, 168, 168f – muscles of, 158, 158f, 158t – nerves in, 159t – super cial dissection of, 158, 158f – vessels of, 158, 158f, 158t – interpeduncular, 361f – jugular, 33, 33f – lacrim al, 229f – of lacrim al sac, 229f – lesser supraclavicular, 318f–319f – m andibular (glenoid), 27f, 32, 32f, 33, 33f, 156f, 164, 164f–165f, 167f, 357f – com partm ent s of, 164 – on dental panoram ic tom ogram (DPT), 200f – inferior view of, 164, 164f – of temporal bone, 40 – m axillary – canine, 38f – incisive, 38f – for lacrim al sac, 38f – ovalis (heart), 423f – lim bus of, 423f – valve of, 423f – pterygoid, 30, 31f, 39f – pterygom axillary, 177f – pterygopalatine, 30, 156, 156f, 158–159, 168, 168f, 181f, 228, 229f, 231t, 378f – borders of, 168t – com m unications of, 169, 169f, 169t – lateral approach to, 168, 168f – nerves transm it ted through, 171, 171f, 171t – openings of, 168t – topography of, 170–171 – tum ors of, 168 – retrom olar, 40, 41f – rhom boid, 88f, 89, 89f, 92, 92f, 93 – scaphoid, 27f, 39f, 264f – sublingual, 40f – subm andibular, 23f, 40f – temporal, 156, 156f, 231t – borders of, 157t – m uscles of, 157t – neurovasculature of, 157, 157f, 157t – tonsillar, developm ent of, 9t – triangular, 264f Fovea, pterygoid, 40, 164f Fovea centralis, 244, 244f, 245, 245f, 252, 252f, 253, 253f, 255, 255f – ophthalm oscopic exam ination of, 247, 247f Foveola (pl., foveolae), granular, 25, 25f Fracture(s) – m andibular, 43 – m idfacial, Le Fort classi cation of, 20f – nasal, 37 – of skull base, 28, 28f – zygom atic bone, 36 Frontal bone, 18f–21f, 24f, 25, 25f–26f, 28f–30f, 35, 36f–37f, 157t, 161f, 172f–173f, 176f, 228, 353f – developm ent of, 16t – orbital surface of, 228f, 230f – supraorbital m argin, 228f – zygom atic process, 156f, 157t, 168f Frontal crests, 25, 25f, 29f

Frontal gyrus, superior, 352f–353f Frontal lobe, 78, 78t, 163f, 348, 348f–350f – ventricular system and, 95 Frontal notch, 21f, 242f Frontal pole, 78f Frontal suture. See Sutures, frontal Frontonasal duct, 176f, 176t Frontonasal prom inence, in facial developm ent 12-14, 12f-14f Funiculus (pl., funiculi) – anterior, 76f, 105t – lateral, 76f, 86t, 105t – posterior, 76f, 86t, 105t – posterolateral, 107, 107f

G Gag re ex, 219f Gait ataxia, 134 Galea aponeurotica, 144f, 145, 145f, 150f, 151, 151f Galen’s anastom osis, 342f Gallbladder, 442t, 444f, 446f–448f, 450f, 453, 453f, 461f – blood supply to, 440, 440f–441f – body of, 451f – fundus of, 451f – infundibulum of, 451f – neck of, 451f – opened, 451, 451f Ganglion (pl., ganglia) – abdom inal, 112f – aorticorenal, 460f – basal, 5t, 80, 80f, 100f, 381f – hypertensive hem orrhage in region of, 97f – in sensorim otor system , 109, 109f – venous drainage of, 98 – celiac, 110, 110f, 111t, 460f – cervical, 426 – m iddle, 224f–225f, 324f, 332f–333f, 416f–417f, 426f, 437f – superior, 110f, 113, 113f, 113t, 121, 123t, 124, 129t, 219, 219f, 224f–225f, 234f, 237, 242, 328f–329f, 332f–333f, 417f, 426f – cervicothoracic, 437f – ciliary, 110, 111t, 112f, 112t, 113, 113f, 113t, 120t, 121f, 124f, 234f, 236t, 237, 237f, 239, 239f, 258, 258f, 259, 259f – lesion of, 259 – root(s) of – parasym pathetic (m otor), 121, 121f, 236t, 237f – sensory, 121, 124, 124f, 125t, 236t, 237f – sympathetic, 121, 121f, 124, 236t, 237f – dorsal root, 3, 3f – facial nerve, 133, 133f – geniculate, 130, 130f, 130t, 131, 131f, 133f, 208, 208f, 267f, 271f, 274f – im par, 460f – inferior (nodose), 138f, 138t, 208, 208f, 343, 343f – inferior (petrosal), 208, 208f – m esenteric – inferior, 110, 110f, 111t, 460f – superior, 110, 110f, 111t, 460f – near organs, 112t – otic, 110, 111t, 112f, 112t, 113, 123t, 128, 128f, 129t, 133, 136t–137t, 159t, 213t, 267, 267f – root(s) of – parasympathetic, 129t – sympathetic, 129t – parasympathetic, 111t – in head, 110, 110f

– – – –

of parasympathetic cranial nerves, 116t paravertebral, 111t prevertebral, 110, 110f, 111t pterygopalatine, 110, 111t, 112f, 112t, 113, 113f, 113t, 123t, 126f, 127t, 128f, 131, 131f, 133f, 169, 171f, 171t, 180, 180f–181f, 188f, 213t, 237, 242, 267 – branch(es) – posteroinferior lateral nasal, 180f – posterosuperior lateral nasal, 180f – m axillary nerve branches passing through, 126f, 127t – root(s) of – motor, 127t – sensory, 127t – sympathetic, 127t – of sensory cranial nerves, 116t – spinal, 4, 4f, 74f–75f, 104f, 289f, 409f – pseudounipolar cells of, 4 – spiral, 134f–135f, 135t, 271, 271f, 274, 274f, 276, 276f – stellate, 110f, 324f, 417f, 426f – subm andibular, 110, 112f, 112t, 113, 123t, 128f, 129t, 133, 133f, 189f, 206, 206f, 213t, 267, 334f – root(s) of – parasympathetic, 129t – sympathetic, 129t – superior (jugular), 138f, 138t, 343, 343f – sympathetic, 77f – thoracic, 416f, 437f – upper, 426 – trigem inal, 106, 106f, 122f–123f, 123t, 124f, 126f, 131f, 133f, 181f, 189f, 192t, 237f–238f, 378, 378f – vertebral, 225f, 333f – vestibular, 134f, 271, 271f, 280, 280f – inferior part, 134f–135f, 135t, 271, 271f, 278f – superior part, 134f–135f, 135t, 271, 271f, 273f, 278f Ganglion cells – of parasym pathetic nervous system , 417t – retinal, 253, 253f, 254, 254f, 258 – and pupillary light re ex, 259 Garnier space, 245f Gastrulation, 2 Gaze – control of, 260, 260f, 261, 261f – deviations of, 235, 235f, 235t – six cardinal directions of, 233, 233f Genial (m ental) spines, 21f, 23f, 41f – inferior, 40f – superior, 40f Geniculate body(ies) – lateral, 84, 85f, 86, 86f, 119, 119f, 254, 254f, 255, 255f, 258, 258f, 259, 259f – clinically im portant connections of, 86t – m edial, 86, 86f, 119f – clinically im portant connections of, 86t Genitalia, autonom ic innervation of, 110f Germ layer(s), 2 Giant cell arteritis. See Tem poral arteritis Gillies technique, 36 Gingiva (pl., gingivae), 192, 192f, 192t, 193, 193f – at tached, 193, 193f – blood supply to, 186, 186f – connective tissue of, 193f – free, 193, 193f – glands of, parasympathetic innervation of, 112t – labial, 184f – lymphatic drainage of, 71t – venous drainage of, 187, 187f Gingival m argin, 193, 193f

532

ERRNVPHGLFRVRUJ

Index

Gingival sulcus, 193, 193f Glabella, 19f, 21f, 172f, 229f Glandular secretions, 111t Glaucom a, 250t, 251, 251f – acute (closed-angle), 251, 251f – chronic (open-angle), 251, 251f Glial cells, 73t Globe rupture (eye), 244 Globus pallidus, 80, 80f, 85t, 97f – arterial supply to, 96f – lateral segm ent of, 85f – m edial segm ent of, 85f, 377f Glom erulus (pl., glomeruli), olfactory, 183, 183f Glossoptosis, 9 Glot tis, 354f. See also Rim a glot tidis Glutam ate, in gustatory function, 209 Goblet cells – conjunctival, distribution of, 243, 243f – of nasal m ucosa, 179, 179f Goiter, 323, 346 Granule cell(s), in olfactory bulb, 183, 183f Gray mat ter – central, 107, 107f – of spinal cord, 76, 76f–77f, 109 – colum ns (horns) of, 76f Great vessels, 412t Groove(s) – arterial, in skull base, 29f – chiasm atic, 29f, 31f – costal, 409f, 432f – deltopectoral, 399f – for dural venous sinuses, 25, 25f, 29f, 33f, 34, 34f – infraorbital, 229f, 238f – in m axilla, 38f – intertubercular, hum eral, 386f–387f, 390f, 392f–393f – labiom ental, 184f – laryngotracheal, 10t – for lesser petrosal nerve, 29f – meningeal, 25f – for m iddle m eningeal artery, 33f – mylohyoid, in m andible, 23f, 40f, 164f – nasolacrim al, 13f – neural, 2, 2f, 4, 4f – occipital, 33f – prim itive, 2f – radial, in hum erus, 386 – for sigm oid sinus, 29f, 33f – for subclavius m uscle, in clavicle, clavicle, 384f – for superior petrosal sinus, 33f – for superior sagit tal sinus, 25, 25f, 34f – for transverse sinus, 29f, 34f – ulnar, in hum erus, 386, 394f – for vertebral artery, in atlas (C1), 286f–287f, 295f Gustatory pathway, 208, 208f. See also Taste sense Gut tube, 2, 2f Gyrus (pl., gyri) – am bient, 118f, 182, 182f – cingulate, 78f, 82f–83f, 83t, 86t, 108t, 353, 353f – dentate, 82, 378f – frontal, superior, 352f–353f – Heschl, 276 – parahippocampal, 83f, 83t – entorhinal area of, 83f, 83t – paraterm inal, 83t – postcentral, 78, 86t, 104f, 105, 105f, 108f, 208, 208f – som atotopic organization of, 105 – precentral, 78, 108f, 109, 132f, 141f, 381f – som atotopic representation of skeletal m uscle in, 109, 109f

– sem ilunar, 118f, 182, 182f – temporal, transverse, 86t, 276, 276f

H Habenulae, 85t Habenular nuclei, 83f, 83t Hair cell(s) – inner, 274, 274f, 275, 275f, 276, 276f, 277, 277f – outer, 274, 274f, 275, 275f, 277, 277f – vestibular – t ype I, 278, 278f – t ype II, 278, 278f Ham ate, hook of, 389f, 395f–397f Hand – bones of, palmar view of, 389f – intertendinous connections, dorsal digital expansion, 394f – muscles of, 396, 396f, 397, 397f – palm ar (anterior) view of, 396f, 397, 397f Hannover space, 245f Haustra, colonic, 445f, 449f Head – anterior, neurovasculature of, super cal layer, 150, 150f – coronal section(s) – anterior, 348–349, 348f–349f – posterior, 350–351, 350f–351f – through anterior orbital m argin, 348, 348f – through eyeball (MRI), 352, 352f – through m olar region of oral cavit y, 226, 226f – through orbital apex, 350, 350f – through pituitary, 351, 351f – through posterior orbit (MRI), 353, 353f – through retrobulbar space, 349, 349f – lateral – neurovasculature of – deep layer, 155, 155f – interm ediate layer, 154, 154f – super cial layer, 152–153, 152f–153f – sensory innervation of, 153, 153f – lymphatics of, 68, 68f, 70, 70f, 71t – m agnetic resonance im age (MRI) of – coronal, 352–353, 352f–353f – sagit tal, 380, 380f–381f – m idsagit tal section, through nasal septum , 376, 376f – m ovem ent of, 286, 288–289 – neurovasculature of, 150, 150f, 152–155, 152f–155f – pain pathways in, 106, 106f – potential tissue spaces of, 226, 226f, 226t – rotation, interaction of contralateral sem icircular canals during, 279, 279f – sagit tal section(s) – lateral, 378–379, 378f–379f – medial, 376–377, 376f–377f – through approxim ate center of orbit, 379, 379f – through inner third of orbit, 378, 378f – through m edial orbital wall, 377, 377f – through nasal cavit y (MRI), 380, 380f – through orbit (MRI), 381, 381f – sym pathetic innervation of, 113, 113f, 113t – transverse section(s) – caudal, 364–365, 364f–365f – cranial, 360–363, 360f–363f – at level of occlusal plane of m andibular teeth, superior view of, 226, 226f

– through m edian atlantoaxial joint, 365, 365f – through m iddle nasal concha, 363, 363f – through nasopharynx, 364, 364f – through optic nerve and pituitary, 361, 361f – through orbit and ethm oid air cells (MRI), 370, 370f – through orbit and nasolacrim al duct (MRI), 371, 371f – through sphenoid sinus, 362, 362f – through upper level of orbit, 360, 360f – veins of, 62, 62f, 63, 63f, 63t – deep, 66, 66f, 67, 67f – super cial, 64, 64f – venous drainage of, 415t Head injury, 35 – frontal, 29 Hearing, 262, 268, 268f, 269, 269f, 274 – newborn screening test, 277 – sound conduction during, 262, 275, 275f Hearing loss, 131, 134, 135t, 263, 271. See also Deafness – conductive, 268 Heart, 412t, 418t – anterior (sternocostal) surface of, 422, 422f – anterior view of, 427f – apex of, 422f–423f, 425f, 427f, 436f – autonom ic plexuses of, 111t, 139t, 417f, 426, 426f – base of, 422, 422f – cham bers of, 423, 423f. See also Atrium (pl., atria); Ventricle(s), cardiac – opened, 427f – conduction system of, 427, 427f – em bryology of, 3 – inferior (diaphragm atic) surface of, 422, 422f – innervation of, 417f – autonom ic, 110f, 426, 426f – parasympathetic, 426, 426f – sym pathetic, 426, 426f – lateral view of, 427f – portal system and, collateral pathways bet ween, 457, 457f – posterior surface of, 422, 422f – prim itive, 2f – surfaces of, 422, 422f – valves of, 424, 424f Helicotrem a, 270f, 274, 274f Helix, 264f Hem atoma – epidural, 56, 103, 103f – subdural, 98, 103, 103f Hem ianopia, 101, 101f – bitemporal, 256, 256f – hom onym ous, 256, 256f – contralateral to lesion, 256, 256f Hem idesm osom es, 193, 193f Hem iparesis, 101, 101f, 103 Hem ipelvis, lateral view of, 467f Hem isensory de cit, 101, 101f Hem isphere(s) – cerebellar, 79, 79f – cerebral, 78, 78f – left, lateral view of, 81, 81f – right, 82, 82f – left lateral view of, 82f – m idsagit tal section of, 81, 81f Hem orrhage – extracerebral, 97, 103, 103f – in internal capsule, 105 – intracerebral, 97, 256 – subarachnoid, 97, 103, 103f – subdural, 120t

533

ERRNVPHGLFRVRUJ

Hepatic duct(s), 450f–451f – com m on, 451f Hepatic plexus, 139t Hepatopancreatic ampulla, 450f – sphincter of, 450f Hepatopancreatic duct, 451f Heschl gyri, 276 Hilum , 435, 435f Hindbrain, 5t. See also Rhom bencephalon Hindgut, blood supply to, 440, 440f Hip bone(s), 462, 462f – anterior view of, 462, 462f – m edial view of, 462, 462f – sym physeal surface of, 462f Hippocampal formation, 82, 82f–83f, 83t Hippocampus, 80, 82, 82f, 83, 83f, 83t, 85f – arterial supply to, 96f – m bria of, 82f – foot of, 379, 379f – lesions of, 82 – proper, 82 Hoarseness, 138t Hom unculus – m otor, 109, 109f – sensory, 105, 105f Horizontal cells, retinal, 253, 253f Horner syndrom e, 250t, 329 Hum erus, 387f, 389f, 392f, 394f – anatom ic neck of, 386f–387f – anterior view of, 386, 386f – anterolateral surface of, 386f – anterom edial surface of, 386f – capitulum (capitellum ), 386, 386f, 389f – condyle of, 386f – coronoid fossa, 386f – deltoid tuberosit y, 386f, 392f – greater tubercle, 386f–387f, 390f, 393f – crest of, 386f, 390f, 392f – head of, 386f–387f – intertubercular groove, 386f–387f, 390f, 392f–393f – lateral border, 386 – lateral epicondyle, 386f, 393f–394f – lateral supracondylar ridge, 386f – lesser tubercle, 386f–387f, 390f, 392f–393f – crest of, 386f, 390f – m edial border, 386 – m edial epicondyle, 386f, 389f, 393f–395f – m edial supracondylar ridge, 386f, 389f – olecranon fossa, 386 – posterior view of, 386, 386f – radial fossa, 386f – radial groove, 386 – shaft of, 390f, 392f–393f – posterior surface of, 386 – surgical neck of, 386f – trochlea of, 386, 386f, 389f – ulnar groove, 386, 394f Hydrocephalus, 22f, 95, 134 – internal, 95 Hyoid bone, 11f, 185f, 204f, 206f, 210, 210f–212f, 218f–219f, 313f, 323f, 328f, 336, 336f, 340f, 342f, 345f, 347f, 376, 376f–377f, 382f, 426f – anterior view of, 41f – body of, 41, 41f, 336f – greater horn , 7f, 7t, 41, 41f, 222f, 313f, 336f, 378f – inferior part, greater horn, development of, 16t – lesser horn , 7f, 7t, 41f, 313f, 336f, 378f – lower part, 7t – oblique left lateral view of, 41f – posterior view of, 41f – superior part, lesser horn, developm ent of, 16t

Index

– upper part, 7t Hyperacusis, 131 Hyperopia (farsightedness), 245, 245f Hypertension, 97 Hypobranchial em inence, 10, 10f, 10t Hyponatrem ia, 87t Hypopharynx, 216t, 373 Hypophysis, 78f, 95f, 351, 351f, 361f, 370f, 380, 380f Hypothalam us, 5t, 84, 84f, 107, 107f, 182 – anterior preoptic region of – functions of, 87t – lesion of, 87t – anterior region of – functions of, 87t – lesion of, 87t – autonomic upper m otor neurons in, 111t – and balance, 281, 281f – functions of, 85t, 87, 87t – lesions of, 87, 87t – m idanterior region of – functions of, 87t – lesion of, 87t – paraventricular region of – functions of, 87t – lesion of, 87t – posterior region of – functions of, 87t – lesion of, 87t – structures of, 85t Hypothalamic sulcus, 84f, 87, 87f Hypotherm ia, 87t – central, 87t Hypot ympanum , 269, 269f

I Ileocecal labrum , 449f Ileocecal ori ce, 449f Ileocecal recess, inferior, 445f Ileum , 442t, 443f–444f, 448f, 449 – blood supply to, 440, 440f–441f – term inal part, 449f Iliac crest, 298f, 301f, 305f, 462f–463f Iliac fossa, 462f Iliac spine – anterior inferior, 462f–463f – anterior superior, 439f, 462f–463f – posterior inferior, 462f–463f – posterior superior, 462f–463f Iliac tubercle, 463f Iliac tuberosit y, 462f Ilium – auricular surface of, 462f – body of, 462f – gluteal surface of, 463f Incisive foram en, 14, 15f, 178f Incisive suture, 190f Incisor(s), 41f, 190, 190f – deciduous – central, 198, 198f – lateral, 198, 198f – m andibular, 194 – m orphology of, 196, 196f, 197t – radiograph of, 201, 201f – m axillary – m orphology of, 194, 194f, 195t – radiograph of, 201, 201f Incisure – frontal, 229f, 231t, 242f – intertragic, 264f – m astoid (digastric), 27f – t ympanic, 263f Incisure (notch), frontal, 21f, 242f Incus, 7f, 7t, 262f–263f, 266, 266f, 269f, 273f, 275f – anterolateral view of, 268, 268f – articular surface for m alleus, 268f

– body of, 268f – developm ent of, 16t – lenticular process, 268f – long process, 268f – m edial view of, 268, 268f – short process, 268f Indirect laryngoscopy – technique for, 339f – and vocal fold position, 339f Indusium griseum , 82f–83f, 83t Infection(s) – dental – route of, from source, 227, 227f, 227t – spread of, 226, 226f – facial, 240 – nasopharyngeal, spread of, 266 – portals of, venous anastom oses of head as, 66t – of root canal, 201, 201f – spread of – peripharyngeal space and, 334, 334f – potential routes for, 320–321, 334, 334f Inferior brachium , 86t Inferior olive, 108f Inferior vena cava. See Vena cava Infraglot tic cavit y, 340f, 340t, 354f Infratemporal space, 226f, 226t, 227f, 227t Infratentorial space, 103 Infundibular recess, 84f, 95f Infundibulum (pl., infundibula), 84f–85f, 239f – ethm oid, 35, 35f Inguinal ring, super cial, 439f Inion, 23f, 27f, 34f Insula, 78, 78f, 78t, 208f – arterial supply to, 96f – developm ent of, 5, 5f Interarytenoid notch, 335f, 339f Interatrial bundle, 427f Interdental bers, decussating, 193f Interganglionic trunk, 460f Internal auditory canal, 271, 271f, 379, 379f Internal capsule, 80, 80f, 97f, 100f, 105, 105f, 351f, 377f, 378, 378f – arterial supply to, 96f – crus of – anterior, 80f – posterior, 80f – genu of, 80f – hem orrhage in, 105 Internal carotid artery, em bryology of, 8f Internal m edullary lam ina, 85f Interm axillary suture, 21f, 38f Interneuron(s), 4, 4f, 108f Internodal bundle(s), 427f Interpedeuncular nuclei, 83f, 83t Interpeduncular fossa, 89f Interscalene space, 49, 49f, 324, 329, 401f Interscalene triangle, 311f Intersigm oidal recess, 445f Interspinous plane, 438f, 438t Interthalam ic adhesion, 84f, 95f Interventricular foram en, 94f, 95, 95f, 433f Interventricular septum , 423f, 427f Interventricular sulcus, 422f Intervertebral disk(s), 284, 284f, 288, 288f, 290, 290f, 290t, 291f–294f, 357, 357f, 369f, 380f, 402f Intervertebral foram en, 75f Intestinal tube, 2t Intestine(s) – autonom ic innervation of, 110f – large. See also Colon – anterior view of, 449, 449f

– sm all, 449. See also Duodenum; Ileum; Jejunum Intracerebral hem orrhage, 97, 256 Intracranial pressure, increased (intracranial hypertension), 79, 94, 103, 134, 247 Intraem bryonic coelom , 2f Intraocular pressure, 252 – increased, 251 – norm al, 251 Intraparotid plexus, 154f Intubation – endotracheal, 344, 344f, 345, 345f – equipm ent for, 344, 344f – head positioning for, 344, 344f – nasotracheal, 344 – orotracheal, 344 – pertracheal, 344 Iris, 241f, 244, 244f, 247f, 248, 248f, 250, 250f–251f – arterial circle of – greater, 247, 247f, 251, 251f – lesser, 247, 247f, 251, 251f – stroma of, 251, 251f – structure of, 251, 251f Ischial ram us, 462f Ischial spine, 462f–463f Ischial tuberosit y, 462f–463f Ischium , body of, 462f

J Jacobson’s organ. See Vom eronasal organ (VNO) Jejunum , 442t, 443f–444f, 449, 449f, 451f, 461f – blood supply to, 440, 440f–441f Joint(s) – acrom ioclavicular, 384 – atlantoaxial, 288, 288f, 289 – lateral, 288f, 289, 289f, 292f, 294f, 295, 358f – m edian, 288f, 289, 289f, 295, 295f, 365, 365f, 376f – atlanto-occipital, 288, 288f, 289, 292f, 294f, 295, 358f – capsule of, 294f, 295, 295f – of cervical spine, 288, 288f – costotransverse, 402f – craniovertebral, 288, 288f, 289, 289f – ligam ents of, 294–295, 294f–295f – m uscles of, 302, 308–309, 308f–309f, 308t, 383, 383f – oblique posterosuperior view of, 289, 289f – posterior view of, 289, 289f – cricoarytenoid, 336, 336f, 337, 337f – cricothyroid, 336, 336f, 337, 337f – elbow (cubital), 386 – bones of, 389f – facet (zygapophyseal), 286f, 288, 288f, 292f, 358f – capsule of, 293f–294f – glenohum eral, 386 – anterior view of, 387f – bony elem ents of, 387f – posterior view of, 387f – hum eroradial, 389 – hum eroulnar, 389 – incudom alleolar, 268, 268f–269f – incudostapedial, 268, 268f–269f, 272f–273f – intervertebral, 288, 288f – radioulnar – distal, 388f – proxim al, 388f, 389 – sacroiliac, 462f – sternoclavicular, 384

– temporom andibular (TMJ), 32, 40, 157, 164, 164f, 263, 357 – articular disk (m eniscus) of, 162f, 164–165, 165f, 167, 167f, 357, 357f, 372, 372f – biom echanics of, 166, 166f – capsule of, 161f–162f, 164f, 165, 165f, 167f – sensory innervation of, 165, 165f – compartm ent s of, 165 – dislocation of, 165, 165f – injury to, 43 – grinding, 164f, 165f – ligam ents of, 164f, 165f – m ovem ents of, 167, 167f – m ovem ents of m andible in, 166, 166f – opened, 165f – translation of, 166, 166f – venous drainage of, 64t–65t – uncovertebral, 288, 288f Jugular bulb, 364 – superior, 33, 224f Jugular process, 34, 34f Jugular notch, 34f, 402f Jugular trunk(s), 68, 71t, 413f Jugulofacial venous junction, 69, 69f–70f Jugulosubclavian (venous) junction(s), 68–69, 69f, 324 Jugum sphenoidale, 28, 28f, 31f

K Keratoconjunctivitis sicca, 242 Kidney(s), 299f, 442t, 446f–447f, 451f, 461f – autonom ic innervation of, 110f – brous capsule of, 299f Kiesselbach’s area, 59, 180f, 181, 181f Killian’s (dehiscence) triangle, 431f Kinocilia (sing., kinocilium ), of vestibular sensory cells, 278–279, 279f Kinocilia-bearing cells, 179, 179f Korsako syndrom e, 87 Krause glands, 242 Kyphosis, 284

L Labia, 184, 184f Labial crease(s), 184, 184f Labial vestibule – inferior, 377f – superior, 377f Labyrinth – bony, 270, 270f – cochlear, 270 – ethm oid, 361 – m em branous, 270, 270f, 274, 280 – anterior view of, 271, 271f – innervation of, 271, 271f Lacrim al apparatus, 242, 242f, 243, 243f Lacrim al bone, 18f–19f, 37f–38f, 172, 172f–173f, 176f, 228, 229f – developm ent of, 16t – orbital surface of, 228f Lacrimal crest, – anterior, 146f, 229f – posterior, 146f, 229f Lacrimal caruncle, 242f Lacrimal drainage, obstruction of, 243, 243f Lacrimal uid, 241 – ow of, 242 – m echanical propulsion of, 243, 243f – production of, 242 Lacrim al gland(s), 121f, 124f, 133f, 234f, 236, 239f, 242–243, 243f, 352f, 361f, 370f – accessory, 242

534

ERRNVPHGLFRVRUJ

Index

– arterial supply to, 61t – innervation of, 127t, 133, 133f, 242, 267 – orbital part, 240f, 242, 242f – palpebral part, 240f, 242, 242f – parasympathetic innervation of, 112t – venous drainage of, 64t Lacrim al sac, 240f, 242, 242f, 243, 243f Lacrim ation, disturbances of, 131 Lactiferous duct(s), 407, 407f Lactiferous sinus, 407, 407f Lam bda, 17f, 23f Lamboid suture, See Sutures, lam boid Lamina cribrosa, 244, 244f, 253, 253f Lam ina densa, 193f Lam ina lucida, 193f Lam ina papyracea, 175, 228f, 230, 230f, 348 Lam ina propria, brous, 179f Large intestine. See also Colon – anterior view of, 449, 449f Laryngeal cartilage. See Cartilage, laryngeal Laryngeal cavit y – divisions of, 340, 340t – interm ediate, 340f, 340t Laryngeal inlet, 216f, 340t – laryngoscopic view of, 345, 345f Laryngeal ori ce, 10f Laryngeal prom inence, 336–337, 337f Laryngeal vestibule, 340f, 340t, 355, 355f–356f, 366f–367f, 374, 374f Laryngopharynx, 185f, 216t, 351, 351f, 355, 366f, 368f, 373f, 376f–377f, 382 – innervation of, 138t, 139f, 139t – lymphatic drainage of, 71t Laryngoscope, 344, 344f – view of through, 345, 345f Laryngotracheal junction, 336 Larynx, 219f, 322, 355, 374, 374f, 376, 437f – anterior view of, 336f – cartilages of, 336f – edem a of, 340 – on indirect laryngoscopy, 339, 339f – innervation of, 138t, 139f, 139t, 316, 417f – branchiom otor, 343, 343f – m otor, 341–342, 342f, 343, 343f – sensory, 341–342, 342f, 343, 343f – laryngoscopic view of, 345, 345f – left lateral view of, 340f – ligam ent s of, 336f – location of, 336f – lymphatic drainage of, 71t – m ucosa of, 340, 340f – m uscles of, 338–339, 338f, 338t, 339f – neurovasculature of, 340–341, 341f – oblique left anterolateral view of, 336f – pharyngeal com m unication, 216t – posterior view of, 340f – sagit tal section, 336f – surgical approaches to, 342, 342f – topography of, 342, 342f Lateral lacuna, 102f Lateral lem niscus, 90, 90f–91f, 276, 276f Lateral nasal prom inence, in facial developm ent, 12-14, 12f-14f Lateral plate(s), 2t – parietal, 2t – visceral, 2t Lateral recess, 95f Lateral sulcus, 422f Le Fort classi cation, of m idfacial fractures, 20f Lem niscus – lateral, 90, 90f–91f, 276, 276f – m edial, 90, 90f–91f, 92, 92f, 93, 93f, 104f–105f, 219f

Lens, 174f, 241f, 244f–245f, 247f, 251f, 361, 361f, 370f, 379f – axis of, 249, 249f – capsule of, 249f – cortex of, 249f – dynam ics of, 248–249, 249f, 258 – em bryonic nucleus of, 249, 249f – epithelium of, 248–249, 249f – function, 249 – growth of, 249, 249f – light refraction and dynam ics of, 249, 249f – nucleus of – adult, 249, 249f – fetal, 249, 249f – infantile, 249, 249f – oblique lateral view of, 249, 249f – pole(s) of – anterior, 249, 249f – posterior, 249, 249f – position of, 248, 248f – posterior view of, 248, 248f – reference lines of, 249, 249f – refractive power of, 249 – sagit tal section of, 249, 249f – shape of, 248–249, 258 – suspensory apparatus of (zonule), 248, 248f – zones of discontinuit y in, 249, 249f Leukoplakia, 185 Ligam ent(s) (nam ed) – alar, 294, 294f, 295, 295f, 358f – annular – of m alleus, 269f – of radius, 388f – stapedial, 269f, 275f – anterior longitudinal, 290, 290f, 290t, 291, 291f–293f, 382f, 404f, 463f – anterior view of, 291, 291f – apical, of dens, 293f, 294, 294f, 295, 295f – arcuate – lateral, 408f, 438f – m edial, 408f, 438f – m edian, 408f, 438f – coronary, of liver, 450f – cricoarytenoid, 336f–337f – m iddle, 338f – cricothyroid, 336f, 345f–346f – m edian, 336f–337f, 340f, 342f – cricotracheal, 336f – cruciform , of atlas, 294, 294f, 295 – denticulate, 74f, 75, 75f – falciform , of liver, 444f, 446f, 450, 450f – fundiform , of penis, 439f – gastrocolic, 447, 447f – gastrosplenic, 447f–448f – hepatoduodenal, 446f, 448f – hepatoesophageal, 446f – hepatogastric, 443f, 446f, 448f – hyoepiglot tic, 340f – iliolum bar, 463f – inguinal, 405f, 439f, 463f – lateral (temporom andibular), 157f, 161f, 164, 164f – nuchal, 292f, 294f–295f, 321f, 367f, 373f, 376f, 380f, 382f – palpebral – lateral, 240f – m edial, 240f, 242f – periodontal, 192, 192f, 192t, 193, 193f – phrenicocolic, 447f – posterior longitudinal, 290, 290f, 290t, 291, 291f, 293f, 294, 294f, 382f – posterior view of, 291, 291f – pterygospinous, 165f – pulm onary, 435f – radial collateral, 388f – radioulnar

– dorsal, 388f – palm ar, 388f – round – of liver, 429f, 444f–446f, 448f, 450, 450f – of uterus, 465f, 467f – sacroiliac – anterior, 463f – interosseous, 463f – posterior, 463f – sacrospinous, 463f – sacrotuberous, 463f – sphenom andibular, 7f, 7t, 164–165, 165f – spiral, 274f – st ylohyoid, 7f – st ylom andibular, 164, 164f–165f, 204f – suspensory – of ovary, 465f – of penis, 464f – suspensory (Cooper’s), 407f – thyroepiglot tic, 336f – thyrohyoid, 185f, 336f, 340f – m edian, 322f–324f, 342f – transverse, of atlas, 293f, 294, 294f, 295, 365, 365f, 376f – triangular, of liver, 450f – ulnar collateral, 388f – um bilical, m edial, 429f – of vena cava, 450f – vestibular, 336f, 340f – vocal, 336f–337f, 340, 340f, 343f – Weiger, 245f – Ligam ent(s) (of region or organ) – cervical, 382 – of cervical spine, 292–293, 292f–293f, 294–295, 294f–295f – of craniovertebral joint s, 294–295, 294f–295f – of incus – posterior, 269f – superior, 269f – interspinous, 290, 290f, 290t, 291 – intertransverse, 290, 290f, 290t, 291, 291f, 295f – laryngeal, 336f – of m alleus – anterior, 7t – lateral, 263f, 269f – superior, 269f – nuchal, 293f – ovarian, 465f – pelvic, 463, 463f – radiate sternocostal, 404f – supraspinous, 290, 290f, 290t, 293f – vertebral (neural) arch, 290, 290f, 290t – vertebral body, 290, 290f, 290t – of vertebral column, 290, 290f, 290t, 291, 291f Ligamenta ava (sing., ligamentum avum ), 290, 290f, 290t, 291, 291f–295f, 382f Ligam entum arteriosum , 419f, 421f–423f, 429f–430f, 437f Ligamentum venosum , 429f Light cell(s) – olfactory, 183f – taste, 209, 209f Light refraction, in eye, 245, 245f, 249, 249f Lim b (upper) – anterior view of, 398–399, 398f–399f – arteries of, 398, 398f – veins of, 399, 399f – deep, 399f – super cial, 399f – venous drainage of, 415t Lim b buds, 3f, 6f Lim bic system , 82, 82f, 83, 83f, 182

535

ERRNVPHGLFRVRUJ

– inner arc of, 83f, 83t – outer arc of, 83f, 83t – regulation of peripheral autonom ic nervous system , 83, 83f – structures of, 83t Lim en nasi, 178f Line(s). See also Z line – arcuate, 405f, 444f, 462f – m ucogingival, 192t, 193f – mylohyoid, 23f, 214, 313f – nuchal – inferior, 23f, 27f, 34f, 292f, 303f, 307f, 309f – m edian, 23f, 27f, 34f – superior, 23f, 27f, 34f, 289f, 292f, 294f, 301f–303f, 307f, 309f, 330 – suprem e, 23f, 27f, 34f – pectineal, 462f – Sölder, 106, 106f, 122, 122f – temporal – inferior, 25f, 156f, 157t, 161f – superior, 25f, 156f, 157t, 161f Linea alba, 439f Lingual frenulum , 10, 184f, 203t, 206f Lingual gland(s), 202, 202f – anterior, 184f, 206f Lingual m ucosa, 202, 202f, 203t, 204f – dorsal, 203t – ventral, 203t Lingual septum , 163f, 203t, 204f, 350f, 354f, 382f Lingual thyroid, 11 Lingula, 79f, 164f Lip(s), 184, 184f – cleft, 15, 15f – developm ent of, 12f, 12t, 13f – lower, 184f – frenulum of, 184f – lymphatic drainage of, 71t – upper, 178f, 184f – blood supply to, 186, 186f – frenulum of, 184f Liver, 418f, 432f, 442t, 443f, 453, 453f, 461f – anterior view of, 450, 450f – appendix, brous of, 450f – autonom ic innervation of, 110f – bare area, 418f, 443f, 450f – blood supply to, 440, 440f–441f – prenatal, 428, 428f – caudate process, 450f – diaphragm atic surface of, 450f – inferior border of, 450f – inferior view of, 450, 450f – lobes of, 444f, 446f–448f, 450, 450f–451f, 461f – caudate, 450, 450f – quadrate, 450, 450f – in postnatal circulation, 429, 429f – surfaces of, 450, 450f – visceral surface of, 450f Liver prom inence, 6, 6f Lockjaw. See Trism us Locus ceruleus, 90f, 107, 107f Lordosis, 284 Ludwig’s angina, 227t Lum bar anesthesia, 75, 75f Lum bar puncture, 74–75, 75f, 103 Lum bar triangle, 298f Lum bar trunk(s), 413f Lum bocostal triangle, 408f Lum bosacral plexus, 72f Lunate, 389f Lung(s) – anterior border of, 435f – anterior view of, 434, 434f – aortic impression, 435f – apex of, 435f – autonom ic innervation of, 110f

Index

– – – –

base of, 435f cardiac impression, 435f cardiac notch, 435f costal surface of, 435f – vertebral part, 435f – gross anatomy of, 435, 435f – inferior border of, 432f, 435f – horizontal ssure of, 433f–434f, 435, 435f – inferior lobe of, 433f–434f, 435, 435f–436f – inferior border of, 435f – inferior lobe of, 433f–434f, 435, 435f–436f – lateral view of, 435, 435f – superior lobe of, 433f–434f, 435, 435f–436f – lingula, 435f – lobes of – inferior, 433f–434f – superior, 433f–434f – lym phatic drainage of, 71t – m edial view of, 435, 435f – m ediastinal surface of, 435f – m iddle lobe of, 433f–434f, 435, 435f–436f – oblique ssure of, 433f–434f, 435, 435f – pleural dom e of, 369, 369f – superior lobe of, 433f–434f, 435, 435f–436f – topographical relations of, 434, 434f – transverse section, inferior view of, 434, 434f Lung buds, 8, 8f Lupus, 242 Lymphadenopathy, cervical, 68–69, 69f Lymphatic drainage. See subentries under speci c structures Lymphatic duct(s), 68, 69, 69f, 324, 347f, 413f Lym phatics – of head and neck, 68, 68f, 70, 70f – intercostal, 413f – m ediastinal, 418t – thoracic, 413, 413f Lymph node(s) – axillary – interpectoral, 407f – level I, 407, 407f – level II, 407, 407f – level III, 407, 407f – brachiocephalic, 418f, 420f – buccal, 71t – celiac, 461f – cervical, 379f – anterior (level VI), 68, 68f – deep, 68, 68f, 70, 70f, 71t, 265, 265f, 329 – levels, 68, 68f – lower lateral group (level IV), 68, 68f – middle lateral group (level III), 68, 68f – in posterior cervical triangle (level V), 68, 68f – superior, 214, 214t – upper lateral group (level II), 68, 68f – drainage, directions of, 69, 69f – enlarged, 68 – lateral jugular (levels II–IV), 68, 68f – lower, 70f – relationship to system ic lymphatic circulation, 69, 69f – subm andibular (level I), 68, 68f – subm ental (level I), 68, 68f – super cial, 68, 68f, 71t, 326f – anterior, 68f – lateral, 68f – system atic palpation of, 69, 69f

– transverse, 71t – upper, 70f – collecting, 68 – jugular, 70, 70f – anterior, 71t – external, 71t – jugulodigastric, 71t – jugulo-om ohyoid, 71t – juxtavisceral, 71t – lum bar – interm ediate, 461f – lateral, 461f – m astoid, 68f, 70, 70f, 71t, 265, 265f – occipital, 68f, 71t, 330f – parasternal, 407, 407f – paratracheal, 71t – parotid, 70, 70f, 265, 265f – deep, 68f, 70f, 71t, 265f – super cial, 68f, 70f, 71t, 265f – pericardial, 421f – preauricular, 71t – prelaryngeal, 71t – pretracheal, 71t – regional, 68 – retroauricular, 68f, 70f, 71t – retropharyngeal, 71t, 214t–215t, 334f – subm andibular, 70, 70f, 71t, 195t, 197t, 211, 214, 214t–215t – subm ental, 70, 70f, 71t, 211 – superior phrenic, 418f, 421f – tracheal, 71t – tracheobronchial, 418f Lysozym e, salivary, 212

M Macula (pl., m aculae) – saccular. See Saccule – utricular. See Utricle Macula lutea, 252, 252f, 253, 253f – ophthalm oscopic exam ination of, 247, 247f Macular degeneration, 247 Magnetic resonance im age (MRI) – of cervical spine, 293, 293f – of head – coronal, 352–353, 352f–353f – through eyeball, 352, 352f – through posterior orbit, 353, 353f – sagit tal, 380–381, 380f–381f – through nasal cavit y, 380, 380f – through orbit, 381, 381f – transverse – through orbit and ethm oid air cells, 370, 370f – through orbit and nasolacrim al duct, 371, 371f – of neck – coronal – anterior, 354–357, 354f–357f – of great vessels, 356, 356f – of lingual m uscles, 354, 354f – of m uscles of m astication, 355, 355f – posterior, 358–359, 358f–359f – of soft palate, 355, 355f – of temporom andibular joint, 357, 357f – through cervical vertebrae and spinal nerves, 358, 358f – through nuchal m uscles, 359, 359f – m idsagit tal, 382, 382f – transverse – through C4 vertebral body, 374, 374f – through C6 vertebral body, 374, 374f – through C7 vertebral body, 375, 375f

– of oral cavit y, transverse – through hard and soft palates, 372, 372f – through m andible, 373, 373f – through temporomandibular joint, 372, 372f Malar bone. See Zygom atic (m alar) bone Malleolar prom inence, 263f, 269f Malleolus, developm ent of, 16t Malleus, 7f, 7t, 263f, 266, 266f, 268, 268f–269f, 275f – anterior process, 268f–269f – anterior view of, 268, 268f – articular surface for incus, 268f – handle of, 268f, 273f – head of, 262f, 268f – lateral process, 268f – m anubrium of, 263, 263f – neck of, 268f – posterior view of, 268, 268f Mamelon(s), 195t, 197t Mamillary tubercle, 5f Mamm ary gland(s), lymphatic drainage of, 71t Mamm ary ridges, 406, 406f Mamm illary body(ies), 78f, 82f–83f, 83t, 84f–85f, 85t–86t, 87, 87f – lesions of, 87 Mam millothalam ic fasciculus, 85f Mandible, 7t, 18f, 20f, 22f, 128f, 163f, 204f, 206f, 214, 321f–323f, 334f, 354f, 372, 373f, 376, 376f–377f, 379, 382f–383f – in adult s, 42, 42f – age-related changes in, 42, 42f – alveolar process, 40, 40f, 42, 43f, 184, 192t, 373f, 381f. See also Alveolar bone – age-related changes in, 42, 42f – angle of, 40, 40f–41f, 43f, 162f, 223f, 355f – age-related changes in, 42 – on dental panoram ic tom ogram (DPT), 200f – anterior view of, 40, 40f – basal bone, 42 – at birth, 42, 42f – body of, 19f, 21f, 23f, 40, 40f, 43f, 350f, 353, 353f, 373, 379f–380f – buccal shelf of, 40, 41f – in children, 42, 42f – condylar-hinge axis, 164, 166 – condylar process, 40, 40f – coronoid process, 40, 40f–41f, 43f, 156f–157f, 161f–164f, 190f, 313f, 350f – developm ent of, 16t – digastric fossa, 23f, 40f – edentulous, 42, 42f – external oblique ridge, 40f – fractures of, 43, 43f – head (condyle) of, 40, 40f–41f, 43f, 164, 164f, 165, 165f, 167f, 313f, 357, 357f, 363f, 371f–372f – articular surface of, 162f – on dental panoram ic tom ogram (DPT), 200f – inferior border of, 319, 319f – inner surface of, 46f – interalveolar septum, 41f – internal oblique ridge, 40f – lateral excursion of, 166, 166f – lingula, 40f–41f – m ental spines (tubercles), 21f, 23f, 40f–41f – m ovements of, in temporom andibular joint (TMJ), 166, 166f – mylohyoid groove, 23f, 40f, 164f – mylohyoid line, 40f – neck of, 40f, 164f – oblique left lateral view of, 40, 40f

– – – – – –

oblique line, 19f, 21f, 40f in old age, 42, 42f posterior view of, 40, 40f processes of, 164, 164f pterygoid fovea, 40, 40f–41f ram us of, 19f, 21f, 23f, 40, 40f, 43f, 148f, 155f, 158f, 158t, 313f, 350, 350f, 351, 351f, 356f, 357, 365f, 372, 372f – retrom olar fossa, 40, 41f – retrom olar triangle, 40, 41f – sublingual fossa, 40f – subm andibular fossa, 23f, 40f – superior view of, 40, 41f, 190, 190f – teeth of. See Teeth, m andibular Mandibular angle. See Angle, m andibular Mandibular canal. See Canal, mandibular Mandibular fractures, 43 Mandibular notch, 40, 40f, 165f Mandibular prominence, in facial developm ent 12-14, 12f-14f Margin – infraorbital, 21f, 36f – supraorbital, 21f Martegiani ring, 245f Mastication, alteration of, 36 Masticatory m uscular sling, 162, 162f Mastoid air cells, 32, 32f Mastoid antrum, 273f – aditus (inlet) to, 266, 266f Mastoid notch, 23f, 33f Maxilla, 7t, 18f, 20f, 22f, 36f, 172, 172f, 174f, 175, 175f, 178f, 228, 365f, 371f–372f, 376f–377f – alveolar bone, 42 – alveolar process, 21f, 38f, 184, 192t, 230f, 352f–353f, 372f, 381f. See also Alveolar bone – anterior lacrim al crest, 229f – anterior view of, 38f – basal bone, 42 – canine em inence, 38f – canine fossa, 38f – development of, 16t – facial surface of, 38f – fossa for lacrim al sac, 38f – frontal process, 21f, 37f–38f, 172f–173f, 176f, 228f – incisive fossa, 38f – inferior view of, 38f, 190, 190f – infraorbital groove, 38f – infratemporal surface of, 38f, 156f, 158t, 168t – isolated – anterior view of, 38f – left lateral view of, 38f – occlusal view of, 194, 194f – orbital surface of, 36f–38f, 228f–230f, 236f – palatine process, 23f, 26f, 39, 39f, 156f, 172f–176f, 214, 230f, 348f, 376f–377f – teeth of. See Teeth, m axillary – zygomatic process, 19f, 21f, 26f, 38f–39f, 170f, 181f, 228f, 357f Maxillary hiatus, 176f, 228 Maxillary prom inence, 6f – In facial developm ent, 12-14f Maxillary tuberosit y, 38f–39f, 156f, 168f Meatus – external acoustic, 19f, 33f, 156f, 161f, 164f, 262f, 358f, 372f – developm ent of, 8, 8f, 9t, 13t – lymphatic drainage of, 71t – venous drainage of, 64t–65t – inferior nasal, 173, 173f–174f, 175, 175f, 176t, 178f, 230f, 267f, 348f – internal acoustic, 29, 29f, 33, 33f, 131, 131f, 270f, 274f, 293f, 363, 370, 370f – fundus, posterior oblique view of, 271, 271f

536

ERRNVPHGLFRVRUJ

Index

– neurovascular pathways through, 33, 44f, 45t – right, cranial nerves in, 271, 271f – middle nasal, 173, 173f, 175, 175f, 176t, 178f, 230f, 267f, 348f – superior (ethm oid bone), 35f – superior nasal, 173, 173f, 175, 175f, 176t, 178f, 267f, 349f Meckel’s cartilage, 7f, 7t Medial em inence, 89f Medial forebrain bundle, 182 Medial lem niscus, 90, 90f–91f, 92, 92f, 93, 93f, 104f–105f, 219f Medial longitudinal fasciculus, 90f–93f, 260, 260f, 280, 280f, 281, 281f – course of, in brainstem , 261, 261f – lesion of, 261, 261f – rostral interstitial nucleus of, 260, 260f Medial nasal prom inence, in facial developm ent, 12-14, 12f-14f Mediastinitis, 334 Mediastinum , 412, 412f, 412t, 418, 418f, 434f – anterior view of, 419, 419f – content s of, 418, 418f, 418t, 419, 419f, 420, 420f – divisions of, 418, 418f – infection spread to, 334 – inferior, 412f, 412t, 418, 418f – anterior, 412t, 418, 418f, 418t – content s of, 418, 418f, 418t – m iddle, 412t, 418, 418f, 418t – posterior, 412t, 418, 418f, 418t – structures of, 421f – parasagit tal section, lateral view of, 420, 420f, 421, 421f – posterior, venous drainage of, 415t – posterior view of, 419, 419f – structures in, 420, 420f – superior, 412f, 412t, 418, 418f – contents of, 418, 418f, 418t Medulla oblongata, 5t, 44f, 45t, 74, 74f, 88, 88f, 89, 103f, 120f, 364f, 371f–372f – anterior part, 92, 92f – anterior view of, 134, 134f, 138f, 141, 141f – cross section of, 134, 134f, 136f, 138f, 141, 141f – developm ent of, 5, 5f – lower, transverse section through, 93, 93f – middle – transverse section just above, 92, 92f – transverse section just below, 93, 93f – posterior part, 92, 92f – pyram id of, 89f – upper, transverse section through, 92, 92f Meibom ian gland(s), 241, 241f, 243, 243f Melanocytes, in iris, 251 Membrane(s) – atlanto-occipital – anterior, 292f – posterior, 292f–293f, 294, 294f, 295, 295f, 303f – basilar, 274, 274f, 275, 275f, 276 – Bowm an, 249, 249f – Bruch, 248, 253, 253f – buccopharyngeal (oropharyngeal), 12 – Descem et, 249, 249f – intercostal, external, 404f – interosseous, of forearm , 388f, 394f–395f – obturator, 463f – oronasal, 13, 13f, 14, 14f – otolithic, 278, 278f – pharyngeal, 8, 8f – derivatives of, 8, 9t – quadrangular, 340f

– tectorial, 274–275, 275f, 276, 293f, 294, 294f–295f – thyrohyoid, 139f, 206f, 220f, 336f, 342f, 347f – thyroid, 323f – t ym panic, 32, 32f, 262, 262f, 263, 263f, 266f–267f, 268, 268f, 273f, 275, 275f, 277f – arteries of, 273, 273f – cone of light, 263, 263f – developm ent of, 8, 8f, 9t – innervation of, 266–267 – lateral, innervation of, 138t, 139f, 266–267 – lateral surface of, 269f – lateral view of, 263, 263f – m edial view of, 273, 273f – pars accida, 263, 263f – pars tensa, 263, 263f – quadrant s of, 263, 263f – superior recess of, 269f – um bo of, 263, 263f, 269f – venous drainage of, 64t–65t – vestibular (Reissner), 274, 274f Mem ory loss, 82 – in Korsako syndrom e, 87 Meninges, 102, 102f, 253f. See also Arachnoid m ater; Dura m ater; Pia m ater – arterial supply to, 61t – layers of, 102, 102f – spinal, 74f – venous drainage of, 64t, 66 Meningitis, 29, 32, 63, 102, 120t, 151, 331, 334 Mental (genial) spine(s) (tubercles). See Genial (m ental) spines Mental protuberance, 19f, 21f, 40f, 43f Mesencephalon, 5, 5f, 5t, 78f, 84, 84f–85f, 88f, 89, 103f, 107, 107f, 119, 119f, 121f, 234f, 360 – cross-section, superior view of, 120f – transverse section through, 90, 90f – ventricular system and, 95 Mesenchym e, derivatives of, 13t Mesentery(ies), 442, 442f–443f, 444, 445f, 448, 448f–449f – root, 445f Mesoappendix, 449f Mesocolon – sigm oid, 445f, 448f–449f, 464f–465f – transverse, 443f, 444, 444f–445f, 447f, 449f, 461f – root, 448f Mesoderm , 2 – axial, 2t – derivatives of, 2t – interm ediate, 2f, 2t – lateral plate, 2f, 2t – paraxial, 2f, 2t – cranial bones form ed from , 16t Mesopharynx, 216t Mesot ympanum , 269, 269f Metacarpal(s), 397f – base of, 389f – fth, 396f – base of, 394f–395f – rst, 394f, 397f – base of, 394f – head of, 389f – second, 394f, 397f – base of, 394f–395f – shaft of, 394f – shaft of, 389f – third, base of, 394f Metastatic disease, lymph node involvem ent in, 69–70 Metathalam us, 86 Metencephalon, 5t Microcephaly, 22f

Microglial cells, functions of, 73t Micrognathia, 9 Midbrain, 5, 5f, 5t, 88, 88f. See also Mesencephalon Midgut, blood supply to, 440, 440f Migraine, 102, 250t Miosis, 250, 250f, 329 Miotic agents, 250t Mitral cell(s), in olfactory bulb, 183, 183f Modiolus, 271, 271f, 274, 274f. See also Cochlea Molar(s), 41f, 190, 190f – deciduous, root s of, 198 – rst, 348, 348f – deciduous, 198, 198f – perm anent, 198, 198f – m andibular – rst, 197, 197f, 197t – occlusal view of, 197, 197f – rst (right) – buccal view of, 191, 191f – distal view of, 191, 191f – occlusal view of, 191, 191f – morphology of, 196, 196f, 197t – spread of infection from , potential routes for, 227, 227f, 227t – m axillary – rst, 195, 195f, 195t – m orphology of, 194, 194f, 195t – spread of infection from , potential routes for, 227, 227f, 227t – second, deciduous, 198, 198f – third, 191f, 192t, 194 – on dental panoram ic tom ogram (DPT), 200f – m andibular, 196, 196f, 197t, 227f – spread of infection from , potential routes for, 227, 227f, 227t – m axillary, 194, 194f, 195t Moll gland(s), 241, 241f Morgagni space, 343f. See also Ventricle(s), laryngeal Motor cortex – prim ary, 81, 81f, 108f – supplem entary, 108f Motor pathways, 108f, 108t, 109, 109f Mouth. See Oral cavit y Movem ent(s), control of, sensorim otor system and, 109, 109f Mucin(s), 243 Müller cells, 253, 253f Multiple sclerosis (MS), 232, 261 Mumps, 322 Muscarinic receptors, 110 Muscle(s) (named). See also Diaphragm – abductor digiti m inim i, 396f – abductor pollicis brevis, 396f – abductor pollicis longus, 394f – adductor pollicis – oblique head, 396f – transverse head, 396f – anconeus, 393f – aryepiglot tis, 7t – arytenoid – oblique, 7t, 223f, 225f, 333f, 338f – posterior, 7t – transverse, 7t, 223f, 225f, 333f, 338f, 338t – actions of, 338t, 339f – innervation of, 338t – auricular – anterior, 145f–146f, 147t, 264f – posterior, 7f, 145f–146f, 147t, 264f – superior, 145f–146f, 147t, 264f – biceps brachii, 393f – long head, 393f – short head, 393f – brachialis, 393f – brachioradialis, 394f

537

ERRNVPHGLFRVRUJ

– buccinator, 46f, 144f, 148f–149f, 149t, 152f, 155f, 159f, 212f, 214, 214f, 220f, 227f, 334f, 348f–350f, 352f, 354, 354f, 365f, 372f, 383f – buccopharyngeus, 218f, 218t – bulbospongiosus, 443f, 464f – ceratopharyngeus, 218f, 218t – cervical posterior intertransversarius, 331 – chondropharyngeus, 218f, 218t – ciliary, 113, 244, 244f, 248, 248f, 250, 250f – actions of, 258 – bers, 248 – innervation of, 120t – parasympathetic, 112t – sympathetic, 113t – coracobrachialis, anterior view of, 392, 392f – corrugator supercilii, 46f, 144f, 146f–147f, 147t – craniovertebral, 296t – crem aster, 439f – cricoarytenoid – lateral, 7t, 338f, 338t – actions of, 338t, 339f – innervation of, 338t – posterior, 223f, 225f, 333f, 335f, 338f, 338t, 342f – actions of, 338t, 339f – innervation of, 338t – cricopharyngeus, 218f, 218t, 222f – innervation of, 224 – cricothyroid, 7t, 139f, 322f–324f, 338f, 338t, 341f–342f, 346f – actions of, 338t, 339f – innervation of, 139t, 338t, 343, 343f – lateral, 342f – oblique part, 218f, 220f, 338f, 342f – straight part, 218f, 220f, 338f, 342f – deltoid, 298f – acrom ial part, 392f – clavicular part, 392f – lateral view of, 392, 392f – spinal part, 392f – depressor anguli oris, 46f, 144f–145f, 148f–149f, 149t, 296f, 353f, 373f – depressor labii inferioris, 46f, 144f–145f, 148f–149f, 149t – depressor septi nasi, 46f – depressor supercilii, 240f – digastric – action of, 211t, 312t – anterior belly, 7f, 7t, 46f, 163f, 189f, 204f, 210f, 220f, 226f–227f, 312–313, 312f–313f, 312t, 319f, 323f, 348f–350f, 354f, 377f–378f, 381f – innervation of, 122t–123t, 129t, 211t – origin of, 211t – innervation of, 312t, 313 – insertion of, 211t, 312t – interm ediate tendon, 210f – origin of, 312t – posterior belly, 7f, 7t, 47f, 210f, 216f, 220f, 222f–223f, 312–313, 312f–313f, 312t, 319f, 323f, 328, 328f, 357f–359f, 373f, 383f – innervation of, 130t, 131f, 132, 132f, 211t – origin of, 211t – dilator pupillae, 113 – sympathetic innervation of, 113t – erector spinae, 300–301, 304–305, 304f–305f, 304t – extensor carpi radialis brevis, 394f – extensor carpi radialis longus, 394f – extensor carpi ulnaris, 394f – extensor digiti m inim i, 394f

Index

– – – – – – – – – – – – –

–

– – – – – –

– – – – – – –

– – – – – – – –

– – –

– – – –

extensor digitorum , 394f extensor indicis, 394f extensor pollicis brevis, 394f extensor pollicis longus, 394f external oblique, 298f–299f, 300, 300f, 405f, 409f, 411f, 439f, 445f–446f, 448f exor carpi radialis, 395f exor carpi ulnaris, 395f exor digiti m inim i brevis, 396f exor digitorum profundus, 395f exor digitorum super cialis, 395f exor pollicis brevis, 396f exor pollicis longus, 395f frontalis (occipitofrontalis, frontal belly), 144f, 145, 145f–146f, 147t, 157f, 379f genioglossus, 10t, 46f, 141f, 185f, 204f, 210f–212f, 227f, 317f, 348f, 350f, 352, 352f, 353, 353f, 354, 354f, 373f, 378f, 382f action of, 205t innervation of, 205t insertion of, 205t origin of, 205t paralysis of, 141, 141f, 141t, 205, 205f geniohyoid, 46f, 163f, 185f, 204f, 210, 210f, 211, 211f–212f, 226f–227f, 312–313, 312f–313f, 312t, 348f–350f, 354, 354f, 376f, 382f – action of, 211t, 312t – innervation of, 189, 189f, 211t, 312t, 313, 316, 316t, 328 – insertion of, 211t, 312t – origin of, 211t, 312t – posterosuperior view of, 313f glossopharyngeus, 218f, 218t gluteus m axim us, 298f, 300f–301f gluteus m edius, 298f helicis m ajor, 264f helicis m inor, 264f Horner, 146 hyoglossus, 10t, 39f, 141f, 163f, 168t, 169f, 169t, 204f, 206f, 210f–212f, 220f, 317f, 350f, 354f, 373f, 381f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t iliacus, 438f iliocostalis, 304–305, 304f–305f, 304t iliocostalis cervicis, 301f, 304–305, 304f–305f, 304t iliocostalis lum borum , 301f, 304–305, 304f–305f, 304t iliocostalis thoracis, 300, 300f, 301, 301f, 304–305, 304f–305f, 304t iliopsoas, 438f infraspinatus, 298f, 390f – venous drainage of, 65t internal oblique, 298f–299f, 300, 300f–301f, 405f, 411f, 439f, 445f–446f, 448f interosseous, dorsal, 397, 397f interspinales, 304–305, 304f–305f, 304t, 382f–383f interspinales cervicis, 301f, 303, 303f, 304–305, 304f–305f, 304t – insertion of, 303f – origin of, 303f interspinales lum borum , 301f, 304–305, 304f–305f, 304t intertransversarii, 306–307, 306f–307f, 306t intertransversarii anteriores cervicis, 306–307, 306f, 306t intertransversarii cervicis, 303, 303f – insertion of, 303f – origin of, 303f

– intertransversarii laterales lum borum , 301f, 306–307, 306f–307f, 306t – intertransversarii m ediales lum borum , 301f, 306–307, 306f–307f, 306t – intertransversarii posteriores cervicis, 306–307, 306f–307f, 306t – latissim us dorsi, 298f–300f, 409f – aponeurotic origin of, 298f, 300, 300f – levator anguli oris, 46f, 144f, 148f–149f, 149t, 365f, 372f – levator ani, 464f–465f – levatores costarum , 301f, 306–307, 306f–307f, 306t – levatores costarum breves, 301f, 306–307, 306f–307f, 306t – levatores costarum longi, 301f, 306–307, 306f–307f, 306t – levator labii superioris, 144f–146f, 148f, 149t, 379f, 381f – levator labii superioris alaeque nasi, 46f, 144f–147f, 147t, 148f, 149t, 240f – levator palpebrae superioris, 121f, 124f, 232, 232f, 234f, 236, 236f, 238f–239f, 241, 241f–242f, 348f–349f, 352, 352f, 353, 353f–354f, 360f, 371f, 379f – innervation of, 120t – palsy, 235 – levator scapulae, 298f–299f, 327f, 359f, 366f–369f, 373f–375f, 379f, 383f – action of, 297t – innervation of, 297t – insertion of, 297t – origin of, 297t – levator veli palatini, 7t, 47f, 215f, 218f, 218t, 220f–221f, 223f, 267, 267f, 355f–357f, 365f, 371, 371f–372f, 378f, 381f – action of, 215t – innervation of, 138t, 215t – insertion of, 215t – origin of, 215t – longissim us, 304–305, 304f–305f, 304t – longissim us capitis, 46f–47f, 301f–302f, 303, 303f, 304–305, 304f–305f, 304t, 331, 359f, 366f–367f, 374f – insertion of, 303f – longissim us cervicis, 304–305, 304f–305f, 304t, 366f, 373f – longissim us thoracis, 300, 300f, 301, 301f, 304–305, 304f–305f, 304t – longitudinal (tongue), 354, 354f, 382f – inferior, 204f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t – superior, 204f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t – longus capitis, 47f, 310–311, 310f–311f, 310t, 325f, 357f, 371, 371f, 373, 373f–374f, 377f, 380f–381f – longus colli, 299f, 310–311, 310f–311f, 310t, 325f, 357f, 366f, 368f–369f, 373, 373f–375f, 382f – inferior oblique part, 310–311, 310f–311f, 310t – superior oblique part, 310–311, 310f–311f, 310t – vertical part, 310–311, 310f–311f, 310t – lum brical, 397, 397f – m asseter, 7f, 7t, 36, 46f–47f, 144f, 148f, 150f, 152f, 154f–155f, 157f–159f, 160t, 162, 162f, 212f, 216f, 227f, 326f, 334f, 349f–351f, 353f, 354, 354f–356f, 363, 363f–365f, 371f–373f

– – – –

– –

–

– – –

–

– – –

– – –

– action of, 160t, 161 – deep head, 160f, 160t, 162f–163f, 223f – deep part, 161f, 222f, 349f – innervation of, 122t–123t, 129t, 160t – insertion of, 160t – left lateral view of, 161, 161f – m iddle head, 160t – origin of, 160t – palpation of, 163 – spasm of, 36, 161 – super cial head, 160f, 160t, 162f–163f, 223f – super cial part, 161f, 222f, 349f m entalis, 46f, 144f–145f, 148f–149f, 149t, 373f m ulti dus, 301f, 306–307, 306f–307f, 306t, 359f, 374f, 383f m usculus uvulae, innervation of, 138t mylohyoid, 7t, 46f, 163f, 185, 185f, 204f, 210, 210f, 211, 211f–212f, 220f, 226f–227f, 312–313, 312f–313f, 312t, 323f, 348f–350f, 354, 354f, 373f, 376f–379f, 381f–382f – action of, 211t, 312t – innervation of, 122t–123t, 129t, 189, 189f, 211t, 312t, 313 – insertion of, 211t, 312t – origin of, 211t, 312t – posterosuperior view of, 313f mylopharyngeus, 218f, 218t nasalis, 144f–147f, 147t, 240f – alar part, 46f – transverse part, 46f oblique – inferior, 121f, 232, 232f, 234f, 236f, 348f, 352, 352f, 362f, 379f – actions of, 233f, 233t – innervation of, 120t, 233t – superior, 121f, 232, 232f, 234f, 238f–240f, 245, 245f, 349f–350f, 352, 352f, 354f, 360f – actions of, 233f, 233t – innervation of, 120t, 233t obliquus auriculae, 264f obliquus capitis, 383f obliquus capitis inferior, 301f–303f, 308f, 308t, 309, 309f, 331, 359f, 373f, 377f–379f, 381f – insertion of, 303f – origin of, 303f obliquus capitis superior, 46f–47f, 301f–303f, 308f, 308t, 309, 309f, 331, 359f – insertion of, 303f – origin of, 303f occipitalis (occipitofrontalis, occipital belly), 7f, 46f, 145, 145f, 147t occipitofrontalis, 151 om ohyoid, 21f, 299f, 322f, 326, 328f, 366f, 368f–369f – action of, 312t – inferior belly, 312–313, 312f–313f, 312t, 317f, 327f, 329f – insertion of, 312t – origin of, 312t – innervation of, 312t, 313, 316, 322, 328 – superior belly, 312–313, 312f–313f, 312t, 317f, 319f, 328, 329f – insertion of, 312t – origin of, 312t opponens digiti m inim i, 396f opponens pollicis, 396f orbicularis oculi, 144f–148f, 241, 241f, 243, 243f, 348f – lacrim al part, 46f, 146f, 147t – orbital part, 46f, 146f, 147t, 240f–241f, 379f

–

–

–

– – –

–

– –

– –

– – – – – –

– palpebral part, 146f, 147t, 240f–241f, 379f orbicularis oris, 46f, 144f–145f, 148f–149f, 149t, 371f–373f, 378f–379f, 381f–382f palatoglossus, 7t, 204f, 214f, 215, 335f – action of, 205t, 215t – innervation of, 138t, 205t, 206, 215t – insertion of, 205t, 215t – origin of, 205t, 215t palatopharyngeus, 7t, 214f, 221f, 223f, 225f, 333f–335f, 356f, 373f, 377f–378f – action of, 221t – innervation of, 138t, 221t – insertion of, 221t – origin of, 221t palm ar interosseous, 397, 397f palm aris longus, 395f papillary – anterior, 423f, 427f – posterior, 423f – septal, 423f pectoralis m ajor, 407f – abdom inal part, 392f, 439f – anterior view of, 392, 392f – clavicular part, 392f – sternocostal part, 392f, 439f pectoralis m inor, 391f, 407f – anterior view of, 391f pharyngeal constrictor – inferior, 204f, 218f, 218t, 220f, 222f–224f, 317f, 332f, 346f, 366f–367f, 374f, 378f, 419f, 431f – action of, 218t – cricopharyngeal part, 218f, 218t, 431f – innervation of, 218t – insertion of, 218t – origin of, 218t – thyropharyngeal part, 218f, 218t, 342f, 431f – m iddle, 204f, 218f, 218t, 220f, 222f–224f, 332f, 346f, 356f, 373f, 381f – action of, 218t – ceratopharyngeal part, 218f, 218t – chondropharyngeal part, 218f, 218t – innervation of, 218t – insertion of, 218t – origin of, 218t – superior, 214, 214f, 218f, 218t, 220f–224f, 227f, 332f, 382f – action of, 218t – buccopharyngeal part, 218f, 218t – glossopharyngeal part, 218f, 218t – innervation of, 218t – insertion of, 218t – mylopharyngeal part, 218f, 218t – origin of, 218t – pterygopharyngeal part, 218f, 218t piriform is, 466f plat ysm a, 46f, 144f–145f, 148f, 149t, 163f, 296, 296f, 317f, 320t, 321–322, 322f, 346f, 348f, 354f–355f, 366f, 374f, 379f – action of, 297t – innervation of, 296, 297t, 326 – insertion of, 297t – lateral view of, 296, 296f – origin of, 297t procerus, 144f, 146f, 147t, 240f, 378f pronator quadratus, 395f pronator teres, 395f psoas major, 299f, 408f, 411f, 438f, 461f psoas m inor, 408f, 438f pterygoid – lateral, 7t, 40, 46f–47f, 148f, 155f, 157f, 158, 158t, 159f, 161f, 162, 162f, 351f, 355f–357f, 363, 363f, 371, 371f–372f, 378f, 383f

538

ERRNVPHGLFRVRUJ

Index

– – –

– – –

– – – –

–

– –

– – – – – – –

– action of, 160t, 162 – inferior head, 46f, 158f, 160f, 160t, 162, 162f–163f, 167f – inferior part, 379f – innervation of, 122t–123t, 129t, 160t – insertion of, 160t – origin of, 160t – palpation of, 163 – superior head, 46f, 158f, 160f, 160t, 162, 162f–163f, 167f – superior part, 379f – medial, 7t, 30, 46f–47f, 128f, 148f, 155f, 158, 158t, 162, 162f, 216f, 222f–223f, 227f, 334f, 350f–351f, 355f–357f, 364f–365f, 371, 371f–373f, 378f–379f, 381f, 383f – action of, 160t – deep head, 158f–160f, 160t, 162, 162f–163f – innervation of, 122t–123t, 129t, 160t – insertion of, 160t – origin of, 160t – palpation of, 163 – super cial head, 158f–160f, 160t, 162, 162f–163f pterygopharyngeus, 218f, 218t pupillary dilator, 250, 250f, 251, 251f pupillary sphincter, 250, 250f, 251, 251f, 258, 258f – innervation of, 120t – parasympathetic innervation of, 112t quadratus lum borum , 299f, 301f, 408f, 411f, 438f rectii capitis anterioris, innervation of, 316 rectus, 121f, 124f, 232, 232f, 234f, 236f, 238f-239f, 244f-245f, 258, 258f, 348f–350f, 352f–354f, 361f-362f, 360f, 370f, 378, 378f-379f, 381, 383f – actions of, 233f, 233t – innervation of, 120t, 233t rectus abdom inis, 405f, 411f, 439f, 443f–445f, 448f, 464f–465f rectus capitis anterior, 47f, 310–311, 310f–311f, 310t rectus capitis lateralis, 47f, 310–311, 310f–311f, 310t rectus capitis posterior m ajor, 46f–47f, 301f–303f, 308f, 308t, 309, 309f, 331, 377f–378f, 381f, 383f – insertion of, 303f – origin of, 303f rectus capitis posterior minor, 46f–47f, 301f–303f, 308f, 308t, 309, 309f, 331, 377f, 380f, 383f – insertion of, 303f – origin of, 303f rhom boid m ajor, 298f, 300f, 383f rhom boid m inor, 298f, 300f, 367f, 375f, 383f – action of, 297t – innervation of, 297t – insertion of, 297t – origin of, 297t risorius, 144f–145f, 148f–149f, 149t rotatores, 306–307, 306f–307f, 306t rotatores breves, 306–307, 306f–307f, 306t rotatores longi, 306–307, 306f–307f, 306t rotatores thoracis breves, 301f rotatores thoracis longi, 301f salpingopharyngeus, 7t, 221f, 223f, 225f, 267, 267f, 333f – action of, 221t – innervation of, 221t – insertion of, 221t

–

– –

–

– –

– – –

– – – – –

–

–

–

–

–

– origin of, 221t scalene, 296t, 299f, 310–311, 310f–311f, 310t, 323-329, 324f, 325f, 327f, 329f, 357f, 358f, 367, 367f–369f, 369, 374f–375f, 401f, 404f, 412f, 414f, 419f, 426f, 430f – anterior view of, 310f–311f – innervation of, 316 semispinalis, 306–307, 306f–307f, 306t sem ispinalis capitis, 46f–47f, 300f–302f, 303, 303f, 306–307, 306f–307f, 306t, 329f, 330, 330f, 331, 364f–365f, 372f–375f, 377f–381f, 383f – insertion of, 303f sem ispinalis cervicis, 302f, 306–307, 306f–307f, 306t, 366f–368f, 374f–375f, 383f sem ispinalis thoracis, 306–307, 306f–307f, 306t serratus anterior, 298f, 369f, 390, 390f–391f, 409f, 439f – lateral view of, 391f serratus posterior inferior, 298f–299f, 300, 300f superior, 300f, 367f, 375f – action of, 297t – innervation of, 297t – insertion of, 297t – origin of, 297t spinalis, 300, 300f, 301, 301f, 304–305, 304f–305f, 304t spinalis cervicis, 301f, 304–305, 304f–305f, 304t, 373f–374f, 377f spinalis thoracis, 301f, 304–305, 304f–305f, 304t splenius, 306–307, 306f–307f, 306t splenius capitis, 46f–47f, 300f–302f, 303, 303f, 306–307, 306f–307f, 306t, 329f, 330, 330f, 331, 359f, 365f–366f, 372f–375f, 377f–379f, 381f, 383f – insertion of, 303f splenius cervicis, 300f–302f, 306–307, 306f–307f, 306t, 359f, 366f–368f, 374f, 379f stapedius, 7t, 268–269, 269f, 277, 277f – innervation of, 130t, 131, 131f, 269 – paralysis of, 131 – tendon of insertion, 266f sternocleidom astoid, 11, 11f, 46f–47f, 140f, 145, 145f, 152f, 154f, 158f, 212f, 224f–225f, 296, 296f, 297, 297f–299f, 302f, 303, 303f, 317f, 319f, 320t, 321, 321f, 322, 322f–323f, 326, 326f–327f, 328, 328f–329f, 330, 330f, 331, 332f–333f, 346f, 355f–359f, 366, 366f, 368f, 369, 369f, 373f–375f, 383f – action of, 297t – anterior view of, 296, 297f – clavicular head, 296f, 321f – innervation of, 46f–47f, 140t, 297t, 298, 316 – insertion of, 297t, 303f – lateral view of, 296, 296f – origin of, 297t – paralysis of, 140, 140f, 140t – posterior border of, 326f – posterior view of, 298, 298f – sternal head, 296f, 321f–322f sternohyoid, 210f, 220f, 299f, 312–313, 312f–313f, 312t, 317f, 321f–323f, 329f, 354f, 368f–369f, 374f–375f – action of, 312t – innervation of, 312t, 313, 316, 322, 328 – insertion of, 312t – origin of, 312t sternothyroid, 299f, 312–313, 312f–313f, 312t, 317f, 322f, 328f–329f, 369f, 374f–375f

–

–

–

– – – – –

–

– –

–

– – –

– –

– action of, 312t – innervation of, 312t, 313, 316, 322, 328 – insertion of, 312t – origin of, 312t st yloglossus, 10t, 46, 47f, 141f, 204f, 220f, 334f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t st ylohyoid, 7t, 47f, 210f–212f, 216f, 222f–223f, 312–313, 312f–313f, 312t, 317f, 323f, 358f, 373f, 379f, 383f – action of, 211t, 312t – innervation of, 130t, 131f, 132, 132f, 211t, 312t, 313 – insertion of, 211t, 312t – origin of, 211t, 312t st ylopharyngeus, 7f, 7t, 46, 47f, 204f, 218t, 220f, 222f–224f, 317f, 332f, 335f, 379f – action of, 221t – innervation of, 136t–137t, 219, 219f, 221t, 224 – insertion of, 221t – origin of, 221t subclavius, 391f – anterior view of, 391f subscapularis, 390f supinator, 394f supraspinatus, 298f, 390f – venous drainage of, 65t tarsal (of Müller) – inferior, 241, 241f – superior, 240f, 241, 241f – palsy, 235 temporalis, 7f, 7t, 36, 40, 46f–47f, 148f, 155f, 157t, 158f–159f, 160t, 162f, 174f, 350f–351f, 353f, 354, 354f–358f, 360f–361f, 362, 362f–363f, 363, 370f–372f, 379f – action of, 160t, 161 – deep head, 160f, 160t, 163f, 349f – innervation of, 122t–123t, 129t, 160t – insertion of, 160t – left lateral view of, 161, 161f – origin of, 160t – palpation of, 163 – super cial head, 160f, 160t, 163f, 349f temporoparietalis, 145, 145f, 370f tensor t ympani, 7t, 262f, 266f–267f, 268–269, 269f, 273f – innervation of, 122t–123t, 128, 129t, 269 tensor veli palatini, 7t, 47f, 215, 215f, 218f, 220f–221f, 223f, 267, 267f, 356f, 365f, 371, 371f–372f – action of, 215t – innervation of, 122t–123t, 128, 129t, 215t – insertion of, 215t – origin of, 215t teres m ajor, 298f teres m inor, 298f, 390f thyroarytenoid, 7t, 338f, 338t, 340f, 342f–343f, 355f – actions of, 338t, 339f – thyroepiglot tic part, 338f thyroepiglot tis, 7t thyrohyoid, 210f, 219f–220f, 312–313, 312f–313f, 312t, 317f, 322f–323f, 329f, 342f, 366f, 368f, 374f – action of, 312t – innervation of, 312t, 313, 316, 316t, 328 – insertion of, 312t – origin of, 312t

539

ERRNVPHGLFRVRUJ

– thyropharyngeus, 218f, 218t, 222f – transverse (tongue), 204f, 354, 354f–355f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t – transverse perineal, deep, 443f, 464f – transversus abdom inis, 299f, 301f, 405f, 408f, 411f, 438f–439f, 445f–446f, 448f – transversus auriculae, 264f – transversus thoracis, anterior view of, 404, 404f – trapezius, 46f–47f, 140f, 145, 145f, 296, 296f, 297, 297f, 299f–300f, 303, 303f, 317f, 319f, 320t, 321, 321f, 323f–324f, 326, 326f–327f, 330, 330f, 331, 359f, 365f–368f, 373f–375f, 378f, 383f – anterior border of, 326f – anterior view of, 296, 297f – inferior part, 296f, 298f – innervation of, 46f–47f, 140t, 298, 316 – m iddle part, 296f, 298f – origin of, 303f – paralysis of, 140, 140f, 140t – posterior view of, 296, 296f, 298, 298f – superior part, 296f, 298f, 302f – action of, 297t – innervation of, 297t – insertion of, 297t – origin of, 297t – venous drainage of, 65t – triceps brachii, 298f, 393f – lateral head, 393f – m edial head, 393f – uvular, 214f–215f, 221f, 223f, 225f, 333f – action of, 215t – innervation of, 215t – insertion of, 215t – origin of, 215t – vertical (tongue), 204f – action of, 205t – innervation of, 205t – insertion of, 205t – origin of, 205t – vocalis, 7t, 338f, 338t, 340, 340f, 343f, 354, 354f – actions of, 338t, 339f – innervation of, 338t – zygom aticus m ajor, 36, 46f, 144f–146f, 148f–149f, 149t – zygom aticus m inor, 46f, 144f–146f, 148f, 149t Muscle(s) (of region or organ). See also Diaphragm – abdom inal, 300 – abdom inal visceral, innervation of, 138t – of abdom inal wall, 438–439, 438f–439f – of arm , 392–393, 392f–393f – auricular, 264, 264f – left lateral view of, 146f – of back, 298–299, 298f–299f – extrinsic, 298, 300, 300f – innervation of, 298 – intertransverse system , 307, 307f – intrinsic, 3, 3f, 36f–37f, 46f–47f, 296t, 298, 299f, 300–307, 300f–307f, 304t, 306t, 320t, 330, 409f, 411f – innervation of, 298, 300, 330 – posterior view of, 300f–301f – transversospinal system , 307, 307f – buccal, 379 – of calvaria, 145–146, 146f, 147t – of craniovertebral joint, 308–309, 308f–309f, 308t, 383, 383f

Index

– – – – –

–

–

–

–

– – –

– – –

– –

–

–

–

–

–

of ear, 146, 146f, 147t epaxial, 3, 3f epicranial, 145 esophageal, functional architecture of, 431f extraocular, 232, 232f, 233, 233f, 233t, 236, 348–349, 352, 370, 379 – actions of, 233, 233f, 233t – prim ary, 233, 233f, 233t – secondary, 233, 233f, 233t – anterior view of, 232, 232f – arterial supply to, 61t – cranial nerves of, 120, 120f, 120t, 232, 232f, 233t, 234, 234f, 235t–236t, 237, 237f, 260, 260f, 261, 261f – innervation of, 121, 121f, 124, 124f, 125t, 231t, 232, 232f, 233t, 260, 260f, 261, 261f – superior view of, 232, 232f – venous drainage of, 64t of eye (ocular), 146–147, 146f–147f, 147t – extrinsic, 232, 232f – innervation of, 121, 121f of face, super cial – anterior view of, 144, 144f – lateral view of, 145, 145f of facial expression, 7f, 7t, 46f, 144, 146–149 – innervation of, 46f, 131f, 144, 147t, 149t, 150, 150f, 152, 152f – venous drainage of, 65t of forearm , 395f – deep, 395f – deep extensors, 394f – interm ediate, 395f – super cial, 395f – super cial extensors, 394f glossal, 202, 204, 204f, 205t of hand, 396, 396f, 397, 397f of head – inferior view of, 47f – left lateral view of, 46f – origins and insertions, 46f–47f of heart, pectinate, 423f hypaxial, 3, 3f infrahyoid, 7f, 210, 210f, 296t, 312–313, 312f–313f, 312t, 320t, 322 – action of, 162 – anterior view of, 312f–313f – lateral view of, 313f of inner ear, 269, 269f innervation of, 76f – m onosegm ental, 76f – m ultisegm ental, 76f intercostal, 407f, 410f, 420f–421f – external, 300, 300f–301f, 404f, 409f, 432f, 439f – innerm ost, 404f, 409f, 432f – internal, 404f, 409f, 432f, 439f intraocular – innervation of, 120t, 124, 124f, 125t, 234, 237, 237f – palsy, 235, 235f, 235t laryngeal, 7f, 7t, 338–339, 338f, 338t, 339f – actions of, 338t, 339f – innervation of, 139t–140t, 338t, 341–342, 342f, 343, 343f – intrinsic, innervation of, 138t – paralysis of, 343, 343t lingual – extrinsic, 204, 204f, 205t – innervation of, 141f, 141t, 204 – intrinsic, 204, 204f, 205t of m astication, 7f, 7t, 46f–47f, 144, 148f, 160–161, 160f–161f, 349, 354–355, 363, 372, 378, 378f, 379 – bim anual palpation of, 163

– – – – –

– –

– –

– –

– – – – –

– – –

– –

–

– – – –

– –

– blood supply to, 186, 186f – coronal section at level of sphenoid sinus, 163, 163f – deep, 162–163 – innervation of, 46f–47f, 144, 150, 150f, 152, 152f, 160 – posterior view of, 163, 163f – venous drainage of, 65t m etacarpal, 397, 397f of m outh, 148, 148f–149f, 149t anterior view of, 148f left lateral view of, 148f of neck, 296–297, 296f–297f, 298–299, 298f–299f – innervation of, 296t – super cial, 297t – lateral view of, 145, 145f – venous drainage of, 65t of nose, 146–147, 146f–147f, 147t nuchal, 46f–47f, 144, 302, 302f, 383, 383f – innervation of, 46f–47f – short, 296t, 302, 302f, 303, 303f, 308–309, 308f–309f, 308t – innervation of, 303 in nuchal region, 302–303, 302f–303f of oral oor, 210, 210f, 211t, 376 – innervation of, 189, 189f, 211t – lateral view of, 189, 189f of palpebral ssure, 146–147, 146f–147f, 147t pharyngeal, 7f, 7t, 47f, 216, 216f, 220, 220f, 222, 222f, 373f, 378, 378f – innervation of, 138t–139t, 224, 224f, 343, 343f – internal, 222, 223f – posterior view of, 222, 222f pharyngeal constrictors, 7t, 218, 218f, 218t, 219f, 222, 223f, 346f pharyngeal elevators, 221t, 222, 223f – posterior view of, 221, 221f of posterior abdom inal wall, 438, 438f of posterior neck, 302–303, 302f–303f, 365 prevertebral, 47f, 296t, 310–311, 310f–311f, 310t, 320t, 373–374, 378f – anterior view of, 310f–311f – innervation of, 47f rotator cu , 390, 390f of shoulder, 390, 390f, 391, 391f, 392, 392f of soft palate, 215, 215f, 215t, 221, 221f – innervation of, 138t – posterior view of, 221, 221f subcostal, 404f suboccipital, 302, 302f, 309 – lateral view of, 309, 309f – posterior view of, 309, 309f suprahyoid, 210, 296t, 312–313, 312f–313f, 312t – action of, 162 – anterior view of, 313f – lateral view of, 312f–313f thoracic, 300 thoracic visceral, innervation of, 138t of thoracic wall, 404, 404f of tongue, 202, 204, 204f, 205t – coronal section, anterior view of, 204, 204f – developm ent of, 10, 10t – extrinsic, 354 – innervation of, 204 – intrinsic, 348f, 350f, 354, 377f – lateral view of, 204, 204f of trunk, 300, 300f vertebral – anterior, 296t, 311 – lateral, 296t, 311

– of wrist, 396, 396f Muscular triangle (neck), 318f, 318t, 319f Musculus uvulae. See Muscle(s) (nam ed), uvular Mydriasis, 113t, 120t, 235, 235f, 235t, 250, 250f Mydriatic agents, 250t Myelencephalon, 5t Myelination, 73, 73f Myocardium , 426f Myopia (nearsightedness), 245, 245f Myotom e(s), 3, 3f

N Naris (pl., nares), 172, 172f, 364f Nasal aperture(s) – anterior, 173, 173f – posterior. See Choana (pl., choanae) Nasal bone(s), 18f–21f, 24f–25f, 37, 37f–38f, 172, 172f–173f, 176f, 228f–229f, 370f–371f, 380f – anterior view of, 37, 37f – developm ent of, 16t – fractures of, 37 Nasal cavit y, 21f, 35, 39, 39f, 175, 175f, 227f, 231t, 333f, 348, 350f, 361f–363f, 364, 364f, 376, 382 – comm unication with pterygopalatine fossa, 169f, 169t – coronal section, anterior view of, 174, 174f – developm ent of, 13, 13f – oor of, 39f – glands of, 133f – innervation of, 133, 133f – autonom ic, 110 – parasympathetic, 112t – sympathetic, 113t – lymphatic drainage of, 71t – m edial view of, 267, 267f – m ucosa of, 178, 178f – functional states of, 179, 179f – histology of, 179, 179f – innervation of, 267 – pharyngeal com m unication, 216t – posterior view of, 178, 178f – sagit tal section, m edial view of, 176, 176f – transverse section, inferior view of, 174, 174f – wall of – lateral, 126f, 173, 173f, 178, 178f – arterial supply to, 61t – arteries of, 181, 181f – bones of, 172, 172f – lateral view of, 181f – m edial view of, 180, 180f – nerves of, 181, 181f – neurovasculature of, 180, 180f – venous drainage of, 64t – left lateral view of, 118, 118f – m edial, 178 – m ucosa of, 178, 178f Nasal cartilage. See Cartilage, nasal Nasal concha (pl., conchae), 20f–21f, 26f, 35, 39f, 118, 172, 172f-176f, 173, 175, 178, 178f–181f, 217f, 230f, 242f, 348, 348f–349f, 352f–353f, 364f, 372f, 377, 377f, 380, 380f – congested m ucosa of, 179f – decongested m ucosa of, 179f – developm ent of, 13, 13f – venous drainage of, 64t–65t Nasal crest, 39f, 173f Nasal pit, 12, 12f–13f Nasal placode(s), developm ent of, 12, 12f Nasal septum , 126f, 173, 173f, 174, 175f, 178f–179f, 185f, 216f, 350, 350f,

352f–353f, 361f, 364f, 371f, 376, 376f, 380 – anterosuperior – arterial supply to, 61t – venous drainage of, 64t – arteries of, 181, 181f – bones of, 172, 172f – bony, 173 – cartilaginous, 173, 174f, 348, 348f, 362f–364f – on dental panoram ic tom ogram (DPT), 200f – development of, 13–14, 14f – deviations of, 173 – innervation of, 180, 180f, 181, 181f – lateral view of, 181, 181f – left lateral view of, 118, 118f – m ucosa of, 178, 178f – nerves of, 181, 181f – neurovasculature of, 180, 180f – parasagit tal section, left lateral view of, 180, 180f – posterior m argin of, 179f – posterosuperior – arterial supply to, 61t – venous drainage of, 64t – venous drainage of, 64t–65t Nasal spine(s) – anterior, 19f, 21f, 38f–39f, 172f – posterior, 27f, 39f Nasal turbinate(s) – inferior, 216f, 225f, 333f – m iddle, 216f, 225f, 333f – m ucosal folds of, 175f Nasal vestibule, 178f – lymphatic drainage of, 71t Nasion, 21f, 37f, 172f, 228f–229f Nasolabial crease(s), 184, 184f Nasolacrim al duct, 228, 231t, 242, 242f, 371, 371f – development of, 12 – drainage of, 176, 176f, 176t Naso-optic furrow, 12 Nasom axillary suture, 172f Nasopharyngeal bleeding, 59 Nasopharynx, 163f, 177f, 185f, 216t, 351, 351f, 355, 355f, 356, 356f–357f, 364, 364f, 376f, 380, 380f, 382, 382f – com m unication with pterygopalatine fossa, 169f, 169t – innervation of, 136t–137t – lymphatic drainage of, 71t Nasotracheal intubation, 344 Neck – anterior, 322, 322f – anterior view of, 321f, 324, 324f – arteries of, 314, 314f, 314t – bony prom inences in, 319, 319f – boundaries in – inferior, 319, 319f – superior, 319, 319f – coronal MRI – anterior, 354–357, 354f–357f – posterior, 358–359, 358f–359f – coronal section(s) – of great vessels (MRI), 356, 356f – of lingual m uscles (MRI), 354, 354f – of m uscles of m astication (MRI), 355, 355f – of soft palate (MRI), 355, 355f – of temporom andibular joint (MRI), 357, 357f – through cervical vertebrae and spinal nerves (MRI), 358, 358f – through nuchal m uscles (MRI), 359, 359f – cyst s in – lateral, 11, 11f – median, 11, 11f

540

ERRNVPHGLFRVRUJ

Index

– deepest layers of, anterior view of, 325, 325f – fascial planes of, 299, 299f – fascial relationships in, 321, 321f – fascial spaces in, 320, 320f, 320t – stulas in – lateral, 11, 11f – m edian, 11, 11f – innervation of, 316, 316f, 316t – lateral, 326, 326f–327f – deep, 328, 328f, 329, 329f – sensory innervation of, 153, 153f – lymphatic drainage of, directions of, 69, 69f – lymphatics of, 68, 68f, 70, 70f, 71t – m idsagit tal section, lateral view of, 321, 321f – m idsagit tal section (MRI), 382, 382f – m uscles of, 296–297, 296f–297f, 298–299, 298f–299f – anterior, 296t – dissection of, 319, 319f – innervation of, 296t – posterior, 296t – super cial, 296, 296f–297f, 296t–297t – posterior, 330–331, 330f–331f – cutaneous innervation of, 331, 331f – m uscles of, 302–303, 302f–303f – root, 323, 323f, 324, 324f – sagit tal section(s), 382–383, 382f–383f – through carotid bifurcation, 383, 383f – super cial, venous drainage of, 65, 65f, 65t – transverse section(s) – caudal, 368–369, 368f–369f – cranial, 366–367, 366f–367f – at level of C6/C7 vertebral junction, 368, 368f – at level of C7/T1 vertebral junction, 369, 369f – at level of C5 vertebral body, 366, 366f – at level of C6 vertebral body, 368, 368f – at level of T1/T2 vertebral junction, 369, 369f – through C4 vertebral body (MRI), 374, 374f – through C6 vertebral body, 367, 367f – through C6 vertebral body (MRI), 374, 374f – through C7 vertebral body (MRI), 375, 375f – veins of, 62, 62f, 315, 315f, 315t – swelling of, 328, 328f – venous drainage of, 415t Neocortex, 80 – Brodm ann areas in, 81, 81f Nerve(s) (nam ed) – abducent (CN VI), 44f, 45t, 89f, 114f, 114t, 120, 120f, 120t, 121, 121f, 124f, 225f, 231t, 232f, 234, 234f, 235t–236t, 237f, 239f, 333f, 351f – course of, 120t, 235t – intracavernous, 238, 238f – bers, 235t – distribution of, 120t – t ypes of, 115t – function, 115t, 235t – lesions of, 120t – nucleus/nuclei of, 88f, 91, 91f, 116t, 117f, 120f, 120t, 130f, 235t, 260, 260f, 261, 261f, 280f, 281, 281f – palsy, 120t, 235, 235f, 235t – passage through skull, 115t – traum a to, 232 – accessory (CN XI), 44f, 45t, 46f–47f, 89f, 93f, 114f, 114t, 140, 140f, 140t,

–

–

– –

–

– – – – – – – –

– –

–

– – –

224, 224f–225f, 298, 316, 323f–324f, 326, 326f–328f, 329, 329f, 330, 330f, 332f–333f, 343, 364, 364f–365f, 366, 371, 371f, 378f – branch(es), external, 140f, 366f – course of, 140t – cranial root, 45t, 140f, 140t – bers, 140t – branchiom otor, 140t – general som atom otor, 140t – t ypes of, 115t – function, 115t – lesions of, 140, 140f, 140t – nucleus/nuclei of, 93, 93f, 116t, 117f, 280f – spinal, 117f, 140f, 140t – passage through skull, 115t – spinal part, 297t – spinal root, 140f, 140t, 364f alveolar – anterior, 127t – inferior, 348f–349f, 351f, 356f, 365f, 379f – m iddle, 127t – superior, 127t – anterior, 126f, 127t – m iddle, 126f, 127t ampullary – anterior, 135f, 271f, 278f – lateral, 135f, 271f, 278f – posterior, 135f, 271f, 278f antebrachial cutaneous, m edial, 400t, 401f auricular – great, 152f, 153, 153f–154f, 265, 265f, 316f, 316t, 317f, 322f, 326, 326f–327f, 330, 330f, 331, 331f – posterior, 130t, 131f, 132, 132f, 149t, 154f, 266 auriculotem poral (CN V3 ), 112t, 128, 128f, 129t, 150f, 152f, 154f–155f, 157f, 157t, 158f, 159, 159f, 159t, 165, 165f, 188f, 213t, 265, 265f, 266–267, 364f, 371f axillary, 400f, 400t, 401f brachial cutaneous, m edial, 400f, 400t, 401f buccal, long, 128f, 129t, 155f, 158f–159f, 159t, 188f, 349f, 364f cardiac, 418t – cervical, 426, 426f caroticot ympanic, 137f cervical, transverse, 153, 153f, 316f, 316t, 317f, 322f, 326, 326f–327f chorda t ympani, 32f, 33 ciliary (CN V1 ) – long, 113, 113f, 113t, 121, 124, 124f, 125t, 237, 239f – short, 112t, 121, 121f, 124, 124f, 125t, 234f, 236t, 237f, 239, 239f cochlear, 266f, 271f, 273f, 274, 274f, 276, 276f, 277, 277f cranial. See individually nam ed nerves (abducent, accessory spinal, facial, glossopharyngeal, hypoglossal, olfactory, optic, ocular, oculomotor, trigeminal, trochlear, vagal) deep temporal, 129t, 155f, 157t, 158f–159f, 159t–160t – anterior, 129t – posterior, 129t, 165, 165f descendens cervicalis, 189f descendens hypoglossi, 189f, 224f, 332f ethm oidal – anterior, 124f, 125t, 126f, 181f, 231t, 239f – branch(es) – external nasal, 126f, 181f – internal nasal, 126f, 181f

–

– –

– – –

– lateral nasal, 126f, 181f – posterior, 124f, 125t, 231t, 239f facial (CN VII), 7, 7f, 7t, 32f, 33, 44f, 45t, 46f–47f, 79f, 89f, 91f, 108f, 110, 110f, 112, 112f, 112t, 114f, 114t, 123t, 128, 128f, 132f, 133, 133f, 144, 149t, 150, 150f, 152, 155f, 157f–159f, 206, 207f, 208, 208f, 211t, 213t, 225f, 237, 241, 257, 257f, 264–265, 265f–266f, 267, 267f, 269f–270f, 271, 271f–272f, 272t, 273f–274f, 277f, 296, 312t, 333f, 363, 363f–365f, 370, 370f, 379, 379f anastom osis, 326f–327f branch(es), 130, 130f, 130t, 131, 131f, 132, 132f, 133, 133f, 267 – auricular, 267 – buccal, 132, 132f, 149t, 150f – cervical, 132, 132f, 149t, 297t, 322, 326, 326f – external, 130, 130f, 130t – glandular, 133, 133f – internal, 130, 130f, 130t – m andibular, 132, 132f, 149t, 150f, 328f – stapedial, 269 – super cial, 130 – temporal, 132, 132f, 149t, 150f, 157f, 157t – zygom atic, 132, 132f, 149t, 150f, 157f – course of, 130, 130f, 130t, 131, 131f – bers, 130, 133, 133f – branchiom otor, 130t, 131, 131f, 132, 132f, 277 – distribution of, 130t – general som atic a erent, 130t – parasympathetic, 130t – postganglionic sympathetic, 133, 133f – som atosensory, 131, 131f – special visceral a erent, 130t – t ypes of, 115t – function, 115t – ganglia, 133, 133f – genu of, 242 – external, 130–131 – lesions of, 131, 131f – internal, 130f – lesions of, 130t, 131, 131f, 207 – m otor root, 111t – nucleus/nuclei of, 88f, 116t, 117f, 123t, 130, 130f, 130t – m otor, 91, 91f, 117f, 130f, 130t, 132, 132f – lower (caudal) part, 132 – upper (cranial) part, 132 – paralysis (Bell palsy), 131, 131f, 146 – passage through skull, 29, 32–33, 115t – preganglionic parasym pathetic, 133 frontal (CN V1 ), 44f, 45t, 121f, 124, 124f, 125t, 231t, 234f, 236t, 237f–239f geniohyoid, 189, 189f glossopharyngeal (CN IX), 7, 7f, 7t, 44f, 45t, 47f, 89f, 110, 110f, 112, 112f, 112t, 114f, 114t, 123t, 128, 136, 136f, 136t, 203t, 206f, 207, 207f, 208, 208f, 213t, 218t, 219, 219f, 221t, 224, 224f–225f, 267, 267f, 316, 329, 332f–333f, 335f, 343, 343f, 364, 364f–365f, 371, 371f, 378f – branch(es), 136f–137f, 137t – carotid, 137f, 137t – lingual, 137f, 137t – m uscular, 137f, 137t – pharyngeal, 137f, 137t – tonsillar, 137f, 137t – course of, 136t – bers, 137t

541

ERRNVPHGLFRVRUJ

– –

–

–

–

– – – – –

–

–

–

–

– branchiom otor, 136t – distribution of, 136f, 136t – general som atic a erent, 136t – parasympathetic, 136t – t ypes of, 115t – viscerosensory, 136t – function, 115t – ganglia, 136f, 136t, 137f – lesions of, 136t, 217 – m otor root, 111t – nucleus/nuclei of, 116t, 117f, 136f, 136t – passage through skull, 115t hypogastric, 460f hypoglossal (CN XII), 10, 10t, 34, 34f, 44f, 45t, 47f, 89f, 92f–93f, 108f, 114f, 114t, 116f, 189, 189f, 204, 205t, 206, 206f, 224f–225f, 312t, 313, 316, 316f–317f, 322, 322f, 328, 328f, 329, 329f, 332f–333f, 352, 364, 365f, 378f – arc of, 317f – course of, 141, 141f, 141t – bers – distribution of, 141f, 141t – t ype of, 115t, 141t – function, 115t – lesions of, 141, 141f, 141t – nucleus of, 88f, 92f, 93, 93f, 116f, 116t, 117f, 141, 141f, 141t – palsy, unilateral, 205, 205f – passage through skull, 115t – trigone of, 89f, 141f inferior alveolar, 40, 128f, 129t, 155f, 158, 158f–159f, 159t, 163f, 188f–189f, 197t, 211f–212f, 227f, 313, 334f, 350f – branch(es) – incisive, 129t, 197t – inferior dental, 128f, 188f inferior nasal, posterior – lateral, 171t – m edial, 171t infraorbital (CN V2 ), 36, 126f, 127t, 128f, 150f, 152f, 154f–155f, 169t, 171f, 171t, 174, 174f, 188f, 231t, 236f, 236t, 238, 240, 240f–241f, 348, 348f, 352, 352f–353f, 363, 363f inferior palpebral branches, 240f infratrochlear, 124f, 125t, 150f, 152f, 154f–155f, 231t, 239f–240f intercostobrachial, 401f interosseous (arm ), anterior, 400f labial – inferior, 150f – superior, 188f lacrim al (CN V1 ), 44f, 45t, 112t, 121f, 124, 124f, 125t, 127t, 133, 150f, 155f, 213t, 231t, 234f, 236t, 237, 237f, 238, 238f–240f, 242 laryngeal, 7f – external, 139f, 139t, 218t, 224, 322, 322f, 324f, 338t, 341, 341f, 342, 342f, 343, 343f – internal, 139f, 139t, 207, 218t, 225f, 322, 322f, 328f, 333f, 335f, 341, 341f, 342, 342f–343f – foram en for, in thyrohyoid m em brane, 336f – superior, 332f–333f, 417f lingual, 112t, 123t, 128, 128f, 129t, 131, 131f, 133, 133f, 155f, 158f–159f, 159t, 188f–189f, 203t, 206, 206f, 207, 207f, 208, 208f, 211, 211f–212f, 213t, 317f, 334f, 349f–351f, 352, 352f, 365f, 377f – branch(es) – postganglionic, 206f – preganglionic, 206f m andibular (CN V3 ), 7, 7f, 7t, 10, 10t, 44f, 45t, 46f–47f, 106, 106f, 122,

Index

– – –

– – – – – –

–

–

– – –

–

122f–123f, 123t, 124f, 126f, 128, 128f, 129t, 131f, 133, 133f, 152, 153f, 159, 159t, 160, 181f, 188, 188f–189f, 203t, 206, 207f, 351, 351f, 363, 363f, 370f, 371, 371f – anterior division of, 129t, 165, 165f – autonomic sca olding, 129t – branch(es), 158, 165, 165f – direct, 159t – m eningeal, 44f – recurrent laryngeal, 45t – recurrent m eningeal, 159t – posterior division of, 129t, 165, 165f – trunk of, 129t m asseteric, 128f, 129t, 159t–160t, 165, 165f, 188f, 364f m axillary, 127t m axillary (CN V2 ), 36, 44f, 45t, 106, 106f, 112t, 113, 113t, 122f–123f, 123t, 124f, 126, 126f, 127t, 128f, 131f, 133f, 153f, 159t, 169, 169t, 171f, 171t, 180, 180f, 188, 188f, 213t, 214, 238, 267, 348, 350f–351f, 370f, 378f – autonom ic sca olding, 127t, 169 – branch(es), 169t, 181, 181f – direct, 126f, 127t – ganglionic, 126f, 127t – lateral superior posterior nasal, 181f – medial superior posterior nasal, 180f–181f – orbital, 126f, 127t, 171f, 171t – passing through pterygopalatine ganglion, 126f, 127t – pharyngeal, 169t m edian, 400f, 400t, 401f m eningeal, 125t – m iddle, 126f, 127t m ental, 128f, 129t, 150f, 152f, 154f–155f, 188f m usculocutaneous, 400f, 400t, 401f mylohyoid, 128f, 129t, 159t, 188f, 189, 189f, 211f, 211t, 212f, 312t, 313 nasal – external, 125t, 150f, 152f, 154f–155f – internal, 125t nasociliary (CN V1 ), 44f, 45t, 113, 113f, 113t, 121, 124, 124f, 125t, 231t, 236t, 237, 237f, 238, 238f–239f nasopalatine, 44f, 45t, 112t, 126f, 127t, 169t, 171f, 171t, 180f–181f, 188f, 214, 214f, 214t nervus interm edius, 271, 271f, 273f occipital greater, 152f–153f, 154, 154f, 330f, 331, 331f, 378f – site of em ergence from fascia, 331, 331f – lesser, 152f, 153, 153f, 154, 154f, 265, 265f, 316f, 316t, 317f, 326, 326f–327f, 330, 330f, 331, 331f – site of em ergence from fascia, 331, 331f – palpation of, 331, 331f – third, 330f, 331 oculom otor (CN III), 44f, 45t, 89f–90f, 110, 110f, 112, 112f, 112t, 114f, 114t, 120, 120f, 120t, 121, 121f, 124f, 225f, 231t, 232f, 234, 234f, 235t–236t, 237f, 239f, 241, 257, 257f, 258, 258f, 261f, 333f, 351f, 353, 361, 361f, 377f – branch(es) – inferior, 236t, 237, 237f–238f – superior, 238f – course of, 120t, 235t – intracavernous, 238, 238f – bers, 234, 234f, 235t – distribution of, 120t – t ypes of, 115t – function, 115t, 235t

– – – – – –

– –

–

–

–

– –

– – –

–

–

– inferior division, 234f – lesions of, 120t – m otor root, 111t – nucleus/nuclei of, 88f, 90, 90f, 116t, 117f, 120, 120f, 120t, 235t, 260, 260f, 261, 261f, 280, 280f, 281, 281f – palsy, 120t, 232–233, 235, 235f, 235t, 241, 250t – passage through skull, 115t – traum a to, 232 olfactory (CN I), 13, 44f, 45t, 78f, 99f, 114f, 114t, 118, 118f, 126f, 181 bers, 180f, 181, 181f–182f – t ypes of, 115t function, 115t passage through skull, 115t trigone of, 82f ophthalm ic (CN V1 ), 44f, 45t, 89, 106, 106f, 119f, 122f–123f, 123t, 124, 124f, 125t, 126f, 131f, 153f, 180, 180f, 231t, 238, 351f – branch(es), 181, 181f – anterior septal, 180f – m edial nasal, 180f–181f divisions of, in orbit, 124, 124f, 125t optic (CN II), 13t, 44f, 45t, 78f, 84, 85f, 89, 102f, 114f, 114t, 119, 119f, 121f, 124f, 163f, 174f, 231t, 232, 232f, 234f, 236, 236f, 236t, 237, 237f, 238, 238f, 239, 239f, 244, 244f–245f, 247f, 252, 252f, 253–254, 254f, 255, 255f, 257, 257f, 258, 258f, 259, 259f, 349, 349f–351f, 353, 353f–354f, 361, 361f, 370, 370f, 377f, 378, 378f, 380, 380f, 381, 381f, 383f – arteries of, 247, 247f – constriction of, 251 – ber t ype, 115t – function, 115t – injury to, 361 – lesions of, 119, 256, 256f – unilateral, 259 – passage through skull, 115t – sheath of, 236f palatine, 44f, 45t, 112t, 126f, 127t, 169t, 171f, 171t, 180f–181f, 188f, 214, 214f, 214t, 348f – descending, 180f – posteroinferior lateral nasal branches, 181f pectoral – lateral, 400f, 400t, 401f – m edial, 400f, 400t, 401f petrosal, 44, 44f, 45t, 112t, 113, 113f, 113t, 127t, 128, 128f, 129t, 130, 130t, 131, 131f, 133, 133f, 137f, 137t, 159t, 169t, 171t, 213t, 242, 266f, 267, 267f, 271f–272f, 274f pharyngeal, 126f, 127t, 171f phrenic, 316, 316f, 316t, 323, 323f, 324, 324f, 325, 325f, 326, 327f, 329, 329f, 367, 367f, 369f, 400f–401f, 409f, 410, 410f–412f, 416, 416f, 418t, 419f–421f, 426f, 433f – pericardial branches, 412f to posterior digastric, 131f, 132, 132f, 154f pterygoid, 128f, 129t, 159t–160t, 188f, 215t, 269 of pterygoid canal (vidian), 112t, 113, 113f, 113t, 133, 133f, 169t, 171f, 171t, 213t, 267 radial, 400f, 400t, 401f – branch(es) – deep, 400f – super cial, 400f recurrent laryngeal, 139t, 140f, 218t, 224, 225f, 323, 323f, 324, 324f–325f, 333f, 335f, 338t, 341, 341f, 342,

– – – – – –

–

– – – – – –

– –

– –

342f, 343, 343f, 347, 347f, 412f, 416, 416f–417f, 418t, 419f, 421f, 426f, 437f – injury to, 416 – lesions of, 138t, 343f, 343t – palsy, 138t, 338t, 341, 347 – tracheal branches, 342f recurrent m eningeal, 128, 129t, 188f saccular, 135f, 271f, 278f sacculo-ampullary, 271f sacral, rst, anterior ram us, 460f scapular, dorsal, 297t, 401f spinal, 289, 289f – anterior ram us, 289f – anterior root, 289f – C1, 141f, 189, 189f, 289, 289f, 316, 316f, 316t, 317f – anterior ram us, 189f, 211t, 310t, 312t – branch(es) – geniohyoid, 189, 189f, 317f, 322 – thyrohyoid, 206f, 317f, 322, 322f, 328f – m otor bers of, 328 – posterior ram us, 308, 308t, 309 – ventral root, 89f – C2, 154, 154f, 316, 316f, 316t, 317f, 331, 377f – posterior ram us, 330f – C3, 317f, 331, 377f–378f – posterior ram us, 330f – C4, 366f, 368f, 377f – root, 358f – C5, 289, 289f, 316f, 366f–368f, 377f, 400f–401f – root, 358f – C6, 366f–368f, 377f, 401f – anterior ram us of, 369f – posterior ramus, 330f – C7, 289, 289f, 367f–368f, 377f, 401f – anterior ram us of, 369f – root, 374f – C8, 368f, 401f – anterior ram us of, 369f – root, 324f, 375, 375f – C2-C3, 316, 316f, 316t – C2-C6, anterior ram i, 310t – C3-C4, 316, 316f, 316t – C4-C5, anterior ram i, 297t – m otor bers, 316 – posterior ram us, 289f – posterior root, 289f – sensory bers, 316 – T1, 369f, 400f–401f – root, 324f – thoracic, anterior ram i, 297t splanchnic – greater, 110f, 411f, 416f–417f, 417t, 420f, 437f, 460f – lesser, 417f, 417t, 460f stapedial, 130t, 131, 131f, 132, 277f to stapedius, 267, 267f, 269f to st ylohyoid, 131f, 132, 132f, 154f to subclavius, 400f, 400t, 401f suboccipital, 303, 308, 308t, 310t, 331 subscapular, 400f–401f – dorsal, 400f, 400t – lower, 400t – upper, 400t superior alveolar, 126f, 127t, 128f, 158f, 159t, 169t, 171f, 188f, 195t superior laryngeal, 139f, 139t, 224f–225f, 341, 341f–342f, 343, 343f, 426f, 437f – lesions of, 343f, 343t superior nasal, posterior, 126f, 127t, 171t superior palpebral, 150f

– supraclavicular, 153, 153f, 316f, 316t, 317f, 322f, 326, 326f-327f, 331, 331f, 406f – supraorbital, 121f, 124f, 125t, 152f, 154f–155f, 231t, 234f, 236t, 237f, 239f, 240, 240f, 331f, 352, 352f, 353, 353f – branch(es) , 150f, 231t, 238f–239f, 240f – suprascapular, 400f, 400t, 401f – supratrochlear, 124f, 125t, 150f, 152f, 154f–155f, 231t, 236t, 238f–240f – of tensor t ym pani, 128f – of tensor veli palatini, 128f – thoracic, long, 400f, 400t, 401f – thoracodorsal, 400f, 400t, 401f – trigem inal (CN V), 47f, 79f, 89f, 91f, 111t, 114f, 114t, 122, 122f, 122t, 128f, 131, 131f, 133f, 144, 150, 150f, 153, 153f, 159f, 188, 188f, 225f, 257, 257f, 265, 265f, 313, 333f, 343, 362, 362f, 372f – branch(es), 181, 181f – m ental, 40 – branchiom otor nerve territories, 123, 123f, 123t – divisions of, 106, 106f, 122, 122f, 123, 123f, 123t – bers – distribution of, 123t – t ypes of, 115t – function, 115t, 122, 122t–123t – lesions of, 122, 122f, 122t, 207 – m andibular division. See Nerve(s) (nam ed), m andibular (CN V3 ) – m axillary division. See Nerve(s) (nam ed), m axillary (CN V2 ) – m otor root, 89f, 238f – nucleus/nuclei of, 93, 116f, 116t, 117f, 122, 122f, 122t–123t – mesencephalic, 90, 90f, 116t, 117f, 122, 122f, 122t–123t, 219f – m otor, 88f, 91, 91f, 116t, 117f, 122, 122f, 122t–123t – principal (pontine) sensory, 91, 91f, 117f, 122, 122f, 122t–123t, 219f – spinal, 91, 91f, 92, 92f–93f, 106, 106f, 117f, 122, 122f, 122t–123t, 136f, 136t, 138f, 208f, 219f – ophthalmic division. See Nerve(s) (nam ed), ophthalm ic (CN V1 ) – passage through skull, 115t – right lateral view of, 188, 188f – sensory root, 89f, 123t, 238f – som atosensory nerve territories, 123, 123f, 123t – trochlear (CN IV), 44f, 45t, 89, 89f–90f, 114f, 114t, 120, 120f, 120t, 121, 121f, 124f, 225f, 231t, 232f, 234, 234f, 235t–236t, 237f, 239f, 333f, 351f – course of, 120t, 235t – intracavernous, 238, 238f – bers, 235t – distribution of, 120t – t ypes of, 115t – function, 115t, 235t – lesions of, 120t – nucleus/nuclei of, 88f, 90, 90f, 116t, 117f, 120f, 120t, 235t, 260, 260f, 261, 261f, 280f, 281, 281f – palsy, 120t, 235, 235f, 235t – passage through skull, 115t – traum a to, 232 – t ympanic, 136f–137f, 137t, 219f, 266, 266f, 267, 267f – ulnar, 400f, 400t, 401f – utricular, 135f, 271f, 278f – utriculo-am pullary, 271f – vagus (CN X), 7, 7f, 7t, 10, 10t, 44f, 45t, 89f, 92f, 110f, 112, 112f, 112t, 114f,

542

ERRNVPHGLFRVRUJ

Index

114t, 116f, 137f, 137t, 138, 138f, 138t, 139f–140f, 140t, 141f, 203t, 205t, 206–207, 207f, 208, 208f, 215t, 218t, 219, 219f, 221t, 224, 224f–225f, 265, 265f, 299f, 314, 316, 320t, 323, 323f, 324, 324f–325f, 328, 328f, 329, 329f, 332, 332f, 334f, 341f, 346f–347f, 364, 364f–365f, 366, 366f–367f, 367, 368f, 369, 369f, 371, 371f, 375, 378f, 412f, 416, 416f–417f, 417t–418t, 419f–421f, 426f, 430f, 433f, 437f – branch(es), 139t – to abdom en, 139t – auricular, 139t, 265–266 – bronchial, 417t – cardiac, 139f, 417f, 417t – carotid, 139t – esophageal, 417f, 417t – m eningeal, 139t – in neck, 139, 139f – pharyngeal, 139f, 139t, 343, 343f – to thorax, 139t – tracheal, 417t – course of, 138t – distribution of, 138t, 139f, 139t – bers, 138t – branchiom otor, 138t – distribution of, 138 – general som atic a erent, 138t – parasympathetic, 138t – viscerosensory, 138t – ber t ype, 115t – function, 115t – ganglia, 138f, 138t – lesions of, 138t, 343, 343f, 343t – m otor root, 111t – nucleus/nuclei of, 92, 92f, 93, 116f, 116t, 117f, 138f, 138t – dorsal (m otor), 88f, 92f, 112, 112f, 112t, 116t, 117f, 138f, 138t, 182, 208f, 280f, 426f, 437f – spinal, 138t – passage through skull, 115t – trigone of, 89f – vestibular, 266f, 271f, 273f–274f, 281f – central connections of, 280, 280f – vestibulocochlear (CN VIII), 33, 44f, 45t, 79f, 89f, 91, 91f, 114f, 114t, 117f, 131, 131f, 134, 134f, 135, 135f, 135t, 225f, 257, 257f, 270f, 271, 271f, 277, 277f, 280f, 333f, 363, 363f, 370, 370f, 379, 379f – cochlear com m unicating branch, 271f – cochlear part, 271, 271f – cochlear root, 92f, 134, 134f, 135, 135f, 135t, 262f – course of, 135t – bers – distribution of, 135, 135f, 135t – t ypes of, 115t, 135t – function, 115t – lesions of, 131, 135t – nucleus/nuclei of, 91, 91f, 92, 92f, 116f, 116t, 117f, 135t – cochlear, 117f, 134, 134f, 135t – vestibular, 117f, 134, 134f, 135t – passage through skull, 115t – vestibular part, 271, 271f – vestibular root, 134, 134f, 135, 135f, 135t, 262f – zygom atic (CN V2 ), 112t, 125t, 126f, 127t, 128f, 133, 169t, 171f, 171t, 188f, 231t, 237–238, 242 – zygom aticofacial, 127t, 155f, 231t – zygom aticotemporal, 125t, 127t, 133, 231t, 237 Nerve(s) (of region or organ) – cervical – anterior ram i of, 47f, 154, 154f

– posterior rami of, 46f–47f, 154, 154f – cranial, 72, 72f, 114, 114f, 114t. See also Nerves (nam ed), cranial – ber t ypes, 114t – motor roots of, 109 – nuclei, 111t, 116, 116f, 116t, 117, 117f – a erent, 116t, 117f – e erent, 116t, 117f – parasympathetic ganglia, 111t, 116t – sensory ganglia, 116t – sites of em ergence from brainstem , 89f, 117f – sites of entry in brainstem , 89f – of diaphragm , 411f – of hard palate, 188, 188f – hypogastric, 460f – intercostal, 297t, 405f, 407f, 410f–411f, 416, 416f, 417t, 420f–421f, 432f, 461f – anterior (ventral) ram us/ram i of, 409f – branch(es) – collateral, 409f – cutaneous – anterior, 409f – lateral, 409f – lateral m am m ary, 406f – m edial m am m ary, 406f – posterior, 416f, 420f–421f – laryngeal, 341, 341f – of lateral nasal wall, 181, 181f – mediastinal, 418t – of nasal septum , 181, 181f – pelvic splanchnic, 110f, 111t, 460f – in petrous bone, 267, 267f – of pterygopalatine fossa, 171, 171f, 171t – spinal, 72, 72f, 74, 74f–75f, 94f, 377 – anterior divisions of, 401f – cervical, anterior ram i, 310t, 311 – m eningeal branch, 77f – m ixed, 3, 77, 77f, 109 – posterior divisions of, 401f – ram us/ram i of, 357f – anterior (ventral), 3, 3f, 74f, 77, 77f, 153–154, 154f, 298, 300, 401f – posterior (dorsal), 3, 3f, 74f, 77, 77f, 153, 153f, 154, 154f, 298, 300, 330, 331f, 401f – rootlet(s) of – anterior, 77, 77f – posterior, 77, 77f – root(s) of, 358 – anterior (motor), 108f, 109, 111t – anterior (ventral), 3, 4f, 74f, 75, 75f, 77, 77f, 401f – posterior (dorsal), 3, 3f–4f, 74f, 75, 75f, 77, 77f, 401f – posterior (sensory), 108f, 109 – thoracic, 416–417, 416f–417f, 417t Nerve cell(s). See Neuron(s) Nerve ber(s), 72, 72f Nervous system – a erent (sensory) cells of, 72, 72f – anterior view of, 72f – autonom ic division of, 72, 72f. See also Autonom ic nervous system – lim bic regulation of, 83, 83f – e erent (m otor) cells of, 72, 72f – organization of, 72, 72f – parasympathetic. See Parasympathetic nervous system – posterior view of, 72f – somatic division of, 72, 72f – sym pathetic. See Sym pathetic nervous system – visceral division of. See Nervous system , autonom ic division of Nervus interm edius, 89f, 130, 130f, 130t

Nervus spinosum , 188f. See also Nerve(s) (nam ed), recurrent m eningeal Neural crest, 2, 2f, 2t – developm ent of, 4, 4f – of head, 2t – of trunk, 2t Neural plate, 2, 2f, 4, 4f Neural plexus. See Plexus(es), neural Neural tube, 2, 2t, 3, 3f, 5t, 6f – closure of, 2f – developm ent of, 4, 4f – di erentiation into spinal cord, 4, 4f – open caudal part, 2f Neurocranium , 16f, 16t, 376 – cartilaginous, 16f, 16t – m em branous, 16f, 16t Neuroectoderm , derivatives of, 13t Neurohypophysis, 84, 84f, 85t. See also Pituitary gland, posterior lobe Neuron(s), 73, 73f – a erent, 4, 4f, 76, 76f, 116, 116f – alpha m otor, 4, 104f, 108f – cortical, distribution of, 81, 81f – e erent, 76, 76f, 116, 116f – functions of, 73t – glutaminergic, 107 – gustatory, 208 – motor, 3, 109, 111t – noradrenergic, 107, 107f – olfactory, 182 – regeneration of, 118, 183 – parasympathetic postganglionic, 110, 111t – parasympathetic preganglionic, 110, 111t – postganglionic, 417t, 426 – preganglionic, 417t, 426 – retinal, 119, 253, 253f, 254, 254f – rst, 253, 253f, 254, 254f, 258 – and pupillary light re ex, 259 – second, 253, 253f, 254, 254f, 258 – third, 254, 254f, 258 – sensory, 3 – rst-order, 104, 104f, 105t, 118, 118f – second-order, 104, 104f, 105t, 118, 118f – third-order, 104, 104f, 105t, 118, 118f – serotoninergic, 107, 107f – som a of, 73, 73f – sympathetic, 110, 111t Neurotransm it ter(s), 73 Neutrophil(s), 193f Nicotinic receptors, 110 Nipple, 406f, 407, 407f Node of Ranvier, 73f Norepinephrine, 110 Nose, 174, 174f. See also Nasal entries – blood supply of, 61t – bridge of, arterial supply to, 61t – cartilage of, 172, 172f – developm ent of, 12, 12f, 12t – external, skeleton of, 172, 172f Nosebleed, 181. See also Epistaxis Notch – clavicular, 402f – frontal, 21f, 242f – interarytenoid, 335f, 339f – jugular, 34f, 402f – m andibular, 40, 40f, 165f – m astoid, 23f, 33f – scapular, 385f, 387f, 390f – supraorbital, 231t – suprasternal, 319, 319f – tentorial, 102f – thyroid, 337f Notochord, 2f, 2t, 3–4, 4f Nuchal region, 318, 318f, 318t – m uscle at tachm ent s in, 303, 303f

543

ERRNVPHGLFRVRUJ

– m uscles in, 302–303, 302f–303f – posterior view of, 302, 302f Nucleus (pl., nuclei) – accessory nucleus cuneatus, 93f, 104f – anterior olfactory, 182, 183f – caudate, 80, 80f, 85f, 97f – arterial supply to, 96f – head of, 105f, 351f, 377f, 380f – tail of, 105f – cerebellar, 5t – cochlear, 277f – anterior, 92f, 116t, 134f, 276, 276f – posterior, 116t, 134f, 276, 276f – collicular – inferior, 276, 276f – superior, 90, 90f – cranial nerve (CN), 88, 88f. See also speci c nerve – dentate, 91, 91f, 363, 363f – dorsal m otor (vagal), 88f, 92f, 112, 112f, 112t, 116t, 117f, 138f, 138t, 182, 208f, 280f, 426f, 437f – em boliform , 91, 91f – facial, 277, 277f – fastigial, 91, 91f, 280f – globose, 91, 91f, 280f – habenular, 83f, 83t, 182, 182f – hypothalam ic, 87, 87f, 87t, 182 – anterior (rostral) group, 87, 87f – functions of, 87t – lesion of, 87t – dorsom edial, 87, 87f – infundibular, 87f – m am m illary, 87, 87f – m iddle (tuberal) group, 87, 87f – paraventricular, 87, 87f – functions of, 87t – lesion of, 87t – posterior (m am m illary) group, 87, 87f – preoptic, 87, 87f – supraoptic, 87, 87f – functions of, 87t – lesion of, 87t – tuberal, 87, 87f – ventrom edial, 87, 87f – interpeduncular, 182f – interstitial (Cajal nucleus), 280f – of lateral lem niscus, 276, 276f – of m edial geniculate body, 276, 276f – m esencephalic, 116t – olivary – inferior, 92, 92f, 93 – superior, 91f, 276, 276f, 277, 277f – oval, 208f – parabrachial, m edial, 208, 208f – paraventricular, 85f – parvocellular, in visual pathway, 257, 257f – Perlia’s, 258, 258f – of posterior com missure (Darkschewit sch nucleus), 280f – prepositus hypoglossi, 260, 260f – pretectal, anterior, 107f – principal (pontine) sensory, 116t – raphe, 107, 107f – red, 86t, 90, 90f, 108f, 120f, 280f, 360, 360f – salivatory, 182 – inferior, 112, 112f, 112t, 116t, 117f, 136f, 136t, 208, 213t – superior, 112, 112f, 112t, 116t, 117f, 130f, 130t, 133f, 208, 213t – solitary, 219f – spinal, 116t – subcortical, 83, 83f, 83t – subthalam ic, 85f, 85t – suprachiasm atic, in visual pathway, 257, 257f

Index

– tegm ental, 108f, 182f – dorsal, 83f, 83t, 208f – thalam ic – anterior, 83f, 83t, 85f, 86, 86f – clinically important connections of, 86t – centrom edian, 86, 86f – clinically important connections of, 86t – dorsal, 86, 86f – dorsal m edial, 86f – intralam inar, 86, 86f, 106 – lateral dorsal, 86f – lateral geniculate, 86 – clinically im portant connections of, 86t – lateral posterior, 86f – m edial, 85f, 86, 86f – m edial geniculate, 86 – clinically im portant connections of, 86t – nonspeci c, 86 – posterior, 377f – reticular, 85f – spatial arrangem ent of, 86, 86f – speci c, 86 – ventral anterior, 86f – ventral interm ediate, 86f – ventral posterolateral, 86f – clinically important connections of, 86t – ventral posterom edial, 86f, 106, 106f, 208, 208f – clinically important connections of, 86t – ventrolateral, 86, 86f, 108f – clinically important connections of, 86t – in visual pathway, 257, 257f – of trapezoid body, 276, 276f – vestibular, 280, 280f – a erent bers to, 281, 281f – in balance, 281, 281f – central connections of, 281, 281f – e erents from , 280–281, 281f – inferior (of Roller), 91f, 134f, 281, 281f – lateral (of Deiters), 91f, 134f, 281, 281f – m edial (of Schwalbe), 91f, 134f, 281, 281f – superior (of Bechterew), 91f, 134f, 281, 281f – topographic organization of, 280–281, 281f – in visual pathway, 257, 257f – visceral oculom otor (EdingerWestphal), 112, 112f, 112t, 116t, 117f, 120f, 120t, 258, 258f, 259, 259f – lesion of, 259 Nucleus ambiguus, 88f, 92f, 116f, 116t, 117f, 136f, 136t, 138f, 138t, 140f, 140t Nucleus cuneatus, 93, 93f, 104f – tubercle of, 89f Nucleus gracilis, 93, 93f, 104f – tubercle of, 89f Nucleus of solitary tract, 92, 117f, 130f, 136t, 138f, 138t, 208f – gustatory part, 208, 208f – inferior part, 116t, 136f, 136t, 138f, 138t – lower part, 116f – superior part, 116t, 130f, 130t, 136f, 136t, 138f, 138t – upper part, 116f Nucleus pulposus, 290f, 293f Nystagm us – abducting, 261, 261f – optokinetic, 257

– vestibular, 270

O Obesit y, hypothalam ic lesion and, 87t Occipital bone, 18f, 22f–24f, 25, 25f–26f, 28f, 30, 30f, 32f, 34f, 172f, 217f, 221f, 224f, 289f, 292f, 294f, 302f, 332f, 365f, 370f–372f – basilar part, 34, 34f, 178f, 292f–293f – isolated – inferior view of, 34, 34f – internal surface of, 34, 34f – left lateral view of, 34, 34f – lower portion, developm ent of, 16t – pharyngeal tubercle, 27f, 34, 34f, 215f – position in exterior skull base, 34f Occipital condyle(s), 23f, 26f–27f, 34, 34f, 156f, 294f, 358f Occipital crest – external, 294f – internal, 292f Occipital lobe, 78, 78t, 363f – lesion in, and visual eld defect s, 256, 256f – ventricular system and, 95 Occipital pole, 78f, 119f – lesion of, and visual eld defects, 256, 256f Occipital protuberance – external, 23f, 27f, 34, 34f, 289f, 292f–294f, 302f–303f, 309f, 319, 319f – internal, 29f, 34f, 292f, 370f Occipital region, 318f Occipital squam a, 34, 34f Occipital triangle, 318f, 318t Occiput, veins of, 67, 67f Occlusion, 194 – class I, 195 – class II, 195 – class III, 195 – cusp-and- ssure, 195, 195f – evaluation of, 43 Oculom otor palsy, 120t, 232–233, 235, 235f, 235t, 241, 250t – complete, 235, 235f, 235t Olfaction, and taste, 208 Olfactory bulb, 5, 5f, 13, 78f, 82, 82f, 86, 118f, 126f, 180f, 181, 181f, 182, 182f, 183, 183f, 349, 349f, 353f, 376, 376f – synaptic pat terns in, 183, 183f Olfactory cell(s), 182, 183f Olfactory cortex, 80, 82, 82f – prim ary, 182 Olfactory epithelium , 13 Olfactory ber(s), 118, 118f, 180f–182f, 183, 183f Olfactory receptor(s), 183 Olfactory stria (pl., striae), 118, 182, 182f Olfactory system , 86, 182, 182f Olfactory tract, 82f, 117f–118f, 180f, 182–183, 183f, 350f – inferior view of, 182, 182f – m idsagit tal section, 182, 182f – m ucosa of, 21f, 182, 182f, 183, 183f Olfactory trigone, 182, 182f Olfactory tubercle, 182 Oligodendrocytes, 73, 73f – functions of, 73t Olive, 79f, 89, 89f, 116f, 141f – superior, 277f – e erent bers from , to organ of Corti, 277, 277f Olivocochlear bundle, 277, 277f Olivospinal tract, 108f, 108t Om ental bursa, 443f, 444, 444f, 447, 447f, 461f – vestibule of, 447f Om entum

– greater, 442f–443f, 444, 444f–449f, 453, 453f, 455f, 461f – lesser, 442f, 446f, 448f, 453, 453f Ophthalm oscopy, direct, 247, 247f Optic canal, 29f, 30, 31f, 39f, 119, 119f, 121, 124f, 228, 229f–230f, 231t, 232, 234, 237f, 353, 361, 361f – neurovascular pathways through, 44f, 45t – neurovasculature in, 238, 238f Optic chiasm , 85t, 87f, 95f, 117f, 119f, 230, 238f–239f, 254, 254f, 255, 255f, 360, 360f, 380 – lesions of, 256, 256f Optic cup, 5f Optic disk, 244, 244f, 252f, 253, 253f – ophthalm oscopic exam ination of, 247, 247f – papilledem a of, 247 Optic radiation, 119f, 254, 254f – lesion of, 259 – unilateral – in anterior temporal lobe, 256, 256f – in parietal lobe, 256, 256f Optic tract, 84, 85f, 85t–86t, 87f, 99f, 119f, 254, 254f, 258, 258f, 360, 360f – end of, 255, 255f – lateral root, 254 – lesions of, unilateral, 256, 256f – m edial root, 254, 259 – start of, 255, 255f Optic vesicle(s), 3, 3f, 6f Oral axis, 344, 344f Oral cancer, 185, 185f Oral cavit y, 128f, 174, 174f, 176f, 184, 184f, 348, 348f, 376, 377f – anterior view of, 184, 184f – blood supply to, 186, 186f – com m unication with pterygopalatine fossa, 169f, 169t – coronal section through m olars, 227, 227f – developm ent of, 13, 13f – oor of, 210–211, 210f–211f, 219f – blood supply to, 186, 186f, 211, 211f – cancer of, 185, 185f – inferior oblique view of, 226, 226f – lateral view of, 210, 210f – lymphatic drainage of, 70, 70f, 71t, 211 – m uscles of, 210, 210f, 348 – innervation of, 189, 189f – superior view of, 210, 210f, 226, 226f – topography of, 211, 211f – venous drainage of, 187, 187f, 211, 211f – glands of, innervation of, 127t, 133, 133f – innervation of, 188–189, 188f–189f – lateral view of, 184, 184f – lymphatic drainage of, 70, 70f, 71t – m idsagit tal section, lateral view of, 185, 185f – m ucosa of, 210f–212f – blood supply to, 186, 186f – venous drainage of, 187, 187f – pharyngeal com m unication, 216t – proper, 184, 184f – roof of, 39, 39f, 185, 185f – sagit tal section through canines, 227, 227f – topography of, 185, 185f – transverse MRIs – through hard and soft palates, 372, 372f – through m andible, 373, 373f – through temporom andibular joint, 372, 372f

– transverse section of area posterior to third molar, superior view of, 227, 227f – vasculature of, 186–187 – venous drainage of, 64, 64f, 64t, 187, 187f Oral dysesthesia, 106 Oral vestibule, 184, 184f, 334f, 379, 379f Ora serrata, 244, 244f, 248, 248f, 252, 252f Orbit(s), 21f, 35, 174f–175f, 349, 379, 379f, 381 – anterior, sagit tal section through, 241, 241f – anterior view of, 228, 228f–229f – blood supply to, 236t, 237, 237f – bones of, 228, 228f–229f, 230, 230f – adjacent cavities, 230, 230f – com m unications, 230, 230f, 231t – with pterygopalatine fossa, 169f, 169t – coronal section, anterior view of, 230, 230f – cranial nerves that enter, intracavernous course of, 238, 238f – on dental panoram ic tom ogram (DPT), 200f – disease spread into and out of, 230 – oor of, 36, 175, 230f, 236, 236f – fractures of, 230 – innervation of, 236t, 237, 237f – lateral view of, 119, 119f, 124f, 228, 228f–229f, 234, 234f, 237, 237f – levels of – lower, 236, 236t – m iddle, 236, 236t – content s of, 239, 239f – superior view of, 239, 239f – upper, 236, 236t – content s of, 239, 239f – superior view of, 239, 239f – m edial view of, 228, 228f–229f – neighboring structures, 230, 230f – neurovascular structures of, 228, 231t, 236–237, 236f, 236t, 237f – deep layer, 240, 240f – super cial layer, 240, 240f – opened – anterior view of, 234, 234f, 238, 238f – lateral view of, 237, 237f – superior view of, 234, 234f, 237, 237f – periosteum of, 236, 236f, 238, 238f – roof of, 236, 236f, 241f, 352f–353f, 381f – sagit tal section, m edial view of, 236, 236f – superior view of, 124f – topography of, 238–239, 238f–239f, 240–241, 240f–241f – venous drainage of, 64t–65t, 236t, 237, 237f – walls of – lateral, 36 – m edial, 35 Orbital ssures. See Fissures, orbital Orbital plate, 35, 35f Organ(s) – abdom inal peritoneal, 442t – extraperitoneal, 442f, 442t – infraperitoneal, 442t – intraperitoneal, 442f, 442t – pelvic peritoneal, 442t – retroperitoneal, 442t – subperitoneal, 442t Organ of Corti, 274, 274f, 276, 276f – a erent bers from , 277, 277f – de ected by traveling wave, 275, 275f – e erent bers from olive to, 277, 277f – at rest, 275, 275f – structure of, 275, 275f Oribital rim , 228

544

ERRNVPHGLFRVRUJ

Index

– lateral aspect, 231t – m edial aspect, 231t Oro-antral stula, 174 Oropharyngeal isthm us, 203t Oropharynx, 163f, 185f, 203t, 216t, 351, 351f, 355–356, 356f, 373, 373f, 376, 376f, 380, 380f, 382, 382f – innervation of, 133, 136t–138t – lymphatic drainage of, 71t Orotracheal intubation, 344 Ossicular chain, 268, 268f. See also Auditory ossicles – arteries of, 273, 273f – function of, 268, 268f – in t ym panic cavit y, 269, 269f Ossi cation – endochondral, of cranial bones, 16f, 16t – intram embranous – congenital defect s of, 16t – of cranial bones, 16f, 16t Osteom eatal unit (complex), 176, 176f Otitis m edia, 269 Otoacoustic em issions (OAE), 277 Otolith(s), 278, 278f Otoscopy, 263, 263f Oval window, 262, 267f, 268, 268f, 270f–271f, 275, 275f Ovary(ies), 442t, 465f, 467f – ligam ent of, 465f Oxycephaly, 22f

P Pacem aker of heart, 427 Pain – perception of, 107, 107f – treatment of, 107, 107f Pain pathways – central lesions involving, 106 – in head, 106, 106f Palatal space, 226f, 226t, 227f, 227t Palate, 344f – cleft, 9, 15, 15f, 39 – developm ent of, 14, 14f – hard, 38f, 178f, 184f, 185, 214, 214f, 348, 353f, 372f, 376, 376f, 380f, 382f – anterior view of, 214, 214f – autonom ic innervation of, 110 – blood supply to, 186, 186f, 214t – bones of, 39, 39f – developm ent of, 14–15 – glands of, parasympathetic innervation of, 112t – inferior view of, 39, 39f, 188f – innervation of, 214, 214t – lymphatic drainage of, 71t, 214, 214t – m ucoperiosteum of, 365f – m ucosa of, 214, 215f – neurovasculature of, 188, 188f, 214t – oblique posterior view of, 39, 39f – superior view of, 39, 39f – venous drainage of, 64t–65t, 187, 187f, 214t – prim ary, 13, 13f, 14, 14f–15f – secondary, 13, 13f, 14, 14f–15f – developm ent of, 14, 14f – soft, 178f–179f, 184f, 185, 185f, 216f–217f, 219f, 350, 350f, 355, 355f–356f, 365f, 373, 376, 376f, 382, 382f – autonom ic innervation of, 110 – blood supply to, 186, 186f, 215t – developm ent of, 14–15 – glands of, parasympathetic innervation of, 112t – inferior view of, 215, 215f – innervation of, 215t – lym phatic drainage of, 71t, 215t – m uscles of, 215, 215f, 215t

– palatine septum, 178f – taste buds of, 133f – venous drainage of, 64t–65t, 187, 187f, 215t Palatine bar, m axillary process, 156f Palatine bone, 7t, 22f–23f, 26f–27f, 30f, 38f, 39, 39f, 172, 172f, 215f, 228 – developm ent of, 16t – horizontal plate, 39, 39f, 172f–173f, 214 – nasal crest, 39f – orbital process, 228f – perpendicular plate, 39f, 168t, 172f, 176f – pyram idal process, 39, 39f, 156f, 158t, 168f, 228f Palatine canal, greater, 39f, 168t, 169f, 169t Palatine raphe, 214f Palatine shelves – elevation of, 14, 14f – fusion of, 14, 14f – m erging of, 14, 14f Palatine suture. See Sutures, palatine Paleocortex, 82f Pallidum , 105f Pancoast tum or, 329 Pancreas, 442t, 443f, 447f–449f, 451f, 453f, 461f – autonom ic innervation of, 110f – blood supply to, 440, 440f, 441, 441f – head of, 461f – uncinate process, 443f Pancreatic duct, 451f – accessory, 449f, 451f – m ain, 449f – sphincter of, 450f Papilla (pl., papillae) – connective tissue, 193f – duodenal – m ajor, 449f, 451f – m inor, 449f, 451f – ileal, 449f – incisive, 214f – interdental, 193f – of parotid duct, 184f – sublingual, 184f, 206f, 210f–212f – of tongue, 202, 202f, 203t – circumvallate, 202, 202f, 203t, 209, 209f – liform , 202, 202f, 203t – foliate, 202, 202f, 203t, 209, 209f, 335f – fungiform , 202, 202f, 203t, 209, 209f – vallate, 335f – innervation of, 208 Papilledem a, of optic disk, 247 Para-aortic body, innervation of, 138t, 139f Parafollicular cells, 9t, 11 Parahippocampal gyrus, 83f, 83t – entorhinal area of, 83f, 83t Paranasal sinuses. See Sinus(es), paranasal Parapharyngeal space, 226f, 226t, 227f, 227t, 334, 355f – anterior, 334 – neurovasculature of, 335, 335f – posterior, 334 Parasympathetic nervous system , 110, 110f – cranial, 110f, 111t, 112, 112f, 112t – peripheral, 417t – sacral, 110f, 111t – in thorax, 417, 417f, 417t Parasympathetic pathways, 111t Paraterm inal gyrus, 83t Parathyroid gland(s), 224f, 332f, 346, 346f – developm ent of, 11

– inadvertent rem oval of, 346 – inferior, 346f – developm ent of, 8f, 9t, 11, 11f – posterior view of, 346f – superior, 346f – developm ent of, 8f, 9t, 11, 11f Parietal bone, 18f–20f, 23f–24f, 25, 25f–26f, 28f, 30f, 32f, 157t, 161f, 230f, 302f Parietal em inence, 23f Parietal lobe, 78, 78t, 351, 351f Parietal region, 318f Parieto-occipital sulcus, 78f, 81f Parkinson disease, 80 Parotid duct, 144f, 148f, 150f, 152f, 154f, 157f, 212, 212f, 213t, 334f – ori ce of, 184f – papilla of, 184f Parotid space, 226f, 226t Passavant ridge, 219f Peau d’orange, 407 Pelvic girdle, 462, 462f – anterosuperior view of, 462, 462f Pelvis – anterior view of, 460, 460f – arteries of, 466–467, 466f–467f, 466t – fem ale – arteries of, 466, 466f, 467, 467f – content s of, 465, 465f – midsagit tal section of, 465, 465f – parasagit tal section of, 465, 465f – veins of, 466, 466f, 467, 467f – m ale, 463, 463f – anterior view of, 460, 460f – anterosuperior view of, 464, 464f – arteries of, 466, 466f, 467, 467f – content s of, 464, 464f – posterior view of, 464, 464f – veins of, 466, 466f, 467, 467f – m idsagit tal section of, 463, 463f – parasagit tal section of, 463, 463f – veins of, 466–467, 466f–467f, 466t Penis – corpus cavernosum of, 464f – corpus spongiosum of, 464f – fundiform ligam ent of, 439f – prepuce of, 464f – suspensory ligam ent of, 464f Periarchicortex, 82f Pericardial cavit y, 418f Pericardial sac, 325 Pericardium , 409f, 410, 411f, 412t, 418t, 422f – brous, 325, 412f, 419f–421f, 426f, 430f, 432f, 434f – innervation of, 416 – venous drainage of, 415t Pericranium , 151, 151f Periglom erular cell(s), in olfactory bulb, 183, 183f Perilym ph, 268, 270, 275 Perilym phatic space, 270, 274 Perineal body, 464f–465f Periodontitis, 193 Periodontium , 192, 192f, 192t – functions of, 192 – structures of, 192, 192f Periorbita, 236, 236f, 238, 238f, 241f Periorbital fat, 236, 236f, 238f, 242f, 348, 348f, 352f–353f, 360f, 362f, 370f, 379, 379f, 381 Peripharyngeal space, 332, 332f, 334, 334f Peripheral nervous system (PNS), 72, 72f – cells of, 73t – developm ent of, 4, 4f Perirenal fat capsule, 299f, 461f Peritoneal cavit y, 431f, 442f, 444, 444f – anterior view of, 448, 448f

545

ERRNVPHGLFRVRUJ

– greater sac, 444, 444f – infracolic compartm ent of, 444, 444f–445f – lesser sac, 443f, 444, 444f – organs of, 448, 448f – supracolic compartm ent of, 444 Peritoneum , 442 – parietal, 299f, 431f–432f, 439f, 442f, 444f–446f, 464f–465f – visceral, 431f–432f, 442f, 464f–465f Peritonsillar space, 226f, 226t Pertracheal intubation, 344 Petit space, 245f Petrous apex, 33, 33f, 262f Petrous bone, 32, 274f. See also Tem poral bone, petrous part – anterior view of, 272f – nerves in, 267, 267f Petrous pyram id, 33 Phalanx (pl., phalanges), 395f – distal, 389f, 395f, 397f – base of, 394f–395f – tuberosit y of, 389f – m iddle – base of, 389f – head of, 389f – shaft of, 389f – proxim al, 389f, 397f – base of, 394f – fth, 396f – rst, 396f Pharyngeal axis, 344, 344f Pharyngeal canal , 27f Pharyngeal cleft(s), 6, 6f – derivatives of, 11, 11f – developm ent of, 8, 8f – ectoderm al, 6, 6f – rst, 8f – fourth, 8f – second, 8f – innervation of, 132, 132f – third, 8f Pharyngeal gap(s), 218f – transm it ted structures, 218t Pharyngeal gut, 6, 6f, 8 Pharyngeal pouch(es), 6, 6f – derivatives of, 8, 8f, 9t – developm ent of, 8, 8f – endoderm al, 6, 6f – fth, 8f – rst, 8f – fourth, 8f – second, 8f – third, 8f Pharyngeal raphe, 34, 216f, 222f, 224f, 332f, 431f Pharyngeal recess, 178f, 216f, 371, 371f Pharyngeal (lingual) swellings, 10, 10f, 10t Pharyngeal tubercle, 27f, 34, 34f, 215f Pharyngot ympanic (auditory/ Eustachian) tube, 32, 32f, 178, 178f, 215, 215f, 218t, 262f, 266, 266f, 267, 267f, 272f–273f, 356f–357f, 364, 364f, 377, 377f – bony part, 267, 267f – cartilaginous part, 221f, 267, 267f, 355f, 378, 378f – developm ent of, 8f, 9t, 11, 11f – innervation of, 136t, 267, 267f – lymphatic drainage of, 71t – m em branous lam ina of, 267, 267f – ori ce of, 221f – pharyngeal ori ce, 178f–179f, 185f, 267f, 345f Pharynx, 320t, 321, 334f – blood supply to, 224 – glands of, parasym pathetic innervation of, 112t

Index

– innervation of, 47f, 219, 219f, 316, 343, 343f – autonom ic, 110 – levels of, 216t – m ucosa of, 216, 216f, 342f – m uscles of, 218, 218f, 218t, 220, 220f – internal, 216, 216f – lateral view of, 220, 220f – neurovascular topography of, 224, 224f–225f – opened, posterior view of, 216, 216f, 217, 217f, 224, 225f – posterior view of, with fascia rem oved, 224, 224f – roof of, 217, 217f, 221f – topography of, 185, 185f – venous drainage of, 224 Philippe-Gom bault triangle, 76f Philtrum , 184f – developm ent of, 12f, 12t Phobia(s), 83 Photoreceptors, 253, 253f, 254, 254f, 258 – and pupillary light re ex, 259 Pia m ater, 102, 102f – spinal, 74f Pial vascular plexus, 246f Pierre-Robin syndrom e, 9 Pineal body, 95f Pineal gland, 5t, 84, 84f–85f, 85t, 89f Pineal recess, 95f Pink eye (conjunctivitis), 241 Piriform (anterior nasal) aperture, 21f Piriform recess (sinus), 216f, 335f, 339f–340f, 345f, 355f, 366f, 367, 367f Pisiform bone, 389f, 395f–397f Pituitary gland, 30, 88f, 175f, 230, 351, 351f, 361f, 370f, 376, 376f, 380, 380f – anterior lobe of, 84f, 87f. See also Adenohypophysis – posterior lobe of, 84f, 85t, 87f. See also Neurohypophysis – prim ordium of, 5, 5f – surgery on, transnasal procedures, 175 Placenta, 428, 428f Placode(s), 2t Plagiocephaly, 22f Plaque, dental, 193 Plasm acytom a, 24f Pleura – m ediastinal, 325 – parietal, 412f, 432, 432f – cervical part, 419f, 430f, 432f, 434f – costal part, 409f, 411f, 420f–421f, 432, 432f, 434f – diaphragm atic part, 411f–412f, 419f, 430f–432f, 434f – m ediastinal part, 411f–412f, 419f, 430f–432f, 434f – visceral, 432f Pleural cavit y(ies), 412, 412f, 412t, 419f – anterior view of, 432, 432f Pleural dom e, 325f Plexus(es) – brachial. See Brachial plexus – celiac, 139t – choroid. See Choroid plexus – esophageal, 111t, 139t, 416f–417f, 430f – anterior, 139f – facial artery, 113, 113f, 113t – hepatic, 139t – inferior hypogastric, 110f – intraparotid, 154f – lum bosacral, 72f – m iddle meningeal, 113 – neural, 3, 72, 72f, 111t – abdom inal, 460, 460f – anterior gastric, 416f – aortic, 426, 426f

– cardiac, 111t, 139t, 417f, 426, 426f – carotid, 45t – cervical, 47f, 152f, 153, 153f, 154, 154f, 265, 265f, 310t, 316, 316f, 316t, 325–326, 329–331 – branches, 316, 316f, 316t – com m on carotid, 417f – external carotid, 113f, 113t, 417f – gastric, 139t, 426f – interm esenteric, 460f – internal carotid, 113, 113f, 113t, 121f, 133, 133f, 137f, 234f, 267f, 417f – internal carotid sympathetic, 44f – m otor nerves of, 317, 317f – parotid, 130t, 131f, 132, 132f, 152f, 154, 154f, 326 – branch(es), 130f – buccal, 154f – m arginal m andibular, 154f – temporal, 154f – zygom atic, 154f – pharyngeal, 137t, 139t, 140f, 206, 215t, 218t, 219, 219f, 221t, 224, 343, 417f – pulm onary, 111t, 139t, 417f, 426, 426f, 437f – bronchial branches, 437f – renal, 139t, 460f – sacral, 452f, 460f – sensory nerves of, 317, 317f – subclavian, 417f – superior hypogastric, 460f – suprarenal, 460f – testicular/ovarian, 460f – thoracic aortic, 417f, 426f – t ympanic, 133, 137f, 137t, 266f, 267, 267f – ureteral, 460f – vertebral, 417f – pial vascular, 246f – pterygoid, 62f, 63, 63f–64f, 64t, 65f–66f, 66t, 67, 67f, 158, 158t, 169t, 187, 187f, 195t, 197t, 214, 214t–215t, 236t, 247, 272 – rectal, 458f, 466f, 466t – subm ucosal, 335f – superior alveolar, 126f, 127t – thyroid, 315, 315t, 341, 341f, 347, 347f – uterine, 458f, 466f, 466t, 467f – vaginal, 466f, 466t, 467f – venous, 94f – of foram en m agnum, 67f – of foram en ovale, 66f – of hypoglossal canal, 44f, 45t, 67f – pharyngeal, 224, 224f, 332f – prostatic, 466f, 466t – vertebral, 94f, 364f, 461f – anterior internal, 75f – external, 66t, 67f, 315t – internal, 315t – posterior internal, 75f – vesical, 458f, 466f, 466t Polythelia, 406 Pons, 5t, 88, 88f–89f, 103f, 120f–122f, 130f, 234f, 361, 361f–362f, 370f – anterior view of, 134, 134f – developm ent of, 5, 5f – lower, transverse section through, 91, 91f – midportion, transverse section through, 91, 91f – upper, transverse section through, 90, 90f Pontom edullary junction, 121f, 234f Portal system , and heart, collateral pathways bet ween, 457, 457f Postcentral gyrus, 78, 86t, 104f, 105, 105f, 108f, 208, 208f – som atotopic organization of, 105

Posterior triangle, 319f Posterior venous con uence, 99, 99f Posterolateral sulcus, 89f Postglenoid tubercle, 19f, 33f Post-traum atic stress disorder, 83 Precentral gyrus, 78, 108f, 109, 132f, 141f, 381f – som atotopic representation of skeletal m uscle in, 109, 109f Prefrontal cortex, 107, 107f Prem olar(s), 41f, 190, 190f – m andibular – m orphology of, 196, 196f, 197t – spread of infection from , potential routes for, 227, 227f, 227t – m axillary – rst, 195, 195f, 195t – m orphology of, 194, 194f, 195t – spread of infection from , potential routes for, 227, 227f, 227t Prem otor cortex, 86t Preoptic area, 84f Prepiriform area, 118, 118f, 182, 182f Pressure receptor(s) – of aortic arch, 138t, 139f – of carotid sinus, 136t–137t Pretectal area, in visual pathway, 257, 257f, 258, 258f, 259, 259f Prim itive node, 2f Prim itive streak, 2f Prom inence(s). See also speci c prom inences – in facial developm ent, 12-14, 12f-14f Prom ontory, 267f Proprioceptive system , 280, 280f, 281, 281f Prosencephalon, 5t, 6, 6f Prostate, 442t, 443f, 464f, 467f Pterion, 17f, 19f Pterygoid (vidian) canal, 31f, 39f, 133f, 168t, 169f, 169t Pterygoid ham ulus, 27f, 31f, 39f, 156f, 168f, 214, 215f, 221f Pterygoid plexus. See Plexus(es), pterygoid Pterygom andibular raphe, 214, 214f Pterygom andibular space, 162, 162f, 226f, 226t, 227f, 227t Ptosis, 120t, 235t, 241, 329 Pubic ram us – inferior, 462f, 464f–465f – superior, 462f, 464f–465f Pubic symphysis, 462f–465f – superior border of, 438f Pubic tubercle, 462f–463f Pubis, body of, 462f Pulm onary apex, 434f, 435, 435f Pulm onary trunk, 418t, 419f, 422f–423f, 426f–427f, 429f–430f, 434f, 436, 436f–437f – in postnatal circulation, 429, 429f – in prenatal circulation, 428f – valve of, 423f Pulm onary valve, 425f – cusp of, 424f Pulp, dental, 192t – innervation of, 192t Pulp cham ber, 192f, 192t, 193f Pulvinar, 85f, 86, 86f – in visual pathway, 257, 257f Puncta (sing., punctum ) – inferior, 242, 242f–243f – superior, 242, 242f–243f Pupil (ocular), 248f, 250, 250f – Argyll-Robert son, 258 – constriction of, 250, 250f, 250t, 258, 258f, 259 – dilation of, 111t, 113, 250, 250f, 250t, 259

– di culties with, 120t – innervation of, 250, 250t – light response – consensual, 259 – direct, 259 – indirect, 259 – neural pathways of, 259, 259f – testing, 259 – size of, norm al, 250, 250f – Pupillary light re ex, 259, 259f – a erent lim b of, 259, 259f – e erent lim b of, 259, 259f – pathway for, 257, 257f, 259, 259f – lesions of, 259, 259f Purkinje bers, 427, 427f Putam en, 80, 80f, 85f, 97f, 105f, 351f, 378, 378f – arterial supply to, 96f Pyloric antrum , 446f Pyloric canal, 446f Pyloric ori ce, 446f, 449f Pyloric sphincter, 446f, 449f Pyram id(s), 108f, 141f – decussation of, 89, 89f, 93, 93f, 103f, 108f, 109 Pyram idal em inence, 269f Pyram idal tract(s), 90, 90f–91f, 92, 92f–93f, 97, 103f, 105, 105f, 108f, 108t, 360 – anterior, 93, 93f – decussation of, 89, 89f, 93, 93f, 103f, 108f, 109 – lateral, 93, 93f

Q Quadrantanopia – lower, contralateral to lesion, 256, 256f – upper, contralateral to lesion, 256, 256f Quadrigem inal plate, 84f, 89, 89f

R Radial tuberosit y, 388f–389f, 393f, 395f Radiograph(s) – of cervical spine, left lateral view, 288, 288f – of teeth, 200–201, 200f–201f – bitewing, 201, 201f – eccentric images, 201 – radiolucencies on, 201, 201f Radius, 388, 388f–389f, 393f–395f, 397f – anterior border of, 388f – axis of pronation/supination, 388f – dorsal tubercle, 388f, 394f – head of, 389f – interosseous border of, 388f – lateral surface of, 388f – neck of, 388f – posterior border of, 388f – posterior surface of, 388f – st yloid process, 388f–389f, 394f Ram i com municantes, 420f–421f – gray, 74f, 77f, 110, 111t, 289f, 460f – white, 74f, 77f, 111t, 289f Rathke’s pouch, 8, 8f Rectal plexus, 458f, 466f, 466t Rectouterine pouch, 465f Rectovesical pouch, 443f, 464f Rectum , 442t, 443f, 448f–449f, 458f, 464f–465f – autonom ic innervation of, 110f – blood supply to, 440, 440f–441f Rectus sheath, 439, 439f – anterior layer of, 439f – posterior layer of, 405f, 439f Re ex(es), 76. See also Pupillary light re ex

546

ERRNVPHGLFRVRUJ

Index

– baroreceptor, 329 – brainstem , 257, 257f – corneal (blink), 146, 241, 241f, 249 – neural pathway for, 257, 257f – gag, 219f – salivary, 208 – stapedius, 277, 277f – swallowing, 219f – vestibulo-ocular, 270 – neural pathway for, 257, 257f Reinke space, 343f Reticular form ation, 90, 90f–91f, 92, 92f–93f, 182, 182f, 280f – mesencephalic, 260, 260f – neuronal net work of, 88, 88f – nucleus/nuclei of, 90, 90f, 219f – param edian pontine, 260, 260f – structural-functional relationships in, 88, 88f – in visual pathway, 257, 257f Reticulospinal tract, 108f, 108t, 280f Retina, 84, 241f, 244, 244f–245f, 247f, 252–253, 252f–253f, 254 – arterial supply to, 61t – detachm ent of, 247, 253 – im age projection on, 255 – layers of, 252, 252f, 253, 253f – nasal, 254, 254f – neural layer of, 252, 252f – nonvisual, 252, 252f – nuclear layer, 253f – ophthalmoscopic exam ination of, 247, 247f – part(s) of, 252, 252f – ciliary, 252, 252f – iridial, 252, 252f – optical, 248f, 252, 252f – pigm ented layer of, 252, 252f – temporal, 254, 254f – transverse section, superior view of, 252, 252f – venous drainage of, 64t Retinopretectal system , 257, 257f Retinotectal system , 257, 257f Retrobulbar space, 349 Retrocecal recess, 445f Retrom olar triangle, 40, 41f Retropharyngeal space, 226f, 226t, 227f, 227t, 321, 321f, 334, 378f – in neck, 320f Retropubic space, 464f Rheum atoid arthritis, 242 Rhinoscopy, 179, 179f Rhom bencephalon, 5t – ventricular system and, 95 Rhom boid fossa, 88f, 89, 89f, 92, 92f, 93 Rib(s), 391f, 410f – body (shaft) of, 403f – eighth, 432f – eleventh, 403f – fth, 307f, 403f – rst, 311f, 325f, 359f, 369f, 375, 375f, 401f–402f, 404f, 412f, 414f, 416f, 420f–421f – groove for subclavian artery, 311f – head of, 403f – neck of, 403f – crest of, 403f – scalene tubercle, 311f – second, 311f, 358f, 369f, 403f – tuberosit y for serratus anterior, 403f – sixth, 403f – structure of, 403f – third, 369f – t welfth, 301f, 402f, 408f Rim a glot tidis, 340, 340f, 368f – m uscle action on, 338t Rim a vestibuli, 340, 340f Rods, 119, 253–254, 254f

Root(s). See Tooth, root(s) of Root canal(s). See Tooth, root canal(s) of Root sleeve, spinal, 75, 75f Rotator cu , 390, 390f Round window, 267f, 270f–271f, 275, 275f Rubrospinal tract, 90f–93f, 108f, 108t Rugae – gastric, 431f, 446f – palatine, 214, 214f

S Saccades, 260 Saccule, 262, 270, 270f, 280, 280f – laryngeal, 340f – macula of, 270f, 280 – structure of, 278, 278f Sacral canal, 285f Sacral crest, 284f–285f, 285t Sacral hiatus, 74f, 75, 75f Sacral prom ontory, 285f, 463f Sacrum , 305f, 307f, 462, 462f – articular surface of, 284f – base of, 285f – spinous process, 285f, 285t – structure of, 285, 285f, 285t – superior articular facet, 285f – wings of, 285f, 285t Sagit tal suture. See Sutures, sagit tal Saliva – functions of, 212 – production, per day, 212 Salivary gland(s) – autonom ic innervation of, 110, 110f – bim anual exam ination of, 213, 213f – labial, 213f – inferior, innervation of, 133, 136t – superior, 213t – innervation of, 267 – lymphatic drainage of, 213t – major, 212, 212f – lateral view of, 212, 212f – superior view of, 212, 212f – m inor, 213, 213f – blood supply to, 213t – innervation of, 213t – palatine, 213f, 213t, 214f – innervation of, 267 – parot id, 70f, 133f, 144f, 146f, 150f, 152, 152f, 163f, 212, 212f, 227f, 265f, 317f, 323f, 326f–327f, 334f, 356f, 357, 357f–358f, 364f–365f, 372f, 373, 373f – accessory, 212f – blood supply to, 213t – capsule of, 321, 321f, 322, 322f, 326 – deep lobe, 212 – glenoid lobe of, 164 – innervation of, 129t–130t, 133, 136t, 213t, 267 – lymphatic drainage of, 71t, 213t – m alignant tum ors of, 212 – parasympathetic innervation of, 112t – super cial lobe, 212 – swelling of, 322 – sym pathetic innervation of, 113, 113t – venous drainage of, 65t – pharyngeal, 213f, 213t – sublingual, 133f, 204f, 211f, 212, 212f, 227f, 334f, 352, 380f – bim anual exam ination of, 213, 213f – blood supply to, 213t – innervation of, 129t, 133, 133f, 206, 213t, 267 – lymphatic drainage of, 71t, 213t – parasympathetic innervation of, 112t – sym pathetic innervation of, 113, 113t

– subm andibular, 133f, 211f, 212, 212f, 328f, 353, 353f, 356f, 373f–374f, 378, 378f–379f, 383, 383f – bim anual exam ination of, 213, 213f – blood supply to, 213t – extraoral lobe, 163f, 212f – innervation of, 129t, 133, 133f, 206, 213t, 267 – intraoral lobe, 212f – lymphatic drainage of, 71t, 213t – parasympathetic innervation of, 112t – sympathetic innervation of, 113, 113t – tum ors of, 212 – venous drainage of, 64t–65t Salivary re ex, 208 Salivation – disturbances of, 131 – innervation of, 182, 208 Satellite cells, of peripheral nervous system , functions of, 73t Scala media. See Cochlear duct Scala t ympani, 270f, 274, 274f–275f Scala vestibuli, 270f, 274, 274f, 275, 275f Scalp, 24f, 151, 151f – infections of, 151 – lacerations of, 151 – layers of, 151, 151f – lymphatic drainage of, 71t – posterior, venous drainage of, 65t Scaphocephaly, 22f Scaphoid, 396f – tubercle of, 389f Scapula, 384–385, 385f, 391f–392f, 408f – acrom ial angle of, 385f – acrom ion, 298f, 319, 319f, 385f, 387f, 389f, 391f–393f – anterior surface of, 393f – anterior view of, 385, 385f – coracoid process, 385f, 387f, 389f, 391f–393f – costal surface of, 385f – glenoid cavit y of, 385f, 387f, 391f – inferior angle of, 385f, 390f–391f – infraglenoid tubercle, 385f, 387f, 393f – infraspinous fossa, 385f, 387f – lateral border of, 385f, 387f, 390f, 393f – lateral view of, 385, 385f – m edial border of, 298f, 385f, 389f, 391f – neck of, 385f – posterior surface of, 385f, 393f – posterior view of, 385, 385f – subscapular fossa, 385f – superior angle of, 385f, 390f – superior border of, 385f, 390f – supraglenoid tubercle, 385f, 387f, 393f – supraspinous fossa, 385f Scapular angle. See Angle, scapular Scapular notch, 385f, 387f, 390f Scapular spine, 298f, 385f, 387f, 390f, 392f–393f Schwann cells, 4, 73, 73f – functions of, 73t Sclera, 174f, 236f, 241f, 244, 244f, 247f, 248, 248f, 250f–252f – venous sinus, 247f Scleral spur, 248, 248f, 251f Sclerotom e(s), 3, 3f Scoliosis, 284 Scotom a(s), 256, 256f – hom onym ous hem ianopic central, 256, 256f Scrotum, 443f Sebaceous gland(s) – of ear, 263, 263f – of eyelids, 241, 241f Sectional anatomy – of abdom en, 461, 461f – transverse section(s), 439, 439f, 461, 461f

547

ERRNVPHGLFRVRUJ

– of abdom inopelvic cavit y, m idsagit tal section, 442f–443f – of anterior abdom inal wall, transverse section, 439, 439f – of cerebral hemispheres, right, m idsagit tal section of, 81, 81f – of cervical spine, m idsagit tal section, lateral view of, 292, 293f – of costodiaphragm atic recess, coronal section, anterior view of, 432, 432f – of diaphragm , coronal section, 408, 408f – of external auditory canal, coronal section, anterior view of, 263, 263f – of eye – sagit t al sect ion, 249, 249f, 252, 252f – transverse section, 248, 248f – at level of optic nerve, 247f – superior view of, 250, 250f – of eyeball – sagit tal section, 252, 252f – transverse section, superior view of, 244, 244f, 245, 245f – of fem ale breast, sagit tal section, 407, 407f – of head – coronal section(s) – anterior, 348–349, 348f–349f – posterior, 350–351, 350f–351f – through anterior orbital m argin, 348, 348f – through eyeball (MRI), 352, 352f – through m olar region of oral cavit y, 226, 226f – through orbital apex, 350, 350f – through pituitary, 351, 351f – through posterior orbit (MRI), 353, 353f – through retrobulbar space, 349, 349f – midsagit tal section, through nasal septum, 376, 376f – sagit tal section(s) – lateral, 378–379, 378f–379f – m edial, 376–377, 376f–377f – through approxim ate center of orbit, 379, 379f – through inner third of orbit, 378, 378f – through medial orbital wall, 377, 377f – through nasal cavit y (MRI), 380, 380f – through orbit (MRI), 381, 381f – transverse section(s) – caudal, 364–365, 364f–365f – cranial, 360–363, 360f–363f – at level of occlusal plane of m andibular teeth, superior view of, 226, 226f – through m edian atlantoaxial joint, 365, 365f – through m iddle nasal concha, 363, 363f – through nasopharynx, 364, 364f – through optic nerve and pituitary, 361, 361f – through orbit and ethm oid air cells (MRI), 370, 370f – through orbit and nasolacrim al duct (MRI), 371, 371f – through sphenoid sinus, 362, 362f – through upper level of orbit, 360, 360f – of larynx, sagit tal section, 336f – of lens, sagit tal section, 249, 249f – of lungs, transverse section, inferior view of, 434, 434f

Index

– of m ediastinum , parasagit tal section, lateral view of, 420, 420f, 421, 421f – of m edulla oblongata – cross section, 134, 134f, 136f, 138f, 141, 141f – lower, transverse section, 93, 93f – m iddle – transverse section just above, 92, 92f – transverse section just below, 93, 93f – upper, transverse section through, 92, 92f – of m esencephalon – cross-section, superior view of, 120f – transverse section, 90, 90f – of m uscles of m astication, coronal section at level of sphenoid sinus, 163, 163f – of nasal cavit y – coronal section, anterior view of, 174, 174f – sagit tal section, m edial view of, 176, 176f – transverse section, inferior view of, 174, 174f – of nasal septum , parasagit tal section, left lateral view of, 180, 180f – of neck – coronal section(s) – of great vessels (MRI), 356, 356f – of lingual m uscles (MRI), 354, 354f – of m uscles of m astication (MRI), 355, 355f – of soft palate (MRI), 355, 355f – of temporomandibular joint (MRI), 357, 357f – through cervical vertebrae and spinal nerves (MRI), 358, 358f – through nuchal m uscles (MRI), 359, 359f – m idsagit tal section, lateral view of, 321, 321f – m idsagit tal section (MRI), 382, 382f – sagit tal section(s), 382–383, 382f–383f – through carotid bifurcation, 383, 383f – transverse section(s) – caudal, 368–369, 368f–369f – cranial, 366–367, 366f–367f – at level of C6/C7 vertebral junction, 368, 368f – at level of C7/T1 vertebral junction, 369, 369f – at level of C5 vertebral body, 366, 366f – at level of C6 vertebral body, 368, 368f – at level of T1/T2 vertebral junction, 369, 369f – through C4 vertebral body (MRI), 374, 374f – through C6 vertebral body, 367, 367f – through C6 vertebral body (MRI), 374, 374f – through C7 vertebral body (MRI), 375, 375f – of olfactory tract, m idsagit tal section, 182, 182f – of oral cavit y – coronal section through m olars, 227, 227f – m idsagit tal section, lateral view of, 185, 185f – sagit tal section through canines, 227, 227f

– transverse section of area posterior to third m olar, superior view of, 227, 227f – of orbit – anterior, sagit tal section, 241, 241f – coronal section, anterior view of, 230, 230f – sagit tal section, m edial view of, 236, 236f – of pelvis – fem ale – m idsagit tal section, 465, 465f – parasagit tal section, 465, 465f – m idsagit tal section, 463, 463f – parasagit tal section, 463, 463f – of pons – lower, transverse section, 91, 91f – m idportion, transverse section, 91, 91f – upper, transverse section, 90, 90f – of retina, transverse section, superior view of, 252, 252f – of skull base, m idsagit tal section, 28f – of thoracic cavit y, coronal section, anterior view of, 412, 412f – of thorax, transverse section – anterosuperior view, 409f – inferior view of, 432f – of tongue m uscles, coronal section, anterior view of, 204, 204f Sella turcica, 30, 31f, 293f Semicircular canal(s), 134f, 262, 262f, 270, 270f, 274f – ampulla of. See Ampulla – anterior, 262f, 266f–267f, 270, 270f, 278f – contralateral, interaction during head rotation, 279, 279f – lateral, 262f, 266f–267f, 270, 270f – prom inence of, 266f – location of, 270, 270f – posterior, 262f, 266f–267f, 270, 270f, 370f Sem icircular duct(s), 270, 270f, 278, 278f, 280 – anterior, 271f, 278f – lateral, 271f, 278f – posterior, 271f, 278f Sem ilunar gyrus, 118f, 182, 182f Sem ilunar hiatus, 35, 176f, 179f Sem ilunar valve(s), 424, 424f Sem inal gland, 467f Sem inal vesicle, 442t, 464f Sensorim otor system , and voluntary m ovem ent s, 109, 109f Sensory cells – olfactory, 183 – secondary, 276 Sensory cortex, 104, 104f Sensory pathways, 104, 104f Sentinel node, 69 Sepsis, 63 Septal area, 83f, 83t Septum (pl., septa) – interalveolar, 190, 190f – interradicular, 190, 190f – interventricular, 423f, 427f – lingual, 163f, 203t, 204f, 350f, 354f, 382f – nasal. See Nasal septum – orbital, 236, 240, 240f, 242f – inferior, 236f, 241f – superior, 236f, 241f – rectovesical, 464f – scrotal, 464f Septum pellucidum , 78f, 380f Sesam oid bones, 389f Sharpey bers, 193, 193f Shoulder – anterior view of, 392f

– lateral view of, 392f–393f – m uscles of, 390, 390f, 391, 391f, 392, 392f – venous drainage of, 65t Sinoatrial node, 426, 426f, 427, 427f Sinus(es) – aortic, 425f – carotid, 136t, 137f, 137t, 329, 329f – m assage of, 329 – cervical, 8, 8f, 9t – ductal portions, rem nant s of, 11, 11f – coronary, 422f, 424f–425f, 425t – valved ori ce of, 423f – dural venous. See Venous sinus(es), dural – lactiferous, 407, 407f – paranasal, 21f, 35, 174, 174f, 348, 352f–353f – autonom ic innervation of, 110 – bony structure of, 175, 175f – ciliary beating and uid ow in, 177, 177f – drainage of, 176, 176f, 176t, 177, 177f – ethm oid, 360 – drainage of, 177, 177f – frontal, 25f, 29f, 35, 126f, 173f, 175, 175f–176f, 178f, 181f, 185f, 229f–230f, 231t, 370, 370f, 376f–377f, 378, 378f, 380f, 382f – arterial supply to, 61t – bony structure of, 175, 175f – ciliary beating and uid ow in, 177, 177f – drainage of, 176, 176f, 176t, 177, 177f – ostium of, 177f – pneumatization of, 175, 175f – posterior wall, 177f – venous drainage of, 64t – lymphatic drainage of, 71t – m axillary, 35, 39f, 126f, 174, 174f–175f, 179f, 227f, 228, 228f–230f, 231t, 232f, 236f, 348, 348f–350f, 354f, 363, 363f, 371, 371f–372f, 378, 378f–379f, 381, 381f, 383f – bony structure of, 175, 175f – ciliary beating and uid ow in, 177, 177f – on dental panoram ic tom ogram (DPT), 200f – drainage of, 176, 176f, 176t, 177, 177f – endoscopy of, 177, 177f – uncinate process as landmark for, 35 – m edial wall, 177f – ostium of, 175, 175f, 177f, 228, 229f – pneum atization of, 175, 175f – roof of, 175 – m ucosa of, innervation of, 267 – parasympathetic innervation of, 112t – projection onto skull, 175, 175f – sphenoid, 103f, 126f, 163f, 173f–176f, 178f, 180f–181f, 185f, 230, 231t, 267f, 293f, 351, 351f, 355, 355f–357f, 362f, 370, 370f, 372f, 376f, 377, 377f, 378, 378f, 380, 380f, 382f – aperture of, 30, 31f – arterial supply to, 61t – drainage of, 176t, 177, 177f – ostium of, 39f – septum of, 39f, 351f – venous drainage of, 64t – venous drainage of, 64t–65t Sinusitis, 174–177 – acute maxillary, 174 – chronic, 176

Sjögren syndrome, 242 Skeletal muscle(s), of trunk, 3 Skull. See also Cranium – anterior view of, 20f–21f, 38f – asym m etric, asym m etrical suture closure and, 22f – bones of. See Bone(s), cranial – deform it y, premature closure of cranial sutures and, 22f – lateral view of, 18f–19f, 30f – long and narrow, prem ature closure of sagit tal suture and, 22f – pointed, prem ature closure of coronal suture and, 22f – posterior view of, 22f–23f, 294, 294f – triangular, premature closure of frontal suture and, 22f Skull base, 363 – bones of – external surface, inferior view of, 26f–27f – internal surface, superior view of, 28f – exterior, 26f–27f, 30f – inferior view of, 34f, 38f, 43f–44f – external aspect, neurovascular structures in, 45t – form ation of, 16f – fracture lines of, 28, 28f – inferior view of, 47f – interior, 28f, 30f – superior view of, 35f, 43f–44f – internal surface, superior view of, 29, 29f – internal view of, neurovascular structures in, 45t – m idsagit tal section of, 28f – neurovascular pathways through, 44, 44f – oblique external view of, 156, 156f – openings in, 45t – tumors of, 343f, 343t Sm all intestine, 449. See also Duodenum ; Ileum ; Jejunum Sm ooth m uscle, 465f Sni ng position, 344, 344f Solitary tract, 91f, 92, 92f–93f Som atopleura, 2f Som atosensory cortex, prim ary, 81, 81f, 105–106, 106f, 108f Som ite(s), 2, 2f, 2t, 3, 10, 10t Space(s) – Berger, 245f – buccal, 226f, 226t, 227f, 227t – canine, 226f, 226t, 227f, 227t – cerebrospinal uid (CSF), 94, 94f – endolymphatic, 270, 274 – endoneural, 94f – epidural, spinal, 75, 75f – episcleral, 236, 236f – Fontana, 251, 251f – Garnier, 245f – Hannover, 245f – infratemporal, 226f, 226t, 227f, 227t – infratentorial, 103 – interscalene, 49, 49f, 324, 329, 401f – Morgagni, 343f. See also Ventricle, laryngeal – palatal, 226f, 226t, 227f, 227t – parapharyngeal, 226f, 226t, 227f, 227t, 334, 355f – anterior, 334 – neurovasculature of, 335, 335f – posterior, 334 – parotid, 226f, 226t – perilymphatic, 270, 274 – peripharyngeal, 332, 332f, 334, 334f – peritonsillar, 226f, 226t – Petit, 245f

548

ERRNVPHGLFRVRUJ

Index

– pterygomandibular, 162, 162f, 226f, 226t, 227f, 227t – Reinke, 343f – retrobulbar, 349 – retropharyngeal, 226f, 226t, 227f, 227t, 320f, 321, 321f, 334, 378f – retropubic, 464f – subarachnoid, 94, 94f, 95, 102, 103f, 253, 253f, 293f – spinal, 74f–75f – subdural, spinal, 74f – subglot tic, 340t – sublingual, 226f, 226t, 227f, 227t – subm andibular, 226f, 226t, 227f, 227t – subm asseteric, 226f, 226t, 227f, 227t – subm ental, 226f, 226t, 227f, 227t – supraglot tic, 340t – supratentorial, 103 – transglot tic, 340t Sperm atic cord, 439f, 467f Sphecoid bone, 30 Sphenoethm oid recess, 176f, 176t, 178f Sphenoid bone, 22f, 26f, 28f, 30, 32f, 34–35, 36f, 157t, 172, 172f, 176f, 216f–217f, 221f, 228, 232f, 370f, 372f – body of, 31f, 173f, 221f, 363, 363f – developm ent of, 16t – greater wing, 18f–21f, 29f, 30, 30f–32f, 36f, 158t, 168t, 228f–229f, 355f, 362, 362f – cerebral surface of, 31f – infratemporal crest, 157t–158t, 168f – infratemporal surface of, 168f – orbital surface of, 228f, 230f – temporal surface of, 168f – isolated, 30, 31f – left lateral view of, 30f – lesser wing, 20f–21f, 28, 28f–29f, 30, 31f, 173f, 228f–229f, 354f – orbital surface of, 228f, 230f – orbital surface of, 31f – position in skull, 30, 30f – pterygoid process, 23f, 30, 30f, 188f – developm ent of, 16t – lateral plate, 26f–27f, 30, 31f, 39, 39f, 156f, 158f, 162f–165f, 168f, 170f, 173f, 215f, 365f, 371, 371f – medial plate, 26f–27f, 30, 31f, 39f, 156f, 162f, 164f–165f, 168f, 173f, 176f, 221f, 371, 371f – root, 168t – spine of, 164f – temporal surface of, 31f – view of – from skull base exterior, 30, 30f – from skull base interior, 30, 30f Sphenoid crest, 173f Sphenofrontal suture, 17f Spheno-occipital synchondrosis, 26f Sphenoparietal suture, 19f Sphenosquam ous suture, 17f, 19f, 168f Spina bi da, 4 Spinal cord, 72, 72f, 74, 74f, 94f, 284, 289f, 293f, 299f, 359, 365, 365f, 367f, 369f, 373f, 375, 375f, 409f, 411f, 417t, 426f, 461f – alar plate of, 4, 4f – anterior funiculus. See Funiculus (pl., funiculi) – ascending tract s, 76f, 104, 104f, 105t – and balance, 281, 281f – basal plate of, 4, 4f – blood supply to, 325 – cervical, 77, 77f – descending tracts, 76f, 108, 108f, 108t – em bryology of, 4, 4f, 116, 116f – enlargem ent of – cervical, 74, 74f – lum bosacral, 74, 74f

– oor plate of, 4, 4f – gray m at ter of, 76, 76f–77f, 109 – horn(s) of – anterior, 3, 3f, 4, 4f, 76f, 109, 116, 116f – central, 4, 4f – lateral, 4, 4f, 76f, 111t, 113, 113t, 116, 116f – posterior, 3, 3f, 4, 4f, 76f, 116, 116f – intrinsic fascicles of, 76f – lateral funiculus. See Funiculus (pl., funiculi) – lesions, e ects of, 77, 77f – levels, age-related changes in, 75, 75f – lum bar, 77, 77f – m eningeal layers of, 74, 74f – nuclear colum n, 76f – posterior funiculus. See Funiculus (pl., funiculi) – prim itive, 3 – roof plate of, 4, 4f – sacral, 77, 77f – segm ent s of, 77, 77f – in sensorim otor system , 109, 109f – thoracic, 77, 77f – T1 segm ent, 437f – in vertebral canal, 75, 75f – white m at ter of, 4, 4f, 76, 76f–77f Spinal curvature, 284, 284f Spine. See also Vertebra/Vertebrae – cervical, 284, 284f, 286–287, 286f–287f – anterior view of, 292, 292f – anterosuperior view of, 295, 295f – injury to, 288–289 – joints of, 288, 288f – ligam ent s of, 292–293, 292f–293f, 294–295, 294f–295f – m agnetic resonance im age of, 293, 293f – m idsagit tal section, lateral view of, 292, 293f – neurovasculature of, 289, 289f – posterior view of, 292, 292f, 294, 294f – radiograph of, left lateral view, 288, 288f – lum bar, 284, 284f – sacral. See Sacrum – thoracic, 284, 284f Spinocerebellar tract(s), 104 – anterior, 79f, 91, 91f–92f, 105t – posterior, 92f–93f, 105t Spinom edullary junction, 109 Spinotectal tract, 90f Spinothalam ic tract(s) – anterior, 105t – lateral, 90, 90f–93f, 105f, 105t Spiral lam ina, 274, 274f – lim bus of, 274f Spiral sulcus, 274f Splanchnopleura, 2f Spleen, 442t, 446f–447f, 451f, 453f, 461f – blood supply to, 441f – gastric surface of, 448f – superior border of, 448f Squam ous suture, 17f, 19f Stapedius re ex, 277, 277f – a erent lim b of, 277, 277f – e erent lim b of, 277, 277f Stapedius re ex test, 269, 277 Stapes, 7f, 7t, 262f–263f, 266f, 270f, 275f, 277f – crus of – anterior, 268f – posterior, 268f – developm ent of, 16t – footplate of, 268, 269f – head of, 268f

– m edial view of, 268, 268f – neck of, 268f – position of, 268, 268f – superior view of, 268, 268f Statoliths, 278 Stensen’s duct. See Parotid duct Stereocilia, 276 – of hair cells, 274–275, 275f – in m acular organs, 278, 278f – of vestibular sensory cells, 278, 278f, 279, 279f – specialized orientations of, 279, 279f Sternal angle, 402f Sternum , 392f, 403f–404f, 408f–409f, 411f, 418f, 430f, 433f, 439f – body of, 402f – m anubrium , 402f, 404f, 418f – superior border of, 438f – xiphoid process, 402f, 404f, 408f, 418f, 439f Stom ach, 416f, 430f, 442t, 443f–444f, 453, 453f – angular notch of, 446f – anterior view of, 446, 446f – autonomic innervation of, 110f – blood supply to, 440, 440f–441f – body of, 446f, 461f – cardiac ori ce, 448f – cardia of, 431f, 446f – curvature of – greater, 446f–447f – lesser, 446f – fundus of, 431f, 446f – posterior surface of, 447f – pyloric part, 448f, 461f – wall of – anterior, 461f – posterior, 461f Strabism us, m edial, 235t Stria (pl., striae) – diagonal, 182f – of Gennari, 254, 254f – longitudinal, 182f – m alleolar, 263, 263f, 269f – m edullary, 84f, 89f, 182, 182f, 276f – olfactory, 118 – lateral, 118f, 182, 182f – m edial, 118f, 182, 182f Stria medullaris thalam i, 84f, 89f Striate area, 86t, 119, 119f Stria vascularis, 274, 274f Stroke, 97, 314 – hem orrhagic, 97 – ischem ic, 100–101, 101f Strom a, corneal, 249, 249f Strom edeum , 12, 12f Subarachnoid hem orrhage, 97, 103, 103f Subarachnoid space, 94, 94f, 95, 102, 103f, 253, 253f, 293f – spinal, 74f–75f Subcallosal (paraolfactory) area, 83f, 83t Subclavian trunk, 413f Subcostal plane, 438f, 438t Subdural hematom a, 98, 103, 103f Subdural hemorrhage, 120t Subdural space, spinal, 74f Subglot tic space, 340t Subiculum , 82 Sublingual space, 226f, 226t, 227f, 227t Subm andibular duct, 206f, 211f, 212, 212f, 213t, 352 Subm andibular space, 226f, 226t, 227f, 227t Subm andibular triangle, 318f, 318t, 319f Subm asseteric space, 226f, 226t, 227f, 227t Subm ental space, 226f, 226t, 227f, 227t Subm ental triangle, 318f, 318t, 319f Subm ucosal plexus, 335f

549

ERRNVPHGLFRVRUJ

Suboccipital fat, 382f Suboccipital triangle, 309, 331, 331f Substantia gelatinosa, 93f Substantia nigra, 85f, 90, 90f, 108f, 120f, 360, 360f Subthalam us, 5t – functions of, 85t – structures of, 85t Sulcus (pl., sulci) – anterolateral, 89f – calcarine, 81f – central, 78f, 81f – coronary, 422f–423f – gingival, 193, 193f – hypothalam ic, 84f, 87, 87f – interventricular (heart), 422f – lateral, 78f, 81f, 276f – parieto-occipital, 78f, 81f – posterolateral, 89f – for spinal nerves, vertebral. See Vertebra/Vertebrae – spiral, internal, 274f – term inal (sulcus term inalis), 10, 10f, 202f, 203t, 209f – telodiencephalic, 5f – ventral diencephalic, 84f Superior m edullary velum , 79, 79f, 89f, 91f Superior vena cava. See Vena cava Supporting cell(s), olfactory, 183f Suprabasal layer, 193f Supraclavicular triangle, 318f, 318t Supracrestal plane, 438f, 438t Supraglot tic space, 340t Supram astoid crest, 156f, 157t Supraoptic recess, 84f, 95f Supraorbital notch, 231t Suprapineal recess, 95f Suprarenal gland(s), 442t, 447f, 451f, 461f Suprasternal notch, 319, 319f Supratentorial space, 103 Supraventricular crest (cardiac), 423, 423f Supraventricular tachycardia, 329 Surgery – carotid, 343f, 343t – endoscopic, of m axillary sinus, 35 – laryngeal, approaches for, 342, 342f – thyroid, 343f, 343t, 347 – tracheal, approaches for, 342, 342f – transnasal procedures, on pituitary, 175 Suture(s) – coronal, 19f, 25f – in adult, 17f – age at ossi cation, 17t – neonatal, 17f – prem ature closure of, 22f – cranial – in adult skull, 17f – age at ossi cation, 17t – left lateral view of, 17f – order of closure of, 17f – prem ature closure of, 17f, 22f – superior view of, 17f – frontal, 17f – age at ossi cation, 17t – prem ature closure of, 22f – incisive, 190f – interm axillary, 21f, 38f – interpalatine, 39f – lam bdoid, 19f, 23f, 25f, 381f – in adult, 17f – age at ossi cation, 17t – neonatal, 17f – nasom axillary, 172f – palatine – m edian (interm axillary), 26f, 39, 39f, 188f, 190f

Index

– transverse (palato-m axillary), 26f, 39f, 190f – sagit tal, 17f, 23f, 25f – age at ossi cation, 17t – prem ature closure of, 22f – sphenofrontal, 17f – sphenoparietal, 19f – sphenosquam ous, 17f, 19f, 168f – squam ous, 17f, 19f – zygomaticofrontal, 36 Swallowing, 219, 219f. See also Dysphagia – laryngeal m otion in, 336 – phases (stages) of, 219 Swallowing re ex, 219f Sweat glands, sympathetic innervation of, 113t Sympathetic nervous system , 110, 110f – peripheral, 417t – in thorax, 417, 417f, 417t Sympathetic pathways, 111t Sympathetic trunk(s), 110, 110f, 224f–225f, 324f, 328–329, 329f, 332f–333f, 411f, 416f–417f, 417t, 421f, 426f, 433f – inferior cervical ganglion, 426f – interganglionic trunk, 460f – lum bar ganglia, 460f – middle cervical ganglion, 416f, 426f – sacral ganglia, 460f – thoracic ganglion, 416f, 420f, 426f Synapse(s) – axoaxonal, 73f – axodendritic, 73f – axosom atic, 73f Synchondrosis (pl., synchondroses), spheno-occipital, 26f Syndesm osis, 23f Synostosis, of cranial bones, 17f Systole, ventricular, 424f

T Taenia cinerea, 89f Tarsal gland(s), 241, 241f Tarsus, 241, 241f Taste, ve basic qualities of, 202, 209 Taste buds – m icroscopic structure of, 209, 209f – of pharynx, 202, 209 – of soft palate, 133f, 202, 209 – of tongue, 208–209 – innervation of, 133, 133f Taste pore, 209f Taste sense. See also Gustatory pathway – disturbances of, 131 – neural pathways for, 127t, 129t, 130, 133, 133f, 138t, 139f, 207, 207f Tear lm , structure of, 243, 243f Tectospinal tract, 90f–93f, 108f, 108t Tectum , 5t, 120f Teeth, 26f. See also Dentition; Tooth – deciduous, 190, 198, 198f – coding (let tering), 198, 198f – eruption of, 199, 199f, 199t – and permanent, di erence bet ween, 198 – eruption of, 199, 199f, 199t – lym phatic drainage of, 71t – m andibular, 190, 190f, 352, 352f – anterior, spread of infection from , potential routes for, 227, 227f, 227t – blood supply to, 186, 186f, 197t – coding (num bering), 191, 191f – innervation of, 40, 197t – lym phatic drainage from , 197t – perm anent, m orphology of, 196, 196f, 197t – radiograph of, 201, 201f – surfaces of, designation of, 191, 191f

– venous drainage of, 187, 187f, 197t – of 6-year-old child, 198, 198f – m axillary, 174, 174f, 175, 190, 190f, 381 – anterior, spread of infection from , potential routes for, 227, 227f, 227t – blood supply to, 186, 186f, 195t – coding (num bering), 191, 191f – eruption of, 199f – innervation of, 195t – lymphatic drainage from , 195t – perm anent, 194, 194f – m orphology of, 194, 194f, 195t – radiograph of, 201, 201f – surfaces of, designation of, 191, 191f – venous drainage of, 187, 187f, 195t – of 6-year-old child, 198, 198f – perm anent, 190 – in adult s, 190, 190f – coding (num bering), 191, 191f – and deciduous, di erence bet ween, 198 – eruption of, 199, 199f, 199t – m andibular, m orphology of, 196, 196f, 197t – m axillary, 194, 194f – morphology of, 194, 194f, 195t – radiographs of, 200–201, 200f–201f – venous drainage of, 64t–65t – of 6-year-old child, 198, 198f Tegm entum , 5t, 84f Tegm entum t ympani. See Tympanic cavit y, roof of Tegm en t ympani, 273f Telencephalon, 5, 5f, 5t, 72, 80, 86, 89, 103, 103f, 174f, 182. See also Cerebrum – divisions of, 80, 80f – internal structure of, 85f Telodiencephalic sulcus, 5f Temporal arteritis, 58 Temporal bone, 20f–21f, 30f, 36f, 157t, 161f, 230f, 294f, 357f, 370f – arcuate em inence, 33f – articular tubercle (em inence), 19f, 33f, 156f, 164f–165f, 167f – on dental panoram ic tom ogram (DPT), 200f – fractures of, 130t, 131 – inferior view of, 32f, 33, 33f – internal view of, 32f – left lateral view of, 32f, 33, 33f – m astoid process, 19f, 23f, 26f, 32, 32f, 33, 33f, 161f, 164f, 210f, 262f, 270f, 292f, 294f, 303f, 305f, 307f, 309f, 359f – tip of, 319, 319f – m edial view of, 33, 33f – petrom astoid part, 18f, 22f, 26f, 28f, 32, 32f – developm ent of, 16t – petrous part, 23f, 29, 29f, 32, 32f–33f, 262, 262f, 266, 266f, 358f–359f, 362, 362f, 379f – superior view of, 270, 270f – petrous ridge (crest), 28, 28f, 33f – position in skull, 32f – projection of clinically im portant structures onto, 32f – squam ous part, 7t, 18f, 22f–23f, 26f, 28f, 32, 32f, 156f, 158t, 168f – developm ent of, 16t – lateral view of, 270, 270f – st yloid process, 7f, 7t, 19f, 23f, 32, 32f–33f, 158t, 161f, 164f, 204f, 210f, 223f, 262f, 294f – developm ent of, 16t – temporal surface of, 33f – t ympanic part, 18f, 26f, 32, 32f, 263, 263f – developm ent of, 16t

– zygom atic process, 19f, 26f, 33f, 36f, 156f, 164f, 351f Temporal crescent, 255, 255f Temporal lobe, 78, 78t, 103f, 163f, 174f, 351, 351f, 370f – m esiobasal, 103f – ventricular system and, 95 Temporal region, 318f Temporofacial trunk, 154f Temporal gyri, transverse, 86t, 276, 276f Tendon(s) – biceps brachii, 393f – brachialis, 393f – brachioradialis, 394f – exor digitorum profundus, 397f – lateral canthal, 36 – om ohyoid, interm ediate, 313f – stapedius, 266f, 269f – temporalis, 157f, 158t – tensor t ympani, 267f, 269f, 272f – trapezius, 331 Tenia coli, 444f, 448f–449f, 464f–465f Tenon’s capsule, 236, 236f Tentorial notch, 102f Tentorium cerebelli, 102, 102f, 103, 103f, 361, 361f–362f, 377f, 380f–381f Term inal sulcus (sulcus term inalis), 84f Tetany, 346 Thalam ic a erent(s), 86t Thalam ic e erent(s), 86t Thalam us, 80f, 84, 84f–86f, 97f, 100f, 104, 104f, 105, 105f, 119f, 182, 380f–381f – arterial supply to, 96f – and balance, 281, 281f – dorsal, 5t – functional organization of, 86, 86f – functions of, 85t – lesions of, 86 – m edullary stria of, 84f, 89f, 182, 182f, 276f – in sensorim otor system , 109, 109f – structures of, 85t Thoracic aperture(s), 402f Thoracic cage, opened, anterior view of, 410f Thoracic cavit y – coronal section, anterior view of, 412, 412f – divisions of, 412, 412f – m ajor structures of, 412f, 412t – nerves of, 416–417, 416f–417f, 417t – opened, 412, 412f – veins of, 415f Thoracic duct, 68–69, 69f, 71t, 324, 324f, 325, 325f, 347f, 412t, 413, 413f, 418t, 421f, 430f, 433f Thoracic inlet, 323, 323f, 418f Thoracic segm ent, structure of, 403f Thoracic skeleton, 402, 402f – anterior view of, 402f – lateral view of, 402f – posterior view of, 402f Thoracic wall – anterior – lym phatic drainage of, 71t – neurovascular structures of, 405, 405f – deep, 405, 405f – super cial, 405, 405f – innervation of, 416 – m uscles of, 404, 404f Thorax – lymphatic trunks in, 413, 413f – nerves of, 416–417, 416f–417f, 417t – opened, anterior view of, 413, 413f, 416f – parasympathetic nervous system in, 417, 417f, 417t

– sympathetic nervous system in, 417, 417f, 417t – transverse section – anterosuperior view of, 409f – inferior view of, 432f – vertical reference lines of, 432, 432f Throm bus (pl., thrombi), 100, 100f Thymus, 412f, 412t, 418f, 418t, 419, 419f–420f – developm ent of, 8f, 9t, 11, 11f – venous drainage of, 415t Thyrocervical trunk, 48f–49f, 49t, 314f, 314t, 323f–324f, 325, 325f, 341, 341f, 347, 347f, 369f, 398f, 414f Thyroglossal duct, 347f – persistent, 346 – rem nants of, 11, 11f Thyroid gland, 185f, 216f, 222f, 224f, 299f, 320t, 322, 328f–329f, 332f, 335f, 342f, 345f, 346, 346f–347f, 355f–357f, 367f, 368, 368f, 369, 369f, 374f, 375, 375f, 382f, 412f, 426f – anlage, 8, 8f – anterior view of, 346f – arterial supply to, 347, 347f – blood supply of, 347, 347f – capsule of, 346, 346f – external, 346, 346f – internal, 346 – developm ent of, 8, 8f, 9t, 11, 11f – ectopic, 11, 347, 347f – enlargem ent of, 346 – innervation of, 347, 347f – isthm us of, 346, 346f – lingual, 11, 347, 347f – lobes of, 346, 346f, 419f – lobules of, 346 – lymphatic drainage of, 71t – pyram idal lobe of, 11f, 323f, 346, 346f–347f – surgical rem oval of, 347 – topography of, 346, 346f – venous drainage of, 347, 347f, 415t Thyroid lam ina, 337, 337f, 342f, 378f Thyroid plexus, 315, 315t, 341, 341f, 347, 347f Thyroid notch, 337f Tinnitus, 271 Tongue, 163f, 174f, 349, 349f, 352f–353f, 378f, 380f – anterior t wo thirds of (oral/presulcal portion), 202, 202f, 203t – developm ent of, 10, 10f, 10t – innervation of, 203t, 207–208 – apex of, 184f, 202, 202f, 203t, 204f, 206f, 348 – base (root) of, 10f, 178f–179f, 202, 203t, 216f, 225f, 333f, 339, 339f, 344f–345f, 355f, 376 – developm ent of, 10, 10f, 10t – innervation of, 139t – taste bers, 133 – blood supply to, 186, 186f, 206, 206f, 207t – body of, 10f, 202 – cancer of, 185, 185f – developm ent of, 10, 10f, 10t, 13f – dorsum (superior surface) of, 184f, 202, 202f, 203t, 204f – m briated fold of, 184f – functions of, 202 – innervation of, 203t, 205t, 206, 206f, 207, 207f – som atosensory, 207, 207f – taste, 207, 207f – lymphatic drainage of, 70, 70f, 71t – m edian furrow of, 202f, 203t – m uscles of, 202, 204, 204f, 205t

550

ERRNVPHGLFRVRUJ

Index

– coronal section, anterior view of, 204, 204f – developm ent of, 10, 10t – extrinsic, 354 – innervation of, 204 – intrinsic, 348f, 350f, 354, 377f – lateral view of, 204, 204f – neurovasculature of, 206, 206f – papillae of, 202, 202f, 203t – part s of, 202, 202f, 203t – posterior one third of (postsulcal/ pharyngeal portion), 202, 202f, 203t – developm ent of, 10, 10f, 10t – innervation of, 136t–137t, 203t, 207–208 – taste bers, 133 – regions of, 203t – surface anatomy of, 202, 202f, 203t – taste buds of, 202, 203t, 208 – innervation of, 133, 133f – taste receptors in, 209, 209f – venous drainage of, 187, 187f, 206, 206f, 207t – ventral (inferior) surface of, 184, 184f, 202 Tonotopic organization, of auditory pathway, 274, 276 Tonsil(s), 217, 217f – cerebellar, 79, 79f, 103, 103f, 372f – lingual, 178f, 185f, 202f, 203t, 217, 217f, 334f–335f, 340f – palatine, 10f, 178f, 184f–185f, 202f, 203t, 214f, 216f, 217, 217f, 334f–335f, 351f, 356, 356f, 373f, 378f, 382f – abnorm al enlargem ent of, 217 – developm ent of, 8f, 9t, 11, 11f – innervation of, 136t–137t – pharyngeal, 178, 178f–179f, 185f, 216f, 217, 217f, 221f, 267f, 356, 356f – abnorm al enlargem ent of, 217 – tubal (tonsillae tubariae), 185f, 217, 217f Tonsillae tubariae. See Tonsil(s), tubal Tonsillectomy, 217, 335 Tonsillitis, 217 Tooth. See also Teeth – body of, 192f, 192t – crown of, 192, 192f – of m axillary perm anent teeth, 194, 194f, 195t – cusp of, 192f – neck of, 192, 192f, 192t – part s of, 192, 192f, 192t – protective coverings of, 192t – root canal(s) of, 193f – of m axillary perm anent teeth, 194, 194f, 195t – root(s) of, 192, 192f – apex of, 192f, 192t – of m axillary perm anent teeth, 194, 194f, 195t Tooth surface(s) – buccal, 191, 191f – designation of, 191, 191f – distal, 191, 191f – labial, 191, 191f – lingual, 191, 191f – of m axillary permanent teeth, 194, 194f, 195t – mesial, 191, 191f – occlusal, 191, 191f – palatal, 191, 191f Tori, 39 Torticollis, 140, 140f, 140t – congenital, 297 Torus m andibularis, 39 Torus palatinus, 39 Torus tubarius, 178f, 180f, 185f, 333f Trabecula (pl., trabeculae)

– cancellous, 30, 31f – carneae, 423, 423f – septom arginal, 423f, 427f Trabecular m eshwork (ocular), 248f, 251, 251f Trachea, 11f, 185f, 216f, 218f, 220f, 299f, 320t, 321, 325f, 335f, 339f, 342f, 344f–347f, 354f–357f, 369, 369f, 375, 375f, 382, 382f, 412f, 412t, 414f, 416f, 418f, 418t, 419f–420f, 426f, 431f, 436f–437f – anlage, 8f – cervical part, 418f, 430f – lymphatic drainage of, 71t – m em branous wall of, 340f – surgical approaches to, 342, 342f – thoracic part, 418f, 430f – venous drainage of, 415t Tracheal axis, 344, 344f Tracheal cartilage. See Cartilage, tracheal Tracheobronchial tree – autonomic innervation of, 437, 437f – parasympathetic innervation of, 437f – sympathetic innervation of, 437f Tracheostomy, 344 Tracheotomy, 342, 342f Tragus, 264f Transglot tic space, 340t Transient ischemic at tacks, 314 Transpyloric plane, 438f, 438t Transtubercular plane, 438f, 438t Trapezium , 395f–396f – tubercle of, 389f, 395f Trapezoid, 397f Trapezoid body, 91, 91f, 389f Traum atic spondylolisthesis, 288 Traveling wave, 275, 275f, 276 Treacher Collins syndrom e, 9 Triangle – carotid, 318f, 318t, 319f, 328, 328f – lateral view of, 328, 328f – cervical region, 318, 318f, 318t – anterior, 318, 318f, 318t, 322, 322f, 329 – lateral, 318f, 318t – deep, 329, 329f – posterior, 318, 318f, 318t, 319f, 326, 326f–327f, 329 – sternocleidom astoid, 318, 318f, 318t, 319f, 329 – interscalene, 311f – Killian’s (dehiscence), 431f – lum bar, 298f – lum bocostal, 408f – m uscular (neck), 318f, 318t, 319f – occipital, 318f, 318t – Philippe-Gom bault, 76f – posterior, 319f – retrom olar, 40, 41f – subm andibular, 318f, 318t, 319f – subm ental, 318f, 318t, 319f – suboccipital, 309, 331, 331f – supraclavicular, 318f, 318t Tribasilar bone, 30 Trigem inal neuralgia, 122t Trigem inothalam ic tract, 86t, 106, 106f Triquetrum , 389f Trism us, 36, 43, 161, 227t Trochlea, 121f, 124f, 232, 232f, 234f, 239f–240f Trochlear nerve palsy, 120t, 235, 235f, 235t Trogonocephaly, 22f Trunk, m uscles of, 300, 300f Trunk wall – anterior, neurovascular structures of, 405, 405f – deep, 405, 405f – super cial, 405, 405f

– fascial planes of, 299, 299f Tuber cinereum , 84f, 85t Tuberculous osteomyelitis, of cervical spine, 321 Tuberculum impar, 10, 10f, 10t Tufted cell(s), in olfactory bulb, 183 Tympanic bone, 263f Tympanic cavit y, 32, 131f, 262f, 263, 263f, 266, 266f, 274f, 358f – arteries of, 272, 272f, 272t – clinically important levels of, 269, 269f – developm ent of, 8, 8f, 9t, 11, 11f – oor of, 267f – innervation of, 136t, 267 – m ucosal lining of, 269, 269f – ossicular chain in, 269, 269f – pharyngeal com m unication, 216t – roof of, 267f – veins of, 272 – wall of, 266, 266f, 267f

U Ulna, 388, 388f–389f, 393f–394f, 397f – coronoid process, 388f–389f, 395f – head of, 388f–389f – interosseous border of, 388f – olecranon, 388f, 393f–394f – shaft of, 388f – st yloid process, 388f–389f – trochlear notch, 388f Ulnar tuberosit y, 388f, 393f, 395f Ultim obranchial body, 11, 11f – developm ent of, 8f, 9t Um bilical cord, 3, 3f, 429f Um bilicus, 405f, 428f–429f, 439f Um bo, 263, 263f, 269f Uncus, 182f, 377f Ureter(s), 442t, 452f, 458f, 461f, 464f–465f, 467f Urethra – fem ale, 458f – m ale, 464f Urinary bladder, 442t, 443f, 464f–465f – autonom ic innervation of, 110f – dysfunction of, 101, 101f Uterine cervix, 442t, 465f Uterine plexus, 458f, 466f, 466t, 467f Uterine tubes, 442t, 465f, 467f Uterus, 442t, 465f – body of, 465f – cervix of, 442t, 465f – fundus of, 465f Utricle, 262, 270, 270f, 280, 280f – m acula of, 270f, 280 – structure of, 278, 278f Uveal tract, 244, 250, 252, 252f Uvula, 15f, 178f–180f, 184f–185f, 215f–217f, 351f, 373, 373f, 376, 376f, 380f, 382 – developm ent of, 14–15 – innervation of, 136t – m uscular, 7t – of verm is, 79f, 370f

V Vagal trunk(s), 417f – anterior, 416f, 433f, 460f – posterior, 460f – celiac branch, 460f Vagina, 442t, 458f, 465f Vaginal fornix, 465f Vaginal plexus, 466f, 466t, 467f Vallecula (pl., valleculae), 79f, 185f, 209f, 339, 339f–340f, 345f, 355, 355f–356f, 376, 376f–377f – epiglot tic, 203t

551

ERRNVPHGLFRVRUJ

– innervation of, 208 Valve(s) – cardiac, 424, 424f – of Kerckring, 449f Vasa recta, 454f Vasoconstriction, 111t Vein(s) (named) – alveolar, inferior, 187, 187f, 197t, 227f, 348f–350f, 379f – angular, 62f, 64f, 64t, 65f–66f, 66t, 67f, 150f, 152f, 187f, 236t, 237f, 240, 240f – antebrachial, m edian, 399f – apical (pulm onary), 437f, 437t – apicoposterior (pulm onary), 437f, 437t – appendicular, 457f – auricular, posterior, 62, 62f–63f, 63t, 64f, 65, 65f, 65t, 66f, 66t, 152f – axillary, 62, 399f, 406f – azygos, 409f–411f, 411t, 413f, 415f, 415t, 418f, 418t, 419f–420f, 430f, 433f, 456f–457f – basilar, 66f, 98f–99f – regions drained by, 99, 99f – basilic, 399f – m edian, 399f – brachial, 399f – brachiocephalic, 62, 62f, 64f–65f, 225f, 315f, 325f, 328f, 333f, 341, 341f, 347, 347f, 356f, 410f, 411t, 412f–413f, 415f, 415t, 418f, 418t, 419f–420f, 430f, 434f – branches, 315, 315f, 315t – buccal, 349f – cardiac – anterior, 425t – great, 425f, 425t – m iddle, 425f, 425t – small, 425f, 425t – cecal, 459f – central retinal, 247f – cephalic, 399f, 405f – accessory, 399f – m edian, 399f – cerebral – anterior, 98f, 99, 99f – deep, 98–99, 99f – great, 98, 98f, 99, 99f – inferior, 98f – throm bosis, 101, 101f – internal, 98f–99f – thrombosis, 101, 101f – m iddle – deep, 99, 99f – super cial, 98f–99f – regions drained by, 99, 99f – super cial, 98, 98f–99f – ascending, 99, 99f – descending, 99, 99f – regions drained by, 99, 99f – superior, 98f, 102f – throm bosis, 101, 101f – term inal, 99f – cervical – ascending, 315t – deep, 66f, 315t, 359f – super cial, 326f – transverse, 65, 65t, 315f, 315t, 324f, 327f – choroidal, 99f – inferior, 99f – clitoral, deep dorsal, 467f – cochlear, 273f – colic, 457f, 459f – m iddle, 444f, 447f, 457f, 459f – com municating, anterior, 99, 99f – cubital, m edian, 399f – deep, 399f – cystic, 457f – digital, palm ar, 399f – epigastric

Index

– –

–

– – – – –

–

– – – –

– – – –

– –

–

– –

– inferior, 405f, 444f–445f, 457f–458f – super cial, 405f – superior, 405f, 457f esophageal, 457f ethm oidal, 45t – anterior, 231t – posterior, 231t facial, 62, 62f, 63, 63f, 63t, 64, 64f, 64t, 65f–66f, 67, 67f, 150f, 152f, 158f–159f, 187, 187f, 206f, 207t, 212f, 237f, 240f, 315f, 315t, 326f, 329f, 341f, 364f, 383f – com m on, 62, 63f, 63t, 64, 64f, 66f–67f, 187f, 328f – tributaries of, 64, 64f, 64t – deep, 63f–64f, 64t, 67, 67f, 187f – deep portion, 158t fem oral, 62, 452f, 458f frontal, 66f gastric, 457f, 459f – short, 457f gastro-omental, 457f, 459f gluteal – inferior, 458f, 466f, 466t – superior, 458f, 466f, 466t, 467f hem iazygos, 410f–411f, 411t, 413f, 415f, 418t, 421f, 433f, 456f–457f – accessory, 413f, 415f, 415t, 421f hepatic, 415f, 456f, 456t, 458f ileal, 457f, 459f ileocolic, 457f, 459f iliac – circum ex – deep, 458f – super cial, 405f – com m on, 415f, 443f, 455f–456f, 456t, 457f–459f, 464f–467f – external, 458f, 465f–467f – internal, 458f, 466f–467f inferior anastom otic (of Labbé), 98f infraorbital, 169t, 187, 187f, 231t, 237f, 238, 352, 352f–353f interosseous (arm), anterior, 399f interventricular (cardiac) – anterior, 425t – posterior, 425t jejunal, 457f, 459f jugular – anterior, 62f–63f, 63t, 64f–65f, 65t, 152, 315, 315f, 315t, 322f, 369f, 374f–375f – arch of, 315f, 322f – external, 62f–63f, 63t, 64f, 66f, 152, 152f, 154f, 225f, 272, 315, 315f, 315t, 322f, 326, 326f–328f, 333f, 357f, 366f–369f, 373f–375f, 383, 383f, 410f, 415t – posterior, 65, 65t, 315t – swelling of, 328, 328f – tributaries of, 65, 65f, 65t – inferior bulb of, 347f – internal, 32f, 44f, 62, 62f–63f, 63t, 64, 64f–67f, 68, 70f, 152, 187f, 206, 207t, 211, 224, 224f–225f, 265f, 267f, 299f, 314–315, 315f, 315t, 320t, 322f, 323, 323f–324f, 325, 328f, 329, 329f, 332, 332f–334f, 341, 341f, 346f, 347, 347f, 356f–358f, 364, 364f–365f, 366, 366f–367f, 367, 368f, 369, 369f, 371, 371f–374f, 375, 375f, 379, 379f, 383, 383f, 410f, 412f–413f, 415f, 415t, 419f, 430f – bulb of, 45t – passage through skull, 32 – tributaries of, 328 labial – inferior, 64f, 64t – superior, 64f, 64t labyrinthine, 44f, 45t, 271–273, 273f lacrim al, 231t, 236t, 237f

– laryngeal – inferior, 341, 341f – superior, 218t, 225f, 333f, 341, 341f–342f, 347f – lenticular – inferior, 99f – superior – lateral, 99f – m edial, 99f – lingual, 62, 63f, 63t, 67f, 70f, 187, 187f, 206, 206f, 207t, 315t – deep, 63f, 206f, 207t, 349f–350f, 352, 352f, 377f – dorsal, 63f, 207t – lingular (pulm onary), 437f, 437t – lum bar, 415f, 456f, 456t – ascending, 411f, 415f, 456f, 456t, 457f–458f – third, 458f m arginal (cardiac), 425t – m axillary, 62f–64f, 64t, 65f, 65t, 66f, 67, 67f, 158, 158t, 187f, 272, 364f – m ental, 150f, 187f – m esenteric – inferior, 456f–457f, 459, 459f – anterior view of, 459, 459f – superior, 449f, 451f, 456f–457f, 459f, 461f – metacarpal, palm ar, 399f – m iddle lobe (pulm onary), 437f, 437t – m usculophrenic, 411t, 415t – nasal – dorsal, 231t, 237f, 240f – external, 64f, 64t – oblique, of left atrium , 425f, 425t – obturator, 458f, 466f, 466t, 467f – occipital, 34, 62, 62f–66f, 66t, 67f, 315t, 330f – internal, 98f – ophthalm ic, 63, 124f, 237f, 370f – inferior, 45t, 62f–66f, 66t, 67, 67f, 124f, 169t, 187f, 231t, 236t, 237f–239f, 247 – superior, 44f, 45t, 62f–66f, 66t, 67, 67f, 121f, 124f, 187f, 231t, 234f, 236t, 237f–239f, 240, 247, 352, 352f – ovarian, 415f, 456f, 456t, 457f–458f, 465f, 467f – palatine – greater, 215t – lesser, 215t – palatine (paratonsillar), 66t – external, 64t, 187f – pancreatic, 457f – pancreaticoduodenal, inferior, 457f – paraum bilical, 457f – parotid, 64t – penile, deep dorsal, 466f–467f – pericardial, 415t – pericardiophrenic, 409f, 410, 411f, 411t, 412f, 415t, 418t, 419f–421f – pericardial branches, 412f – perium bilical, 457f – pharyngeal, 63t, 315t – phrenic – inferior, 411t, 455f–456f, 456t, 458f – superior, 411t, 415t – portal, 429f, 450f, 453f–454f, 457, 457f, 459f – distribution of, 457, 457f – location, anterior view of, 457, 457f – in prenatal circulation, 428f – posterior ventricular, left, 425t – pudendal, internal, 458f, 466f, 466t, 467f – pulm onary, 429f, 436f, 437f – inferior, 436f – superior, 436f – radial, 399f

– rectal – inferior, 457f, 466f, 466t, 467f – m iddle, 457f–458f, 466f, 466t – superior, 456f–457f, 459f, 466t, 467f – renal, 415f, 443f, 454f, 456f, 456t, 457f–458f – tributaries of, 456f – retrom andibular, 62, 62f–63f, 63t, 66f, 67, 67f, 158, 187f, 334f, 364f, 372f, 373, 373f – anterior division, 63, 63f, 63t, 64, 64f, 64t, 67f, 187f – posterior division, 63f, 63t, 65, 65f, 65t, 67f, 152f, 158f, 187f – of round window, 273f – sacral – lateral, 458f, 466f, 466t, 467f – m edian, 456f, 456t, 458f – saphenous, great, 405f – scrotal, posterior, 466f–467f – of septum pellucidum , anterior, 98f – sigm oid, 457f, 459f – sphenopalatine, 169t – spinal, 44f – anterior, 74f – splenic, 443f, 456f–457f, 459f, 461f – subclavian, 62, 62f, 64f, 65, 65f, 315, 315f, 315t, 323–324, 324f, 325, 325f, 327f–328f, 329, 333f, 341f, 347f, 355f–356f, 383f, 399f, 406f, 410f, 412f–413f, 415f, 415t, 419f–421f, 430f, 434f, 457f – sublingual, 206f, 211 – submandibular, 64t – submental, 62f, 64f, 64t, 65f, 206f, 207t – superior alveolar, 187, 187f – anterior, 187, 187f – m iddle, 187, 187f – posterior, 169t – superior anastom otic (of Trolard), 98f – superior pancreaticoduodenal, posterior, 457f – supraorbital, 63f, 67f, 187f, 231t, 236t, 237f – suprarenal, 455f–456f, 456t, 457f–458f – suprascapular, 62f, 64f, 65, 65f, 65t, 315f, 315t, 327f – supratrochlear, 63f, 67f, 187f, 236t, 237f, 240f – temporal – deep, 62f, 64f, 65t, 67f, 157t, 187f – super cial, 62f–64f, 64t, 65f, 65t–66t, 67f, 150f, 152f, 155f, 157t, 158f–159f, 187f, 272, 360f, 363f – testicular, 415f, 456f, 456t – thalam ostriate, 98f – thoracic – internal, 325f, 405f–406f, 409f, 411f, 411t, 412f, 415t, 433f, 457f, 461f – branches, 406f – lateral, 405f–406f – thoracodorsal, 399f – thoracoepigastric, 399f, 405f – thym ic, 415t – thyroid – inferior, 315f, 315t, 322f, 323, 323f, 325f, 335f, 341, 341f, 347, 347f, 355f, 410f, 415f, 415t, 419f – m iddle, 62, 63t, 315f, 315t, 323f, 341f–342f, 347, 347f – superior, 62, 62f, 63t, 64f–65f, 315f, 315t, 323f, 341, 341f, 347, 347f, 366f–369f – ulnar, 399f – um bilical, 428, 428f, 450 – in postnatal circulation, 429, 429f – uterine, 458f, 467f – ventricular, posterior, 425f

– vertebral, 66f, 315, 315f, 315t, 325f, 357f, 368f–369f, 374f – vesical, 466f, 466t, 467f – inferior, 458f, 467f – superior, 467f – of vestibular aqueduct, 273f Vein(s) (of region or organ) – of abdom en, 456–457, 456f–457f – alveolar, 195t – cardiac – anterior view of, 425, 425f – divisions of, 425t – posteroinferior view of, 425, 425f – of caudate nucleus – longitudinal, 99f – transverse, 99f – of centrum sem iovale, 99f – cerebral, bridging, 98, 102f – of cochlear aqueduct, 273f – cortical, 98, 98f – of cubital fossa, 399, 399f – of diaphragm , 411t – diploic, 24f, 364f – episcleral, 251, 251f – of face, 67, 67f – “danger zone,” 151, 151f – of head and neck, 62, 62f – deep, 66, 66f, 67, 67f – super cial, 64, 64f, 152, 152f – hepatic, 429f, 451f – in prenatal circulation, 428f – of inner ear, 273, 273f – intercapitular, 399f – intercostal, 405f, 407f, 420f–421f, 432f, 461f – anterior, 415t – posterior, 409f–410f, 415t, 420f–421f – posterior (dorsal) branch, 409f – superior, 415t, 421f – suprem e, 415t – interpeduncular, 99f – laryngeal, 341, 341f – m ediastinal, 418t – m edullary, 98, 98f–99f – anastomotic, 99f – of neck, 315, 315f, 315t – swelling of, 328, 328f – of occiput, 67, 67f – of oral cavit y, 187, 187f – orbital, 236t, 237, 237f – pelvic, 466–467, 466f–467f, 466t – penile, deep, 466f – of penile bulb, 466f – perforator (arm), 399f – of pterygoid canal, 169t – pulm onary, 415f, 418t, 419f–423f, 425f–426f, 429f–430f, 434f–435f, 436, 436f–437f, 437t – in prenatal circulation, 428f – tributaries to, 437f, 437t – of right ventricle, anterior, 425t – of scalp, 151f – em issary. See Em issary vein(s) – subm andibular, 63t – of thoracic cavit y, 415f – of upper lim b, 399, 399f – uterine, 466f – vertebral, 75f – vorticose, 247, 247f, 251 Velum palatinum , 345f. See also Palate, soft Vena cava – inferior, 299f, 409f–411f, 411t, 415f, 419f, 422f–423f, 425f, 429f, 436f, 450f–456f, 457, 457f–459f, 461f, 466f – anterior view of, 457, 457f – location of, 456, 456f – in prenatal circulation, 428, 428f – tributaries of, 456f, 456t

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Index

– valved ori ce of, 423f – superior, 225f, 315, 315f, 328f, 333f, 347f, 410f, 412f–413f, 418t, 419f–420f, 422f–423f, 425f–427f, 429f, 434f, 436f, 457f – anterior view of, 415f – in prenatal circulation, 428, 428f – thoracic tributaries of, 415f, 415t Venous catheterization, 62 Venous plexus. See Plexus(es), venous Venous sinus(es), dural, 24f, 63f, 67, 67f, 94, 98 – cavernous, 62f, 63, 63f, 66f, 66t, 67, 67f, 99, 175f, 187f, 226t, 232, 236t, 237f, 238, 238f, 247, 351, 351f, 357f, 361, 361f–362f – cranial nerves in, course of, 238, 238f – throm bosis, 63, 66t, 120t, 238 – con uence of, 34, 62f, 66f, 66t, 67f, 94f, 102f, 370f, 380f – grooves for, 34, 34f – occipital, 98f – petrosal, 63 – inferior, 44f, 45t, 62, 63t, 66f–67f, 187f, 273, 315t, 363f – superior, 66f–67f, 187f, 272 – groove for, 33f – sagit tal – inferior, 66f, 98f, 103f, 163f, 360f–361f – superior, 34, 62f, 66f, 66t, 67f, 94f, 98f–99f, 102f–103f, 163f, 349, 349f–350f, 351, 351f–353f, 360f–361f, 362f–363f, 371f, 380f – groove for, 25f, 34f – sigmoid, 34, 44f, 45t, 62f, 63, 63f, 63t, 66f, 66t, 67f, 187f, 216f, 224f, 266f–267f, 315t, 332f, 364, 364f, 370, 370f–371f – groove for, 29f, 33f – straight, 66f, 94f, 98, 98f, 99, 361, 362f–363f, 380f – transverse, 34, 62f, 66t, 67f, 98f, 99, 272–273, 363, 363f–364f, 376f, 378f–379f, 381f – groove for, 29f, 34f – venous connections to, 66, 66f, 66t Ventricle(s) – cardiac, 422f–423f, 425f, 427f, 429f, 433f, 436f – anterior veins of, 425f – anterior view of, 423, 423f – lateral view of, 423, 423f – opened, 427f – in prenatal circulation, 428, 428f – cerebral, 94, 94f, 95, 95f – fourth, 79, 79f, 88f, 89, 91, 91f, 92–93, 94f, 95, 95f, 98f, 122f, 370f–372f, 380f – lateral aperture, 89f, 94–95, 95f – m edian aperture, 94, 94f, 95, 95f – lateral, 85f, 94f, 95, 351f, 377f, 381f – anterior horn, 80f, 95, 95f – arterial supply to, 96f – central part, 95, 95f – collateral trigone, 95f – inferior horn, 95, 95f – occipital horn, 360f, 360f–361f – posterior horn, 80f, 95, 95f – temporal horn, 370f – third, 84, 84f–85f, 87f, 94f, 95, 95f, 360, 360f – laryngeal, 339f–340f, 343f Verm illion border, 184f Verm iform appendix, 442t, 449f Verm is, 79, 79f, 360, 360f–361f, 361, 363, 363f, 370f – folium of, 79f – pyram id of, 79f

– uvula of, 79f, 370f Vertebra prominens (C7). See Vertebra/ Vertebrae, cervical Vertebral plexus. See Plexus(es), vertebral. Vertebra/Vertebrae, 358 – arch (neural arch) of, 284–285, 285f, 293f, 299f – articular facets of, 284f – body of, 284, 284f, 285, 285f, 285t, 290f–291f, 357f, 403f – cervical, 284f, 286, 286f, 357, 382 – anterior tubercle, 285f–288f, 292f, 295f – anterior view of, 287f – arch of, 287f – articular process, 358 – atlas (C1), 74f, 284f, 286, 286f, 288, 288f, 289, 289f, 292f, 294f, 305f, 309f, 325f, 336f, 365f, 404f – anterior arch, 178f, 185f, 287f, 293f, 295f, 365, 376f, 380f – anterior tubercle, 286f–287f, 295f – anterior view of, 287f – facet for dens, 287f – groove for vertebral artery, 286f–287f, 295f – inferior articular facet, 286f–287f – lateral m asses, 287f, 289f, 294f–295f, 358, 358f – lateral view of, 286f – opening for vertebral artery, 292f – posterior arch, 286f–287f, 289f, 293f, 294, 294f–295f, 303f, 309f, 359f, 376f, 380f, 382f – posterior tubercle, 286f–287f, 293f, 295f, 309f – posterosuperior view of, 295, 295f – superior articular facet, 286f–287f – superior view of, 287f, 295, 295f – transverse foram en of, 286f–287f, 331 – transverse process, 284f, 287f, 302f–303f, 309f, 331, 358f, 383f – vertebral foram en of, 286f–287f – axis (C2), 284f, 286, 286f, 288, 288f, 289, 289f, 292f, 294f, 305f, 309f, 336f, 404f – anterior articular facet, 286f–287f – anterior view of, 287f – body of, 286f–287f, 293f–295f, 373f – dens of, 178f, 185f, 284f, 286f–288f, 289, 289f, 293f–295f, 334f, 358, 358f, 365, 365f, 376f, 380f, 382f – inferior articular facet, 286f–287f – inferior articular process, 287f – lam ina of, 286f–287f – lateral view of, 286f – posterior articular facet, 286f – posterosuperior view of, 295, 295f – spinous process, 286f–287f, 295f, 302f–303f, 309f, 331, 359f – superior articular facet, 286f–287f – superior view of, 287f, 295, 295f – transverse foram en of, 286f–287f – transverse process, 286f–287f – vertebral foram en of, 287f – body of, 286f–287f, 289f, 293f–294f – C3, 376f – body of, 373f – posterior arch of, 373f – C5, 366f – body of, 382f – C6, 299f, 367f–368f, 430f – articular process, 358f – body of, 366f, 374, 374f – C7, 368f

– – – – –

– – – – – – – – –

– inferior articular facet, 286f–288f – inferior articular process, 286f – lam ina of, 285f, 287f, 294f – lateral view of, 286, 286f – pedicle, 285f, 287f – posterior tubercle, 285f–288f, 292f – spinous process, 285f, 285t, 286, 286f–287f, 294f – structure of, 285, 285f, 285t, 286, 286f – sulcus for spinal nerve, 286, 286f–288f, 289, 289f, 292f – superior articular facet, 285f–287f, 289f, 295f – superior articular process, 286f–287f – superior view of, 287f – transverse foram en, 285f, 285t, 286, 287f, 289, 289f, 294f–295f – transverse process, 285f, 285t, 286, 286f–288f, 289, 289f, 292f, 294f–295f – uncinate process, 287f, 288, 288f–289f – vertebral foram en, 287f, 289f, 295f – vertebra prom inens (C7), 74f, 286, 286f, 292f–293f, 401f – anterior tubercle, 287f – anterior view of, 287f – arch of, 367f – body of, 286f–287f, 293f – inferior articular facet, 286f–287f – inferior articular process, 287f – lam ina of, 287f – lateral view of, 286f – posterior arch of, 374, 374f – spinous process, 284f, 286, 286f–287f, 293f, 303f, 305f, 307f, 319, 319f, 330, 359, 359f, 366, 366f, 374, 374f, 382f – sulcus for spinal nerve, 287f – superior articular facet, 286f–287f – superior articular process, 286f–287f – superior view of, 287f – transverse foramen of, 286f–287f – transverse process, 286f–287f, 303f – uncinate process, 287f – vertebral foram en, 287f foram en of. See Foramen (pl., foram ina) inferior articular facet, 290f–291f inferior articular process, 290f–291f lam inae of, 284f, 285, 285f, 285t, 290f–291f lum bar, 284f, 411f – L1, 461f – body of, 402f – spinous process, 402f – transverse process, 408f – L3, 299f – L4, spinous process, 463f – L5, 443f, 464f–466f – m am illary process, 284f–285f, 285t, 307f – structure of, 285, 285f, 285t transverse process, 305f pedicle of, 285, 285f, 285t, 291f posterior tubercle, 307f sacral. See Sacrum spinous process, 284f, 285, 285f, 285t, 290f–293f, 299f, 307f, 402f–403f structure of, 285, 285f, 285t superior articular facet, 285f, 290f–291f superior articular process, 290f–291f thoracic, 284f – body of, 285f – costal facet s of, 285, 285f, 285t – costal process, 291f, 299f, 359f – lam ina of, 285f – pedicle, 285f – spinous process, 285f

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– structure of, 285, 285f, 285t – superior articular facet, 285f – T1, 369f – arch of, 368f – body of, 359, 402f – spinous process, 402f – transverse process, 375, 375f – T2 – body of, 382f – transverse process, 369f – T4, 430f – T10, 430f – T12 – body of, 402f – spinous process, 402f – transverse process, 285f – transverse process, 284f, 285, 285f, 285t, 290f–292f, 301f, 307f, 402f–403f – costal facet of, 284f Vertebral canal, 284, 289, 289f, 294 Vertebral colum n – cervical, 284, 284f – em bryology of, 3, 3f – ligam ent s of, 290, 290f, 290t, 291, 291f – lum bar, 284, 284f – prim ary curvature of, 284 – sacral, 284, 284f – seconday curvatures of, 284 – thoracic, 284, 284f Vertebral (spinal) sulcus. See Vertebra/ Vertebrae Vertigo, 135t, 262, 270, 281. See also Dizziness Vesical plexus, 458f, 466f, 466t Vesicouterine pouch, 465f Vestibular apparatus, 262, 262f, 270, 278–279, 278f–279f – sensory cells of, 278, 278f – depolarization of, 278–279, 279f – hyperpolarization of, 278–279, 279f – stim ulus transduction in, 279, 279f – structure of, 278, 278f Vestibular aqueduct, 33f, 271f, 273f Vestibular area, 89f Vestibular pathway, 280–281, 280f–281f Vestibular schwannom a, 134, 134f, 271 Vestibular system , 281, 281f – and balance, 280, 280f – receptors of, 280, 280f Vestibule(s), 227f Vestibulocerebellar bers, 280, 280f, 281, 281f Vestibulocochlear organ, developm ent of, 13t Vestibulo-ocular re ex, 270 – neural pathway for, 257, 257f Vestibulospinal tract, 108f, 108t – lateral, 280, 280f, 281, 281f Vidian (pterygoid) canal, 31f, 39f, 133f, 168t, 169f, 169t Viscera – abdom inal, innervation of, 112t, 138t, 139f – innervation of, 111t–112t, 136t, 138t, 139f – thoracic, innervation of, 112t, 138t, 139f Viscerocranium , 16f, 16t – boundaries of, 21f Vision – binocular, 232 – far, adjustm ent of eye for, 249, 249f – loss of, 119, 247. See also Blindness – near, adjustm ent of eye for, 249, 249f Visual accom m odation, 112t, 113, 113t, 244, 248 – adjustm ent of eye for, 249, 249f – di culties with, 120t, 235, 235f, 235t – pathway for, 258, 258f

Index

Visual convergence, pathway for, 258, 258f, 261, 261f Visual cortex, 254, 254f, 255, 255f – lesion of, 259 – prim ary, 81, 81f, 258, 258f – representation of visual elds in, 254, 254f – secondary, 258, 258f Visual eld(s) – defect s of, 256, 256f – exam ination of, 255, 255f – m acular, 255, 255f – nasal, 254, 254f – quadrants of, 255, 255f – representation of, in visual cortex, 254, 254f – temporal, 254, 254f Visual hem i eld(s), 255, 255f Visual pathway, 84, 119, 119f, 254–255, 254f–255f – for accom m odation, 258, 258f – for convergence, 258, 258f – geniculate part, 254, 254f, 258, 258f, 259, 259f – topographic organization of, 255, 255f – lateral view of, 254, 254f – lesions of, 256, 256f – nongeniculate part, 254, 257, 257f, 259 Visual system , and balance, 280, 280f, 281, 281f Vitam in B1 (thiam ine), de ciency of, 87

Vitrectomy, 245 Vitreous base of Salzm ann, 245f Vitreous body (vitreous hum or), 174f, 244f, 245, 245f, 250, 348, 348f, 360f–361f, 362f, 378f–379f – at tachm ents to other ocular structures, 245, 245f – function of, 245 Vocal cords. See Vocal fold(s) – false. See Fold(s), vestibular Vocal fold(s), 185f, 340, 340f, 340t, 345f, 382f – histologic section of, 343, 343f – muscle action on, 338t – pathology of, 343, 343t – positions of, 339f, 343, 343f – squam ous cell carcinom a of, 343 – vagus nerve lesions and, 343, 343f Vom er, 7t, 21f–23f, 26f, 30f, 37f–38f, 39, 39f, 172, 172f–175f, 178f–179f, 181f, 188f, 221f, 230f, 348f, 355f, 362f – development of, 16t Vom eronasal organ (VNO), 183, 183f Von Ebner glands, 202, 202f, 209

– cerebral, 5t, 80, 80f – venous drainage of, 98, 98f – of spinal cord, 4, 4f, 76, 76f–77f Whitnall tubercle, 36 Wisdom teeth, 191f, 192t, 194 – on dental panoram ic tom ogram (DPT), 200f Wolfring glands, 242 Worm ian (sutural) bones, 23f Wrist – bones of, 389f – m uscles of, 396, 396f Wryneck. See Torticollis

X Xerophthalm ia (dry eye), 242 Xerostom ia, 242

Zygom atic (m alar) bone, 7t, 18f–20f, 26f, 32f, 36, 36f, 38f, 156f, 168f, 228, 352f–354f, 356f, 370f, 372f – developm ent of, 16t – fracture of, 36 – frontal process, 19f, 21f, 36f, 156f, 157t, 228f – inferior view of, 36, 36f – infraorbital m argin, 21f, 36f – isolated – inferior view of, 36, 36f – left lateral view of, 36, 36f – left lateral view of, 36, 36f – m axillary process, 36f – orbital surface of, 37f, 228f, 230f – temporal process, 19f, 32f, 36f, 164f, 355f – temporal surface of, 36f

Y Yolk sac, 2, 2f

Z

W Waldeyer’s ring, 217, 217f Wasting diseases, 350 Wharton’s duct. See Subm andibular duct Whiplash injury, 288 White m at ter, 379

Zeis gland(s), 241, 241f Z line, 431, 431f Zona incerta, 85t Zonular bers, 244f, 248, 248f, 250f–251f Zonule (of lens), 248, 248f Zygom a. See Zygom atic (m alar) bone

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