Human Anatomy & Physiology Elaine N. Marieb Katja N. Hoehn Ninth

Human Anatomy & Physiology Marieb Hoehn Ninth Edition Human Anatomy & Physiology ISBN 978-1-29202-649-7 Elaine N. Marieb Katja N. Hoehn 9 781292 026497 Ninth Edition ISBN 10: 1-292-02649-9 ISBN 13: 978-1-292-02649-7 Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: www.pearsoned.co.uk © Pearson Education Limited 2014 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without either the prior written permission of the publisher or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, Saffron House, 6–10 Kirby Street, London EC1N 8TS. All trademarks used herein are the property of their respective owners. The use of any trademark in this text does not vest in the author or publisher any trademark ownership rights in such trademarks, nor does the use of such trademarks imply any afﬁ liation with or endorsement of this book by such owners. ISBN 10: 1-292-02649-9 ISBN 13: 978-1-292-02649-7 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Printed in the United States of America The Muscular System MUSCLE GALLERY Table 1 Muscles of the Head, Part I: Facial Expression (Figure 7 ) The muscles that promote facial expression lie in the scalp and smile. The tremendous importance of facial muscles in nonverbal face just deep to the skin. They are thin and variable in shape and communication becomes especially clear when they are paralyzed, strength, and adjacent muscles tend to be fused. They are unusual as in some stroke victims and in the expressionless “mask” of muscles in that they insert into skin (or other muscles), not bones. patients with Parkinson’s disease. In the scalp, the main muscle is the epicranius, which has Cranial nerve VII, the facial nerve, innervates all muscles listed distinct anterior and posterior parts. The lateral scalp muscles in this table. are vestigial in humans. Muscles clothing the facial bones lift the The external muscles of the eyes direct the eyeballs, and the eyebrows, fl are the nostrils, open and close the eyes and mouth, levator palpebrae superioris muscles raise the eyelids. and provide one of the best tools for infl uencing others—the ORIGIN (O) AND NERVE MUSCLE DESCRIPTION INSERTION (I) ACTION SUPPLY MUSCLES OF THE SCALP Epicranius (occipitofrontalis) Bipartite muscle consisting of the frontal and occipital bellies connected by the epicranial aponeurosis. The (epЉı˘-kraЈne-us; alternate actions of these two muscles pull scalp forward and backward. ok-sipЉı˘-to-fron-taЈlis) ( epi ϭ over; cran skull) ■ Frontal belly Covers forehead and O—epicranial aponeurosis With aponeurosis fi xed, Facial nerve (cranial VII) (fronЈtal) dome of skull; no bony I—skin of eyebrows and raises the eyebrows (as ( front ϭ forehead) attachments root of nose in surprise). Wrinkles forehead skin horizontally ■ Occipital belly Overlies posterior occiput; O—occipital and Fixes aponeurosis and Facial nerve (ok-sipЉı˘-talЈ) by pulling on the epicranial temporal bones pulls scalp posteriorly ( occipito ϭ base of skull) aponeurosis, fi xes origin of I—epicranial aponeurosis frontal belly MUSCLES OF THE FACE Corrugator supercilii Small muscle; activity O—arch of frontal bone Draws eyebrows together Facial nerve (korЈah-ga-ter sooЉper-sı˘Јle-i) associated with that of above nasal bone and inferiorly; wrinkles ( corrugo ϭ wrinkle; orbicularis oculi I—skin of eyebrow skin of forehead vertically supercilium ϭ eyebrow) (as in frowning) Epicranial aponeurosis Frontal belly of epicranius Occipital belly Corrugator of epicranius supercilli Sternocleidomastoid (covered by fascia) Platysma (a) Figure 7 Lateral view of muscles of the scalp, face, and neck. (a) Photograph. David Bassett ➤ 369 The Muscular System MUSCLE GALLERY Table 1 Muscles of the Head, Part I: Facial Expression (Figure 7) (continued) ORIGIN (O) AND NERVE MUSCLE DESCRIPTION INSERTION (I) ACTION SUPPLY Orbicularis oculi Thin, fl at sphincter muscle O—frontal and maxillary Closes eye ; various Facial nerve (cranial VII) (or-bikЈu-lar-is okЈu-li) of eyelid; surrounds rim of bones and ligaments parts can be activated ( orb circular; ocul eye) the orbit around orbit individually; produces I—tissue of eyelid blinking and squinting; draws eyebrows inferiorly Zygomaticus —major and Muscle pair extending O—zygomatic bone Raises lateral corners of Facial nerve minor (zi-go-matЈı˘-kus) diagonally from cheekbone I—skin and muscle at mouth upward (smiling ( zygomatic cheekbone) to corner of mouth corner of mouth muscle) Risorius (ri-zorЈe-us) Slender muscle inferior and O—lateral fascia Draws corner of lip Facial nerve ( risor laughter) lateral to zygomaticus associated with masseter laterally ; tenses lips; muscle synergist of zygomaticus I—skin at angle of mouth Levator labii superioris Thin muscle between O—zygomatic bone and Opens lips ; raises and Facial nerve (le-˘ vaЈtor laЈbe-i orbicularis oris and inferior infraorbital margin of furrows upper lip soo-perЉe-orЈis) eye margin maxilla 10 ( leva raise; labi lip; I—skin and muscle of superior above, over) upper lip Depressor labii inferioris Small muscle running from O—body of mandible Draws lower lip inferiorly Facial nerve (de-presЈor laЈbe-i mandible to lower lip lateral to its midline (as in a pout) in-ferЉe-orЈis) I—skin and muscle of ( depressor depresses; lower lip infer below) Depressor anguli oris Small muscle lateral to O—body of mandible Draws corners of mouth Facial nerve (angЈgu-li or-is) depressor labii inferioris below incisors down and laterally (a ( angul angle, corner; I—skin and muscle at “tragedy mask” grimace); or mouth) angle of mouth below zygomaticus antagonist insertion of zygomaticus Orbicularis oris Complicated, multilayered O—arises indirectly from Closes lips ; purses and Facial nerve muscle of the lips with maxilla and mandible; protrudes lips; kissing and fi bers that run in many fi bers blend with fi bers whistling muscle different directions; most of other facial muscles run circularly associated with the lips I—encircles mouth; inserts into muscle and skin at angles of mouth Mentalis (men-taЈlis) One of the muscle pair O—mandible below Wrinkles chin ; protrudes Facial nerve ( ment chin) forming a V-shaped muscle incisors lower lip mass on chin I—skin of chin Buccinator Thin, horizontal cheek O—molar region of Compresses cheek (as in Facial nerve (buЈsı˘-naЉter) muscle; principal muscle of maxilla and mandible whistling and sucking); ( bucc cheek or cheek; deep to masseter I—orbicularis oris trampoline-like action “trumpeter”) (see also Figure 8 ) holds food between teeth during chewing; draws corner of mouth laterally; well developed in nursing infants Platysma (plah-tizЈmah) Unpaired, thin, sheetlike O—fascia of chest (over Tenses skin of neck (as Facial nerve ( platy broad, fl at) superfi cial neck muscle; pectoral muscles and during shaving); helps not strictly a head muscle, deltoid) depress mandible; pulls but plays a role in facial I—lower margin of lower lip back and down, expression mandible, and skin and producing downward sag muscle at corner of mouth of mouth 370 The Muscular System MUSCLE GALLERY Table 1 (continued) Epicranial aponeurosis Frontal Epicranius belly Corrugator supercilii Occipital belly Orbicularis oculi Levator labii superioris Temporalis Zygomaticus minor and major Buccinator Masseter Risorius Sternocleidomastoid Orbicularis oris Mentalis Trapezius Depressor labii inferioris Splenius capitis Depressor anguli oris Platysma (b) Figure 7 (continued) Lateral view of muscles of the scalp, face, and neck. (b) Superfi cial muscles. Imagineering STA Media Services 371 The Muscular System MUSCLE GALLERY Table 2 Muscles of the Head, Part II: Mastication and Tongue Movement ( Figure 8 ) Four pairs of muscles are involved in mastication (chewing). All are The tongue is composed of muscle fi bers that curl, squeeze, innervated by the mandibular branch of cranial nerve V. and fold the tongue during speaking and chewing. These intrinsic The prime movers of jaw closure (and biting) are the powerful tongue muscles change the shape of the tongue and contribute to masseter and temporalis muscles, which are easily palpated when its exceptional nimbleness, but they do not really move the tongue. the teeth are clenched ( Figure 8a ). The pterygoid muscles In this table, we consider only the extrinsic tongue muscles, produce side-to-side grinding ( Figure 8b ). The buccinator which anchor and move the tongue ( Figure 8c ). Cranial nerve XII, muscles (see Table 1 ) also play a role in chewing. Normally, the hypoglossal nerve, innervates all extrinsic tongue muscles. gravity is suffi cient to depress the mandible, but if there is resistance to jaw opening, neck muscles such as the digastric and mylohyoid muscles (see Table 3 ) are activated. ORIGIN (O) AND NERVE MUSCLE DESCRIPTION INSERTION (I) ACTION SUPPLY MUSCLES OF MASTICATION Masseter (mah-seЈter) Powerful muscle that O—zygomatic arch and Prime mover of jaw Trigeminal nerve ( maseter chewer) covers lateral aspect of zygomatic bone closure ; elevates mandible (cranial V) mandibular ramus I—angle and ramus of 10 mandible Temporalis (temЉpor-a ˘ Јlis) Fan-shaped muscle O—temporal fossa Closes jaw ; elevates Trigeminal nerve ( tempora time; pertaining

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