OF AN Richard L. Drake 1, A. Wayne Vogl Adam W. M. Mitchelt Richard M. Tibbitts Paul E. Richardson i Richard L. Drake, PhD Director of Anatomy Professor of Surgery Cleveland Clinic Lerner College of Medicine Cleveland, Ohio, USA A. Wayne Vogl, PhD Professor of Anatomy and Cell Biology Director of Gross Anatomy Department of Cellular and physiological Sciences Faculty of Medicine University of British Columbia Vancouver, British Columbia, Canada Adam W. M. Mitchell, MBBS, FRCS, FRCR Joint Head of Graduate Entry Anatomy lmperialCollege University of London Consultant Radiologist Department of lmaging Charing Cross Hospital London, UK lllustrated by Richard M. Tibbitts Saffron Walden, UK Paul E. Richardson Cambridge, UK Photographs by Ansell Horn CHURCHILL LIVINGSTONE EISEVIER 1 600 John F. Kennedy Blvd. Ste 1 800 Philadelphia, PA 1 91 03-2899 GRAY'S ATLAS OF ANATOMY ISBN: 978-0-443 -06721 -1 Copyright o 2008 by Churchill Livingstone, an imprint of Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier's Health Sciences Rights Department in Philadelphia, PA, USA: phone: (+1) 215 239 3804, fax: (+l ) 21 5 239 3805, e-mail: