Principal Gray’s Anatomy Review
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Any screen. Any time. Anywhere. Activate the eBook version of this title at no additional charge. Student Consult eBooks give you the power to browse and find content, view enhanced images, share notes and highlights—both online and offline. Unlock your eBook today. 1 Visit studentconsult.inkling.com/redeem 2 S cratch off your code Scan this QR code to redeem your eBook through your mobile device: 3 Type code into “Enter Code” box 4 C lick “Redeem” 5 L og in or Sign Up 6 G o to “My Library” It’s that easy! For technical assistance: email email@example.com call 1-800-401-9962 (inside the US) call +1-314-447-8200 (outside the US) Use of the current edition of the electronic version of this book (eBook) is subject to the terms of the nontransferable, limited license granted on studentconsult.inkling.com. Access to the eBook is limited to the first individual who redeems the PIN, located on the inside cover of this book, at studentconsult.inkling.com and may not be transferred to another party by resale, lending or other means. GRAY’S ANATOMY REVIEW This page intentionally left blank GRAY’S ANATOMY REVIEW Marios Loukas, MD, PhD Professor, Department of Anatomical Sciences Dean of Basic Sciences St. George’s University School of Medicine Grenada, West Indies R. Shane Tubbs, MS, PA-C, PhD Professor of Anatomy Children’s of Alabama Birmingham, Alabama; Department of Anatomical Sciences St. George’s University Grenada, West Indies; Centre of Anatomy and Human Identification University of Dundee Dundee, United Kingdom SECOND EDITION Peter H. Abrahams, MBBS, FRCS(ED), FRCR, DO(Hon), FHEA Professor Emeritus of Clinical Anatomy Institute of Clinical Education Warwick Medical School University of Warwick Coventry, United Kingdom Stephen W. Carmichael, PhD, DSc Professor Emeritus of Anatomy and Orthopedic Surgery Mayo Clinic Rochester, Minnesota 1600 John F. Kennedy Blvd. Ste. 1800 Philadelphia, PA 19103-2899 GRAY’S ANATOMY REVIEW, SECOND EDITION ISBN: 978-0-323-27788-4 ; Copyright 2016 by Elsevier, Inc. All rights reserved. First edition copyright 2010, Churchill Livingstone, an imprint of Elsevier Inc. 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. Details on how to seek permission and further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. International Standard Book Number: 978-0-323-27788-4 VP Global Medical Education Content: Madelene Hyde Senior Content Strategist: Jeremy Bowes Content Development Specialist: Lauren Boyle Publishing Services Manager: Patricia Tannian Senior Project Manager: John Casey Design Direction: Julia Dummitt Printed in Canada Last digit is the print number: 9 8 7 6 5 4 3 2 1 To my daughter, Nicole, my son, Chris, and my wife, Joanna, for their continuous support and love ML To Kevin, Kendall, and Logan Tubbs— the perfect family RST To “Lucy in the Sky with Diamonds,” who puts up with my early mornings and late nights— For all the descendants of “Papi and Lulu” PA To Susan Stoddard and Allen Carmichael SC v This page intentionally left blank PREFACE Rote memorization of anatomic facts has been the cardinal feature of exhaustive, and exhausting, courses in human anatomy for many generations of students in medicine, dentistry, and other allied health science programs. Often, little distinction was made between the wheat and the chaff, and little attention was given to the practical, clinical application of the data. In the face of the modern explosion of information and technical advances in the medical sciences, Gray’s Anatomy for Students was conceived and written as a clinically oriented, student-friendly textbook of human anatomy. The authors, Richard L. Drake, A. Wayne Vogl, and Adam W. M. Mitchell, have provided a sound basis for student learning and understanding of both normal and altered human anatomy in the clinical setting. Gray’s Anatomy Review was designed for use by students after they have read the textbook and is in keeping with the objectives of a course that uses this textbook. The questions, answers, and explanations in this book are intended to serve multiple purposes for students in various programs. 1. This review provides a thought-provoking source for study by students in preparation for examinations in various programs of gross anatomy. 2. To avoid pointless memorization by the student, all the questions are framed within clinical vignettes that guide the student toward practical applications of the textual material. 3. The multiple-choice, single-best-answer format of the questions is designed to facilitate student review in preparation for the USMLE and similar qualifying examinations. 4. The explanations of the answers emphasize the critical importance of understanding normal and dysfunctional human anatomy. 5. Student understanding is further enhanced by critical examination of alternative, incorrect answers that students might be tempted to choose. 6. Finally, the review provides a succinct distillation of the plethora of facts in clinical anatomy, assisting the student’s learning and understanding of important concepts in the practice of medicine, irrespective of the student’s career choice. The questions in this review are correlated with the following textbooks: • Gray’s Anatomy for Students, ed 3, by Richard L. Drake, A. Wayne Vogl, and Adam W. M. Mitchell • Netter Atlas of Human Anatomy, ed 6, by Frank Netter • McMinn’s and Abrahams’ Clinical Atlas of Human Anatomy, ed 7, by Peter H. Abrahams, Jonathan D. Spratt, Marios Loukas, and Albert N. Van Schoor Each answer is referenced to pages in Gray’s (GAS), Netter’s (N) and McMinn’s (McM). For the embryology chapter we have correlated the clinical vignettes with Before We Are Born: Essentials of Embryology and Birth Defects, ed 8, by Keith L Moore, TVN Persaud, and Mark G. Torchia. We have incorporated or adapted many drawings, full-color illustrations, and radiographic images in an attempt to accelerate the learning process and to enhance understanding of both the anatomy and the clinical applications. The primary sources on which we have drawn for illustrative material are from McMinn’s and Abrahams’ Clinical Atlas of Human Anatomy. vii This page intentionally left blank ACKNOWLEDGMENTS A clinical review book is the work not only of the authors but also of numerous scientific and clinical friends and colleagues who have been so generous with their knowledge and given significant feedback and help. This book would not have been possible were it not for the contributions of the colleagues and friends listed below. A very special group of medical students, members of the Student Clinical Research Society at the Department of Anatomical Sciences at St. George’s University, helped enormously with the completion of this project through their comments and criticism of each chapter as part of the advisory board of this book. Advisory Board Nkosi Alvarez (Neck) Meha Bhargava (Pelvis and Perineum) Liann Chin Casey (Lower Limb) Rana Chakrabarti (Upper Limb) Ramya Chitters (Embryology) Monica Dandapani (Abdomen) Piyumika De Silva (Upper Limb) Uta Guo (Embryology) Rich Hajjar (Abdomen) Roland Howard (Lower Limb) Lijo C. Illipparambi (Upper Limb) Theofannis Kollias (Upper Limb) Jun Lee (Back) Olivia Lu (Lower Limb) Prateek Mathur (Head) Spiro Mavromatis (Neck) Lewis Musoke (Lower Limb) Anastasiya Nelyubina (Pelvis and Perineum) Georgia Paul (Pelvis and Perineum) Tony Sadek (Thorax) Shanojan Thiyagalingam (Back) David Thornton (Abdomen) Randy Tigue (Head) Ryan Uyan (Thorax) Lindsey Van Brunt (Head and Neck) Danielle Van Patten (Head and Neck) The following professors from the Department of Anatomical Sciences at St. George’s University have also been very helpful with their comments and criticism as part of the advisory board: Emanuel Baidoo, MD Feisal Brahim, PhD Kathleen Bubb, MD Danny Burns, MD, PhD James Coey, MBBS Maira Du Plessis, MSc Francis Fakoya, MD, PhD Deon Forrester, MD Iketchi Gbenimacho, MD Rachael George, MD Robert Hage, MD, PhD Robert Jordan, PhD Ahmed Mahgoud, MD Ewarld Marshall, MD Vid Persaud, MD, PhD Kazzara Raeburn, MD Ramesh Rao, MD Vish Rao, PhD Deepak Sharma, MD Alena Wade, MD Dr. Anthony D’Antoni, PhD, Clinical Professor and Director of Anatomy at The City College of New York (CUNY), has always been a great friend and colleague. His continuous support, comments, criticism, and enthusiasm have contributed enormously to the completion of this project. We are especially thankful to Ms. Madelene Hyde, publisher at Elsevier, for her invaluable insights, advice, and encouragement. The authors would also like to thank Jeremy Bowes and Lauren Boyle, our developmental editor, and all the team at Elsevier for guiding us through the preparation of this book. The authors thank the following individuals and their institutions for kindly supplying various clinical, operative, endoscopic, and imaging photographs: Dr. Ray Armstrong, Rheumatologist, Southampton General Hospital, Southampton, and Arthritis ix Research Campaign Acknowledgments Professor Paul Boulos, Surgeon, Institute of Surgical Studies, University College London Medical School, London Professor Norman Browse, Emeritus Professor of Surgery, and Hodder Arnold Publishers, for permission to use illustrations from Symptoms and Signs of Surgical Disease, 4th edition, 2005. Mr. John Craven, formerly Consultant Surgeon, York District Hospital, York Professor Michael Hobsley, formerly Head of the Department of Surgical Studies, The Middlesex Hospital Medical School, London Mr. Ralph Hutchings, photographer for Imagingbody .com Mr. Umraz Khan, Plastic Surgeon, Charing Cross Hospital, London x Professor John Lumley, Director, Vascular Surgery Unit, St. Bartholomew’s and Great Ormond Street Hospitals, London Dr. J. Spratt, Consultant Radiologist, University Hospital of North Durham Dr. William Torreggiani, Radiologist, The Adelaide and Meath Hospital, Tallaght, Dublin Miss Gilli Vafidis, Ophthalmologist, Central Middlesex Hospital, London Mr. Theo Welch, Surgeon, Fellow Commoner Queens’ College, Cambridge Professor Jamie Weir, Department of Clinical Radiology, Grampian University Hospitals Trust, Aberdeen, Scotland, and editor of Imaging Atlas of Human Anatomy, 3rd edition, Elsevier, 2003. CONTENTS 1 BACK 5 LOWER LIMB 2 THORAX 6 UPPER LIMB 3 ABDOMEN 7 HEAD AND NECK 4 PELVIS AND PERINEUM 8 EMBRYOLOGY Questions, 1 Answers, 20 Questions, 39 Answers, 67 Questions, 103 Answers, 139 Questions, 191 Answers, 206 Questions, 233 Answers, 258 Questions, 287 Answers, 319 Questions, 355 Answers, 401 Questions, 459 Answers, 467 Bonus Online-Only Content—To see a list of objectives for each question in the book, activate your title on www.StudentConsult.Inkling.com using the pin code on the inside front cover xi This page intentionally left blank 1 BACK INTRODUCTION First Order Question 1 A 35-year-old man is admitted to the emergency department after a severe car crash. After examining the patient the emergency medicine physician concludes that the serratus anterior muscle is damaged. Which of the following nerves innervates the serratus anterior muscle? A. Long thoracic B. Axillary C. Spinal accessory D. Dorsal scapular E. Thoracodorsal Explanation A: The long thoracic is the only nerve that innervates the serratus anterior. The axillary nerve innervates the deltoid, the spinal accessory nerve innervates the sternocleidomastoid and trapezius, the dorsal scapular nerve supplies the rhomboid muscles and levator scapulae, and the latissimus dorsi is the muscle supplied by the thoracodorsal nerve. First Order Question 2 A 35-year-old man is admitted to the emergency department after a severe car crash. After examining the patient the emergency medicine physician concludes that the serratus anterior muscle is damaged. Which of the following functions does the serratus anterior muscle serve? A. Adducts scapula B. Depresses ribs C. Protraction and rotation of scapula D. Elevation of scapula E. Adducts, extends, and medially rotates arm Explanation C: The functions of the serratus anterior are protraction and rotation of the scapula. The rhomboid major and minor adduct the scapula, the serratus posterior inferior depresses the lower ribs, the levator scapulae elevates the scapula, and the latissimus dorsi adducts, extends, and medially rotates the arm. Second Order Question 3 A 35-year-old man is admitted to the emergency department after a severe car crash. After examining the patient the emergency medicine physician concludes that the serratus anterior muscle is damaged. Which of the following functions will the patient most likely be unable to perform? A. Retraction of the scapula B. Elevation of the scapula C. Depression of the scapula 1 Back D. Protraction of the scapula E. Medial rotation of the scapula Explanation D: The serratus anterior muscle pulls the scapula forward (protraction) over the thoracic wall. Elevation of the scapula is carried out mainly by the trapezius and levator scapulae muscles while depression is performed primarily by the lower fibers of the trapezius. Different muscles contribute to the movement of the scapula such as the serratus anterior, trapezius, levator scapulae, rhomboids, and pectoralis minor. Second Order Question 4 A 35-year-old man is admitted to the emergency department after a severe car crash. During physical examination of the patient the emergency medicine physician observes a winged scapula. Which of the following muscles is most likely injured? A. Levator scapulae B. Serratus anterior C. Trapezes D. Rhomboid major and minor E. Serratus posterior superior Explanation B: The serratus anterior muscle pulls the scapula forward (protraction) and keeps the costal surface of the scapula closely opposed to the thoracic wall, preventing “winging” of the scapula. The levator scapulae elevates the scapula. The trapezius muscle is a powerful elevator of the shoulder and also rotates the scapula during reaching overhead. The rhomboid major and minor elevate and retract the scapula. muscles. The deltoid abducts, flexes, and extends while the teres minor laterally rotates the arm. The spinal accessory nerve is responsible for supplying the trapezius and sternocleidomastoid muscles. The trapezius elevates and upwardly rotates the scapula while the sternocleidomastoid flexes and pulls the chin upward to the opposite side. The dorsal scapular nerve supplies the rhomboid major and minor muscles and are responsible for retraction of the scapula. The thoracodorsal nerve supplies the latissimus dorsi muscle, which adducts, medially rotates, and extends the arm. Third Order Question 6 A 35-year-old man is admitted to the emergency department after a severe car crash. The emergency medicine physician examines the patient and observes what is shown in Figure 1-1. Which of the following nerves is most likely injured? A. Long thoracic B. Axillary C. Spinal accessory D. Dorsal E. Thoracodorsal Explanation A: The long thoracic nerve innervates the serratus anterior muscle, which protracts the scapula, holds the Second Order Question 5 A 35-year-old man is admitted to the emergency department after a severe car crash. While performing the physical examination the emergency medicine physician observes a winged scapula. Which of the following nerves is most likely injured? A. Long thoracic B. Axillary C. Spinal accessory D. Dorsal E. Thoracodorsal Explanation A: The long thoracic nerve innervates the serratus anterior muscle, which protracts and upwardly rotates the scapula. Persons with injury to this nerve will have their scapulae protrude on their back like a wing. The 2 axillary nerve supplies the deltoid and teres minor Fig. 1-1 Back scapula close to the thoracic wall preventing it from “winging”, and abducts and upwardly rotates the scapula. Patients with injury to this nerve will have their scapulae protruding on their back like a wing. The axillary nerve supplies the deltoid and teres minor muscles. The deltoid abducts, flexes, and extends and the teres minor laterally rotates the arm. The spinal accessory nerve is responsible for supplying the trapezius and sternocleidomastoid muscles. The trapezius elevates and upwardly rotates the scapula while the sternocleidomastoid flexes and pulls the chin upward to the opposite side. The dorsal scapular nerve supplies the rhomboid major and minor muscles and are responsible for retraction of the scapula. The thoracodorsal nerve supplies the latissimus dorsi muscle, which adducts, medially rotates, and extends the arm. Fourth Order Question 7 A 35-year-old man is admitted to the emergency department after a severe car crash. The emergency medicine physician examines the patient and observes what is shown in Figure 1-1. Which of the following functions will the patient most likely be unable to perform during physical examination? A. Lateral rotation of the shoulder joint B. Abduction of the shoulder joint from 0 to 90 degrees C. Flexion of the shoulder joint D. Extension of the shoulder joint E. Abduction of the shoulder joint above 90 degrees Explanation E: In this image, the patient has a winged scapula. This occurs as a result of damage to the long thoracic nerve, which innervates the serratus anterior muscle. The functions of this muscle are protraction of the scapula and superior rotation of the glenoid fossa. The supraspinatus abducts the arm for about the first 12 degrees, and then the deltoid abducts the arm to about 90 degrees. Elevating the arm further requires rotation of the scapula (including superior rotation of the glenoid fossa) that is normally done by the serratus anterior. 3 Back MAIN QUESTIONS 1 A 55-year-old man with severe coughing is admitted to the hospital. Radiologic examination is consistent with tuberculosis of the right lung, with extension to the thoracic vertebral bodies of T6 and T7, producing a “gibbus deformity.” Which of the following conditions is most likely also to be confirmed by radiologic examination? A. Hyperlordosis B. Hyperkyphosis C. Scoliosis D. Spina bifida E. Osteoarthritis 2 A 68-year-old man is admitted to the hospital due to severe back pain. Radiologic examination reveals severe osteoporosis of the vertebral column, with compression fractures to vertebrae L4 and L5. Which of the following parts of the vertebrae are most likely to be fractured in this patient? A. Spinous process B. Vertebral bodies C. Transverse process D. Superior articular process E. Intervertebral disc 3 A 45-year-old man is admitted to the hospital because of severe pain in the back and lower limb. Radiologic examination reveals spinal canal stenosis syndrome. Which of the following conditions is most likely to be confirmed by a magnetic resonance imaging (MRI) examination? A. Hypertrophy of supraspinous ligament B. Hypertrophy of interspinous ligament C. Hypertrophy of ligamentum flavum D. Hypertrophy of anterior longitudinal ligament E. Hypertrophy of nuchal ligament 4 A 35-year-old man is admitted to the hospital after a severe car crash. Radiologic examination reveals an injury to the dorsal surface of the neck and a fracture of the medial border of the right scapula. During physical examination, the patient presents with the scapula retracted laterally on the affected side. Which of the following nerves has most likely been injured on that side? A. Axillary B. Long thoracic C. Dorsal scapular 4 D. Greater occipital E. Suprascapular 5 A 64-year-old man arrived at the clinic with a painful rash and skin eruptions that are localized entirely on one side of his body, closely following the dermatome level of the spinal nerve C7. The patient was diagnosed with the a herpes zoster virus infection known as “shingles.” In what structure has the virus most likely proliferated to cause the patient’s current condition? A. The sympathetic chain B. The dorsal root ganglion of the C7 spinal nerve C. The lateral horn of the C7 spinal cord segment D. The posterior cutaneous branch of the dorsal primary ramus of C7 E. The ventral horn of the C7 spinal cord segment 6 A 45-year-old woman states that she has experienced moderate pain for 2 years over her left lower back; pain that radiates to her left lower limb. She states that after lifting a case of soft drinks, the pain suddenly became intense. She was admitted to the emergency department. Radiologic examination revealed intervertebral disc herniation between vertebral levels L4 and L5. Which of the following nerves was most likely affected by the disc herniation? A. L1 B. L2 C. L3 D. L4 E. L5 7 A 3-year-old boy is brought by his mother to the emergency department with severe headache, high fever, malaise, and confusion. Radiologic and physical examinations reveal that the patient suffers from meningitis. A lumbar puncture is ordered to confirm the diagnosis. Which vertebral level is the most appropriate location for the lumbar puncture? A. T12 to L1 B. L1 to L2 C. L2 to L3 D. L4 to L5 E. L5 to S1 8 When a lumbar puncture is performed to sample cerebrospinal fluid, which of the following external landmarks is the most reliable to determine the position of the L4 vertebral spine? Back A. B. C. D. E. The The The The The inferior angles of the scapulae highest points of the iliac crests lowest pair of ribs bilaterally sacral hiatus posterior inferior iliac spines 9 A 39-year-old man presents with severe neck pain after a whiplash injury, sustained when his car was struck from behind. Radiologic studies reveal trauma to the ligament lying on the anterior surface of the cervical vertebral bodies. Which ligament is most likely disrupted? A. Anterior longitudinal ligament B. Ligamentum flavum C. Nuchal ligament D. Posterior longitudinal ligament E. Transverse cervical ligament 10 A 65-year-old man complains of severe back pain and the inability to move his left lower limb. Radiologic studies demonstrate compression of nerve elements at the intervertebral foramen between vertebrae L5 and S1. Which structure is most likely responsible for this space-occupying lesion? A. Anulus fibrosus B. Nucleus pulposus C. Posterior longitudinal ligament D. Anterior longitudinal ligament E. Ligamentum flavum 11 A 27-year-old man is admitted to the emergency department after a car crash. Physical examination reveals weakness during medial rotation and adduction of the humerus. Which of the following nerves was most probably injured? A. Thoracodorsal B. Axillary C. Dorsal scapular D. Spinal accessory E. Radial 12 A 39-year-old woman complains of an inability to reach the top of her head to brush her hair with her right hand. History reveals that she had undergone a mastectomy procedure of her right breast 2 months earlier. Physical examination demonstrates winging of her right scapula. Which nerves were most likely damaged during surgery? A. Axillary B. Spinal accessory C. Long thoracic D. Dorsal scapular E. Thoracodorsal 13 A 19-year-old man is brought to the emergency department after dislocating his shoulder while playing football. Following treatment of the dislocation, he cannot initiate abduction of his arm. An MRI of the affected shoulder shows a torn muscle. Which muscle was most likely damaged by the injury? A. Coracobrachialis B. Long head of the triceps brachii C. Pectoralis minor D. Supraspinatus E. Teres major 14 A 1-year-old girl is brought to the clinic for a routine checkup. The child appears normal except for a dimpling of the skin in the midline of the lumbar region with a tuft of hair growing over the dimple. What is this relatively common condition that results from incomplete embryologic development? A. Meningomyelocele B. Meningocele C. Spina bifida occulta D. Spina bifida cystica E. Rachischisis 15 A young resident complains of an itch on his back that appears to be caused by an insect bite. Which nerve fibers carry the sensation of a mosquito bite on the back, just lateral to the spinous process of the T4 vertebra? A. Somatic afferent B. Somatic efferent C. Visceral afferent D. Visceral efferent E. Somatic efferent and visceral afferent 16 A 15-year-old woman was suspected of having meningitis. To obtain a sample of cerebrospinal fluid by spinal tap in the lumbar region (lumbar puncture), the tip of the needle must be placed in which of the following locations? A. In the epidural space B. Between anterior and posterior longitudinal ligaments C. Superficial to the ligamentum flavum D. Between arachnoid mater and dura mater E. In the subarachnoid space 5 Back 17 A 19-year-old man is diagnosed with a herniated disc but he has no symptoms of spinal cord injury. In the event of intervertebral disc herniation in the cervical region, which of the following ligaments is in an anatomic position to protect the spinal cord from direct compression? A. Supraspinous B. Posterior longitudinal C. Anterior longitudinal D. Ligamentum flavum E. Nuchal ligament 18 In spinal anesthesia, the needle is often inserted between the spinous processes of the L4 and L5 vertebrae to ensure that the spinal cord is not injured. This level is safe because in the adult the spinal cord usually terminates at the disc between which of the following vertebral levels? A. T11 and T12 B. T12 and L1 C. L1 and L2 D. L2 and L3 E. L3 and L4 19 A 22-year-old woman is diagnosed with Ray naud’s disease. In such a case, the patient suffers chronic vasospasm in response to cold. This can lead to arterial constriction and painful ischemia, especially in the fingers or toes. Relief from the symptoms in the hands would require surgical division of which of the following neural elements? A. Lower cervical and upper thoracic sympathetic fibers B. Lower cervical and upper thoracic ventral roots C. Lower cervical and upper thoracic dorsal roots D. Lower cervical and upper thoracic spinal nerves E. Bilateral spinal accessory nerves 20 A 69-year-old woman visits her physician due to severe neck pain. Radiologic studies reveal bony growths (osteophytes) in the intervertebral foramen between vertebrae C2 and C3. Which of the following muscles would be most likely affected by this condition? A. Rhomboideus major B. Serratus anterior C. Supraspinatus D. Diaphragm 6 E. Latissimus dorsi 21 A 42-year-old woman is diagnosed with stenosis of the cervical vertebral canal. A laminectomy of two vertebrae is performed. Which of the following ligaments will most likely also be removed? A. Anterior longitudinal B. Denticulate C. Ligamentum flavum D. Nuchal E. Cruciate 22 A 28-year-old pregnant woman is admitted to the obstetrics department for delivery. In the final stages of labor, a caudal anesthetic is administered via the sacral hiatus. Into which of the following spaces in the sacral canal is the anesthetic placed? A. Vertebral canal B. Vertebral venous plexus C. Epidural space D. Subarachnoid space E. Subdural space 23 A 12-year-old child was brought to the emergency department by his parents because he has been suffering from a very high fever and severe stiffness in his back. The initial diagnosis is meningitis. The attending physician orders a lumbar puncture to confirm the diagnosis. Upon microscopic examination of the cerebrospinal fluid, hematopoietic cells are seen. Which of the following ligaments was most likely penetrated by the needle? A. Supraspinous B. Denticulate C. Anterior longitudinal D. Posterior longitudinal E. Nuchal ligament 24 A 25-year-old male racing car driver is admitted to the emergency department after a severe car crash. Radiologic studies reveal damage to the tip of the transverse process of the third cervical vertebra, with a significantly large pulsating hematoma. What artery is the most likely to have been damaged? A. Anterior spinal artery B. Vertebral artery C. Ascending cervical artery D. Deep cervical artery E. Posterior spinal arteries 25 A 79-year-old man, a retired military veteran, presents to the outpatient clinic with an abnormal curvature of the vertebral column. He complains that it Back has become increasingly painful to walk around town. Upon physical examination, he has an abnormally increased convexity to his thoracic curvature resulting from osteoporosis. Which of the following is the most likely clinical condition of this patient’s spine? A. Scoliosis B. Hyperkyphosis C. Spinal stenosis D. Lordosis E. Herniated disc 26 A 42-year-old woman complains of pain and stiffness in her neck. She was injured sliding into second base headfirst during her company’s softball game. Radiographs reveal no fractures of her spine. However, upon physical examination, her right shoulder is drooping and she has difficulty in elevating that shoulder. If you ordered an MRI, it would most likely reveal soft tissue damage involving which of the following nerves? A. Thoracodorsal nerve B. Spinal accessory nerve C. Dorsal scapular nerve D. Greater occipital nerve E. Axillary nerve 27 A 53-year-old man was in a head-on vehicle collision that resulted in compression of his spinal cord by the dens (odontoid process) of the axis, with resulting quadriplegia. Which of the following ligaments was most probably torn? A. Anterior longitudinal ligament B. Transverse ligament of the atlas C. Ligamentum flavum D. Supraspinous ligament E. Nuchal ligament 28 An 18-year-old woman passenger injured in a rollover car crash was rushed to the emergency department. After the patient is stabilized, she undergoes physical examination. She demonstrates considerable weakness in her ability to flex her neck, associated with injury to CN XI. Which of the following muscles is most probably affected by nerve trauma? A. Iliocostalis thoracis B. Sternocleidomastoid C. Rhomboid major D. Rhomboid minor E. Teres major 29 A 23-year-old man was killed in a high-speed motor vehicle collision after racing his friend on a local highway. When the medical examiner arrives at the scene, it is determined that the most likely cause of death was a spinal cord injury. Upon confirmation by autopsy, the medical examiner officially reports that the patient’s cause of death was a fracture of the pedicles of the axis (C2). Breaking of which of the following ligaments would be most likely implicated in this fatal injury? A. Ligamentum flavum B. Nuchal ligament C. Cruciform ligament D. Posterior longitudinal ligament E. Supraspinous ligament 30 A 65-year-old man is injured when a vehicle traveling at a high rate of speed hits his car from behind. Radiologic examination reveals that two of his articular processes are now locked together, a condition known as “jumped facets.” In which region of the spine is this injury most likely to occur? A. Cervical B. Thoracic C. Lumbar D. Lumbosacral E. Sacral 31 Following a car crash, a 47-year-old woman complains of severe headache and back pain. Radiologic examination reveals bleeding of the internal vertebral venous plexus (of Batson), resulting in a large hematoma. In what space has the blood most likely accumulated? A. Subarachnoid space B. Subdural space C. Central canal D. Epidural space E. Lumbar cistern 32 A 32-year-old man, an elite athlete, was lifting heavy weights during an intense training session. The athlete felt severe pain radiating to the posterior aspect of his right thigh and leg. The patient was taken to the hospital where MRI revealed a ruptured L4/L5 intervertebral disc. Which nerve is most probably affected? A. L3 B. L4 C. L2 D. L5 E. S1 7 Back 33 A 24-year-old patient suffered a lower back strain after a severe fall while skiing. MRI studies reveal injury to the muscles responsible for extending and laterally bending the trunk. What arteries provide blood supply for these muscles? A. Subscapular B. Thoracodorsal C. Anterior intercostal D. Suprascapular E. Posterior intercostal lesion between the trapezius and latissimus dorsi muscles on the right lateral side of his back. Upon admission to the hospital, physical examination reveals weak adduction and medial rotation of his arm. Which of the following muscles is most probably injured? A. Teres minor B. Triceps brachii C. Supraspinatus D. Infraspinatus E. Teres major 34 A 22-year-old male soccer player is forced to leave the game following a head-to-head collision with another player. He is admitted to the hospital, and radiologic examination reveals slight dislocation of the atlantoaxial joint. As a result, he experiences decreased range of motion at that joint. What movement of the head would most likely be severely affected? A. Rotation B. Flexion C. Abduction D. Extension E. Adduction 38 A 22-year-old man is thrown through a plate glass wall in a fight. Radiologic examination reveals that the lateral border of his right scapula is shattered. He is admitted to the emergency department, and physical examination reveals difficulty laterally rotating his arm. Which of the following muscles is most probably injured? A. Teres major B. Infraspinatus C. Latissimus dorsi D. Trapezius E. Supraspinatus 35 A 42-year-old man is struck in the back, rupturing the internal vertebral venous plexus (of Batson). Radiologic studies reveal a hematoma causing compression of the spinal cord. When aspirating the excess blood, the physician performing the procedure should stop the needle just before puncturing which of the following structures? A. Spinal cord B. Pia mater C. Arachnoid mater D. Dura mater E. Ligamentum flavum 39 A 24-year-old woman presents with severe headache, photophobia, and stiffness of her back. Physical examination reveals positive signs for meningitis. The attending physician decides to perform a lumbar puncture to determine if a pathogen is in the cerebrospinal fluid (CSF). What is the last structure the needle will penetrate before reaching the lumbar cistern? A. Arachnoid mater B. Dura mater C. Pia mater D. Ligamentum flavum E. Posterior longitudinal ligament 36 A 35-year-old man pedestrian is crossing a busy intersection and is hit by a truck. He is admitted to the emergency department, and a CT scan reveals a dislocation of the fourth thoracic vertebra. Which of the following costal structures is most likely also involved in the injury? A. Head of the fourth rib B. Neck of the fourth rib C. Head of the third rib D. Tubercle of the third rib E. Head of the fifth rib 40 A 19-year-old presents at the emergency department with high fever, severe headache, nausea, and stiff neck that have persisted for 3 days. The attending physician suspects meningitis and obtains a sample of CSF using a lumbar puncture. From which of the following spaces was the CSF collected? A. Epidural space B. Subdural space C. Subarachnoid space D. Pretracheal space E. Central canal of the spinal cord 37 A 20-year-old male hiker suffers a deep puncture 41 A 38-year-old man is admitted to the emergency department after a car collision. During physical 8 wound during a fall. Physical examination reveals a Back examination several lacerations to the back are discovered. Pain from lacerations or irritations of the skin of the back is conveyed to the central nervous system by which of the following? A. Dorsal primary rami B. Communicating rami C. Ventral primary rami D. Ventral roots E. Intercostal nerves 42 A 66-year-old woman had been diagnosed with a tumor on her spine. She has started to retain urine and is experiencing rectal incontinence. Both of these symptoms are signs of conus medullaris syndrome. At which of the following vertebral levels is the tumor probably located? A. L3/L4 B. L3 C. L4 D. T12 to L2 E. T11 43 Examination of a 3-day-old male infant reveals protrusion of his spinal cord and meninges from a defect in the lower back. Which of the following describes this congenital anomaly? A. Avulsion of meninges B. Meningitis C. Spina bifida occulta D. Spina bifida with myelomeningocele E. Spina bifida with meningocele 44 A 32-year-old mother complains of serious pain in the coccygeal area some days after giving birth. To determine whether the coccyx is involved, a local anesthetic is first injected in the region of the coccyx and then dynamic MRI studies are performed. Physical examination reveals pain with palpation to the region of the coccyx. The local anesthetic is used to interrupt which of the following nerve pathways? A. Visceral afferents B. Somatic efferent C. Somatic afferent D. Sympathetic preganglionic E. Parasympathetic preganglionic 45 During a routine physical examination, a 65-yearold man is tested for ease and flexibility of the movements of his lumbar region. Which of the following movements is most characteristic of the intervertebral joints in the lumbar region? A. B. C. D. E. Circumduction Lateral flexion Abduction Adduction Inversion 46 A 72-year-old man with cancer of the prostate gland presents with loss of consciousness and seizures. A CT scan is performed and a brain tumor is diagnosed. The tumor spread to the brain from the pelvis via the internal vertebral venous plexus (of Batson). What feature of the plexus allows this to happen? A. The internal venous plexus contains the longest veins in the body. B. The internal venous plexus has valves that ensure one-way movement of blood. C. The internal venous plexus is located in the subarachnoid space. D. The internal venous plexus is, in general, valveless. E. The internal venous plexus is located in the subdural space. 47 A 26-year-old man painting his house slipped and fell from the ladder, landing on the pavement below. After initial examination in the emergency department, the patient is sent to the radiology department. Radiographs reveal that the portion of his left scapula that forms the tip, or point, of the shoulder has been fractured. Which part of the bone was fractured? A. Coracoid process B. Superior angle of the scapula C. Glenoid D. Spine of the scapula E. Acromion 48 A 43-year-old male construction worker survived a fall from a two-story building but lost all sensation in his lower limbs and was admitted to the hospital for examination and treatment. Radiologic studies revealed that he crushed his spinal cord at vertebral level C6. Which of the following muscles will most likely be paralyzed? A. Sternocleidomastoid B. Trapezius C. Diaphragm D. Latissimus dorsi E. Deltoid 49 A maternal serum sample with high alphafetoprotein alerted the obstetrician to a possible neural 9 Back tube defect. Ultrasound diagnosis revealed a myelomeningocele protruding from the back of the child. Which of the following is the most likely diagnosis of this congenital anomaly? A. Cranium bifida B. Spina bifida occulta C. Spina bifida cystica D. Hemothorax E. Caudal regression syndrome 50 A 7-year-old girl who is somewhat obese is brought to the emergency department because of a soft lump above the buttocks. Upon physical examination you note the lump is located just superior to the iliac crest unilaterally on the left side. The protrusion is deep to the skin and pliable to the touch. Which of the following is the most probable diagnosis? A. Tumor of the external abdominal oblique muscle B. Herniation at the lumbar triangle (of Petit) C. Indirect inguinal hernia D. Direct inguinal hernia E. Femoral hernia 51 A 54-year-old woman is admitted to the emergency department due to increasing back pain over the preceding year. MRI reveals that her intervertebral discs have been compressed. It is common for the discs to decrease in size in people older than 40, and this can result in spinal stenosis and disc herniation. At which locations are the spinal nerves most likely to be compressed? A. Between the denticulate ligaments B. As they pass through the vertebral foramen C. Between the superior and inferior articular facets D. Between inferior and superior vertebral notches E. Between the superior and inferior intercostovertebral joints 52 A 37-year-old pregnant woman is given a caudal epidural block to alleviate pain during vaginal delivery. Caudal epidural blocks involve injection of local anesthetic into the sacral canal. Which of the following landmarks is most commonly used for the caudal epidural block? A. Anterior sacral foramina B. Posterior sacral foramina C. Cornua of the sacral hiatus 10 D. Intervertebral foramina E. Median sacral crest 53 A 34-year-old pregnant woman in the maternity ward was experiencing considerable pain during labor. Her obstetrician decided to perform a caudal epidural block. What are the most important bony landmarks used for the administration of such anesthesia? A. Ischial tuberosities B. Ischial spines C. Posterior superior iliac spines D. Sacral cornua E. Coccyx 54 A 22-year-old man is brought into the emergency department following a brawl in a tavern. He has severe pain radiating across his back and down his left upper limb. He supports his left upper limb with his right hand, holding it close to his body. Any attempt to move the left upper limb greatly increases the pain. A radiograph is ordered and reveals an unusual sagittal fracture through the spine of the left scapula. The fracture extends superiorly toward the suprascapular notch. Which nerve is most likely affected? A. Suprascapular nerve B. Thoracodorsal nerve C. Axillary nerve D. Subscapular nerve E. Suprascapular nerve and thoracodorsal nerve 55 A 5-year-old boy is admitted to the hospital because of pain in the upper back. Radiologic examination reveals abnormal fusion of the C5 and C6 vertebrae and a high-riding scapula. Which of the following is the most likely diagnosis? A. Lordosis B. Kyphosis C. Scoliosis D. Spina bifida E. Klippel-Feil syndrome 56 A 53-year-old man is admitted to the emergency department due to severe back pain. MRI examination reveals anterior dislocation of the body of the L5 vertebra upon the sacrum. Which of the following is the most likely diagnosis? A. Spondylolysis B. Spondylolisthesis C. Herniation of intervertebral disc D. Lordosis E. Scoliosis Back 57 A male newborn infant is brought to the clinic by his mother and diagnosed with a congenital malformation. MRI studies reveal that the cerebellum and medulla oblongata are protruding inferiorly through the foramen magnum into the vertebral canal. What is this clinical condition called? A. Meningocele B. Klippel-Feil syndrome C. Chiari II malformation D. Hydrocephalus E. Tethered cord syndrome 58 A 62-year-old woman is admitted to the hospital because of her severe back pain. Radiologic examination reveals that the L4 vertebral body has slipped anteriorly, with fracture of the zygapophysial joint (Fig. 1-2). What is the proper name of this condition? A. Spondylolysis and spondylolisthesis B. Spondylolisthesis C. Crush vertebral fracture D. Intervertebral disc herniation E. Klippel-Feil syndrome 59 A 40-year-old woman survived a car crash in which her neck was hyperextended when her vehicle was struck from behind. At the emergency department, a plain radiograph of her cervical spine revealed a fracture of the odontoid process (dens). Which of the following was also most likely injured? L Fig. 1-2 A. B. C. D. E. Anterior arch of the atlas Posterior tubercle of the atlas Atlanto-occipital joint Inferior articular process of the axis Anterior tubercle of the atlas 60 A 34-year-old woman is admitted to the emergency department after a car crash. Radiologic examination reveals a whiplash injury in addition to hyperextension of her cervical spine. Which of the following ligaments will most likely be injured? A. Ligamentum flavum B. Anterior longitudinal ligament C. Posterior longitudinal ligament D. Anulus fibrosus E. Interspinous ligament 61 A 23-year-old college student is admitted to the emergency department after jumping from a 50-foot high waterfall. The MRI of his back reveals a lateral shift of the spinal cord to the left. Which of the following structures has most likely been torn to cause the deviation? A. Posterior longitudinal ligament B. Tentorium cerebelli C. Denticulate ligaments D. Ligamentum flavum E. Nuchal ligament 62 A 6-year-old boy is admitted to the hospital with coughing and dyspnea. During taking of the history, he complains that it feels like there is glass in his lungs. Auscultation reveals abnormal lung sounds. The abnormal lung sounds are heard most clearly during inhalation with the scapulae protracted. Which of the following form the borders of a triangular space where one should place the stethoscope in order to best hear the lung sounds? A. Latissimus dorsi, trapezius, medial border of scapula B. Deltoid, levator scapulae, trapezius C. Latissimus dorsi, external abdominal oblique, iliac crest D. Quadratus lumborum, internal abdominal oblique, inferior border of the twelfth rib E. Rectus abdominis, inguinal ligament, inferior epigastric vessels 63 A 45-year-old woman is admitted to the outpatient clinic for shoulder pain. During physical examination she presents with weakened shoulder movements. 11 Back A. Injury to the left vertebral artery B. Injury of the great radicular artery (of Adamkiewicz) C. Ligation of the posterior spinal artery D. Transection of the conal segment of the spinal cord E. Division of the thoracic sympathetic chain Fig. 1-3 Radiologic examination reveals signs of quadrangular space syndrome, causing weakened shoulder movements. Which of the following nerves is most likely affected? A. Suprascapular B. Subscapular C. Axillary D. Radial E. Ulnar 64 A 29-year-old female elite athlete was lifting heavy weights during an intense training session. The athlete felt severe pain radiate suddenly to the posterior aspect of her right thigh and leg. The patient was taken to the hospital where an MRI was performed (Fig. 1-3). Which nerve was most probably affected? A. L3 B. L4 C. L2 D. L5 E. S1 65 A 58-year-old man in the intensive care ward exhibited little voluntary control of urinary or fecal activity following repair of an abdominal aortic aneurysm. In addition, physical examination revealed widespread paralysis of his lower limbs. These functions were essentially normal prior to admission to the hospital. The most likely cause of this patient’s problems 12 is which of the following? 66 A 23-year-old woman is admitted to the hospital due to back pain. Radiologic examination reveals that she suffers from a clinical condition affecting her vertebral column. Her history reveals that she suffered from polio and has a muscular dystrophy. Which of the following conditions of the vertebral column will most likely be present in this patient? A. Hyperlordosis B. Hyperkyphosis C. Scoliosis D. Spina bifida E. Osteoarthritis 67 A 26-year-old competitive football player has been complaining of pain, weakness, numbness, and tingling for the past 2 months in his upper limb. Imaging studies reveal a cervical disc herniation compressing the nerve roots and a portion of the spinal cord. An anterior cervical discectomy and fusion (ACDF) surgery is performed. The intervertebral disc is examined upon removal and the anulus fibrosus and nucleus pulposus are severely damaged posterolaterally. What type of cartilage most likely gives the tensile strength of the intervertebral disc? A. Hyaline B. Elastic C. Fibrous D. Epiphysial E. Elastic and fibrous 68 A 26-year-old competitive football player has been complaining of pain, weakness, numbness, and tingling for the past 2 months in his upper limb. Imaging studies reveal a cervical disc herniation compressing the nerve roots and a portion of the spinal cord. An ACDF surgery is performed. The intervertebral disc is examined upon removal and the nucleus and anulus and nucleus pulposus are severely damaged posterolaterally. What is the embryologic origin of the anulus fibrosus and nucleus pulposus, respectively? A. Notochord and neural crest cells B. Neural crest cells and ectoderm C. Sclerotome and myotome Back D. Mesenchymal cells from sclerotome and neural crest cells E. Mesenchymal cells from sclerotome and notochord 69 A 55-year-old woman has suffered from a middle ear infection for the past month. She recently developed right-sided miosis, partial ptosis, anhydrosis, and redness of the conjunctiva. Biopsy examination of which of the following structures would show the cell bodies of neurons affected by this disease? A. Anterior gray horn of the spinal cord B. Lateral gray horn of the spinal cord C. Posterior gray horn of the spinal cord D. Spinal ganglia E. Lateral column of spinal cord white matter 70 A 62-year-old man is admitted to the emergency department after a severe car crash resulting in a whiplash injury. MRI examination reveals several hairline vertebral fractures in the cervical region impinging the dorsal primary rami of the same levels. Two months after the injury the patient recovered well, however, there is still some weakness in the function of a muscle. Which of the following muscles is most likely affected? A. Rhomboid major B. Levator scapulae C. Rhomboid minor D. Semispinalis capitis E. Latissimus dorsi 71 A 22-year-old man has suffered from headaches and some muscle weakness to his upper muscles of the back for the last 6 months. An MRI shows a large tumor compressing the suboccipital and greater occipital nerves. Which of the following muscles will most likely still be functioning normally? A. Rectus capitis posterior major and minor B. Semispinalis capitis C. Splenius capitis D. Obliquus capitis superior E. Obliquus capitis inferior and lateral 72 A 36-year-old man was found guilty of first-degree murder and sentenced to death by judicial hanging. The radiological image below shows the vertebra that is fractured as a result of the hanging. The mechanism of injury resulting in death is forcible hyperextension resulting in a fracture of which of the following structures? A. Odontoid process B. Transverse process C. Lateral mass D. Pedicle (pars articularis) E. Spinous process 73 A 72-year-old woman presented to her primary care physician after sustaining a fall in her bathroom. Her vital signs were normal and routine blood work was obtained for analysis. As part of her work up, a radiograph of her vertebral column was performed and revealed a wedge fracture at the fourth thoracic vertebra and thin cortical bone showing signs of osteoporotic changes. What will be the most likely type of abnormal spinal curvature in such a patient? A. Hyperkyphosis B. Scoliosis C. Hyperlordosis D. Normal E. Primary 74 A 65-year-old woman who has been otherwise well presents to her physician with complaints of a group of painful blisters over her back in the distribution of the T9 dermatome. She noticed that a few days prior to the eruption of the blisters she experienced an intense burning sensation over her skin. She was diagnosed with herpes zoster (shingles). Where are the neural cell bodies located that are responsible for the pain sensation? A. Dorsal horn B. Lateral horn C. Dorsal root ganglia D. Sympathetic chain ganglia E. White rami communicans 75 A 53-year-old man was in a head-on collision resulting in the dens crushing the spinal cord. Which ligament was most likely torn for the dens to crush the spinal cord? A. Anterior and posterior longitudinal ligaments B. Transverse ligament of the atlas C. Interspinous ligament D. Supraspinous ligament E. Nuchal ligament 76 A 16-year-old girl is sent for a presports physical examination prior to the beginning of her school year. She has no medical complaints or any clinical past history. On physical examination, the physician notices one shoulder is higher than the other. The student is then asked to bend forward at the waist to touch her toes. This maneuver results in a posterior bulging of 13 Back the ribs on the right side. Which one of the following is most likely diagnosis? A. Kyphosis B. Spondylosis C. Lordosis D. Spondylolisthesis E. Scoliosis 77 A 60-year-old man has been feeling sharp pains over his left lower chest and back for several days. A rash of red erupted vesicles is seen at the left border of the sternum just at the level of the xiphoid process. Antiviral treatment is given for herpes zoster. Which of the following locations will contain the neural cell bodies responsible for the painful sensation? A. Ventral horn of T6 spinal cord segment B. Lateral horn of T6 spinal cord segment C. Dorsal root ganglion of T4 spinal nerve D. Dorsal root ganglion of T6 spinal nerve E. Dorsal root ganglion of T10 spinal nerve 78 A 70-year-old man with prostate cancer is experiencing sharp shooting pains radiating from his neck into the upper limb. An MRI of his spine demonstrates a small metastatic mass in the cervical region extending into the left intervertebral foramen between C6 and C7. The intervertebral discs appear normal. Which neural structure is most likely being compressed by the metastatic mass to account for the pain? A. C8 spinal nerve B. Dorsal horn of C6 spinal cord segment C. C6 spinal nerve D. Dorsal horn of C7 spinal nerve E. C7 spinal nerve 79 A 3-day-old girl develops a fever. She is irritable and not feeding. As part of the workup for fever of unknown origin, a lumbar puncture is performed. This puncture must be done below the spinal cord which usually ends at which vertebral level in a patient of this age? A. L1 B. S1 C. L3 D. S3 E. L5 80 During a surgical procedure to debride an abscess involving the erector spinae muscle at vertebral level T8, the nerve branch supplying the skin and this muscle 14 is unavoidably severed. What are the anatomical locations of the cell bodies of the nerve fibers normally found in this branch? A. Ventral horn and dorsal horn B. Ventral horn, dorsal horn, and lateral horn C. Ventral horn, dorsal root ganglion, and lateral horn D. Ventral horn, dorsal root ganglion, and sympathetic paravertebral ganglion E. Ventral horn, dorsal horn, and dorsal root ganglion 81 While waiting in his car at a stop sign, a 28-yearold man was rear-ended by a van, resulting in neck hyperextension. He was admitted to the emergency department and a whiplash injury was diagnosed. The next day his neck was stiff and painful. Which structure was most likely damaged to cause the pain? A. Anterior longitudinal ligament B. Posterior longitudinal ligament C. Ligamentum flavum D. Intervertebral disc E. Supraspinous ligament 82 A 38-year-old man who is a professional golfer complains of chronic lower back pain with radiating pain to the heel. The pain is so debilitating that he now has trouble ambulating. MRI of the lower back reveals severe narrowing of an intervertebral foramen (IVF), which has caused compression of the exiting nerve root. Surgery is required to correct the problem. During surgery the neurosurgeon carefully accesses the IVF using a lateral approach and shaves bone off the superior margin (roof) of the IVF to decompress the exiting nerve root. Which of the following vertebral bony features is the neurosurgeon most likely shaving off? A. Superior articular process B. Lamina C. Inferior articular process D. Pedicle E. Spinous process 83 The following statement was found in the radiology report of a magnetic resonance imaging scan of the cervical spine: “An acute posterolateral herniation of the most superiorly located intervertebral disc is located within the corresponding intervertebral foramen and compressing the exiting nerve.” Which of the following nerves was the radiologist most likely referring to in the report? A. C1 B. C2 Back C. C3 D. C4 E. C5 84 A 14-year-old girl accidentally flipped her bicycle off a curb, fell, and landed on her face. Although she was wearing a helmet, she landed in such a way that her neck was forced into hyperextension. Which of the following ligaments of the cervical spine was stretched to the greatest degree during her injury? A. Posterior longitudinal ligament B. Ligamentum nuchae C. Ligamenta flava D. Supraspinous ligament E. Anterior longitudinal ligament 85 An orthopedic surgeon was teaching two residents during a workshop. For the purpose of learning, one resident acted as the patient and the other as the clinician. The surgeon asked the resident-clinician to use a marker and draw a horizontal line connecting the highest points of the iliac crests on the skin of the resident-patient. The surgeon then asked the residentclinician to palpate the midline area on the skin where the subarachnoid space terminates inferiorly. Which of the following most likely represents the area on the skin where the resident-physician palpated? A. Three spinous processes superior to the horizontal line B. Two spinous processes inferior to the horizontal line C. Three spinous processes inferior to the horizontal line D. Two spinous processes superior to the horizontal line E. The spinous process bisected by the horizontal line 86 An MRI scan of the thoracic spine of a 68-year-old man with acute midback pain revealed a large tumor arising from the anterior median fissure of the spinal cord at the level of the T3 vertebra. The artery compressed by the tumor is most likely formed superiorly by direct branches from which of the following arteries? A. Ascending cervical B. Segmental medullary C. Vertebral D. Segmental spinal E. Posterior spinal 87 Radiographs of a 12-year-old girl with midback pain reveal a hemivertebra of the lower thoracic spine. Which additional finding would most likely be demonstrated on the radiographs? A. Osteoporosis B. Scoliosis C. Hyperlordosis D. Spondylolisthesis E. Sacralization 88 In a report of a radiograph of the cervical spine the radiologist wrote the following: “Severe narrowing of the C7-T1 intervertebral foramen (IVF) on the left.” Which nerve was most likely compressed as a result of this finding? A. C6 B. C7 C. C8 E. T1 89 A mother brought her 15-month-old previously healthy child to the pediatrician and nervously told the physician that her child now had “a curvature in her low back.” The mother stated that this curvature was not present previously and that she noticed it when the child started standing and walking. The physician examined the child and then reassured the mother that the spinal curvature was normal. Which curvature did the mother most likely observe? A. Thoracic kyphosis B. Cervical lordosis C. Lumbar lordosis D. Cervical kyphosis E. Thoracic lordosis 90 During a gross anatomy laboratory session, a professor demonstrates a large back muscle that inserts onto the floor of the intertubercular sulcus of the humerus. Which of the following structures is most likely the vertebral origin of the muscle that the professor is demonstrating? A. Spinous processes of T7 to L5 B. Spinous processes of C7 to T12 C. Transverse processes of C1 to C4 D. Spinous processes of T2 to T5 E. Spinous processes of C7 and T1 91 A drug that preferentially destroys sclerotomes during embryogenesis would most likely result in 15 Back underdevelopment of which of the following structures? A. Nucleus pulposus of intervertebral disc B. Vertebral bodies C. Dorsal root ganglion D. Spinal cord E. Anulus fibrosus of intervertebral disc 92 Which of the following muscles is most likely located immediately deep to the semispinalis muscles, pass from a lateral point of origin in a superomedial direction to attach to spinous processes, and cross between 2 and 4 vertebrae? A. Multifidus B. Rotatores C. Longissimus D. Iliocostalis E. Spinalis 93 A 32-year-old construction worker falls from a scaffold and is brought to the emergency department with severe lower back pain. Radiographs of the lumbar spine reveal bilateral pars interarticularis fractures of the L5 vertebra. Which of the following radiographic views would most likely reveal these fractures? A. Anteroposterior B. Lateral C. Posteroanterior D. Oblique E. Anteroposterior open mouth 94 A radiology report of a cervical spine MRI scan contains the following statement: “A small 1-cm tumor is located within a muscle on the lateral border of the right suboccipital triangle.” The muscle to which the radiologist is most likely referring inserts on which of the following bony features? A. Transverse process of atlas B. Lateral portion of occipital bone below inferior nuchal line C. Occipital bone between superior and inferior nuchal lines D. Medial portion of occipital bone below inferior nuchal line E. Posterior tubercle of atlas 95 Radiographs of the lumbar spine of a 68-year-old woman with lower back pain were taken and in the radiology report the following was written: “The anteroposterior view demonstrates marked bilateral enlarge16 ment of the transverse processes of a single vertebra. The length and width of both transverse processes of this single vertebra are enlarged and the inferior aspects of these bony features appear to be articulating with the bone immediately below it, so much so that the single vertebra appears to have morphologic characteristics similar to the bone immediately below it.” The single vertebra referred to by the radiologist in the report is most likely which of the following? A. L1 vertebra B. L4 vertebra C. S2 vertebra D. S1 vertebra E. L5 vertebra 96 A 45-year-old man was injured in a motor vehicle crash and brought to the emergency department. Radiographs of the upper cervical spine revealed a type III dens fracture demonstrated by a horizontal radiolucent line on the superior half of the posterior aspect of the C2 vertebral body. Which of the following ligaments most likely has direct attachment to the bony area where the fracture was located? A. Apical ligament of dens B. Superior longitudinal band of cruciform ligament C. Transverse ligament of atlas D. Inferior longitudinal band of cruciform ligament E. Ligamenta flava 97 A 35-year-old man underwent a laminectomy of the T8 to T9 vertebrae. During the surgery, the neurosurgeon observed that the posterior roots were compressed at that level due to a space-occupying lesion. Which of the following arteries was most likely directly compressed by the lesion? A. Radicular B. Segmental spinal C. Segmental medullary D. Anterior spinal E. Posterior spinal 98 An 8-year-old girl was brought to a pediatrician for a routine physical examination. The figure associated with this question is a photograph of the child (Fig. 1-4). Which of the following best describes the embryologic basis for this child’s condition? A. Underdevelopment of the secondary ossification center in the vertebral arch B. Underdevelopment of the primary ossification center in the spinous process Back 100 A 38-year-old woman has been in labor for 14 hours and has agreed to have an epidural anesthetic injection for pain control. Which of the following structures is most likely to be the last penetrated by the needle before it reaches the epidural space? A. Supraspinous ligament B. Interspinous ligament C. Anterior longitudinal ligament D. Posterior longitudinal ligament E. Ligamenta flava Fig. 1-4 C. Underdevelopment of the primary ossification center in the vertebral body D. Underdevelopment of the secondary ossification center in the vertebral body E. Underdevelopment of the primary ossification center in the vertebral arch 99 The following statement is written in the radiology report of an MRI scan of the cervical spine: “A large osteophyte is emanating from the posterolateral area of the vertebral body of the vertebra immediately above the C3 nerve root and is severely compressing the C3 nerve root.” The osteophyte is most likely emanating from which of the following vertebrae? A. C2 B. C3 C. C4 D. C5 E. C1 101 A 48-year-old man underwent suboccipital surgery whereby the surgeon made a midline incision through the ligamentum nuchae that began 1-cm inferior to the external occipital protuberance and ended at the level of the C2 vertebra. The surgeon then placed self-retaining retractors into the incision to forcibly separate the tissue so that an adequate surgical field existed for the duration of the surgery which lasted for 3 hours. During recovery, the patient complained of severe occipital pain and was diagnosed with postsurgical occipital neuralgia. Which of the following nerves was most likely directly stretched by the retractors during the surgery and resulted in this patient’s post-surgical pain? A. Third occipital B. Suboccipital C. Greater occipital D. Lesser occipital E. Spinal accessory 102 A 7-year-old boy is undergoing a surgery to remove a tumor from his spinal cord. During surgery of the spinal cord, which of the following structures is used as a landmark to identify anterior rootlets from posterior rootlets? A. Denticulate ligament B. Filum terminale C. Conus medullaris D. Posterior longitudinal ligament E. Ligamenta flava 103 A 45-year-old male driver involved in a motor vehicle crash was taken to the emergency department and MRI revealed a complete tear of the right alar ligament. None of the other ligaments of the upper cervical spine were torn. Upon physical examination, which of the following cervical spine movements will be most likely increased as a result of the tear? A. Flexion B. Extension C. Lateral flexion 17 Back D. Rotation E. Abduction 104 A 25-year-old male bodybuilder complains of difficulty moving his right shoulder for the past 2 weeks. Upon physical examination, the muscles of the left upper back and shoulder were notably larger than the right side. There was a notable decrease of muscle power on his right sided upper back and shoulder muscles when he was asked to pull the shoulder blades toward the middle of his back against resistance. Nerve conduction examination confirmed neurapraxia of the nerves supplying the rhomboid major and minor muscles. In which of the following functions will the bodybuilder most likely also demonstrate weakness? A. Abduction of the right arm above the horizontal level and protraction of the scapula B. Medial rotation and adduction of the right arm C. Extensions, adduction, and medial rotation of the right arm D. Elevation of the scapula and inferior rotation of the right shoulder E. Abduction of the right arm from 0 to 15 degrees 105 A 38-year-old woman with a history of carcinoma of the left breast and who had had a lumpectomy 2 years previously, presents to her surgeon with complaints of a hard mass in the left breast. On ultrasound examination, a 3 cm × 4 cm hard mass is discovered in the upper outer quadrant extending in the axillary tail (of Spence). A radical mastectomy is performed successfully and the tumor is removed. Three weeks postoperatively the patient complains of difficulty raising her left arm above her head. Which of the following is most likely expected to be found during physical examination? A. Protraction of the both scapulae B. Protrusion of the medial border of the left scapula when hands are pushed against the wall C. Weak abduction of the left upper limb in the 15 to 90 degree range D. Weak retraction of the scapula E. Weak adduction of the humerus 106 A 2-month-old infant is admitted to the emergency department with symptoms of meningitis. A lumbar puncture is performed in order to examine the CSF to confirm the diagnosis. The needle is inserted into the lumbar cistern (dural sac). At which vertebral 18 level will the conus medullaris typically be found in this patient? A. L3 B. L4 C. L5 D. S1 E. S2 107 Examination of a 3-day-old male infant reveals a large cystic of approximately 15 cm × 10 cm in the sacrococcygeal region. The mass was removed and histopathological studies identified tissue from all three embryological germ layers. Which of the following embryonic tissues is most likely responsible for this condition? A. Remnants of the primitive streak B. Chorionic villi C. Neural folds D. Intraembryonic coelom E. Neural crest 108 A 53-year-old man is admitted to the emergency department with severe back pain. MRI examination reveals fracture of the pars interarticularis and normal alignment of the body of the L5 vertebra upon the sacrum. What is the most likely diagnosis? A. Spondylolysis B. Spondylolisthesis C. Herniation of intervertebral disc D. Lordosis E. Scoliosis 109 A 22-year-old pregnant woman underwent epidural anesthesia in anticipation of labor. After delivery she developed back pain and right lower extremity weakness. Imaging revealed a hematoma in the epidural space resulting in compression of the nerve that exits at the level of L2 to L3. Which of the following vessels is most likely responsible for the hematoma? A. Internal vertebral plexus B. Great radicular artery (of Adamkiewicz) C. Anterior spinal artery D. Posterior spinal artery E. External vertebral plexus 110 Idling at a stoplight in his vintage car without headrests, a 71-year-old-man’s car is struck from behind by a truck. The man is brought to the emergency department suffering from a severe hyperextension neck injury due to the crash. The T2-weighted MRI Back shows a rupture of the anterior anulus fibrosus of the C4 to C5 intervertebral disc and a prevertebral hematoma which compromised his airway and required intubation. Which of the following ligaments is most likely disrupted in this injury? A. Anterior longitudinal ligament B. Posterior longitudinal ligament C. Ligamentum flavum D. Interspinous ligament E. Intertransverse ligament 111 An anesthesiologist administers epidural anesthetic immediately lateral to the spinous processes of vertebrae L3 and L4 of a pregnant woman in labor. During this procedure, what would be the last ligament perforated by the needle in order to access the epidural space? A. Ligamentum flavum B. Anterior longitudinal ligament C. Posterior longitudinal ligament D. Interspinous ligament E. Intertransverse ligament 112 A 38-year-old man presents to the emergency department with complaints of lower back pain during the past 5 days. Examination revealed tenderness of the spine over the L5 vertebra with an obvious “step-off” defect at that level. There was some weakness of the limbs. An MRI examination revealed an anterior displacement of the L5 vertebral body and narrowing of the vertebral canal. This pathology will most likely be associated with which of the following? A. Compression of the spinal cord and bilateral lower limb weakness B. Compression of the spinal cord and unilateral lower limb weakness C. Compression of the spinal nerve roots and L5 with unilateral lower limb weakness D. Compression of the cauda equina and bilateral lower limb weakness E. Compression of the cauda equina and low back pain only 113 A 62-year-old man visits his physician for his annual medical check-up. During physical examination it is noted that the patient has noticeable pulsations on palpation of the lower abdomen. Ultrasound examination reveals a large abdominal aortic aneurysm. The patient is operated on and during the repair his aorta is temporarily clamped. Which of the following arterial anastomoses will most likely prevent ischemia of the spinal cord if the blood pressure drops dangerously low? A. Segmental arteries from the vertebral, intercostals, superficial epigastric, lumbar, and medial sacral arteries B. Segmental arteries from the vertebral, intercostal, lumbar, spinal anterior, and posterior and lateral sacral arteries C. Anterior and posterior spinal arteries D. Radicular arteries of the vertebral, lumbar, intercostal, lateral sacral arteries, and artery of Adamkiewicz E. Segmental arteries from vertebral and intercostals 114 A 22-year-old woman is diagnosed with the presence of a chondroma at her index finger. Which of the following structures are sharing the same embryologic with the tumor? A. Denticulate ligament B. Dentate ligament C. Nucleus pulposus D. Apical ligament of the atlas E. Alar ligament 115 A 40-year-old woman survived a car crash in which her neck was hyperextended when her vehicle was struck from behind. At the emergency department a plain radiograph of her cervical spine is shown below (Fig. 1-5). Which of the following was also most likely injured? A. Anterior arch of the atlas B. Posterior tubercle of the atlas C. Atlanto-occipital joint D. Inferior articular process of the axis E. Anterior tubercle of the atlas 116 A 32-year-old man was lifting heavy weights during an intense training session. He felt severe pain radiating to the posterior aspect of his right thigh and leg. He was taken to hospital where an MRI scan (see Fig. 1-3) revealed a ruptured intervertebral disc. Which of the following nerves was most likely affected? A. L2 B. L3 C. L4 D. L5 E. S1 19 Back B A C Fig. 1-5 ANSWERS 1 B. Hyperkyphosis is characterized by a “hunchback” due to an abnormal increase in curvature of the thoracic region of the vertebral column. Hyperlordosis, or “swayback,” is an increase in lumbar curvature of the spine. Lordosis can be physiologic, such as seen in a pregnant woman. Scoliosis is a lateral curvature of the spine with rotation of the vertebrae. Spina bifida is a neural tube defect characterized by failure of closure of the vertebral arch. Osteoarthritis is a degenerative disorder that affects the articular carti- 20 lage of joints and is not specifically related to the thoracic region of the spine. GAS 76; N 153; McM 97 2 B. A crush fracture is characterized by compression of the entire vertebral body. The wedge fracture is similar in that it affects the vertebral bodies, but it involves small fractures around the perimeter of the vertebral body. Both of these fractures cause reductions in overall height. Fracture of the spinal, transverse, or superior articular processes can be due to an oblique, transverse, or comminuted fracture. Back Intervertebral discs are associated with disc herniation, not compression fractures. GAS 82; N 153-154; McM 88, 107 3 C. The ligamentum flavum connects the laminae of two adjacent vertebrae and forms the posterior wall of the vertebral canal. It is the only answer choice that is in direct contact with the vertebral foramen. Therefore, hypertrophy of only the ligamentum flavum would present as spinal canal stenosis. The supraspinous and interspinous ligaments connect spinous processes. The anterior longitudinal ligament connects the anterior portion of the vertebral bodies and intervertebral discs. Finally, the nuchal ligament is a thickened extension of the supraspinous ligament above the level of C7. GAS 84; N 159; McM 99 4 C. The dorsal scapular nerve (from the ventral ramus of C5) is responsible for innervating rhomboids major and minor. The rhomboids are responsible for retraction of the scapula. Therefore, if this nerve is damaged, individuals present with a laterally displaced scapula. In this case, the levator scapulae remains functional due to additional innervation provided by C3 to C4 spinal nerves. The axillary nerve innervates the deltoid and teres minor muscles. The deltoid muscle abducts the humerus, and the teres minor laterally rotates the humerus. The long thoracic nerve innervates the serratus anterior, which functions to protract and upwardly rotate the scapula. The greater occipital nerve is mainly sensory but also contributes to the innervation of the semispinalis capitis. In addition, the greater occipital nerve can be involved in occipital neuralgias. The suprascapular nerve innervates the supraspinatus and infraspinatus muscles. The supraspinatus abducts the humerus, and the infraspinatus muscles laterally rotate the humerus. Injury to any of these other nerves would not present with a laterally retracted scapula. GAS 90; N 174; McM 133 the L4 and L5 vertebrae, it exits from the spinal canal superior to the intervertebral disc, whereas the L5 spinal nerve root lies directly posterior to the disc. GAS 79; N 161; McM 97 7 D. A lumbar puncture is performed by taking a sample of CSF from the lumbar cistern (the subarachnoid space below the spinal cord) between vertebrae L4 and L5 or sometimes between L3 and L4. It is done in this region because the spinal cord typically ends at the level of L1 to L2 and the dural sac ends at the level of S2. Therefore, it is the safest place to do the procedure because it lies between these areas and the risk of injuring the spinal cord is minimized. (Remember in children the cord ends more caudally.) GAS 116; N 160-161; McM 97 8 B. The highest points of the iliac crests are used as a landmark for locating the position of L4 to L5 for a lumbar puncture; they are identified and traced medially toward the vertebral column (Tuffier’s line). The inferior angles of the scapulae lie at vertebral level T7; the lowest ribs lead one to T12; the sacral hiatus is located lower at the distal portion of the sacrum; the posterior inferior iliac spines lie below S2. GAS 106, 114-116; N 160-161; McM 97 9 A. The anterior longitudinal ligament lies anterior to the vertebral bodies along the vertebral column. The ligamentum flavum connects the laminae of two adjacent vertebrae. The nuchal ligament is a continuation of the supraspinous ligament above C7, which connects spinous processes. The posterior longitudinal ligament lies on the posterior margin of the vertebral bodies. The transverse cervical (cardinal) ligament is associated with the pelvic region of the body and not the spinal column (GAS Figs. 2-31 and 2-34). GAS 80; N 159; McM 98 5 B. Herpes zoster is a viral disease that remains latent in the dorsal root ganglia of the sensory nerves and when the virus becomes active presents as a painful skin lesion. It is associated only with sensory nerve fibers and has no motor involvement. The only answer choice that is solely responsible for sensory innervation is the dorsal root ganglion. GAS 109; N 161-162; McM 95 10 B. Compression of nerves at the intervertebral foramen indicates a disc herniation. A disc herniation is characterized by protrusion of the nucleus pulposus through the anulus fibrosus posterolaterally into the spinal canal or intervertebral foramen. In general, the ligaments may be affected by the herniation but are not responsible for the compression of the spinal nerve roots. GAS 79; N 158; McM 99 6 E. Disc herniation in the lumbar region between L4 and L5 affects the L5 spinal nerve roots. Even though the L4 spinal nerve root lies directly between 11 A. The thoracodorsal nerve innervates the latissimus dorsi, one of major muscles that adduct and medially rotate the humerus. The axillary nerve 21 Back Posterior longitudinal ligament Ligamentum flavum Supraspinous ligament Interspinous ligament Anterior longitudinal ligament GAS Fig. 2-31 Ligamentum flavum Supraspinous ligament GAS Fig. 2-34 supplies the deltoid muscle, the dorsal scapular nerve supplies the rhomboids and levator scapulae muscles, and the spinal accessory nerve innervates the trapezius. None of these nerves medially rotates or adducts the humerus. The radial nerve is responsible for the innervation on the posterior aspect of the arm and forearm. The medial and lateral pectoral nerves and the lower subscapular nerve supply the other medial rotators of the humerus. GAS 87, 99; N 174; McM 101 12 C. The long thoracic nerve innervates the serratus anterior, which is responsible for elevation and protraction of the scapula beyond the horizontal level while maintaining its position against the thoracic wall. Along with the thoracodorsal nerve, the long thoracic nerve runs superficially along the thoracic wall and is subject to injury during a mastectomy procedure. The axillary nerve, the spinal accessory nerve, and the thoracodorsal nerve supply the deltoid 22 muscle, trapezius muscle, and latissimus dorsi muscles, respectively. The dorsal scapular nerve is responsible for innervation of the rhomboids and levator scapulae. Aside from the long thoracic and thoracodorsal nerves, the remaining nerves do not course along the lateral thoracic wall. GAS 726; N 180, 413; McM 140 13 D. The rotator cuff muscles are common sites of damage during shoulder injuries. These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis (SITS). Initiation of abduction of the humerus (the first 15 degrees) is performed by the supraspinatus, followed by the deltoid from 15 to 90 degrees. Above the horizontal, the scapula is rotated by the trapezius and serratus anterior muscles, causing the glenoid fossa to turn superiorly and allowing the humerus to move above 90 degrees. The teres major Back and the pectoralis major are responsible for medial rotation and adduction of the humerus. These muscles are therefore not involved in abduction at the glenohumeral joint. GAS 711-712, 717; N 134-135; McM 411, 413 14 C. Spina bifida is a developmental condition resulting from incomplete fusion of the vertebral arches within the lumbar region. Spina bifida occulta commonly presents asymptomatically with midline, lumbar, cutaneous stigmata such as a tuft of hair and a small dimple. More severe forms (spina bifida cystica) are categorized into three types: Spina bifida cystica with meningocele presents with protrusion of the meninges through the unfused vertebral arches; spina bifida with myelomeningocele is characterized by protrusion both of the meninges and central nervous system (CNS) tissues and is often associated with neurologic deficits; and rachischisis, also known as spina bifida cystica with myeloschisis, results from a failure of neural folds to fuse and is characterized by protrusion of the spinal cord or spinal nerves and meninges. GAS 74; N 14, 160; McM 77, 88 15 A. Somatic afferents are responsible for conveying pain, pressure, touch, temperature, and proprioception to the CNS. Afferent fibers carry only sensory stimuli, whereas efferent fibers convey motor information. Visceral innervation is associated with the autonomic nervous system. Visceral afferents generally carry information regarding the physiologic changes of the internal viscera whereas visceral efferents deliver autonomic motor function to three types of tissue: smooth muscle, cardiac muscle, and glandular epithelium. GAS 32-35; N 174; McM 211 16 E. CSF is found within the subarachnoid space and is continuous with the ventricles of the brain (CSF flows from the ventricles to the subarachnoid space). The epidural space, positioned between the dura mater and periosteum, contains fat and the internal vertebral venous plexus (of Batson). The subdural space, between the arachnoid mater and dura mater, exists only as a potential space and does not contain cerebrospinal fluid. The anterior and posterior longitudinal ligaments traverse the length of the vertebral bodies. GAS 106, 114-116; N 166; McM 97 17 B. The posterior longitudinal ligament is the only ligament spanning the posterior aspect of the vertebral bodies and intervertebral discs. With inter- vertebral disc herniation, the nucleus pulposus of the intervertebral disc protrudes posterolaterally. The anterior longitudinal ligament traverses the anterior side of the vertebral bodies and thus would not protect the spinal cord from direct compression. The supraspinous and ligamentum flavum ligaments connect the spinous processes and the laminae of adjacent vertebrae, respectively. The nuchal ligament is a continuation of the supraspinous ligaments near the C7 vertebrae and runs to the occipital protuberance. GAS 80-81; N 159; McM 94 18 C. This is the location of the conus medullaris, a tapered conical projection of the spinal cord at its inferior termination. Although the conus medullaris rests at the level of L1 and L2 in adults, it is often situated at L3 in newborns. The cauda equina and filum terminale extend beyond the conus medullaris. GAS 99, 100; N 161; McM 97 19 A. The sympathetic division of the autonomic nervous system is primarily responsible for vasoconstriction. Separation of ventral or dorsal roots would lead to undesired consequences, such as a loss of motor or sensory activity. Similarly, surgical division of spinal nerves would also have unwanted consequences, but such are not related to the increased arterial constriction and the painful ischemia in the digits. Division of selected sympathetic chain ganglia, however, would decrease the sympathetic outflow to the upper limbs. GAS 38-39; N 163; McM 94-95 20 D. The diaphragm is innervated by the phrenic nerve, which arises from C3 to C5. The rhomboid, serratus anterior, supraspinatus, and latissimus dorsi are innervated by the ventral rami of the brachial plexus (C5 to T1). GAS 161-162; N 161; McM 194 21 C. The anterior longitudinal ligament runs along the anterior-most aspect of the vertebral column from C1 to the sacrum and would therefore be unaffected by a laminectomy. Denticulate ligaments extend laterally from the pia mater to the arachnoid mater along the length of the spinal cord. The ligamentum flavum is one of the two ligaments found in the vertebral canal and is adherent to the anterior aspect of the vertebral arches and often greatly thickened in spinal pathology. It is thus simultaneously removed upon excision of the lamina. The nuchal ligament is a thick longitudinal extension continuing from the supraspinous ligament at the level of C7 to the external 23 Back occipital protuberance (inion). The cruciate ligament is an incorrect answer because it is located anterior to the spinal cord, and thus would not be involved in laminectomy. GAS 80; N 159; McM 98 22 C. The vertebral canal is the longitudinal canal that extends through the vertebrae, containing the meninges, spinal cord, and associated ligaments. The internal vertebral venous plexus is the mostly valveless network of veins extending longitudinally along the vertebral canal. Neither of these answer choices describes a specific space. The spinal epidural space is found superficially to the dura mater. It is a fat-filled space extending from C1 to the sacrum. The subarachnoid space is a true space containing CSF. It is found within the CNS and extends to the level of S2. The subdural space is a potential space between the dura and the arachnoid mater. Normally, these two layers are fused due to the pressure of CSF in the subarachnoid space. GAS 103-110; N 166; McM 94, 96 23 A. Lumbar puncture is generally performed at the level of L4 or L5. The supraspinous ligament extends between spinous processes on the dorsal aspect of the vertebrae. The needle will bypass this structure. The denticulate ligaments are not correct because they terminate with the conus medullaris at the level of L2 and are located laterally. The anterior longitudinal ligament extends along the most anterior aspect of the vertebral bodies and can be reached only ventrally. The posterior longitudinal ligament is present at the correct vertebral level but will be punctured only if the procedure is performed incorrectly as in this case, where hematopoietic cells were aspirated from the vertebral body anterior to the ligament. The nuchal ligament extends cranially from the supraspinous ligament in the lower cervical region to the skull. GAS 103-110; N 159; McM 94, 96 24 B. The anterior spinal artery is located anteriorly along the spinal cord and is not directly associated with the vertebrae. The vertebral arteries run through the transverse foramina of cervical vertebrae C6 through C1 and are therefore most closely associated with injury to the transverse processes. The ascending cervical artery is usually a very small branch from the thyrocervical trunk of the subclavian artery, running on the anterior aspect of the vertebrae. The deep cervical artery arises from the costocervical trunk and is also a very small artery and courses along the posterior aspect of the cervical vertebrae. The posterior 24 spinal arteries are adherent to the posterior aspect of the spinal cord. GAS 100; N 167; McM 94-95 25 B. Scoliosis is defined as a lateral deviation of the spinal column to either side. Hyperkyphosis is an increased primary curvature of the spinal column. This curvature is associated with thoracic and sacral regions and is most likely this patient’s clinical condition. Spinal stenosis is a narrowing of the vertebral canal and is not directly associated with a displacement of the spinal column. Hyperlordosis is the increased secondary curvature affecting the cervical and lumbar regions. A herniated disc is a rupture of the anulus fibrosus of the intervertebral disc, commonly causing a posterolateral displacement of the nucleus pulposus into the vertebral canal. GAS 75; N 153; McM 87 26 B. The thoracodorsal nerve innervates the latissimus dorsi, which has no direct action on the shoulder girdle. The spinal accessory nerve is the eleventh cranial nerve (CN XI) and innervates both the trapezius and sternocleidomastoid muscles. The loss of CN XI results in drooping of the shoulder due to paralysis of the trapezius. In addition to the clinical findings of the MRI, one can test the innervation of this nerve by asking the patient to shrug his or her shoulders against resistance (testing the trapezius), as well as turning his or her head against resistance (testing the sternocleidomastoid). The dorsal scapular nerve usually innervates the levator scapulae muscle and the rhomboid muscles. The greater occipital nerve is primarily a sensory nerve innervating the posterolateral aspect of the scalp. The axillary nerve is a branch of the brachial plexus and innervates the deltoid and teres minor muscles. It is not involved in shoulder elevation. GAS 87, 99; N 171; McM 101 27 B. The anterior longitudinal ligament runs on the anterior aspect of the vertebrae and is not affected. The transverse ligament of the atlas anchors the dens laterally to prevent posterior displacement of the dens. This ligament has been torn in this injury. The ligamentum flavum is found on the posterior aspect of the vertebral canal and does not contact the anteriorly placed dens. The supraspinous ligament is located along the spinous processes of the vertebrae. The nuchal ligament is a longitudinal extension of the supraspinous ligament above the level of C7. GAS 80; N 159; McM 97 28 B. The iliocostalis thoracis muscle is found in the deep back and functions to maintain posture. It is Back not associated with neck flexion. The sternocleidomastoid muscle is innervated by CN XI and functions in contralateral rotation (unilateral contraction) and flexion (bilateral contraction) of the neck. Rhomboid major and minor are both innervated by the dorsal scapular nerve and serve to adduct the scapulae. Teres major is innervated by the lower subscapular nerve and serves to medially rotate and adduct the humerus. GA 93-97; N 171; McM 101 29 C. The pedicles are bony structures connecting the vertebral arches to the vertebral body. The ligamentum flavum runs on the posterior aspect of the vertebral canal and is more closely associated with the laminae than to the pedicles of the vertebrae. The nuchal ligament is a longitudinal extension of the supraspinous ligament from C7 to the occiput, both running on the most posterior aspect of the vertebrae along the spinous processes. The cruciform (also called cruciate or transverse ligament of the atlas) ligament is a stabilizing ligament found at the skull base and C1/C2. It attaches to the pedicles and helps stabilize the dens. The posterior longitudinal ligament extends the length of the anterior aspect of the vertebral canal and is anterior to the pedicles. GAS 68-69; N 23; McM 85 30 A. Spondylolysis is the anterior displacement of one or more vertebrae. This is most commonly seen with the cervical vertebrae because of their small size and structure and the oblique angle of the articular facets. Lumbar vertebrae are somewhat susceptible to this problem because of the pressures at lower levels of the spine and the sagittal angles of the articular facets. It is much less common in the thoracic vertebrae due to the stabilizing factor of the ribs. It is not seen in the sacral vertebrae because they are fused together. GAS 82-83; N 153; McM 86 31 D. The internal vertebral plexus (of Batson) surrounds the dura mater in the spinal epidural space; hence the bleeding would cause the hematoma in that space. The subarachnoid space, containing the CSF, is located between pia and arachnoid mater. A subarachnoid hemorrhage would most likely result from a ruptured intercerebral aneurysm. A subdural hematoma would result most likely from a venous bleed from a torn cerebral vein as it enters the superior sagittal venous sinus within the skull. The central canal is located within the gray matter of the spinal cord. The lumbar cistern is an enlargement of the subarachnoid space between the conus medullaris of the spinal cord and the caudal end of the subarachnoid space. GAS 102; N 169; McM 108 32 D. In the lumbar region spinal nerves exit the vertebral column below their named vertebrae. In an L4, L5 intervertebral disc herniation, the L5 spinal nerve would be affected as it descends between L4, L5 vertebrae to exit below the L5 level. L2, L3, and L4 spinal nerves have already exited above the level of herniation; therefore, they would not be affected by this herniation. An “L6” spinal nerve normally does not exist. (The National Board of Medical Examiners does not allow “made up” structures, but in cases of lumbarization of S1, some people recognize an L6 nerve.) GAS 79, 108; N 161; McM 97 33 E. Posterior intercostal arteries supply the deep back muscles, which are responsible for extending and laterally bending the trunk. The subscapular artery supplies the subscapularis muscle, the thoracodorsal artery supplies the latissimus dorsi, the anterior intercostal supplies the upper nine intercostal spaces, and the suprascapular artery supplies the supraspinatus and infraspinatus muscles. These muscles are not responsible for extension and lateral flexion of the trunk. GAS 100-101; N 168; McM 102 34 A. The atlantoaxial joint is a synovial joint responsible for rotation of the head, not flexion, abduction, extension, or adduction. The atlantooccipital joint is primarily involved in flexion and extension of the head on the neck. GAS 71; N 19; McM 85 35 D. The internal vertebral plexus (of Batson) lies external to the dura mater in the epidural space. To aspirate excess blood, the physician must pass the needle through the ligamentum flavum to reach the epidural space wherein the blood would accumulate. The spinal cord, pia mater, and arachnoid mater are located deep to the epidural space. GAS 102; N 169; McM 97 36 E. The T4 thoracic vertebra articulates with the head of the fifth rib. The head of the rib has two facets. The rib articulates with the superior facet on the body of its own vertebra (the fourth rib articulates with the superior facet T4 vertebra) and with the inferior facet on the body of the vertebra above (the fourth rib articulates with the inferior facet of T3 vertebra). Taking the T4 vertebra into consideration, 25 Back the superior facet of this vertebra articulates with the head of the fourth rib and the inferior facet articulates with the head of the fifth rib. The head of the fourth rib has two points of articulation (a joint with the vertebral body and a costotransverse joint) on T4, so when it is injured it moves as a unit, whereas the fifth rib has only one articulation with T4. GAS 124; N 183; McM 174 37 E. The teres major is responsible for adduction and medial rotation of the humerus, the teres minor is responsible for lateral rotation of the humerus, the triceps brachii is responsible for extension of the forearm, the supraspinatus is responsible for the first 0 to 15 degrees of abduction, and the infraspinatus is a lateral rotator. GAS 717; N 171; McM 103 38 B. The infraspinatus is responsible for lateral rotation of the humerus (along with the teres minor, not a choice here). The teres major is responsible for adduction and medial rotation of the humerus. The latissimus dorsi is responsible for adduction, extension, and medial rotation of the humerus. The trapezius is an elevator of the scapula and rotates the scapula during abduction of the humerus above the horizontal plane. The supraspinatus is responsible for the first 0 to 15 degrees of abduction. GAS 717; N 171; McM 102 39 A. When a lumbar puncture is performed, the needle must penetrate the ligamentum flavum, the dura mater, and finally the arachnoid mater to reach the subarachnoid space where the CSF is located. The lumbar cistern is a continuation of the subarachnoid space below the conus medullaris. The pia mater is adherent to the spinal cord, and the posterior longitudinal ligament is attached to the posterior aspect of the vertebral bodies. GAS 106, 114-116; N 161; McM 97 40 C. The subarachnoid space, containing the CSF, is located between the pia and the arachnoid mater. Neither the epidural space, the subdural space, nor the pretracheal space contains CSF. Although the central canal, contained within the substance of the spinal cord, does contain CSF, extraction of CSF from this space would result in spinal cord injury. CSF circulates within the subarachnoid space and can be aspirated only from that location. The subdural space is only a potential space between the dura and arachnoid mater. The epidural space contains the epidural fat and Batson’s venous plexus and is the site to 26 inject an anesthetic for epidural anesthesia. CSF is not located in the pretracheal space. GAS 106; N 166; McM 97 41 A. General somatic afferent fibers are conveyed from the skin of the back via the dorsal primary rami. Communicating rami contain general visceral efferent (sympathetic) fibers and general visceral afferent fibers of the autonomic nervous system. Ventral primary rami convey mixed spinal nerves to/from all other parts of the body excluding the back, and parts of the head innervated by cranial nerves. The ventral roots contain only efferent (motor) fibers. Intercostal nerves are the ventral rami of T1 to T11. The ventral ramus of T12 is the subcostal nerve. GAS 32-48; N 177; McM 98 42 D. The conus medullaris is usually located at the L1 to L2 vertebral level; therefore, any choice that contains that region is the correct answer. L3 to L4 is a common location to perform lumbar puncture, but it is caudal to the apex of the conus medullaris. L3 and L4 are caudal to the conus medullaris. T11 is superior to the conus medullaris. GAS 99-110; N 161, 163, 164; McM 97 43 D. Because the meninges and spinal cord are included in the protrusion, the patient’s condition is a classic presentation of spina bifida with myelomeningocele. If the protrusion contains only meninges but no CNS tissue, it is known as spina bifida with meningocele. Meningitis is an inflammation of the meninges caused by bacteria, viral, or numerous other irritants (e.g., blood). It does not cause deformation of the vertebrae or result in protrusion of spinal cord contents. Spina bifida occulta is a normally asymptomatic condition in which the vertebral laminae fail to fuse completely during embryologic development. A tuft of hair is commonly seen growing over the affected region (usually lumbar in position). GAS 74; N 160; McM 97 44 C. Somatic afferent fibers convey localized pain, typically from the body wall and limbs. Visceral afferents convey autonomic nervous system sensory information. Pain from these fibers will present as dull and diffuse. Somatic efferent fibers convey motor information to skeletal muscle. Sympathetic preganglionic fibers are visceral efferent fibers and do not contain sensory information. Parasympathetic preganglionic fibers are also visceral efferents and do not contain sensory information. GAS 32-48; N 174; McM 97 Back 45 B. Lateral flexion is the best answer because other movements of the lumbar portion of the vertebral column are very limited due to the orientation of the articular facets. GAS 64-73; N 155; McM 97 46 D. Batson’s venous plexus, in general, is a valveless network of veins located in the epidural space of the vertebral canal. The lack of valves can provide a route for the metastasis of cancer (e.g., from prostate or breast to brain) because the flow of blood is bidirectional due to local pressures. The length of Batson’s plexus is irrelevant to the question. B is incorrect because Batson’s plexus, in general, does not have valves or one-way movement of blood. Batson’s plexus is located within the epidural space, not the subarachnoid or subdural spaces. GAS 102; N 169; McM 88 4