Heung Sik Kang Joon Woo Lee Jong Won Kwon Radiology

123

Heung Sik KangJoon Woo Lee Jong Won Kwon

Radiology Illustrated Spine

Radiology Illustrated

For further volumes:http://www.springer.com/series/11755

Heung Sik Kang • Joon Woo Lee • Jong Won Kwon

Radiology Illustrated: Spine

Heung Sik Kang Department of Radiology Seoul National University Bundang Hospital Seongnam , Kyonggi-do , Republic of Korea

Joon Woo Lee Department of Radiology Seoul National University Bundang Hospital Seongnam , Kyonggi-do , Republic of Korea

Jong Won Kwon Department of Radiology Samsung Medical Center Seoul Republic of Korea

ISBN 978-3-642-35628-5 ISBN 978-3-642-35629-2 (eBook) DOI 10.1007/978-3-642-35629-2 Springer Heidelberg New York Dordrecht London

Library of Congress Control Number: 2014931859

© Springer-Verlag Berlin Heidelberg 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher's location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.

Printed on acid-free paper

Springer is part of Springer Science+Business Media (www.springer.com)

www.springer.com

To my co-authors Joon Woo Lee and Jong Won Kwon, whose enthusiasm and excellence in the spinal imaging made publication of this book possible.

HSK

To God, for his eternal love and support. To my parents, Lee and Kwack, for their support and understanding. To my wife, Cho, for her love and support. To my children, Ha-yeon and Se-yeon, for their love.

JWL

With love to my devoted wife, Jungwon, my bright and clever son, Sunghyun, and my lovely daughter, Seongju, for their support, understanding, and patience. Thanks to the God Almighty.

JWK

vii

Spinal disorders constitute one of the most commonly encountered ailments, affecting up to 80 % of the population worldwide, and are a major cause of disability and economic loss. The prevalence of spinal problems has increased signifi cantly with a growing proportion of elderly people in the general population. Correspondingly, many physicians and radiologists face a large workload of spinal imaging as part of their daily practice. There is however a limited number of textbooks available for clinicians and radiology trainees who are interested in embarking on a self-learning course in spinal imaging interpretation. With this point in mind, this book aims to cover most of the common and critical spinal disorders by presenting numer-ous representative cases and providing practical tips. This book also addresses many of the common questions that have been asked of the authors by their clinical colleagues over the course of their years of practice.

There are two characteristic features of Radiology Illustrated: Spine . First, this book is aimed to facilitate self-learning. To enhance the reader’s understanding of key concepts, more than 1,300 fi gures, many tables and schematic illustrations are included. We provide essential practical tips from three experienced radiologists and present up-to-date information of critical and distinctive spinal disorders. Second, this book focuses on entities that would expectedly be seen in the course of routine practice rather than the esoteric. The book starts off by presenting the common spinal disorders and concludes by describing differential points between similar spinal disorders.

This book is intended for all physicians and radiologists caring for patients with spinal problems. We hope readers will be as richly rewarded on this self-learning journey from the fi rst through to the last case as it has been for the authors over the course of preparation of this book.

Finally, we thank Dr. Le Roy Chong for his assistance in editing of the manuscript.

Seongnam, Kyonggi-do, Korea, Republic of (South Korea) Heung Sik Kang Seongnam, Kyonggi-do, Korea, Republic of (South Korea) Joon Woo Lee Seoul, Korea, Republic of (South Korea) Jong Won Kwon

Pref ace

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Contents

Part I Basic Step: Common Spinal Disorders

1 Anatomic Considerations of the Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.1 Osseous Structure and Facet (Zygapophyseal) Joints . . . . . . . . . . . . . . . . . 41.2 Intervertebral Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Uncovertebral Joint (Joint of Luschka) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 Central Canal and Neural Foramen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 Spinal Cord, Conus Medullaris, Cauda Equina,

and Spinal Nerve Roots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.6 Ligaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.7 Illustrations: Anatomical Considerations of the Spine . . . . . . . . . . . . . . . . . 6

1.7.1 Normal Anatomy of the Spine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.7.2 Intervertebral Diskal and Ligamentous Anatomy on MR . . . . . . . . 91.7.3 Cervical Spine Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.7.4 Spinal Cord and Nerve Root Anatomy . . . . . . . . . . . . . . . . . . . . . . 12

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2 Common Spine Disorders Associated with Back Pain . . . . . . . . . . . . . . . . . . . . . 172.1 Lumbar Spine MR in Patients with Back Pain:

What Should We Focus on? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.2 Herniated Intervertebral Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.3 Spinal Stenosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.4 Alignment Disorders (Spondylolisthesis, Scoliosis, Kyphosis) . . . . . . . . . . 192.5 Degenerative Changes of the Posterior Elements

(Facet Joint Arthrosis, Baastrup’s Phenomenon) . . . . . . . . . . . . . . . . . . . . . 202.6 Illustrations: Common Spine Disorders Associated with Back Pain . . . . . . 21

2.6.1 Schematic Illustrations of the Nomenclature for Disk Herniation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.6.2 Herniated Intervertebral Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242.6.3 Lumbar Central Canal Stenosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382.6.4 Lumbar Foraminal Stenosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432.6.5 Spondylolysis/Spondylolisthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 472.6.6 Degenerative Changes of the Posterior Elements . . . . . . . . . . . . . . 56

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3 Common Spine Disorders Associated with Neck Pain . . . . . . . . . . . . . . . . . . . . . 613.1 Cervical Spine Imaging in Patients with Neck Pain:

What Should We Focus on? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623.2 Cervical Spondylotic Myelopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623.3 Cervical Spondylotic Radiculopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633.4 Herniated Intervertebral Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

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3.5 Illustrations: Common Spine Disorders Associated with Neck Pain . . . . . . 643.5.1 Cervical Spondylotic Myelopathy . . . . . . . . . . . . . . . . . . . . . . . . . . 643.5.2 Cervical Spondylotic Radiculopathy . . . . . . . . . . . . . . . . . . . . . . . . 693.5.3 Herniated Intervertebral Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

4 Common Traumatic Disorders of the Thoracolumbar Spine . . . . . . . . . . . . . . . 814.1 Stable and Unstable Spinal Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 824.2 Major Thoracolumbar Injury: Denis Classifi cation . . . . . . . . . . . . . . . . . . . 824.3 Benign Osteoporotic Versus Malignant Compression Fractures . . . . . . . . . 834.4 Sacral Insuffi ciency Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844.5 Illustrations: Common Traumatic Disorders of the

Thoracolumbar Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854.5.1 Compression Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854.5.2 Burst Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874.5.3 Distraction Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 914.5.4 Malignant Spine Fracture Due to Metastasis . . . . . . . . . . . . . . . . . 954.5.5 Sacral Insuffi ciency Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

5 MR Imaging of Spinal Bone Marrow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1035.1 Marrow Conversion in the Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1045.2 Inhomogeneous Marrow Signal on MR Images . . . . . . . . . . . . . . . . . . . . . . 1045.3 Marrow Infi ltrative Disorders: Proliferative, Replacement,

Depletion Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1055.4 Illustrations: MR Imaging of Spinal Bone Marrow . . . . . . . . . . . . . . . . . . . 106

5.4.1 Marrow Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1065.4.2 Inhomogeneous Bone Marrow Signal . . . . . . . . . . . . . . . . . . . . . . . 1185.4.3 Marrow Infi ltrative Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6 Common Normal Structures and MR Imaging Artifacts of the Spine That May Mimic Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1296.1 Common Normal Structures and Variants Mimicking

Spinal Disorders on MRI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1306.2 Common MR Artifacts on Spinal Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . 130

6.2.1 Chemical Shift Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1306.2.2 Susceptibility Artifacts Due to Metallic Implants . . . . . . . . . . . . . . 1306.2.3 Truncation Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1306.2.4 Aliasing Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1316.2.5 Motion-Related Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1316.2.6 Saturation Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1316.2.7 Artifacts Due to Radio-Frequency Interference . . . . . . . . . . . . . . . 1316.2.8 Artifacts Due to Incomplete Fat Saturation . . . . . . . . . . . . . . . . . . . 131

6.3 Illustrations: Common Normal Structures and MR Imaging Artifacts of the Spine That May Mimic Pathology . . . . . . . . . . . . . . . . . . . 1336.3.1 Common Normal Structures and Variants Mimicking

Spinal Disorders on MRI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1336.3.2 Chemical Shift Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1356.3.3 Susceptibility Artifact Due to Metallic Implants . . . . . . . . . . . . . . 1366.3.4 Truncation Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Contents

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6.3.5 Aliasing Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1416.3.6 Motion-Related Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1426.3.7 Saturation Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1496.3.8 Artifacts Due to Radio-Frequency Interference . . . . . . . . . . . . . . . 1506.3.9 Artifacts Due to Incomplete Fat Saturation . . . . . . . . . . . . . . . . . . . 151

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7 Postoperative Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1537.1 Normal Post-diskectomy Changes Versus Residual Disk Herniation . . . . . 1547.2 Normal Postoperative Change Versus Early

Postoperative Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1547.3 Postoperative Scarring Versus Recurrent Disk Herniation . . . . . . . . . . . . . . 1547.4 Postoperative Pseudomeningocele Versus Postoperative

Fluid Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1547.5 Fusion Versus Pseudoarthrosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557.6 Adjacent Segment Degeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557.7 Illustrations: Post-operative Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

7.7.1 Normal Postoperative Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1567.7.2 Postoperative Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1617.7.3 Postoperative Scarring Versus Recurrent Disk Herniation . . . . . . . 1647.7.4 Postoperative Pseudomeningocele Versus Postoperative

Fluid Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1697.7.5 Fusion Versus Pseudoarthrosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1747.7.6 Miscellaneous Postoperative Complications . . . . . . . . . . . . . . . . . . 179

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

Part II Intermediate Step: Critical Spinal Disorders

8 Infectious Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1898.1 Pathophysiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1908.2 Pyogenic Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1908.3 Tuberculous Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1918.4 Fungal Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1928.5 Illustrations: Infectious Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

8.5.1 Pyogenic Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1938.5.2 Tuberculous Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1998.5.3 Fungal Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

9 Cervical Trauma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2139.1 Upper Cervical Spine (Occiput (C0)–C1–C2) . . . . . . . . . . . . . . . . . . . . . . . 214

9.1.1 Atlanto-occipital Dislocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2149.1.2 Atlas Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2149.1.3 Atlantoaxial Rotatory Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2149.1.4 Odontoid Process (Dens) Fractures . . . . . . . . . . . . . . . . . . . . . . . . . 2149.1.5 Hangman’s Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

9.2 Lower (Subaxial) Cervical Spine (C3–C7) . . . . . . . . . . . . . . . . . . . . . . . . . 2159.2.1 Flexion Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2159.2.2 Flexion–Rotation Injuries (Unilateral Facet Dislocation) . . . . . . . . 2169.2.3 Extension Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2169.2.4 Vertical Compression Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

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9.3 Spinal Cord Contusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2179.4 Epidural Versus Subdural Hematoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2179.5 Subarachnoid Hemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2179.6 Illustration: Cervical Trauma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

9.6.1 Atlanto-occipital Dislocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2199.6.2 Atlas Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2209.6.3 Atlantoaxial Rotatory Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2229.6.4 Odontoid Process Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2239.6.5 Hangman’s Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2289.6.6 Hyperfl exion Injury of Cervical Spine . . . . . . . . . . . . . . . . . . . . . . 2319.6.7 Hyperextension Injury of Cervical Spine . . . . . . . . . . . . . . . . . . . . 2389.6.8 Intraspinal Hemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

10 Spinal Cord Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24910.1 Spinal Cord Tumors Versus Nonneoplastic Myelopathies . . . . . . . . . . . . . . 25010.2 Common Neoplasms of the Spinal Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

10.2.1 Ependymoma Versus Astrocytoma . . . . . . . . . . . . . . . . . . . . . . . . . 25010.2.2 Hemangioblastoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

10.3 Acute Transverse Myelitis Versus Multiple Sclerosis . . . . . . . . . . . . . . . . . 25110.4 Neuromyelitis Optica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25110.5 Acute Disseminated Encephalomyelitis (ADEM) . . . . . . . . . . . . . . . . . . . . 25110.6 Acute Spinal Cord Infarction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25210.7 Syringomyelia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25210.8 Illustration: Spinal Cord Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

10.8.1 Common Neoplasms of the Spinal Cord . . . . . . . . . . . . . . . . . . . . . 25310.8.2 Acute Transverse Myelitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26010.8.3 Multiple Sclerosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26310.8.4 Neuromyelitis Optica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26610.8.5 Acute Disseminated Encephalomyelitis . . . . . . . . . . . . . . . . . . . . . 26810.8.6 Acute Spinal Cord Infarction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26910.8.7 Subacute Combined Degeneration . . . . . . . . . . . . . . . . . . . . . . . . . 27410.8.8 Compressive Myelopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27510.8.9 Syringomyelia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

11 Spinal Tumor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28311.1 Primary Spinal Bone Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

11.1.1 Multiplicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.2 Clinical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.3 Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.4 Margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.5 Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.6 Pattern of Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28511.1.7 Signal Intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

11.2 Hematologic Malignancies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28611.2.1 Multiple Myeloma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28611.2.2 Spinal Lymphoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28611.2.3 Leukemia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

11.3 Intradural Extramedullary Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28611.4 Intradural Metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

11.4.1 Leptomeningeal Seeding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28711.4.2 Intramedullary Metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

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11.5 Illustration: Tumor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28811.5.1 Bone Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28811.5.2 Hemangioma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29011.5.3 Osteoblastoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29511.5.4 Osteoid Osteoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29811.5.5 Aneurysmal Bone Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30011.5.6 Giant Cell Tumor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30311.5.7 Fibrous Dysplasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30511.5.8 Langerhans Cell Histiocytosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 30811.5.9 Chordoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31111.5.10 Chondrosarcoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31311.5.11 Osteosarcoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31511.5.12 Ewing Sarcoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31811.5.13 Multiple Myeloma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32011.5.14 Lymphoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32411.5.15 Neurogenic Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32811.5.16 Meningioma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33111.5.17 Metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339

12 Congenital Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34112.1 Embryology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34212.2 Myelocele/Myelomeningocele . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34212.3 Lipomyelocele/Lipomyelomeningocele . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34212.4 Meningocele . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34312.5 Myelocystocele . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34312.6 Intradural Lipoma/Fibrolipoma of the Filum Terminale . . . . . . . . . . . . . . . 34312.7 Dorsal Dermal Sinus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34312.8 Diastematomyelia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34312.9 Neurenteric Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34412.10 Caudal Regression Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34412.11 Tethered Cord Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34412.12 Congenital Vertebral Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34412.13 Illustration: Congenital Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

12.13.1 Myelocele/Myelomeningocele . . . . . . . . . . . . . . . . . . . . . . . . . . . 34512.13.2 Lipomyelocele/Lipomyelomeningocele . . . . . . . . . . . . . . . . . . . . 35012.13.3 Intradural Lipoma/ Lipoma of the Filum Terminale . . . . . . . . . . 35612.13.4 Dorsal Dermal Sinus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36012.13.5 Diastematomyelia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36212.13.6 Neurenteric Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36512.13.7 Caudal Regression Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36612.13.8 Congenital Vertebral Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . 367

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

13 Uncommon Degenerative Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37113.1 Ossifi cation of the Posterior Longitudinal Ligament (OPLL) . . . . . . . . . . . 37213.2 Ossifi cation of the Ligamentum Flavum (OLF) . . . . . . . . . . . . . . . . . . . . . . 37213.3 Diffuse Idiopathic Skeletal Hyperostosis (DISH) . . . . . . . . . . . . . . . . . . . . 37213.4 Scheuermann’s Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37313.5 Baastrup’s Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37313.6 Epidural Lipomatosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37313.7 Illustration: Uncommon Degenerative Disorder . . . . . . . . . . . . . . . . . . . . . 374

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13.7.1 Ossifi cation of Posterior Longitudinal Ligament (OPLL) . . . . . . . 37413.7.2 Ossifi cation of Ligamentum Flavum . . . . . . . . . . . . . . . . . . . . . . . . 37713.7.3 Diffuse Idiopathic Skeletal Hyperostosis (DISH) . . . . . . . . . . . . . . 37913.7.4 Scheuermann’s Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38313.7.5 Baastrup’s Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38513.7.6 Epidural Lipomatosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390

14 Infl ammatory Arthritides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39114.1 Spondyloarthropathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

14.1.1 Ankylosing Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39214.1.2 Psoriatic Arthritis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

14.2 SAPHO Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39314.3 Rheumatoid Arthritis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39414.4 Illustrations: Infl ammatory Arthritides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

14.4.1 Ankylosing Spondylitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39514.4.2 Psoriatic Arthritis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40814.4.3 SAPHO Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41214.4.4 Rheumatoid Arthritis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419

15 Spinal Vascular Malformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42115.1 Vascular Anatomy and Imaging Modalities . . . . . . . . . . . . . . . . . . . . . . . . . 42215.2 Dural Arteriovenous (AV) Fistula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42315.3 Spinal Cord Arteriovenous Malformation (AVM) . . . . . . . . . . . . . . . . . . . . 42315.4 Juxtamedullary (Perimedullary) AV Fistula . . . . . . . . . . . . . . . . . . . . . . . . . 42315.5 Intramedullary Cavernous Hemangioma . . . . . . . . . . . . . . . . . . . . . . . . . . . 42415.6 Illustrations: Infl ammatory Arthritides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425

15.6.1 Normal Vascular Anatomy and Schematic Diagrams . . . . . . . . . . . 42515.6.2 Dural Arteriovenous Fistula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42815.6.3 Spinal Arteriovenous Malformation . . . . . . . . . . . . . . . . . . . . . . . . 43115.6.4 Spinal Perimedullary Arteriovenous Fistula . . . . . . . . . . . . . . . . . . 43315.6.5 Spinal Cord Cavernous Angioma . . . . . . . . . . . . . . . . . . . . . . . . . . 434

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436

Part III Rare but Characteristic Spinal Disorders

16 Rare but Characteristic Spinal Disorders: Musculoskeletal . . . . . . . . . . . . . . . . 43916.1 Neuropathic Arthropathy of the Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44016.2 Abdominal Aortic Aneurysm Causing Vertebral Body Destruction . . . . . . 44016.3 Benign Notochordal Cell Tumor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44016.4 Os Odontoideum/Ossiculum Terminale . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44016.5 Condylus Tertius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44116.6 Paget Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44116.7 Rhabdomyolysis of the Back Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44116.8 Calcifi c Tendinitis of Longus Colli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44216.9 Illustrations: Rare but Characteristic Spinal Disorders:

Musculoskeletal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44316.9.1 Neuropathic Arthropathy of the Spine . . . . . . . . . . . . . . . . . . . . . . 44316.9.2 Abdominal Aortic Aneurysm Causing

Vertebral Body Destruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44416.9.3 Benign Notochordal Cell Tumor . . . . . . . . . . . . . . . . . . . . . . . . . . . 44516.9.4 Os Odontoideum/Ossiculum Terminale . . . . . . . . . . . . . . . . . . . . . 44616.9.5 Condylus Tertius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449

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16.9.6 Paget Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45116.9.7 Rhabdomyolysis of the Back Muscles . . . . . . . . . . . . . . . . . . . . . . 45516.9.8 Calcifi c Tendinitis of Longus Colli . . . . . . . . . . . . . . . . . . . . . . . . . 456

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460

17 Rare but Characteristic Spinal Disorders: Neural . . . . . . . . . . . . . . . . . . . . . . . . 46117.1 Idiopathic Spinal Cord Herniation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46217.2 Hirayama Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46217.3 Subacute Combined Degeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46217.4 Radiation Myelitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46317.5 Spinal Visceral Larva Migrans of Toxocara canis . . . . . . . . . . . . . . . . . . . . 46317.6 Conjoined Nerve Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46317.7 Guillain–Barré Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46317.8 Hereditary Motor and Sensory Neuropathies (HMSN) . . . . . . . . . . . . . . . . 46417.9 Illustrations: Rare but Characteristic Spinal Disorders: Neural . . . . . . . . . . 465

17.9.1 Idiopathic Spinal Cord Herniation . . . . . . . . . . . . . . . . . . . . . . . . . 46517.9.2 Hirayama Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46917.9.3 Subacute Combined Degeneration . . . . . . . . . . . . . . . . . . . . . . . . . 47117.9.4 Radiation Myelitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47417.9.5 Spinal Visceral Lava Migrans of Toxocara canis . . . . . . . . . . . . . . 47717.9.6 Conjoined Nerve Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47917.9.7 Guillain–Barré Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48217.9.8 Hereditary Motor and Sensory Neuropathies . . . . . . . . . . . . . . . . . 485

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488

18 Rare but Characteristic Spinal Disorders: Miscellaneous . . . . . . . . . . . . . . . . . . 48918.1 Neurofi bromatosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49018.2 Marfan Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49018.3 Idiopathic Hypertrophic Pachymeningitis . . . . . . . . . . . . . . . . . . . . . . . . . . 49018.4 Spontaneous Intracranial Hypotension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49018.5 Superfi cial Siderosis Caused by Spinal Tumor . . . . . . . . . . . . . . . . . . . . . . 49118.6 Spinal Arachnoid Cysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49118.7 Renal Osteodystrophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49118.8 Extramedullary Hematopoiesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49218.9 Illustrations: Rare but Characteristic Spinal Disorders:

Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49318.9.1 Neurofi bromatosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49318.9.2 Marfan Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49918.9.3 Idiopathic Hypertrophic Pachymeningitis . . . . . . . . . . . . . . . . . . . . 50018.9.4 Spontaneous Intracranial Hypotension . . . . . . . . . . . . . . . . . . . . . . 50318.9.5 Superfi cial Siderosis Caused by Spinal Tumor . . . . . . . . . . . . . . . . 50518.9.6 Spinal Arachnoid Cysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50618.9.7 Renal Osteodystrophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51218.9.8 Extramedullary Hematopoiesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516

Part IV Similar Spinal Disorders

19 Practical Tips for Differential Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51919.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52019.2 Herniated Disk (Sequestration) Versus Schwannoma . . . . . . . . . . . . . . . . . 52119.3 Spondylolytic Spondylolisthesis Versus Degenerative

Spondylolisthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52219.4 Focal Red Marrow Versus Metastasis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523

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19.5 Postoperative Scar Versus Recurrent Disk Herniation . . . . . . . . . . . . . . . . . 52419.6 Benign Vertebral Fracture Versus Malignant Vertebral Fracture . . . . . . . . . 52519.7 Os Odontoideum Versus Odontoid Process Fracture . . . . . . . . . . . . . . . . . . 52619.8 Neurofi bromatosis Type 1 Versus Type 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 52719.9 Infectious Spondylitis Versus Modic Type 1 . . . . . . . . . . . . . . . . . . . . . . . . 52819.10 Spinal Cord Herniation Versus Intradural Arachnoid Cyst . . . . . . . . . . . . . 52919.11 Spinal Arteriovenous Fistula Versus Hypervascular Tumor

with Intratumoral Shunt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53019.12 Ankylosing Spondylitis (AS) Versus Diffuse Idiopathic

Skeletal Hyperostosis (DISH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53119.13 Pyogenic Spondylitis Versus Tuberculous Spondylitis . . . . . . . . . . . . . . . . 53219.14 Spinal Cord Tumor Versus Nonneoplastic Myelopathy . . . . . . . . . . . . . . . . 53319.15 Acute Transverse Myelitis Versus Multiple Sclerosis . . . . . . . . . . . . . . . . . 53419.16 Ependymoma Versus Astrocytoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53519.17 Schwannoma Versus Meningioma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53619.18 Sacral Tumors: Chordoma Versus Giant Cell Tumor . . . . . . . . . . . . . . . . . . 53719.19 Vertebral Hemangioma Versus Paget Disease . . . . . . . . . . . . . . . . . . . . . . . 53819.20 Sacroiliitis of Spondyloarthropathy vs. Osteitis Condensans Ilii . . . . . . . . . 53919.21 Sacral Insuffi ciency Fracture Versus Sacral Osteomyelitis . . . . . . . . . . . . . 540

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541

Contents

Part I

Basic Step: Common Spinal Disorders

3H.S. Kang et al., Radiology Illustrated: Spine, Radiology Illustrated,DOI 10.1007/978-3-642-35629-2_1, © Springer-Verlag Berlin Heidelberg 2014

Anatomic Considerations of the Spine 1

Contents

1.1 Osseous Structure and Facet (Zygapophyseal) Joints ................................................................ 4

1.2 Intervertebral Disk ......................................................................................................................... 4

1.3 Uncovertebral Joint (Joint of Luschka) ....................................................................................... 4

1.4 Central Canal and Neural Foramen ............................................................................................. 5

1.5 Spinal Cord, Conus Medullaris, Cauda Equina, and Spinal Nerve Roots ............................... 5

1.6 Ligaments ........................................................................................................................................ 5

1.7 Illustrations: Anatomic Considerations of the Spine .................................................................. 61.7.1 Normal Anatomy of the Spine ......................................................................................................... 61.7.2 Intervertebral Diskal and Ligamentous Anatomy on MR ................................................................ 91.7.3 Cervical Spine Anatomy .................................................................................................................. 111.7.4 Spinal Cord and Nerve Root Anatomy ............................................................................................ 12

References ................................................................................................................................................... 15

4

Each vertebra is composed of a vertebral body, vertebral arch, and bony appendages. The superior and inferior articular pro-cesses make up the zygapophyseal (facet) joint. Each vertebra has two sets of facet joints. The pars interarticularis is the nar-rowed portion of the vertebral arch between the superior and inferior articular processes. The neural foramen is bounded by the pedicles of the corresponding upper and lower verte-bral levels. Normally, the intervertebral disk shows central T2 hyperintensity and peripheral T2 hypointensity. The spi-nal nerve roots are named with respect to the corresponding lower vertebral level from C1 to C7 and to the corresponding upper vertebral level from T1 to S5, due to the C8 nerve root situated between the C7 and T1 vertebrae.

1.1 Osseous Structure and Facet (Zygapophyseal) Joints

The spine is made up of 32 or 33 vertebral segments, with 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 3–4 coccygeal vertebrae. Each vertebra is composed of a vertebral body, vertebral arch, and bony appendages. The vertebral body is comprised of outer cortical and inner trabecular bone, with bone marrow within the vertebral body. The vertebral arch is situated posterior to the vertebral body and made up of two pedicles anteriorly (one on each side) and the lamina poste-riorly. The pedicle is composed of cortical bone and connects the vertebral body with the lamina. The transverse process and superior and inferior articular processes arise near the junction of the pedicle and lamina (LaMasters and Dorwart 1985 ). The pars interarticularis is the narrowed portion of bone between the superior and inferior articular processes. Spondylolysis refers to a defect of the pars interarticularis and mostly involves the lower lumbar spine (most frequently at L5) (Grogan et al. 1982 ; Grenier et al. 1989 ).

The articulations of the spinal motion segment consist of the intervertebral disk in the anterior column and the zyg-apophyseal joints in the posterior column ( Del Grande et al. 2012 ). The superior and inferior articular processes make up the zygapophyseal joint (Z-joint, or the so-called facet joint). Each vertebra has two sets of facet joints, one on each side. Facet joints are hinge-like and link adjacent vertebrae together. The facet joint is a true synovial joint containing hyaline cartilaginous articular surfaces and synovial fl uid and is bounded by a joint capsule. The cervical facet joints are aligned mainly in a horizontal direction, while the tho-racic and lumbar facet joints are mainly in a vertical direc-tion. The thoracic facet joints are oriented in the coronal plane; the lumbar facets are orientated in the sagittal plane, with the upper lumbar facet joints in the parasagittal plane and the lower lumbar facet joints in an oblique sagittal plane directed anteromedially. In reality, most facet joints are ori-ented between the horizontal and vertical planes, thus allow-ing for some movement in each direction. The joint spaces and synovium of the lumbar facet joints extend beyond the

margins of the articular surfaces in the majority of adults. Extensions of the synovium and joint space along the supe-rior and inferior articular processes, under the ligamentum fl avum and into the ligamentum fl avum, may be recognized on MR and CT. On the ventral aspect of the lumbar facet joint, MR images showed regions of T2 hyperintensity where the joint space extends into the ligamentum fl avum or between the ligamentum fl avum and lamina. On the dorsal aspect of the joint, MR demonstrates prominence of the fi brous joint capsule with the joint space extending under it along the inferior articular process or superior articular pro-cess (Xu et al. 1990 ).

1.2 Intervertebral Disk

The major components of the intervertebral disk space are the hyaline cartilaginous endplates of the adjacent vertebral bodies, the gelatinous core of the intervertebral disk (nucleus pulposus), and its circumferential thick fi brous ring (annulus fi brosus) (Rumboldt 2006 ). The nucleus pulposus has a high water content (85–90 %) and performs the role of a shock absorber to distribute axial loading evenly to the outer annu-lus. Proteoglycans constitute about 65 % of the dry weight of the nucleus with collagen comprising 15–20 % (Del Grande et al. 2012 ). The annulus fi brosus is composed of about 20 fi brocartilaginous circular lamellae, containing part of the nucleus pulposus. The annulus fi brosus resists radial tension caused by axial loading, as well as resisting torsion and fl ex-ion. The normal intervertebral disk in adults is of slightly lower signal intensity than the bone marrow on T1-weighted images, with higher signal on T2-weighted images (Castillo et al. 1990 ). Normally, the intervertebral disk shows central T2 hyperintensity and peripheral T2 hypointensity. The cen-tral T2 hyperintensity area refl ects the central nucleus pulpo-sus and inner annulus fi brosus. A dark horizontal signal zone within the central high signal of the disk represents early degeneration of the nucleus pulposus, which is a common fi nding after the third decade of life (termed the “intranuclear cleft”) (Aguila et al. 1985 ). The cartilaginous endplate is between 0.6 and 1.0 mm thick and composed of hyaline car-tilage and fi brocartilage. As the disk degenerates, the fi bro-cartilage dominates. The endplate is tightly bound to the disk and less fi rmly fi xed to the underlying subchondral bone. The intimate contact of the endplate with subchondral bone marrow is critical in nutrient diffusion of the disk through the cartilaginous endplate and nuclear matrix.

1.3 Uncovertebral Joint (Joint of Luschka)

The intervertebral articulation consists of the intervertebral disk space and the two posterior facet (zygapophyseal) joints. In the cervical spine, there are additional lateral articulations between the vertebral bodies bilaterally known

1 Anatomic Considerations of the Spine

5

as the uncovertebral joints (joints of Luschka) (Rumboldt 2006 ). Each uncovertebral joint is composed of the uncinate process of the lower vertebral body and the lower surface of the upper vertebral body and is not a true synovial joint. The uncinate process is a bony process projecting superiorly from posterolateral surface of the vertebral body. The unco-vertebral joint is a special feature of the cervical spine from C3 to C7.

1.4 Central Canal and Neural Foramen

The central canal is a tubular passage within the vertebrae along the length of the spine, surrounded by the vertebral bodies and neural arches. Within the central canal, there is a dural sac surrounded by the epidural space. The dural sac is a fl uid-fi lled sac containing the cerebrospinal fl uid, spinal cord, and spinal nerve roots. The epidural space is the space outside the dural sac and is composed of fatty tissue, venous plexus, and traversing nerve roots.

The neural foramen (intervertebral foramen) is the bony opening through which the nerve roots exit the spine. There are two neural foramina located between each adja-cent pair of vertebrae, one on each side. The neural fora-men is bounded by the pedicles of the corresponding upper and lower vertebral levels. Within the neural fora-men, the exiting nerve root is protected by surrounding perineural fat tissue.

In the cervical spine, the neural foramen is orientated in an anterolateral direction, thus an ipsilateral oblique view will show the cervical neural foramen in its widest extent. The neural foramen opens up on the oblique view between the ipsilateral pedicles which are shown as a bridge-like con-fi guration, while the contralateral pedicles are shown on end. In the thoracic and lumbar spine, the neural foramen is directed laterally; as such, the lateral view will show the neu-ral foramen to its best advantage.

1.5 Spinal Cord, Conus Medullaris, Cauda Equina, and Spinal Nerve Roots

The spinal cord represents the central nervous system within the dural sac. The spinal cord starts from the level of the foramen magnum and ends near the L1 to L2 level where it has a cone-shaped confi guration known as the “conus medul-laris.” There are two areas of spinal cord enlargement: the cervical enlargement and the lumbar enlargement. The cauda equina (“horse’s tail”) is the name given to the collection of nerve fi bers located below the level of the conus medullaris.

Each spinal nerve root is named with respect to the cor-responding lower vertebral level from C1 to C7 (e.g., C6 nerve above C6 vertebra) and to the corresponding upper vertebral level from T1 to S5 (e.g., L4 nerve below L4 vertebra), due to the C8 nerve root between the C7 and T1

vertebrae. In the lumbar spine, the descending nerve root is situated in the epidural space at the vertebral level above its exit. The lumbar nerve root then descends along the medial side of the pedicle of the same numbered vertebra and exits below the pedicle of same vertebra. For example, the L5 nerve root is located in the epidural space at the L4–5 disk level, descends along the medial side of the L5 pedicle, and fi nally exits below the L5 pedicle through the L5–S1 neural foramen.

On MR, the spinal cord can be differentiated from CSF by its intermediate signal intensity on T1-weighted and T2-weighted images. The spinal cord normally terminates at the L1 to L2 vertebral levels. The spinal nerve roots can be distinguished from surrounding fat as linear low signal inten-sity structures on either T1-weighted or T2-weighted images.

1.6 Ligaments

The anterior longitudinal ligament covers the anterior por-tion of the vertebral bodies from the occipital base to S1. The anterior longitudinal ligament is tightly bounded to the ver-tebral bodies and intervertebral disks. The posterior longitu-dinal ligament covers the posterior portion of the vertebral bodies from C2 to S1 levels and continues proximally to form the tectorial membrane. The posterior longitudinal liga-ment is loosely attached to the vertebral bodies and tightly attached to the intervertebral disks. There is a venous plexus with epidural fatty tissue located between the vertebral bod-ies and posterior longitudinal ligament.

The ligamentum fl avum (yellow ligament) is a fi broelas-tic ligament which connects the anterior portion of the lam-ina of each vertebral level above to the posterior portion of the lamina of the corresponding vertebral level below. The ligamentum fl avum is directed laterally toward the anterior capsule of the facet joints.

The interspinous ligament spans between the spinous pro-cesses. The supraspinous ligament connects the posterior surfaces of the spinous processes, transitioning as the nuchal ligament from the C7 level superiorly.

Forget Me Nots!

• The intervertebral disk normally shows central T2 hyperintensity and peripheral T2 hypointensity.

• The neural foramen is bounded by pedicles from the corresponding upper and lower vertebral levels.

• Each spinal nerve root is named with respect to the corresponding lower vertebral level from C1 to C7 and to the corresponding upper vertebral level from T1 to S5 due to the C8 nerve root situated between the C7 and T1 vertebrae.

1.6 Ligaments

6

1.7 Illustrations: Anatomic Considerations of the Spine

1.7.1 Normal Anatomy of the Spine

VB

TP

SAP

TP

P

VB

IAP

L

SAB

SP

L L

SP

SAP

L

VB

TP

TP

SP

SP

a b

c d

Fig. 1.1 ( a – d ) Schematic illustrations of the spine. Each vertebra is composed of the vertebral body ( VB ), vertebral arch, and bony append-ages. The vertebral arch consists of the pedicles ( P ) anteriorly and lami-nae ( L ) posteriorly. Each pedicle is composed of cortical bone connecting the vertebral body with each lamina. The transverse process

( TP ), superior articular process ( SAP ), and inferior articular process ( IAP ) arise near the junction of the pedicle and lamina. The spinous process ( SP ) is located in the midline between the laminae and projects posteriorly (Published with kind permission of © HealthWave 2014. All Rights Reserved)


7

IVD

VB

TP

SAP

IAP

PI TP

SAP

IAPTPL LSP

SP

IVD

VB

a b c d

Fig. 1.2 Schematic illustrations of the lumbar spine. The vertebral bodies ( VB ) as seen on frontal ( a ) and lateral views ( b ). The interverte-bral disks ( IVD ) are located between the vertebral bodies. In the lumbar spine, the neural foramen (dot) is directed laterally. The superior articu-lar process ( SAP ) and inferior articular process ( IAP ) make up the zyg-apophyseal joint (Z-joint, so called ‘facet joint’, circle in the fi gure), and are well demonstrated on the posterior oblique view ( c ). The pars interarticularis ( PI ) is the narrowed segment of the bone between the

superior and inferior articular processes, and is also well visualized on the posterior oblique view ( c ). In the posterior view ( d ), the laminae ( L ), transverse processes ( TP ), spinous process ( SP ) as well as the supe-rior and inferior articular processes are shown. In between the laminae, there is a space (interlaminar space, dotted arrow ) which may be used as a route for spinal tapping or epidural injection (Published with kind permission of © HealthWave 2014. All Rights Reserved)


8

a b c

d

e

f g

Fig. 1.3 Facet joint orientation. The cervical facet joints are oriented mainly in a horizontal direction and in the coronal plane ( b , c ). The thoracic and lumbar facet joints are primarily directed vertically. The thoracic facet joints are oriented in the coronal plane ( d , e ) while

the lumbar facets are orientated in the oblique sagittal plane anterome-dially ( f , g ), predisposing degenerate lumbar facets to anterior displace-ment ( a , b , d , f ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)


9

1.7.2 Intervertebral Diskal and Ligamentous Anatomy on MR

Fig. 1.4 Normal intervertebral disk and ligaments shown on schematic illustrations ( a , c ) and T2-weighted MR images ( b , d ). The interverte-bral disks ( arrows ) are fi brocartilaginous structures found between the vertebral bodies. The ligamentum fl avum ( LF ) is located just anterior to the lamina. The interspinous ligament ( ISL ) spans across the spinous processes, while the supraspinous ligament ( SSL ) connects the poste-rior surfaces of the spinous processes. The intervertebral disk is com-posed of an inner nucleus pulposus ( NP ) and an outer annulus fi brosus. Normally, the intervertebral disk shows central hyperintensity ( dotted

arrow ) and peripheral hypointensity on T2-weighted MR images. The central T2-hyperintensity refl ects the nucleus pulposus (NP) and inner annulus fi brosus. The ligamentum fl avum (= yellow ligament , LF) is a fi broelastic ligament connecting the anterior portion of the lamina of the upper level to the posterior portion of the lamina of the lower level, and is directed laterally towards the anterior capsule of the facet joint ( a , c ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)

b

ISL

LF SSL

a b

LF

ISL

SSL


10

dc

LF

NP

LF

Fig. 1.4 (continued)


11

1.7.3 Cervical Spine Anatomy

NF

UP

UP

NF

UP

fed

cba

VA

VA

Fig. 1.5 Cervical spine anatomy as demonstrated on anterior ( a – c ) and right oblique views ( d – f ) of the schematic illustrations ( a , d ), plain radiographs ( b , e ), and CT angiogram ( c , f ). The uncinate process ( UP ) is a bony projection arising superiorly from the posterolateral surface of the cervical vertebral body. The cervical neural foramen ( NF ) is directed anteromedially and is well shown on oblique views ( d – f ). The ipsilat-eral neural foramen ( NF ) is shown en face on oblique views between the ipsilateral pedicles ( open arrows ) which appear as bony bridges. The contralateral pedicles are shown on end ( dots ) on the oblique radio-

graph ( e ). The uncovertebral joint ( circle ) is formed by the uncinate process of the lower vertebral body and the inferior surface of the upper vertebral body. The uncovertebral joint ( circle ) is situated along the anterior aspect of the neural foramen, as such hypertrophy of the unco-vertebral joint can lead to neural foraminal narrowing, predisposing to nerve root compression. The vertebral artery ( VA ) courses through the vertebral foramen of the transverse processes from C6 to C1 and is located in the anterior half of the neural foramen ( a , d ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)


12

1.7.4 Spinal Cord and Nerve Root Anatomy

cba

SC

CM

CE

Fig. 1.6 Spinal cord and nerve roots as demonstrated on schematic illustration ( a ), T2-weighted sagittal MR image ( b ) and T1-weighted sagittal MR image ( c ). The spinal cord is the continuation of the central nervous system within the dural sac of the spine. The spinal cord ( SC ) ends as a cone-shaped structure at the L1 level, known as the conus

medullaris ( CM ). There are two areas of spinal cord enlargements: the cervical enlargement and the lumbar enlargement. The cauda equina (CE, “horse’s tail”) refers to the collection of nerve fi bers distal to the conus medullaris ( a ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)


13

L4

L5

S1

S1 nerve

L5 nerve

L4 nerve

C1

C5

C6

C7

T1

T12

L1 nerve

T1 nerve

C8 nerve

C6

C5

L5

L4

L4 nerve

C6 nerveC6 nerve

C1 nerve

c

ba

Fig. 1.7 Schematic illustration of the nerve roots. Each spinal nerve root is named with respect to the corresponding lower vertebral level from C1 to C7 and to the corresponding upper vertebral level from T1 to S5, as a result of the C8 nerve root between the C7 and T1 vertebrae ( a ).

For example, the C6 nerve root exits through the C5/6 neural foramen above the C6 vertebra ( b ), while the L4 nerve root exits through the L4/5 neural foramen below the L4 vertebra ( c ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)


14

L4 L5

L5

L5

L4

a

b

c

Fig. 1.8 Exiting and descending nerve roots of the lumbar spine. On the schematic illustration ( a ), the exiting L4 nerve root is located in the L4/5 neural foramen while the descending L5 nerve root is seen outside the dura coursing along the medial side of the L5 pedicle, fi nally exiting distal to the L5 pedicle through the L5/S1 neural foramen. On the T1-weighted axial MR image at the L4/5 disk level ( b ), the L4 nerve

root is situated in the neural foramen and the L5 nerve root is just out-side the dural sac. At the level just inferior to the L4/5 disk, the L5 nerve root is shown to descend along the medial side of the L5 pedicle ( c ) (Published with kind permission of © HealthWave 2014. All Rights Reserved)


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