Vol 21.1_Spinal Cord Disorders.2015.pdf

Continuum: Lifelong Learning in Neurology—Spinal Cord Disorders, Volume 21, Issue 1, February
2015
Issue Overview
Spinal Cord Disorders, February 2015;21(1)
Continuum: Lifelong Learning in Neurology® is designed to help practicing neurologists stay abreast of
advances in the field while simultaneously developing lifelong self-directed learning skills.
Learning Objectives
Upon completion of this Continuum: Lifelong Learning in Neurology Spinal Cord Disorders issue,
participants will be able to:
►Define the spinal cord syndromes based on anatomic principles and apply that
knowledge to localize spinal cord lesions
►Interpret common MRI abnormalities associated with various spinal cord disorders
►Recognize the clinical and radiographic features of cervical spondylotic myelopathy
and formulate a timely and cost-effective management plan
►Describe vascular disorders of the spinal cord including infarction, hemorrhage, and
arteriovenous fistula
►List the metabolic causes of myelopathy and explain the diagnostic and therapeutic
approach to nutritional myelopathies
►Distinguish infectious from noninfectious causes of spinal cord dysfunction and
recognize specific infectious myelopathies
►Describe the immune-mediated causes of myelitis and formulate the diagnostic and
therapeutic approach to their management
►Define direct neoplastic involvement of the spinal cord in the parenchymal,
subarachnoid, and epidural compartments, and list indirect causes of spinal cord injury in
the setting of neoplasm
►Identify cauda equina syndrome and recognize the need for urgent evaluation and
possible surgical management
Copyright © American Academy of Neurology. Unauthorized reproduction of this article is prohibited.

►Discuss the life-threatening complications of acute spinal cord injury and integrate
neurologic expertise in a multidisciplinary approach to management
►List the most common chronic neurologic complications of spinal cord injury and
discuss the management of these complications
Core Competencies
The Continuum Spinal Cord Disorders issue covers the following core competencies:
► Patient Care
► Medical Knowledge
► Practice-Based Learning and Improvement
► Interpersonal and Communication Skills
► Professionalism
► Systems-Based Practice
Disclosures
CONTRIBUTORS
Tracey A. Cho, MD, Guest Editor
Assistant Professor of Neurology, Harvard Medical School; Associate
Neurologist, Massachusetts General Hospital, Boston, Massachusetts
a
Dr Cho has received compensation as a consultant for OptumInsight, Inc.
b
Dr Cho reports no disclosure.
Gary M. Abrams, MD, FAAN
Professor of Clinical Neurology, University of California, San Francisco,
San Francisco, California
a
Dr Abrams has received personal compensation as a consultant for Boston Scientific; the California Health
Benefits Review Program; Clarity Neurorehab, LLC; Dart Neuroscience, LLC; Halo Neuroscience; and the Los
Angeles Biomedical Research Institute at Harbor-UCLA Medical Center. Dr Abrams has also received personal
compensation as a lecturer from Contemporary Forums and the Hawaii Neurological Society; has received
royalties from UpToDate, Inc; and has received honoraria for grand rounds from New York University, Stanford
University, and the University of California Harbor-UCLA Medical Center. Dr Abrams has received grants from
Innovative Neurotronics and the NIH.
b
Dr Abrams discusses the unlabeled use of prazosin and terazosin for the prevention of autonomic dysreflexia,
indomethacin and bisphosphonates for the treatment of heterotopic ossification, and clonidine and gabapentin for
the treatment of spasticity.
Jeffrey Buchhalter, MD, PhD, FAAN

Professor, Pediatrics and Clinical Neurosciences, Alberta Children’s Hospital,
University of Calgary Faculty of Medicine, Calgary, Alberta, Canada
a
Dr Buchhalter has received personal compensation as a consultant from Eisai Co, Ltd; UCB, Inc; and Upsher-
Smith Laboratories, Inc.
b
Dr Buchhalter reports no disclosure.
Marc C. Chamberlain, MD, FAAN
Professor, University of Washington, Seattle Cancer Care Alliance, Fred
Hutchinson Cancer Research Center, Seattle, Washington
a
Dr Chamberlain has received personal compensation as a consultant and lecturer for Genentech, Inc.
b
Dr Chamberlain reports no disclosure.
Elliot M. Frohman, MD, PhD, FAAN
Professor of Neurology and Neurotherapeutics and Ophthalmology; Director,
Multiple Sclerosis Program and Clinical Center for Multiple Sclerosis, University
of Texas Southwestern Medical Center, Dallas, Texas
a
Dr Frohman has received personal compensation as a speaker and consultant from Acorda Therapeutics,
Genzyme, Novartis International AG, and Teva Pharmaceutical Industries, Ltd.
b
Dr Frohman discusses the unlabeled use of cyclophosphamide, infliximab, IV immunoglobulin
G, rituximab, and steroids for the treatment of myelitis.
Karunesh Ganguly, MD, PhD
Assistant Professor, Department of Neurology, Staff Neurologist, San Francisco
Veterans Affairs Medical Center, University of California, San Francisco,
a
Dr Ganguly reports no disclosures.
b
Dr Ganguly discusses the unlabeled use of prazosin and terazosin for the prevention of autonomic dysreflexia,
indomethacin and bisphosphonates for the treatment of heterotopic ossification, and clonidine and gabapentin for
the treatment of spasticity.
Brent P. Goodman, MD
Assistant Professor, Mayo College of Medicine, Scottsdale, Arizona
a,b
Dr Goodman reports no disclosures.
Benjamin M. Greenberg, MD, MHS
Director, Transverse Myelitis and Neuromyelitis Optica Program, University
a
Dr Greenberg owns stock or stock options and serves as a consultant for Amplimmune, Inc, and DioGenix, Inc. Dr
Greenberg has received personal compensation for developing education presentations from MediLogix and for
serving as a consultant for Novartis International AG.
b
Dr Greenberg discusses the unlabeled use of cyclophosphamide, infliximab, IV immunoglobulin
Joshua P. Klein, MD, PhD
Chief, Division of Hospital Neurology, Brigham and Women’s Hospital;
Assistant Professor of Neurology and Radiology, Harvard Medical School,
Boston, Massachusetts
a
Dr Klein serves on the board of directors of The American Society of Neuroimaging; receives royalties from
McGraw-Hill for Adams and Victor’s Principles of Neurology, 10th Edition; receives compensation for serving on
the editorial boards of AccessMedicine–Neurology

Collection and the Journal of Neuroimaging; and receives compensation for work as a consultant from Guidepoint
Global.
b
Dr Klein reports no disclosure.
Kerry H. Levin, MD, FAAN
Chairman, Department of Neurology; Director, Neuromuscular Center;
Professor of Medicine (Neurology), Cleveland Clinic, Cleveland, Ohio
a
Dr Levin serves as a board member of the American Board of Psychiatry and Neurology and receives royalties
from UpToDate, Inc.
b
Dr Levin reports no disclosure.
Jennifer L. Lyons, MD
Chief, Division of Neurological Infections, Brigham and Women’s Hospital,
Department of Neurology; Instructor of Neurology, Harvard Medical School,
a,b
Dr Lyons reports no disclosures.
Marcus Ponce de Leon, MD
Residency Program Director, Department of Neurology, Madigan Army Medical
Center, Tacoma, Washington; Assistant Professor, Uniformed Services, University
of Health Sciences, Bethesda, Maryland
a,b
Dr Ponce de Leon reports no disclosures.
Alejandro A. Rabinstein, MD, FAAN
Professor of Neurology, Mayo Clinic, Rochester, Minnesota
a
Dr Rabinstein receives a grant from DJO Global, Inc, and receives royalties from Elsevier and Oxford University
Press.
b
Dr Rabinstein reports no disclosure.
Kevin N. Sheth, MD, FAHA, FCCM, FNCS
Chief, Division of Neurocritical Care and Emergency Neurology,
Yale University School of Medicine, New Haven, Connecticut
a
Dr Sheth serves on the editorial boards of Neurocritical Care, Neurosurgery, and Stroke.
b
Dr Sheth reports no disclosure.
Deborah M. Stein, MD, MPH, FACS, FCCM
Associate Professor of Surgery, University of Maryland School of Medicine;
Chief of Trauma, R Adams Cowley Shock Trauma Center, Baltimore, Maryland
a,b
Dr Stein reports no disclosures.
Andrew W. Tarulli, MD
Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center;
Assistant Professor of Neurology, Harvard Medical School, Boston, Massachusetts
a
Dr Tarulli has received personal compensation for serving as a medical expert from TNMG Law and receives
royalties from UpToDate, Inc.
b
Dr Tarulli reports no disclosure.
Jinny O. Tavee, MD
Assistant Professor; Director, Neuromuscular Fellowship, Cleveland Clinic Lerner

College of Medicine, Cleveland Clinic, Cleveland, Ohio
a
Dr Tavee has received personal compensation for manuscript preparation from the Cleveland Clinic Foundation
and Elsevier.
b
Dr Tavee reports no disclosure.
Amy Tsou, MD, MSc
Physician, Department of Neurology, Philadelphia Veterans Affairs Medical
Center, Philadelphia, Pennsylvania; Senior Research Analyst, Agency
for Healthcare Research and Quality Evidence-Based Practice Center,
Emergency Care Research Institute, Plymouth Meeting, Pennsylvania
a,b
Dr Tsou reports no disclosures.
Douglas J. Gelb, MD, PhD, FAAN
Professor of Neurology, University of Michigan, Ann Arbor, Michigan
a
Dr Gelb receives book royalties from Oxford University Press and UpToDate, Inc.
b
Dr Gelb reports no disclosure.
D. Joanne Lynn, MD, FAAN
Associate Dean for Student Life and Clinical Professor of Neurology,
The Ohio State University College of Medicine, Columbus, Ohio
a
Dr Lynn receives book royalties from Lippincott Williams & Wilkins and holds stock in Abbott Laboratories,
Bristol-Myers Squibb Company, Corning Incorporated, Express Scripts Holding Company, General Electric,
Hospira, Inc, and Varian Medical Systems, Inc.
b
Dr Lynn reports no disclosure.
Methods of Participation and Instructions for Use
Continuum: Lifelong Learning in Neurology® is designed to help practicing neurologists stay
abreast of advances in the field while simultaneously developing lifelong self-directed learning
skills. In Continuum, the process of absorbing, integrating, and applying the material presented is
as important as, if not more important than, the material itself.
The goals of Continuum include disseminating up-to-date information to the practicing
neurologist in a lively, interactive format; fostering self-assessment and lifelong study skills;
encouraging critical thinking; and, in the final analysis, strengthening and improving patient
care.
Each Continuum issue is prepared by distinguished faculty who are acknowledged leaders in
their respective fields. Six issues are published annually and are composed of review articles,

case-based discussions on ethical and practice issues related to the issue topic, coding
information, and comprehensive self-assessment and CME offerings, including multiple-choice
questions with preferred responses and a patient management problem. For detailed instructions
regarding Continuum self-assessment and CME activities, visit aan.com/continuum/cme.
The review articles emphasize clinical issues emerging in the field in recent years. Case reports
and vignettes are used liberally, as are tables and illustrations. Video material relating to the
issue topic accompanies issues when applicable.
The text can be reviewed and digested most effectively by establishing a regular schedule of
study in the office or at home, either alone or in an interactive group. If subscribers use such
regular and perhaps new study habits, Continuum’s goal of establishing lifelong learning patterns
can be met.

Continuum (Minneap Minn) 2015;21(1) www.ContinuumJournal.com
aRelationship Disclosure
bUnlabeled Use of Products/Investigational Use Disclosure
LIFELONG LEARNING IN NEUROLOGY®
Spinal Cord Disorders
CONTRIBUTORS
Tracey A. Cho, MD, Guest Editor
Assistant Professor of Neurology, Harvard Medical School; Associate
Neurologist, Massachusetts General Hospital, Boston, Massachusetts
aDr Cho has received compensation as a consultant for OptumInsight, Inc.
bDr Cho reports no disclosure.
Gary M. Abrams, MD, FAAN
Professor of Clinical Neurology, University of California, San Francisco,
aDr Abrams has received personal compensation as a consultant for Boston Scientific; the
California Health Benefits Review Program; Clarity Neurorehab, LLC; Dart Neuroscience, LLC;
Halo Neuroscience; and the Los Angeles Biomedical Research Institute at Harbor-UCLA
Medical Center. Dr Abrams has also received personal compensation as a lecturer from
Contemporary Forums and the Hawaii Neurological Society; has received royalties from
UpToDate, Inc; and has received honoraria for grand rounds from New York University,
Stanford University, and the University of California Harbor-UCLA Medical Center. Dr Abrams
has received grants from Innovative Neurotronics and the NIH.
bDr Abrams discusses the unlabeled use of prazosin and terazosin for the prevention of
autonomic dysreflexia, indomethacin and bisphosphonates for the treatment of
heterotopic ossification, and clonidine and gabapentin for the treatment of spasticity.
Volume 21 Number 1 February 2015
Jeffrey Buchhalter, MD, PhD, FAAN
Professor, Pediatrics and Clinical Neurosciences, Alberta Children’s Hospital,
University of Calgary Faculty of Medicine, Calgary, Alberta, Canada
aDr Buchhalter has received personal compensation as a consultant from Eisai Co, Ltd; UCB,
Inc; and Upsher-Smith Laboratories, Inc.
bDr Buchhalter reports no disclosure.

www.ContinuumJournal.com February 2015
CONTRIBUTORS continued
Assistant Professor, Mayo College of Medicine, Scottsdale, Arizona
a,bDr Goodman reports no disclosures.
Karunesh Ganguly, MD, PhD
Assistant Professor, Department of Neurology, Staff Neurologist, San Francisco
Veterans Affairs Medical Center, University of California, San Francisco,
aDr Ganguly reports no disclosures.
bDr Ganguly discusses the unlabeled use of prazosin and terazosin for the prevention
of autonomic dysreflexia, indomethacin and bisphosphonates for the treatment of
heterotopic ossification, and clonidine and gabapentin for the treatment of spasticity.
Elliot M. Frohman, MD, PhD, FAAN
Professor of Neurology and Neurotherapeutics and Ophthalmology; Director,
Multiple Sclerosis Program and Clinical Center for Multiple Sclerosis, University
aDr Frohman has received personal compensation as a speaker and consultant from Acorda
Therapeutics, Genzyme, Novartis International AG, and Teva Pharmaceutical Industries, Ltd.
bDr Frohman discusses the unlabeled use of cyclophosphamide, infliximab, IV immunoglobulin
Professor, University of Washington, Seattle Cancer Care Alliance, Fred
Hutchinson Cancer Research Center, Seattle, Washington
aDr Chamberlain has received personal compensation as a consultant and lecturer for
Genentech, Inc.
bDr Chamberlain reports no disclosure.
Benjamin M. Greenberg, MD, MHS
Director, Transverse Myelitis and Neuromyelitis Optica Program, University
aDr Greenberg owns stock or stock options and serves as a consultant for Amplimmune, Inc, and
DioGenix, Inc. Dr Greenberg has received personal compensation for developing education
presentations from MediLogix and for serving as a consultant for Novartis International AG.
bDr Greenberg discusses the unlabeled use of cyclophosphamide, infliximab, IV immunoglobulin

Chief, Division of Hospital Neurology, Brigham and Women’s Hospital;
Assistant Professor of Neurology and Radiology, Harvard Medical School,
aDr Klein serves on the board of directors of The American Society of Neuroimaging; receives
royalties from McGraw-Hill for Adams and Victor’s Principles of Neurology, 10th Edition;
receives compensation for serving on the editorial boards of AccessMedicine–Neurology
Collection and the Journal of Neuroimaging; and receives compensation for work as a
consultant from Guidepoint Global.
bDr Klein reports no disclosure.
Chief, Division of Neurological Infections, Brigham and Women’s Hospital,
Department of Neurology; Instructor of Neurology, Harvard Medical School,
a,bDr Lyons reports no disclosures.
Residency Program Director, Department of Neurology, Madigan Army Medical
Center, Tacoma, Washington; Assistant Professor, Uniformed Services, University
of Health Sciences, Bethesda, Maryland
a,bDr Ponce de Leon reports no disclosures.
Kerry H. Levin, MD, FAAN
Chairman, Department of Neurology; Director, Neuromuscular Center;
Professor of Medicine (Neurology), Cleveland Clinic, Cleveland, Ohio
aDr Levin serves as a board member of the American Board of Psychiatry and Neurology
and receives royalties from UpToDate, Inc.
bDr Levin reports no disclosure.
Professor of Neurology, Mayo Clinic, Rochester, Minnesota
aDr Rabinstein receives a grant from DJO Global, Inc, and receives royalties from Elsevier
and Oxford University Press.
bDr Rabinstein reports no disclosure.

www.ContinuumJournal.com February 2015
Kevin N. Sheth, MD, FAHA, FCCM, FNCS
Chief, Division of Neurocritical Care and Emergency Neurology,
Yale University School of Medicine, New Haven, Connecticut
aDr Sheth serves on the editorial boards of Neurocritical Care, Neurosurgery, and Stroke.
bDr Sheth reports no disclosure.
Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center;
Assistant Professor of Neurology, Harvard Medical School, Boston, Massachusetts
aDr Tarulli has received personal compensation for serving as a medical expert from TNMG
Law and receives royalties from UpToDate, Inc.
bDr Tarulli reports no disclosure.
Jinny O. Tavee, MD
Assistant Professor; Director, Neuromuscular Fellowship, Cleveland Clinic Lerner
College of Medicine, Cleveland Clinic, Cleveland, Ohio
aDr Tavee has received personal compensation for manuscript preparation from the
Cleveland Clinic Foundation and Elsevier.
bDr Tavee reports no disclosure.
Deborah M. Stein, MD, MPH, FACS, FCCM
Associate Professor of Surgery, University of Maryland School of Medicine;
Chief of Trauma, R Adams Cowley Shock Trauma Center, Baltimore, Maryland
a,bDr Stein reports no disclosures.
Amy Tsou, MD, MSc
Physician, Department of Neurology, Philadelphia Veterans Affairs Medical
Center, Philadelphia, Pennsylvania; Senior Research Analyst, Agency
for Healthcare Research and Quality Evidence-Based Practice Center,
Emergency Care Research Institute, Plymouth Meeting, Pennsylvania
a,bDr Tsou reports no disclosures.

SELF-ASSESSMENT AND CME TEST WRITERS
Douglas J. Gelb, MD, PhD, FAAN
Professor of Neurology, University of Michigan, Ann Arbor, Michigan
aDr Gelb receives book royalties from Oxford University Press and UpToDate, Inc.
bDr Gelb reports no disclosure.
D. Joanne Lynn, MD, FAAN
Associate Dean for Student Life and Clinical Professor of Neurology,
The Ohio State University College of Medicine, Columbus, Ohio
aDr Lynn receives book royalties from Lippincott Williams & Wilkins and holds stock in
Abbott Laboratories, Bristol-Myers Squibb Company, Corning Incorporated, Express Scripts
Holding Company, General Electric, Hospira, Inc, and Varian Medical Systems, Inc.
bDr Lynn reports no disclosure.

Volume 21 n Number 1 n February 2015
®
7
Volume 21 n Number 1 www.ContinuumJournal.com
Editor’s Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
REVIEW ARTICLES
Spinal Cord Functional Anatomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Tracey A. Cho, MD
A Practical Approach to Spine Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Myelopathy Due to Degenerative and Structural Spine Diseases. . . . . . . . . . . 52
Jinny O. Tavee, MD; Kerry H. Levin, MD, FAAN
Vascular Myelopathies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Metabolic and Toxic Causes of Myelopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Myelopathy Associated With Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Immune-Mediated Myelopathies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Benjamin M. Greenberg MD, MHS; Elliot M. Frohman, MD, PhD, FAAN
Neoplastic Myelopathies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Disorders of the Cauda Equina. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Management of Acute Spinal Cord Injury. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Deborah M. Stein, MD, MPH, FACS, FCCM; Kevin N. Sheth, MD, FAHA, FCCM, FNCS
Management of Chronic Spinal Cord Dysfunction . . . . . . . . . . . . . . . . . . . . . . . . 188
Gary M. Abrams MD, FAAN; Karunesh Ganguly, MD, PhD
www.ContinuumJournal.com
Spinal Cord Disorders
Guest Editor: Tracey A. Cho, MD

8 www.ContinuumJournal.com February 2015
ETHICAL PERSPECTIVES
Ethical Considerations When Counseling Patients About Stem
Cell Tourism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
Amy Tsou, MD, MSc
PRACTICE ISSUES
Teamwork Approach to Prevention and Treatment of Skin Breakdown
in Spinal Cord Patients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206
Diagnosis Coding for Spinal Cord Disorders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .211
Jeffrey Buchhalter MD, PhD, FAAN
APPENDIX
Appendix: Clinical Evaluation and Treatment of Transverse Myelitis . . . . . . .218
SELF-ASSESSMENT AND CME
Learning Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Instructions for Completing Postreading Self-Assessment
and CMETest andTally Sheet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223
Postreading Self-Assessment and CME Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225
Postreading Self-Assessment and CME Test—Preferred Responses . . . . . . . .235
Patient Management Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .252
Patient Management Problem—Preferred Responses. . . . . . . . . . . . . . . . . . . . .258
Tracey A. Cho, MD
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .269
List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Back Cover

Learning Objectives
Upon completion of this Continuum: Lifelong Learning in Neurology
Spinal Cord Disorders issue, participants will be able to:
Define the spinal cord syndromes based on anatomic principles and apply that
knowledge to localize spinal cord lesions
Interpret common MRI abnormalities associated with various spinal
cord disorders
Recognize the clinical and radiographic features of cervical spondylotic
myelopathy and formulate a timely and cost-effective management plan
Describe vascular disorders of the spinal cord including infarction, hemorrhage,
and arteriovenous fistula
List the metabolic causes of myelopathy and explain the diagnostic and
therapeutic approach to nutritional myelopathies
Distinguish infectious from noninfectious causes of spinal cord dysfunction and
recognize specific infectious myelopathies
Describe the immune-mediated causes of myelitis and formulate the diagnostic
and therapeutic approach to their management
Define direct neoplastic involvement of the spinal cord in the parenchymal,
subarachnoid, and epidural compartments, and list indirect causes of spinal cord
injury in the setting of neoplasm
Identify cauda equina syndrome and recognize the need for urgent evaluation
and possible surgical management
Discuss the life-threatening complications of acute spinal cord injury and
integrate neurologic expertise in a multidisciplinary approach to management
List the most common chronic neurologic complications of spinal cord injury
and discuss the management of these complications
Core Competencies
This Continuum: Lifelong Learning in Neurology Spinal Cord Disorders issue
covers the following core competencies:
Patient Care
Medical Knowledge
Practice-Based Learning and Improvement
Interpersonal and Communication Skills
Professionalism
Systems-Based Practice
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s

Disorders That Strike
a Cord
Expertise in the recognition,
diagnosis, and management of
myelopathies is an essential as-
pect of neurologic practice. It is
therefore fitting that an entire
issue in the
curriculum should be devoted
to those disorders that can affect
the spinal cord, whether via
direct (eg, metabolic, inflamma-
tory, or ischemic) or indirect
(eg, compressive) mechanisms.
For this issue, Guest Editor
Dr Tracey A. Cho has assem-
bled a remarkable group of
expert authors and educators
to provide us with a thorough
and up-to-date review of the
many causes of myelopathy
that we encounter in our daily
practice of clinical neurology.
The issue begins with two
introductory articles that serve
as important primers for the
rest of the articles in the issue.
First, Dr Cho provides a detailed and ex-
tremely accessible overview, reminding us of
the functional anatomy of the spinal cord and
the many clinicoanatomic spinal cord syn-
dromes that inform our clinical approach to
the diagnosis of patients with disorders of
the spinal cord (or cauda equina). Next,
Dr Joshua P. Klein provides us with his
thoughtful,clear,andpracticalapproachtospine
and spinal cord imaging that we can emulate
as we order and interpret our patients’ images
of the spine, spinal cord, and nerve roots.
Next, the issue tackles the various
categories of disease processes that can
affect the spinal cord, beginning with the
article by Drs Jinny O. Tavee and Kerry H.
Levin, who thoroughly review and update
us on the many causes of compressive
myelopathy that occur
due to degenerative and
structural processes involv-
ing the spine (both com-
mon and less common)
and their current manage-
ment. Dr Alejandro A.
Rabinstein then provides
an in-depth explanation
and review of the patho-
physiology and manage-
ment of the myelopathies
that occur because of vas-
cular etiologies, such as
spinal cord infarction
due to various causes,
and arteriovenous fistulas
causing spinal cord dys-
function from venous hy-
pertension. Dr Brent P.
Goodman next provides
an encyclopedic review
of the causes, diagnosis,
prevention, and man-
agement of the many
spinal cord disorders that occur because of
metabolic and toxic etiologies. Dr Jennifer L.
Lyons provides an equally comprehensive
review of the diagnosis and treatment of the
many myelopathies that are caused by infec-
tious agents, whether via direct infection,
inflammation of the cord, or via compressive
mechanisms. Drs Benjamin M. Greenberg
and Elliot M. Frohman then carefully review
the various causes of inflammatory and
demyelinative myelopathies (myelitides),
with an emphasis on neuromyelitis optica
and multiple sclerosis. Dr Marc C. Chamberlain
next thoroughly details the diverse causes of
myelopathy that occur in patients with neo-
plasms, whether as a direct effect from tumor,
as a remote effect, or as a complication of the
treatment of neoplastic disorders.
* 2015, American Academy
of Neurology.
The knowledge gained
from this issue will
strike a chord with each
of us as we attempt to
provide the most
informed care to
reverse, improve, or
prevent the disability
that can occur from
myelopathic disorders.
11
Continuum (Minneap Minn) 2015;21(1):11–12 www.ContinuumJournal.com
Editor’s Preface

In an issue devoted primarily to disor-
ders of the spinal cord, Dr Cho and I also
felt that it was important for the issue to
delve somewhat caudal to the spinal cord,
although still within the spinal canal. For
this reason, Dr Andrew W. Tarulli provides
an important additional discussion about
those processes, especially compressive
ones, which can affect the cauda equina,
an important consideration given the clin-
ical similarities (and differences) between
cauda equina and spinal cord dysfunction
and the severe disability that can occur
with cauda equina dysfunction alone.
Drs Deborah M. Stein and Kevin N.
Sheth bring a unique combination of exper-
tise in trauma surgery and neurocritical care
in their review and update for all neurolo-
gists on the current state of the art of
diagnosis and management of acute trau-
matic spinal cord injury. Finally, the review
articles in this issue conclude with a
comprehensive discussion by Drs Gary
M. Abrams and Karunesh Ganguly on the
management and rehabilitation of patients
with chronic spinal cord dysfunction.
In this issue’s Ethical Perspectives
piece, Dr Amy Tsou discusses the com-
plex ethical considerations involved in
counseling patients about ‘‘stem cell tour-
ism,’’ an issue that can arise in the context
of caring for patients with disorders of the
spinal cord as well as other neurologic
disorders. In this issue’s Practice piece,
Dr Marcus Ponce de Leon outlines how a
multidisciplinary and team-based ap-
proach can be utilized to manage and
reduce the risk of skin breakdownVan
important cause of morbidityVin patients
with disorders of the spinal cord. Finally,
Dr Jeffrey Buchhalter presents four brief
and very illustrative case examples as
springboards to review the considerations
involved in coding spinal cord dysfunction
(due to disease or traumatic injury) with
ICD-10-CM as compared to ICD-9-CM.
An update in the American Board
of Psychiatry and Neurology’s (ABPN’s)
self-assessment requirements has prompted
an important change in
CME activities. The ABPN no longer requires
the completion of a pretest in order be
eligible for self-assessment (SA) (part 2) credit
for Maintenance of Certification, so beginning
with this issue, the Self-
Assessment Pretest has been eliminated. By
taking the Postreading Self-Assessment and
CME Test, carefully crafted by Drs Douglas J.
Gelb and D. Joanne Lynn, after reading the
issue, you may earn up to 12 AMA PRA
Category 1 CreditsTM
toward self-assessment
and CME.
The Patient Management Problem,
thoughtfully and expertly written by Dr Cho,
follows a 39-year-old woman from her pre-
sentation in the emergency department with
sensory and motor symptoms in the lower
extremities through the diagnosis and man-
agement of her disorder. By following this
case and answering multiple-choice questions
corresponding to important clinicoanatomic,
pathophysiologic, diagnostic, and manage-
ment decision points along her course, you
will have the opportunity to earn up to 2 AMA
PRA Category 1 CME Credits.
I would like to give my sincere thanks to
Dr. Cho for his dedication to this volume
and similar thanks to his entire group of
experts for providing the most up-to-date
information about the diagnosis and man-
agement of the wide variety of disorders of
the spinal cord (and cauda equina) that we
encounter in our daily practices of clinical
neurology, both in the hospital and in the
clinic. The knowledge gained from this issue
will strike a chord with each of us as we
attempt to provide the most informed care
to reverse, improve, or prevent the disability
that can occur from myelopathic disorders.
VSteven L. Lewis, MD, FAAN
Editor-in-Chief
Editor’s Preface

Spinal Cord Functional
Anatomy
Tracey A. Cho, MD
ABSTRACT
Purpose of Review: This article reviews the neuroanatomical arrangement of the
white matter pathways and gray matter columns of the spinal cord and explores how
injury to the spinal cord leads to a typical constellation of symptoms and signs
depending on the cross-sectional and longitudinal extent of the lesion.
Recent Findings: As refined imaging techniques and novel biomarkers help identify
spinal cord diseases more readily, familiarity with the classic spinal cord syndromes and
localizing principles remains essential for prompt recognition of spinal cord involvement
and efficient diagnostic testing in order to direct therapy and avoid permanent injury.
Summary: Spinal cord disease can progress rapidly and cause debilitating deficits,
making prompt recognition and treatment crucial. Knowledge of the organization of
these pathways and cell columns, along with their surrounding structures and blood
supply, allows the clinician to localize processes within the spinal column. This, in turn,
can suggest the type of pathologic process involved and direct further evaluation
and management.
Continuum (Minneap Minn) 2015;21(1):13–35.
INTRODUCTION
The spinal cord serves as the conduit
for information traveling between the
brain and the periphery. While some
additional processing occurs within the
spinal cord, most of the volume of the
spinal cord consists of these ascending
and descending signals. Thus, patho-
logic processes affecting the spinal
cord, even those limited to a small
area, are usually clinically apparent.
Knowledge of the organization of the
pathways and cell columns within the
spinal cord, along with their surround-
ing structures and blood supply, allows
the clinician to localize processes within
the spinal column. This, in turn, can
suggest the type of pathologic process
involved and direct further evaluation
and management. While most of the
articles in this issue address the specific
disease processes that can affect the
spinal cord, this article will review the
Address correspondence to
Dr Tracey A. Cho, Massachusetts
General Hospital, Department
of Neurology, 55 Fruit Street,
Wang 835, Boston, MA 02114,
tcho@partners.org.
Relationship Disclosure:
Dr Cho has received
compensation as a consultant
for OptumInsight, Inc.
Unlabeled Use of
Products/Investigational
Use Disclosure:
Dr Cho reports no disclosure.
* 2015, American Academy
of Neurology.
clinical symptoms and signs associated
with particular spinal cord syndromes.
LONGITUDINAL ORGANIZATION
AND SURROUNDING STRUCTURES
There are 31 spinal cord segments (eight
cervical, one thoracic, five lumbar, five
sacral, and one coccygeal) (Figure 1-11
).
Except for C1, which has no sensory
nerve root, each segment has a pair of
dorsal (sensory) and ventral (motor) roots
that join to form a mixed spinal nerve just
as they enter the dural sleeve and neural
foramina. Each segment corresponds to a
vertebra, except for C8, which has no
corresponding vertebra. By convention,
spinal nerves in the cervical region exit
above their corresponding vertebra, with
the C1 spinal nerves exiting between the
C1 vertebra and the skull. Because C8 has
no corresponding vertebra, C8 exits
above T1. Starting with T1, the spinal
nerves exit below their corresponding
13
Review Article

vertebra. During embryonic develop-
ment, the vertebral column grows more
rapidly than the spinal cord. At birth,
the newborn spinal cord ends around
the level of the L3 vertebral body and
by 2 months of age has reached the
adult position at the L1-L2 vertebral level,
resulting in a pattern whereby succes-
sively more caudal spinal nerves must
travel farther to reach their exit. The
rostral spinal cervical nerves exit horizon-
tally at the level of their corresponding
vertebral body; the lower cervical and
upper thoracic nerves travel obliquely one
to two segments to reach their exit; and
the lumbosacral nerves travel several seg-
ments vertically, forming the cauda equina
with caudal-most nerves situated centrally.
FIGURE 1-1 Relation of vertebral bodies to spinal cord and spinal roots. Bolded terms refer to
specific regions.
Reprinted from Moore KL, et al, Wolters Kluwer/Lippincott Williams & Wilkins.1 B 2014 Lippincott
Williams & Wilkins.
Spinal Cord Functional Anatomy

The thin, fragile spinal cord is
protected by the vertebral column,
which also serves to maintain the pos-
ture of the body. Each vertebra has a
central ovoid body providing the bulk of
the structural support. An arch of paired
pedicles and laminae branches off the
body and joins posteriorly to form the
borders of the spinal canal, which sur-
rounds the spinal cord. Each pedicle has
a superior and an inferior notch, which
form the exit site for spinal nerves (inter-
vertebral or neural foramina). Three
processes (one spinal and two transverse)
provide attachment sites for spinal
muscles. Each vertebra is connected to
the vertebra above by superior pro-
cesses and below by inferior processes,
which help to determine the range of
motion of the column. Between each
vertebral body is an intervertebral
disk, which serves to cushion the
vertebral column while providing added
flexibility (Figure 1-21
). The vertebral
column is bound together by several
longitudinal ligaments and muscle at-
tachments. The posterior longitudinal
ligament runs along the posterior as-
pect of the vertebral bodies and
intervertebral disks, forming the anteri-
or wall of the spinal canal and helping
to contain the intervertebral disks as
they degenerate.1
In the cervical region,
the posterior longitudinal ligament
tends to constrain disk bulges from
protruding centrally and instead directs
disks laterally toward the neural fora-
men. Loss of disk height and the
mechanical strain of flexion and exten-
sion over time, however, can lead to
posterior ligament hypertrophy and joint
osteophyte formation, contributing to
central canal narrowing and cervical
spondylotic myelopathy. For more infor-
mation on cervical spondylotic and other
degenerative causes of myelopathies,
refer to the article ‘‘Myelopathy Due to
Degenerative and Structural Spine Dis-
eases’’ by Jinny O. Tavee, MD, and Kerry
H. Levin, MD, FAAN, in this issue
of .
Paired ligamenta flava connect the
lamina of each vertebra with the
laminae of the vertebrae above and
below. Often referred to collectively as
the ligamentum flavum, these elastic
fibers form the posterior wall of the
spinal canal. Like the posterior longi-
tudinal ligament, the ligamentum
flavum can hypertrophy over time,
narrowing the central canal. In the
cervical region, the ligamentum
flavum can buckle inward dynamically
with extension, further contributing to
cervical spondylotic myelopathy.
As in the cranium, three layers of
meninges surround the spinal cord for
its entire length. The cranial dura consists
of two tightly adherent layers, and the
cranial epidural space is bound by peri-
osteum outwardly and the two-layered
KEY POINT
h In the cervical region, the
ligamentum flavum can
buckle inward
dynamically with
extension, further
contributing to cervical
spondylotic myelopathy.
FIGURE 1-2 Vertebral body anatomy (A) and relation to
intervertebral disks and neural foramen (B).
Modified from Moore KL, et al, Wolters Kluwer/
Lippincott Williams & Wilkins.1 B 2014
Lippincott Williams & Wilkins.
15

dura inwardly. In the spinal canal (be-
ginning at the foramen magnum), the
periosteal dural layer separates from the
inner layer, creating an anatomical epi-
dural space between the two layers. The
spinal epidural space contains veins and
fatty tissue, which serves as a useful
landmark on MRI.
Additionally, anesthesia can be used
in the spinal epidural space for a
segmental or regional block. The inner
dura, or thecal sac, encloses the arach-
noid, CSF, pia, and spinal cord from the
foramen magnum rostrally to the sec-
ond sacral level caudally. As each spinal
nerve exits the spinal canal in the neural
foramen, it passes through a dural
sleeve investing the nerve components.
Attached to the dura is the arachnoid
with CSF in the subarachnoid space.
The pia is attached to the surface of the
spinal cord, forming the internal bound-
ary of the CSF (subarachnoid) space.
The spinal cord is anchored rostrally
by the cervicomedullary junction and
caudally by the filum terminale (an
extension of the pia at the conus
medullaris, which attaches to the first
coccygeal segment through the sacral
dura). The spinal cord is enlarged in the
cervical and lumbar regions due to the
large volume of motor neurons dedicated
to finely tuned movements in the upper
(cervical) and lower (lumbar) extremities.
These areas are also the points in the
vertebral column where the most range
of motion occurs and, therefore, are
prone to degenerative changes (eg, loss
of disk height, disk protrusion, ligament
hypertrophy, and osteophyte formation).
An anterior and posterior system pro-
vides the blood supply to the spinal cord.
A single anterior spinal artery runs the
length of the cord in the deep anterior
median fissure, and paired posterior
spinal arteries run in the dorsolateral
sulci, where the dorsal nerve roots attach.
The anterior spinal artery supplies
the anterior two-thirds of the spinal
cord while the posterior spinal arteries
serve the posterior third (primarily
posterior columns). The anterior and
posterior spinal arteries originate from
descending branches of the vertebral
arteries in the neck. The spinal arteries
are further fed by segmental radicular
arteries, which branch off the vertebral
arteries in the cervical region, intercos-
tal branches of the aorta in the
midthoracic region, and the great radic-
ular artery (of Adamkiewicz) in the
lower thoracic or lumbar region. While
the posterior spinal artery receives flow
from 10 to 16 posterior radicular
branches, the anterior spinal artery has
fewer, but larger, anterior radicular ar-
teries feeding into it, making the anterior
spinal artery distribution more prone to
clinically apparent embolic or thrombotic
infarction. In addition, the area between
these larger segmental anterior radicular
arteries constitutes the region most theo-
retically vulnerable to hypoperfusion,
which is the midthoracic region in most
people. However, the clinical relevance
of this border zone is ambiguous as this
region is not reliably involved in hypo-
perfused states.
The venous drainage of the spinal cord
feeds into a longitudinal anterior and
longitudinal posterior vein, with a pial
plexus around the spinal cord connecting
them. Radicular veins drain from the pial
plexus into the circumferential and longi-
tudinal epidural plexus. This rich, valve-
less network serves as a conduit for the
hematogenous spread of neoplastic me-
tastases and infectious pathogens, which
can seed the spinal epidural space. For
more information on the vascular anat-
omy of the spinal cord, refer to the
article ‘‘Vascular Myelopathies’’ by
Alejandro A. Rabinstein, MD, FAAN, in
this issue of .
CROSS-SECTIONAL ANATOMY
The spinal cord consists of longitudinal
columns of nuclei (gray matter)
KEY POINTS
h The spinal epidural space
contains veins and fatty
tissue, which serves as a
useful landmark on MRI.
h While the posterior spinal
artery receives flow from
10 to 16 posterior
radicular branches, the
anterior spinal artery has
fewer, but larger, anterior
radicular arteries feeding
into it, making the anterior
spinal artery distribution
more prone to clinically
apparent embolic or
thrombotic infarction.

surrounded by ascending and descend-
ing tracts (white matter) (Figure 1-3).
The butterfly, or H-shaped, gray matter
is divided into posterior (dorsal), ante-
rior (ventral), and lateral (intermediate)
horns. The gray matter horns divide the
white matter into posterior, lateral, and
anterior columns (also referred to as
funiculi). A remnant of the neural tube
central cavity, the central canal is typi-
cally a closed space that runs the length
of the spinal cord, beginning rostrally
from the fourth ventricle. The central
canal lies in the center of the gray
matter, is lined with ependyma, filled
with CSF, and surrounded by glial cells.
Gray Matter Columns
The anterior horn contains alpha and
gamma (lower) motor neurons as well
as interneurons that help to fine-tune
the motor output. The anterior horn is
organized somatotopically; the neurons
controlling the axial muscles are most
medially placed, the neurons controlling
the proximal limb muscles lie in be-
tween, and the neurons serving the fine
motor control of the distal limbs are
most laterally placed. The motor neu-
rons are also organized by function, with
neurons serving extensor muscles lying
ventral to those controlling flexors.
The posterior horn contains second-
ary sensory neurons and interneurons
receiving input from the dorsal root
ganglia (primary sensory neurons).
These neurons are organized in layers
based on synaptic inputs and outputs.
The outermost layers serve exterocep-
tive (superficial) sensations including
pain, temperature, and light touch, and
their outputs form the contralateral
spinothalamic tracts. The deeper layers
receive inputs on unconscious proprio-
ceptive (deep) sensation and contribute
to the ipsilateral spinocerebellar tracts as
well as participate in local reflex arcs.
The intermediolateral cell column in
the lateral horn from C8 to L3 contains
sympathetic autonomic nuclei that re-
ceive inputs from the hypothalamus,
and these ‘‘preganglionic’’ sympathetic
neurons send outputs via the ventral
roots to the sympathetic chain ganglia.
From S2 to S4 the parasympathetic
‘‘preganglionic’’ nuclei are situated in
KEY POINT
h The anterior horn is
organized somatotopically;
the neurons controlling
the axial uscles are most
medially placed, the
neurons controlling the
proximal limb muscles lie
in between, and the
neurons serving the fine
motor control of the
distal limbs are most
laterally placed.
FIGURE 1-3 Gray and white matter divisions of the spinal cord.
17

the intermediate cell column, similarly
exit via the ventral roots, and then pass
to end organ ganglia in the pelvis.
Finally, the posterior thoracic nucleus,
medially situated between anterior and
posterior horns, receives unconscious
proprioception inputs from the poste-
rior column collaterals and send sec-
ondary axons to the cerebellum in the
spinocerebellar tracts.
White Matter Tracts
The gray matter divides the white
matter of the spinal cord into three
columns: posterior, lateral, and anterior
(Figure 1-3). The white matter bundles
may be classified as ascending or
descending. The most prominent as-
cending tracts are the spinothalamic tract
(pain, temperature, and crude touch)
and the pathway made up of the
posterior columnYmedial lemniscus (vi-
bration, proprioception, and fine touch).
See Table 1-1 for details on other
ascending pathways.
The primary sensory neurons in the
dorsal root ganglia have pseudounipolar
axons, with one process transmitting
sensory input from the tissues to the
cell body and another transmitting
signals from the cell body to the spinal
cord. In general, the sensory pathways
synapse ipsilaterally before crossing to
the contralateral side. The spino-
thalamic tract, along with several other
clinically insignificant tracts, constitute
the anterolateral system, in which the
initial synapse occurs in the dorsal horn
gray matter. Second-order neurons then
send axons across the anterior commis-
sure (anterior to the central canal) to
ascend in the contralateral anterolateral
pathway. This decussation usually takes
two to three segments, so that lesions
affecting the anterolateral tract at a given
spinal cord level will have a contralateral
sensory deficit two to three levels lower.
The proximity of the crossing spino-
thalamic fibers in the anterior commis-
sure leads to early deficits in pain and
temperature when syringomyelia adja-
cent to the central canal compresses the
anterior commissure. The spinothalamic
tract in the anterolateral system is ar-
ranged somatotopically, with sacral fi-
bers most lateral and cervical fibers most
medial. This arrangement accounts for
the phenomenon of sacral sparing, in
which a large central cord lesion may
spare the outermost sacral fibers and,
thus, spare sensation in the lower sacral
dermatomes. Spinothalamic fibers as-
cend to the thalamic ventral posterolat-
eral (VPL) nucleus (Table 1-1).
Unlike the anterolateral pathway,
fibers entering the posterior column
system ascend the entire length of
the spinal cord before synapsing with
second-order neurons in the medulla.
The posterior columns enlarge rostrally
as more fibers are added, and two dis-
tinct columns form in the upper thoracic
and cervical cord. Axons carrying vibra-
tion and proprioception (conscious and
unconscious) from the lower extremities
and lower trunk enter the ipsilateral
gracile fasciculus medially, while fibers
from the upper extremities and neck are
added on laterally to form the cuneate
fasciculus. Both gracile and cuneate
pathways synapse in the medulla, where
second-order neurons in their respective
nuclei finally send projections across the
midline via internal arcuate fibers to the
contralateral medial lemniscus and then
to the thalamic VPL nucleus. Thus,
between the medulla and any given level
of the spinal cord, the fibers of the ante-
rolateral system and posterior columns
are dissociated, with the anterolateral
fibers crossing immediately to travel in
the contralateral cord and the posterior
columns remaining ipsilateral until
reaching the medulla.
In addition to the anterolateral and
posterior column systems, several other
tracts ascend the spinal cord with
variable clinical relevance. Unconscious
KEY POINT
h The most prominent
ascending tracts are the
spinothalamic tract (pain,
temperature, and crude
touch) and the pathway
made up of the posterior
columnYmedial lemniscus
(vibration, proprioception,
and fine touch).

proprioception information from the
lower extremities and lower trunk
travels alongside conscious propriocep-
tion in the gracile fasciculus, before
collateral fibers exit to synapse on the
thoracic posterior (Clarke) nucleus.
TABLE 1-1 Ascending Spinal Cord Tracts
Tract Origin Decussation Location in Cord Terminus Function
Posterior (Dorsal) Columns
Gracile fasciculusa
Dorsal root
ganglion
Medulla
(internal
arcuate)
Posterior column
(medial)
Thalamic ventral
posterolateral
nucleus
Fine touch
Vibration
Proprioception
(lower body)
Cuneate fasciculusa
Dorsal root
ganglion
Medulla
(internal
arcuate)
Posterior column
(lateral)
Thalamic ventral
posterolateral
nucleus
Fine touch
Vibration
Proprioception
(upper body)
Anterolateral System
Spinothalamic tracta
Dorsal horn Anterior
commissure
Lateral, anterior
columns
Thalamic ventral
posterolateral
nucleus
Crude touch
Pain
Temperature
Spinoreticular tract Dorsal horn Mostly
uncrossed
Lateral column Medullary
reticular system
Behavioral
response to
pain, arousal
Spinomesencephalic
tract
commissure
Lateral column Periaqueductal
gray
Central
modulation
of pain
Spinotectal tract Dorsal horn Anterior
commissure
Lateral column Superior colliculus Turn head,
eyes toward
painful stimulus
Spinohypothalamic
tract
commissure
Lateral column Hypothalamus Autonomic
response to pain
Spinocerebellar Tracts
Posterior (dorsal)
spinocerebellar
tract
Thoracic
posterior
(Clarke)
nucleus
Uncrossed Posterior column
(first order);
lateral column
(second order)
Ipsilateral
cerebellum
Unconscious
proprioception
(lower body)
Cuneocerebellar
tract (located in
medulla)
Accessory
cuneate
(medulla)
Uncrossed Posterior column
(first order);
lateral medulla
(second order)
Ipsilateral
cerebellum
Unconscious
proprioception
(upper limb,
head)
Anterior (ventral)
spinocerebellar
tract
commissure,
cerebellum
Lateral column Ipsilateral
cerebellum
Unconscious
proprioception
(lower body)
Spino-olivary tract Dorsal horn Anterior
commissure
Lateral, anterior
columns
Ipsilateral
cerebellum
Unconscious
proprioception
Rostral
spinocerebellar
tract (joins anterior
spinocerebellar tract)
Dorsal horn Uncrossed Lateral column Ipsilateral
cerebellum
Unconscious
proprioception
(upper limb,
head)
a
Most relevant for clinical localization.
19

Secondary neurons send fibers through
the ipsilateral posterior spinocerebellar
tracts to the cerebellum via the inferior
cerebellar peduncle. Analogous collat-
erals carrying upper extremity and trunk
unconscious proprioception exit the
cuneate fasciculus to synapse in the
medullary accessory cuneate nucleus,
which sends signals to the ipsilateral
inferior cerebellar peduncle (Table 1-1).
The most prominent descending
tract is the corticospinal (pyramidal)
tract, often referred to as a long tract
due to its uninterrupted passage from
the primary motor cortex in the
precentral gyrus to the anterior horn.
Almost all of the descending motor
fibers cross in the caudal medulla to
form the lateral corticospinal tract. The
few remaining uncrossed fibers form
the anterior corticospinal tract, which
cross at the level of synapse to anterior
horn cells and are primarily involved in
axial and proximal limb (girdle) motor
control. Within the lateral corticospinal
tract, fibers synapsing in more rostral
(cervical) areas are situated medially
and fibers synapsing to caudal (sacral)
regions are situated laterally. This ar-
rangement may account for the early
involvement of lower extremity corti-
cospinal function in compressive cervi-
cal lesions.
Several other less well-defined
tracts descend through the spinal cord
(Table 1-2). Adjacent to the lateral
corticospinal tract in the lateral cord,
the rubrospinal tract has an unclear role
in humans but may be responsible for
upper extremity flexor movements in
animals with lesions above the red
nucleus (ie, decorticate posturing).2
In
the anterior descending motor column,
the vestibulospinal, reticulospinal, and
tectospinal tracts descend along with
the anterior corticospinal tract.3
The
clinical significance of these tracts in
humans is overshadowed by the dom-
inant role of the lateral corticospinal
tract in controlling fine motor move-
ments, but in general, the medial
descending motor systems aid in the
control of axial muscles, posture, bal-
ance, and head movements. It is
postulated that these spinal ‘‘extrapy-
ramidal’’ motor systems evolved to
coordinate an organism’s stride with
minimal conscious input, while the
pyramidal system developed to finely
tune more complex movements using
the hands and feet. The autonomic
fibers constitute another important
descending system. While the lateral
corticospinal tract is densely packed
and grossly identified on cord sections,
the descending autonomic fibers travel
more diffusely in the lateral aspect of the
cord adjacent to the lateral horn, but
without a well-defined tract (Figure 1-4).
Direct and indirect supranuclear auto-
nomic inputs arise from the hypothala-
mus as well as the insula and amygdala,
among other limbic and brainstem
centers. For the sympathetic system,
these supranuclear signals pass laterally
through the brainstem and spinal cord
and synapse in the ipsilateral inter-
mediolateral cell column in the thoracic
and upper lumbar cord. These preg-
anglionic neurons then send outputs
via the ventral spinal roots to either
paravertebral sympathetic ganglia or to
prevertebral ganglia proximate to end
organs. The parasympathetic nuclei lie
in the brainstem and lateral gray matter
in the S2 to S4 segments. Efferent
preganglionic parasympathetic fibers
exit the spinal cord via ventral roots
and travel in the ventral ramus to the
end organs, where they synapse on
postganglionic neurons.
The control of bladder function in-
volves complex interactions between
somatosensory, somatomotor, parasym-
pathetic, and sympathetic systems and
serves as an important clinical indicator
of spinal cord function. In healthy adults,
bladder function is under voluntary
KEY POINTS
h Between the medulla
and any given level of the
spinal cord, the fibers of
the anterolateral system
and posterior columns
are dissociated, with the
anterolateral fibers
crossing within one to
two levels of entering the
spinal cord to travel in the
contralateral cord and
the posterior columns
remaining ipsilateral until
reaching the medulla.
h The somatotopic
organization of the lateral
corticospinal tract
accounts for the early
involvement of lower
extremity corticospinal
function in compressive
cervical lesions.

control. Sensory input from the bladder
and urethra passes through the S2 to S4
nerve roots and via the anterolateral
system and posterior columns to frontal
and pontine micturition centers. The
frontal micturition center (medial frontal
region) triggers the pontine micturition
center (locus caeruleus) to initiate the
voiding reflex. The somatic motor neu-
rons in the medial anterior horns of S2
to S4 control the pelvic floor muscles,
and specialized motor neurons in the
lateral part of the S2 to S4 anterior
horns, called the Onuf nucleus, serve
voluntary control of the urethral (and
anal) sphincter. Sympathetic inputs
from the intermediolateral cell column in
the T11 to L2 region supply a small
component ofmusclein the bladderneck.
Parasympathetic motor neurons in the
lateral horn of S2 to S4 activate the bladder
detrusor muscle, which is the primary
TABLE 1-2 Descending Spinal Cord Tracts
Tract Origin Decussation Location in Cord Terminus Function
Lateral
corticospinal
(pyramidal)a
Primary motor
cortex
Caudal
medulla
Lateral column Contralateral
anterior horn
throughout cord
Control of
contralateral
muscles
Anterior
(ventral)
corticospinal
Primary motor
cortex
Level of
synapse
Anterior column Contralateral
cervical and
upper thoracic
anterior horn
Control of
contralateral
axial and
girdle muscles
Rubrospinal Red nucleus Ventral
midbrain
Lateral column
(anterior to lateral
corticospinal tract)
Cervical
interneurons
Control of
contralateral
muscles
(especially
flexor)b
Vestibulospinal Vestibular
nuclei
Medulla for
medial tract,
otherwise
uncrossed
Anterior column Ipsilateral and
contralateral
interneurons
Head and
neck position,
balance,
center of
gravity
Reticulospinal Pontine and
medullary
reticular
formation
Uncrossed Lateral, anterior
columns
Ipsilateral
interneurons
Contribute
to automatic
posture and
gait control
Tectospinal Superior
colliculus
Dorsal
midbrain
Anterior column Contralateral
interneurons in
cervical cord
Reflex head
movement
to visual,
auditory,
sensory
stimulib
Descending
autonomic
fibersa
Hypothalamus,
brainstem nuclei
None Lateral columnc
Ipsilateral
thoracic
sympathetic,
sacral
parasympathetic
neurons
Autonomic
outputs
a
Most relevant for clinical localization.
b
Function unclear in humans.
c
Poorly defined (diffuse) tract.
21

muscle responsible for voiding. When the
pontine micturition center signals the
voluntary somatic relaxation of the ure-
thral sphincter, reflex inhibition of sympa-
thetic bladder neck contraction occurs,
along with activation of the parasympa-
thetic detrusor contraction. This cascade
is further stimulated by the flow of urine,
and once urine flow stops, a urethral reflex
triggers sphincter contraction.
The parasympathetic system is the
dominant driver of autonomic bladder
control. Isolated lesions to the sympa-
thetic fibers have less of an impact on
bladder dysfunction, and, generally,
spinal cord lesions must be bilateral to
impact bladder function, as well as
bowel and sexual function. A spinal
cord lesion above S2 that disrupts
descending somatic and voluntary path-
ways will cause an initial hypotonic
(flaccid) bladder with reflex contraction
of the urethral sphincter. The bladder
will retain urine and eventually may
have some overflow incontinence. This
is analogous to ‘‘spinal shock,’’ in which
weakness from a spinal cord injury is
initially flaccid. Over weeks to months,
lesions in the spinal cord above S2 will
cause a hypertonic (spastic bladder) in
which the disinhibited detrusor may
contract or spasm in response to small
amounts of bladder filling. The reflex
pathway between detrusor and sphincter
also may become incoordinated, and the
urethral sphincter may spasm, preventing
complete voiding. This combination leads
to urinary frequency, urinary urgency, or
urge incontinence, and is often referred
to as a neurogenic bladder. By contrast,
lesions at S2 to S4 or their roots disrupt
both somatic and parasympathetic motor
inputs to detrusor and sphincter muscles,
as well as afferent information about
bladder filling. This tends to cause a
persistent hypotonic bladder and a hypo-
tonic sphincter, leading to urinary reten-
tion and overflow incontinence.4
Spinal cord lesions disrupting de-
scending autonomic inputs also affect
bowel, sexual, and cardiovascular func-
tions. Constipation may result from lesions
anywhere in the spinal cord. Spinal cord
lesions above S2 cause an acutely flaccid
anal sphincter, followed by the develop-
ment of spastic sphincter contraction,
KEY POINTS
h The control of bladder
function involves
complex interactions
between somatosensory,
somatomotor,
parasympathetic, and
sympathetic systems and
serves as an important
clinical indicator of spinal
cord function.
h Generally, cord lesions
must be bilateral to
impact bladder function,
as well as bowel and
sexual function.
FIGURE 1-4 Principle white matter tracts of the spinal cord.

which further contributes to constipation.
Lesions at S2 to S4 or peripherally will
cause both loss of anal tone and decreased
intestinal motility below the splenic flexure.
Thus,constipationpredominatesinchronic
spinal cord injuries, but fecal incontinence
may also be a problem. Sexual dysfunc-
tion may occur in men and women from
spinal cord injuries at any level.
Lesions (usually severe and acute)
above T6 may lead to a phenomenon of
autonomic dysreflexia. A stimulus, either
noxious or non-noxious, below the spinal
cord lesion is hypothesized to trigger a
sympathetic surge leading to vasocon-
striction and elevation in blood pressure
and heart rate. The intact carotid and
aortic baroreceptors detect this increase
and relay with brainstem and hypotha-
lamic centers. Normally, these centers
would signal an inhibition to the pregan-
glionic sympathetic neurons in the tho-
racic cord, but this feedback is disrupted.
The parasympathetic counterbalance is
also directly activated, leading to vasodi-
latation and bradycardia. Because it does
not reach below the T6 level, however,
the parasympathetic signal does not
affect the large splanchnic vascular bed,
and hypertension persists. For more
information, refer to the articles ‘‘Man-
agement of Acute Spinal Cord Injury’’ by
Deborah M. Stein, MD, MPH, FACS,
FCCM, and Kevin N. Sheth, MD, FAHA,
FCCM, FNCS, as well as the article
‘‘Management of Chronic Spinal Cord
Dysfunction’’ by Gary M. Abrams, MD,
FAAN, and Karunesh Ganguly, MD, PhD,
in this issue of .
CROSS-SECTIONAL SPINAL
CORD LOCALIZATION
Classic spinal cord syndromes are de-
scribed based on the cross-sectional ana-
tomical organization of the spinal cord,
vascular supply, and surrounding struc-
tures of the spinal cord (Table 1-3).4Y6
These syndromes are useful clinical
models to organize neurologic localization
as an aid to diagnosis of specific diseases,
butVas with any syndromeVthe classifi-
cations are not completely specific and
must be taken in the context of other
symptoms and signs, neuroimaging, and
ancillary data.
Complete Cord Transection
In complete transection, all descend-
ing and ascending pathways are sev-
ered (Figure 1-4). Typically, a spinal
sensory level to all modalities will be
found one to two segments below the
actual level of injury. A flaccid paralysis
(spinal shock) and associated ‘‘flaccid’’
autonomic dysfunction may occur
acutely below the level of injury. Over
time, spasticity and hyperreflexia ensue
below the level of the lesion, with a
segmental anterior horn syndrome
sometimes present at the level of the
lesion. Some transverse lesions are
incomplete, depending on the severity
of the injury. When due to inflamma-
tion, this syndrome is termed transverse
myelitis. Longitudinally extensive le-
sions can cause chronic flaccid weak-
ness if the anterior horns are involved
throughout the length of the spinal
cord. Neuromyelitis optica (NMO)
causes a fulminant transverse and often
longitudinally extensive myelitis that
may affect all columns of the spinal
cord. Paraneoplastic necrotizing mye-
lopathy is a relentless progressive mye-
lopathy that extends longitudinally over
days to weeks. Late radiation-induced
myelopathy (radiation myelitis) causes a
slowly progressive spinal cord syn-
drome 6 to 24 months after exposure,
which may begin as partial, but can
involve the entire cross-sectional cord.
For more information on radiation and
paraneoplastic myelopathies, refer to the
article ‘‘Neoplastic Myelopathies’’ by
Marc C. Chamberlain, MD, FAAN, in this
issue of . Additionally,
for more information on inflammatory
myelopathies, including NMO, refer to the
KEY POINTS
h Lesions (usually severe
and acute) above T6
may lead to a
phenomenon of
autonomic dysreflexia.
h Longitudinally extensive
lesions can cause chronic
flaccid weakness if the
anterior horns are
involved throughout the
length of the cord.
23

TABLE 1-3 Cross-sectional Spinal Cord Localization
Syndrome Clinical Features Selected Causes
Complete cord transection Bilateral upper motor neuron (UMN)
pattern weakness below level
Trauma, transverse myelitis,
hemorrhage, epidural abscess or
metastasis, paraneoplastic necrotizing
myelopathy, late radiation-induced
myelopathy
Bilateral sensation loss below level
Autonomic function loss below level
Hemicord (Brown-Séquard
syndrome)
Ipsilateral UMN pattern weakness
below level
Penetrating trauma, multiple sclerosis,
varicella-zoster virus, asymmetric
compression
Ipsilateral lower motor neuron (LMN)
pattern weakness at level
Ipsilateral vibration and position
sensation loss below level
Contralateral pain and temperature
Central cord syndrome Small lesion: suspended pain and
temperature sensation sensory level
Hyperextension injury, syringomyelia,
intramedullary tumor, neuromyelitis
optica
Large lesion: segmental LMN pattern
weakness at level
Bilateral UMN pattern weakness
below level (arms worse than legs)
Bilateral pain and temperature
sensation loss below level (sacral sparing)
Posterior column syndrome Bilateral vibration and position
Tabes dorsalis, cervical spondylotic
myelopathy, posterior spinal artery
infarction, early delayed
radiation-induced myelopathy
Absent reflexes (knees, ankles)
Sensory ataxia
Lhermitte sign (cervical)
Posterolateral column
syndrome
Bilateral vibration and position
Vitamin B12 deficiency, copper
deficiency, cervical spondylotic
myelopathy, HTLV-I-associated
myelopathy/tropical spastic paraparesis,
hereditary spastic paraplegia, HIV,
paraneoplastic myelitis
Bilateral UMN pattern weakness
below level
Sensory ataxia, spastic gait
Anterior horn syndrome Diffuse LMN pattern weakness Poliovirus, West Nile virus, spinal
muscular atrophy, spinobulbar
muscular atrophy, paraneoplastic
subacute motor neuronopathy
Combined anterior horn
and corticospinal tract
disease
Diffuse combined UMN pattern
weakness and LMN pattern
weakness
ALS, cervical radiculomyelopathy
Bulbar weakness
Pure motor syndrome
Continued on next page

article ‘‘Immune-Mediated Myelopathies’’
by Benjamin M. Greenberg, MD, MHS,
and Elliot M. Frohman, MD, PhD, FAAN,
in this issue of .
Hemicord (Brown-Séquard)
Syndrome
Hemicord injury disrupts descending
corticospinal fibers that have already
crossed in the pyramidal decussations,
leading to ipsilateral upper motor
neuron weakness below the level of
the lesion (Figure 1-5). If affecting the
anterior horn, ipsilateral lower motor
neuron weakness occurs in a segmen-
tal fashion at the level of the lesion,
which may cause hemidiaphragm pa-
ralysis if it occurs at the level of C4 or
above. This lower motor neuron
weakness may be hard to identify
clinically in thoracic lesions. Hemicord
lesions lead to ipsilateral impairment
of vibration and position sense below
the level of the lesion (uncrossed
ascending posterior columns) but
affects contralateral pain and tem-
perature sensation (anterolateral
spinothalamic tract) from one to two
segments below the lesion, as these
pathways cross within one to two
segments from entering the spinal
cord. Radicular pain (root irritation)
or complete hemianesthesia (dorsal
root compromise) at the level of the
lesion may sometimes help localize
the level. Damage to descending
autonomic fibers may lead to ipsilat-
eral loss of sweat below the lesion
and ipsilateral Horner syndrome if
the lesion is in the cervical region.
Bladder dysfunction does not occur
because this requires bilateral disrup-
tion of descending autonomic path-
ways. Penetrating trauma (eg, knife
or gunshot) is a classic cause of hemi-
cord syndrome, but can occur as a
result of any cause of asymmetric spinal
cord dysfunction.
Central Cord Syndrome
A small central cord lesion disrupts
bilateral-crossing spinothalamic fibers
KEY POINT
h Hemicord lesions lead to
ipsilateral impairment of
vibration and position
sense below the level of
the lesion (uncrossed
ascending posterior
columns) but affects
contralateral pain and
temperature sensation
(anterolateral
spinothalamic tract)
from one to two segments
below the lesion, as these
pathways cross within
one to two segments
from entering the
spinal cord.
TABLE 1-3 Cross-sectional Spinal Cord Localization (Continued)
Syndrome Clinical Features Selected Causes
Anterior cord syndrome Bilateral LMN pattern weakness
at levels affected
Anterior spinal artery infarction,
poliovirus, West Nile virus
Bilateral UMN pattern weakness below
Bilateral pain and temperature
Autonomic function loss below level
Bilateral vibration and position
sensation spared
Sensory neuronopathy Isolated bilateral nonYlength-dependent
sensory loss
Paraneoplastic, SjPgren syndrome,
celiac disease, chemotherapy,
pyridoxine toxicity
Sensory ataxia
Conus medullaris
syndrome
Flaccid bladder dysfunction early
in course
Lumbar disk disease, trauma,
epidural metastasis or abscess (L1 or
L2), cytomegalovirus, schistosomiasis
Bilateral ‘‘saddle’’ sensory loss
Mild bilateral lumbosacral LMN
pattern weakness
HTLV-I = human T-cell lymphotropic virus type I; HIV = human immunodeficiency virus; ALS = amyotrophic lateral sclerosis.
25

passing in the anterior commissure,
causing loss of pain and temperature in
one or more adjacent dermatomes
bilaterally at the level of the lesion
(Figure 1-6). Because the anterolateral
tracts themselves are spared, sensation
above and below the lesion remains
intact, leading to a ‘‘suspended’’ sensory
level. As these lesions commonly affect
the lower cervical and upper thoracic
cord, the sensory loss is classically seen in
a ‘‘cape’’ or ‘‘vest’’ distribution across the
neck and shoulders or trunk, respectively.
As a central lesion enlarges, it encroaches
FIGURE 1-6 Central cord syndrome.
S = sacral; L = lumbar; T = thoracic; C = cervical.
FIGURE 1-5 Hemicord (Brown-Séquard) syndrome.

on anterior horn cells, causing segmental
lower motor neuron weakness at the
level of the lesion. Further expansion
affects the lateral corticospinal tracts and
anterolateral tracts, causing upper motor
neuron weakness and temperature and
sensation loss below the lesion. Due to
the more lateral location of sacral fibers in
the anterolateral tract, sacral sensation
may be spared (sacral sparing). In an
acute central cord lesion (typically from
severe cervical hyperextension injury),
initial quadriplegia evolves into a more
prominent upper extremity upper motor
neuron pattern weakness with relative
sparing of the lower extremities, referred
to as man-in-the-barrel syndrome. This syn-
drome may be due to the somatotopic
pattern of the lateral corticospinal tracts,
in which the cervical fibers are more
centrally arranged and lumbosacral fibers
are more laterally arranged. In addition
to hyperextension injury, other common
causes of central cord syndrome include
syringomyelia and intramedullary tumor.
NMO may affect the central cord initially
but typically expands to a complete
transverse cord syndrome.
Posterior Column Syndrome
Damage to the posterior columns in
isolation causes impairment in vibration
and proprioception and a pronounced
sensory ataxia with a ‘‘stomping’’ gait
(Figure 1-7). If the dorsal roots are
involved (as in tabes dorsalis), reflexes
are absent, especially in knees and
ankles, but strength is usually preserved.
Cervical involvement may be accompa-
nied by Lhermitte sign, presumably due
to aberrant mechanical activation of
damaged posterior columns with neck
flexion. Injury to the spinocerebellar
tracts in isolation may cause a truncal
ataxia with preserved conscious proprio-
ceptive sensation, which may be the only
sign early in the course of extrinsic
epidural compression, possibly reflecting
a unique vulnerability of spinocerebellar
tracts to compressive ischemia. In pa-
tients with chronic posterior column
dysfunction, the loss of joint sensation
may lead to repeated microtrauma, and
dysregulated autonomic control of
blood flow to the joints increases
osteoclastic resorption, both causing
neuropathic joints (Charcot arthropathy).
KEY POINTS
h In an acute central cord
lesion (typically from
severe cervical
hyperextension injury),
initial quadriplegia
evolves into a more
prominent upper extremity
upper motor neuron
pattern weakness with
relative sparing of the
lower extremities,
referred to as man-in-
the-barrel syndrome.
h Damage to the posterior
columns in isolation
causes impairment in
vibration and
proprioception and a
pronounced sensory
ataxia with a
‘‘stomping’’ gait.
FIGURE 1-7 Posterior column syndrome.
27

Tabes dorsalis due to neurosyphilis is
the canonical disease associated with
posterior column syndrome, but early
cervical spondylotic myelopathy is the
most common cause. Early delayed
radiation-induced myelopathy pre-
sumably causes temporary demyelin-
ation in the posterior columns,
manifested mainly by Lhermitte sign.
Although the posterior columns con-
stitute a vascular territory, the robust
plexus and paired posterior spinal
arteries make infarcts in this distribu-
tion extremely rare.
Posterolateral Column
Syndrome
Involvement of the posterior columns
and lateral corticospinal tracts leads to
impairments in vibratory and proprio-
ceptive sensation and upper motor
neuron weakness, with relative spar-
ing of pain and temperature sensation
(Figure 1-8). Patients develop a spas-
tic and ataxic gait, and reflexes may be
increased due to corticospinal tract
disruption, but may also be depressed
(especially ankle jerks) due to con-
comitant involvement of large myelin-
ated peripheral nerves. Descending
autonomic pathways may also be in-
volved, leading to a spastic bladder.
Vitamin B12 deficiency classically causes
this pattern of subacute combined de-
generation, and copper deficiency can
cause a similar syndrome. For more
information on myelopathy related to
vitamin B12 and copper deficiency, refer
to ‘‘Metabolic and Toxic Causes of Mye-
lopathy’’ by Brent P. Goodman, MD, in
this issue of .
Posterior extrinsic compression, as in
cervical spondylosis, may cause a similar
posterolateral column syndrome.
Paraneoplastic myelitis may cause lateral,
posterior, or combined posterolateral
column syndrome. In some posterolat-
eral column processes, the clinical in-
volvement of the posterior columns is
less manifest, leading to an upper motor
neuron pattern with bladder dysfunc-
tion, but with only mild or subclinical
sensory impairment (eg, Human T-cell
lymphotropic virus type IYassociated
myelopathy/tropical spastic paraparesis
and hereditary spastic paraplegia).
FIGURE 1-8 Posterolateral cord syndrome.
KEY POINT
h In some posterolateral
column processes, the
clinical involvement of
the posterior columns is
less manifest, leading to
an upper motor neuron
pattern with bladder
dysfunction but only
mild or subclinical
sensory impairment.

Anterior Horn Syndrome
Selective damage to anterior horn cells
causes a flaccid weakness with atrophy
and fasciculations with reduced or
absent reflexes (Figure 1-9). Cranial
motor nuclei may also be involved, and
no sensory involvement occurs. Polio-
virus is the textbook example of a disease
causing this syndrome. Other nonpolio
enteroviruses and flaviviruses such as
West Nile virus and Japanese encepha-
litis virus may also primarily affect the
anterior horn. For more information on
infectious myelopathies, refer to the
article ‘‘Myelopathy Associated with
Microorganisms’’ by Jennifer L. Lyons,
MD, in this issue of .
In children, spinal muscular atrophy
is the most important cause of anterior
horn syndrome. Spinobulbar muscular
atrophy (Kennedy disease) causes a
slowly progressive anterior horn syn-
drome in men ages 20 to 60. Lower
motor neuron disease associated with
paraneoplastic subacute motor neuro-
nopathy is infrequently reported.
Combined Anterior Horn and
Corticospinal Tract Disease
The combination of upper and lower
motor neuron signs with sparing of
sensory function is a distinctive pattern
most suggestive of ALS (Figure 1-10).
Cramping is a commonly associated
symptom, but bladder function is typi-
cally preserved due to sparing of the
sacral motor neurons in the Onuf
nucleus. Cervical radiculomyelopathy
can cause a segmental lower motor
neuron pattern of weakness with upper
motor neuron findings below the lesion.
Anterior Cord Syndrome
Due to the vascular territory of the
anterior spinal artery, this syn-
drome involves lateral corticospinal
tracts, anterior horns, spinothala-
mic tracts, and descending autonomic
fibers, but spares posterior columns
(Figure 1-11). Patients have an upper
motor neuron pattern of weakness,
loss of pain and temperature below the
level of the lesion, bladder incontinence,
KEY POINT
h In anterior (spinal artery)
cord syndrome, patients
have an upper motor
neuron pattern of
weakness, loss of pain
and temperature below
the level of the lesion,
and bladder incontinence
but preserved vibration
and position sense.
FIGURE 1-9 Anterior horn syndrome.
29

but preserved vibration and position
sense, which is sometimes referred to
as anterior spinal artery syndrome as it
was originally defined by ischemic
damage to the vascular territory. For
more information, refer to the article
‘‘Vascular Myelopathies’’ by Alejandro
A. Rabinstein, MD, FAAN, in this issue
of . Some processes
that cause anterior horn syndrome
(eg, West Nile virus) can extend into
the lateral columns but spare the
posterior columns, leading to an ante-
rior cord syndrome.
FIGURE 1-11 Anterior cord (anterior spinal artery) syndrome.
FIGURE 1-10 Combined anterior horn and corticospinal tract disease.

KEY POINTS
h A spinal sensory level
is the most useful
sign to determine
longitudinal localization.
h Lesions between C5
and T1 are most readily
localized when they
cause radicular pain and
numbness and segmental
lower motor neuron
weakness with a
caudal upper motor
neuron pattern.
Sensory Neuronopathy
The dorsal root ganglia neurons are
rarely selectively injured, leading to a
nonYlength-dependent pure sensory syn-
drome, involving both posterior columns
and peripheral sensory nerve fibers.
Patients have dysesthesia, areflexia, and
severe sensory ataxia, which may occur as
part of a paraneoplastic syndrome or in
the setting of systemic connective tissue
disease, especially Sjögren syndrome.
Although not strictly a spinal cord syn-
drome, sensory neuronopathy may in-
volve the posterior columns and often
progresses to myelitis in paraneoplastic
disease. Platinum-based chemotherapy
and pyridoxine toxicity are other causes
of sensory neuronopathy.
LONGITUDINAL SPINAL CORD
LOCALIZATION
In addition to cross-sectional cord syn-
dromes, certain clinical features can be
the clues to the longitudinal spinal level
of injury (Table 1-4).4,7
A spinal sensory
level is the most useful sign to determine
longitudinal localization. Typically, the
lesion is two segments rostral to the
sensory level. Additionally, other seg-
mental signs can be useful to help refine
longitudinal localization.
Cervicomedullary Junction and
Upper Cervical Spinal Cord
Lesions at the cervicomedullary junction
that affect the pyramidal decussations
may cause an ‘‘around the clock’’ pat-
tern of weakness. Because the upper
extremity pyramidal fibers cross more
rostral to the lower extremity pyramidal
fibers and the fibers for one side
frequently cross completely before the
other, an upper motor neuron pattern
of weakness spreads from ipsilateral
upper extremity, to ipsilateral lower
extremity, to contralateral lower extrem-
ity, to contralateral upper extremity. With
extrinsic lesions, pain in the occiput and
neck are common. Obstruction of CSF
outflow at the foramen may lead to
downbeat nystagmus and papilledema.
Extension into the caudal brainstem may
cause lower cranial nerve palsies. High
cervical cord lesions may cause
diaphragmatic weakness and respiratory
failure as the phrenic nerve arises from
rootlets at C4-C5. The spinal trigeminal
nucleus descends as low as C4, so
cervical lesions above that level may
cause facial numbness in a circumfer-
ential ‘‘onion skin’’ pattern. It is im-
portant to note that high cervical lesions
can sometimes manifest with lower
cervical and upper thoracic lower motor
neuron signs, presumably due to venous
congestion or anterior spinal artery
compression affecting the more caudal
anterior horns. Extramedullary causes of
foramen magnum and high cervical
lesions include meningioma, neurofibro-
ma, glioma, spondylosis, Chiari malfor-
mation, and trauma; intramedullary
etiologies include syringomyelia, multi-
ple sclerosis (MS), and NMO.
Lower Cervical and Upper
Thoracic Spinal Cord
Lesions between C5 and T1 are most
readily localized when they cause
radicular pain, numbness, and seg-
mental lower motor neuron weakness
with a caudal upper motor neuron
pattern. At C5-C6, lesions lead to de-
pression of biceps and brachioradialis
reflexes with exaggerated triceps and
finger flexor reflexes. Tapping the
brachioradialis causes no flexion or
supination of the forearm, but elicits a
brisk finger flexor response. With le-
sions at C7, biceps and brachioradialis
reflexes are preserved, triceps reflex is
depressed, and finger flexor reflex is
exaggerated. At C8-T1, the finger flexor
reflex is depressed. Involvement of the
sympathetic outflow from the inter-
mediolateral cell column at C8-T1 may
cause Horner syndrome and provide a
clue to this localization.
31

Thoracic Spinal Cord
A sensory level and dermatomal pain
(eg, intercostal neuralgia) are the most
obvious indicators of thoracic cord le-
sions. Because of the minimal motor
TABLE 1-4 Longitudinal Spinal Cord Localization
Cord Location/Syndrome Clinical Features Notes
Foramen magnum/upper cervical Occipital, neck pain False localizing signs include
C6 to T3 sensory and lower
motor neuron (LMN) signs
‘‘Around the clock’’ upper motor
neuron (UMN) weakness
Lower cranial nerve signs Causes include meningioma,
neurofibroma, glioma,
syringomyelia, trauma,
spondylosis, Chiari
malformation, multiple
sclerosis, and neuromyelitis
optica
Downbeat nystagmus
Diaphragmatic paralysis
Trigeminal ‘‘onion skin’’ numbness
Lower cervical/upper thoracic Radicular pain and numbness Extramedullary compressive
lesions most common
Segmental LMN weakness,
UMN weakness caudal
Segmental areflexia with
hyperactive reflexes caudal
Thoracic Dermatomal pain and sensory level Autonomic dysreflexia if
lesion above T6; lesions
tend to be more complete
due to small diameter and
relative vascular border zone
T6 to T12 superficial spinal reflexes
T10 Beevor sign
Lumbosacral Radicular pain and numbness Extramedullary compressive
lesions most common
Segmental LMN weakness, UMN
weakness caudal
Segmental areflexia with hyperactive
reflexes caudal
Conus medullaris Flaccid bladder dysfunction early
in course
Lumbar disk disease, trauma,
epidural metastasis or abscess
(L1 or L2), cytomegalovirus,
schistosomiasis
Bilateral ‘‘saddle’’ sensory loss
Mild bilateral lumbosacral LMN
weakness
Cauda equina Radicular pain Lumbar disk disease, trauma,
epidural metastasis or abscess
(L3 or lower), cytomegalovirus,
schistosomiasis
Asymmetric lumbosacral sensory loss
Marked asymmetric lumbosacral LMN
weakness
Flaccid bladder dysfunction late
in course
Absent reflexes (knees, ankles)
control by thoracic motor neurons, seg-
mental lower motor neuron involvement
is not readily apparent. Because of
the small diameter and the relative
vascularYborder-zone territory of the

thoracic cord, lesions tend to progress
to complete cord syndrome more
rapidly than in the cervical and lumbar
regions. Lesions above T6 may lead to
autonomic dysreflexia due to disrup-
tion of sympathetic outputs from the
splanchnic vascular bed. T6 lesions
will also abolish superficial spinal (ab-
dominal) reflexes. Lesions at T10 will
spare the upper and middle abdomi-
nal reflexes, but the lower abdominal
reflex will be absent, and lesions
below T12 will not affect superficial
abdominal reflexes. Another unique
indicator of a T10 lesion is a Beevor
sign. With neck flexion against resis-
tance (eg, abdominal crunch), pre-
served upper abdominal muscles will
pull the umbilicus upward against the
weakened lower abdominal muscles.
Lumbosacral Spinal Cord
As with lower cervical and upper tho-
racic cord lesions, the segmental lower
motor neuron weakness pattern and
reflexes can help refine localization to
specific levels. A lesion at L1 will cause
spastic paraparesis with increased patel-
lar and ankle reflexes. Lesions from L2
to L4 will cause varying patterns of
weakness and numbness corresponding
to segmental levels, with loss of patellar
reflexes and increase in ankle jerks,
while an L5 lesion will spare patellar
reflexes and cause hyperactive ankle
reflexes. Finally, S1-S2 lesions will abol-
ish the ankle reflexes without impacting
the patellar.
Conus Medullaris and Cauda
Equina Syndromes
Lesions affecting the conus medullaris
(sacral spinal cord, typically vertebral
level L2 [Figure 1-1]) cause early flaccid
bladder and bowel dysfunction, late and
mild pain, and symmetric sensory im-
pairment in a saddle distribution. Sen-
sory loss may be dissociated. Ankle
jerks (S1) are absent, but knee jerks
(L2 to L4) are typically preserved. Motor
impairment is relatively mild and sym-
metric. Conus medullaris syndrome can
be impossible to differentiate from
cauda equina syndrome on clinical
grounds. Due to lesions affecting the
lumbosacral nerve roots, cauda equina
syndrome is typically heralded by radic-
ular pain in one or both lower extrem-
ities, asymmetric sensory loss to all
modalities in the lumbosacral derma-
tomes, and onset of bladder and bowel
dysfunction occurring later in the
course compared with conus medullaris
syndrome. Weakness is generally more
marked and asymmetric compared with
conus medullaris syndrome, and ankle
and knee jerks are absent. External
compression due to disk herniation,
epidural metastasis, or epidural abscess
may cause either syndrome, depending
on location. Certain infections, particu-
larly cytomegalovirus and schistosomia-
sis, have a tropism for the conus and
lumbosacral nerve roots. For more
information on cauda equina syndrome,
refer to article ‘‘Disorders of the Cauda
Equina’’ by Andrew W. Tarullli, MD, in
this issue of .
CLINICAL APPROACH
When considering the diagnosis of a
spinal cord lesion, the first step is to
determine if the lesion is compressive
as this constitutes a surgical emergency
when symptoms present acutely. While
not completely specific, several features
can help differentiate compressive
extramedullary processes from intra-
medullary lesions. Extramedullary le-
sions cause radicular pain, which is
exacerbated by movement, a Valsalva
maneuver, straight leg raise, neck flex-
ion, and notably recumbent positioning.
Vertebral pain is localized to the level of
the lesion and may be worsened with
palpation or percussion. Central pain is
more characteristic of intramedullary
lesions affecting the spinothalamic
KEY POINTS
h Due to lesions affecting
the lumbosacral nerve
roots, cauda equina
syndrome is typically
heralded by radicular
pain in one or both
lower extremities,
asymmetric sensory
loss to all modalities
in the lumbosacral
dermatomes, and onset
of bladder and bowel
dysfunction occurring
later in the course
compared with conus
medullaris syndrome.
h When considering the
diagnosis of a spinal
cord lesion, the first step
is to determine if the
lesion is compressive as
this constitutes a
surgical emergency
when symptoms
present acutely.
33

tracts or posterior columns and is
usually described as vague and deep,
often in places distant from the actual
lesion. Because the corticospinal tracts
are situated laterally, upper motor neu-
ron signs occur early in extramedullary
compressive lesions, whereas lower
motor neuron involvement is more
suggestive of intramedullary processes
(Figure 1-4). The exception is seg-
mental lower motor involvement that
sometimes occurs at the level of a
compressive lesion. In general, extra-
medullary lesions will affect ipsilateral
upper and lower extremity motor
function before progressing to contra-
lateral weakness, whereas intramedullary
lesions are more likely to simultaneously
cause bilateral (especially upper ex-
tremity) motor dysfunction. In addition
to radicular sensory changes, ascending
sensory loss typifies extramedullary le-
sions as the superficially situated caudal
dermatomes are most susceptible to
compression early. Conversely, intra-
medullary lesions cause descending
sensory loss with sacral sparing as
those fibers are most lateral. Bladder
and bowel disturbances due to lesions
above S2 to S4 usually occur only with
bilateral lesions. In conus medullaris
syndrome, (intramedullary) sphincter
dysfunction is an early feature com-
pared with external compression of
cauda equina. While these general
patterns can aid in clinical localization,
the clinician cannot rely fully on
symptoms and signs to exclude a
compressive lesion and should obtain
neuroimaging to exclude this neuro-
logic emergency.
While the longitudinal and cross-
sectional features discussed previously
in the article are useful tools, false
localizing signs and other misleading
presentations should always be consid-
ered. As noted, external cord compres-
sion may cause ascending sensory loss,
and this pattern may be mistaken for
Guillain-Barré syndrome. In a cord
lesion, reflexes typically will be pre-
served or increased, but reflexes may
be depressed or absent (spinal shock)
early in the injury. Similarly, when the
anterior horns are involved, a flaccid
weakness will predominate, which may
falsely suggest a peripheral process.
Exacerbation of symptoms with exer-
tion may occur with lumbar spinal
stenosis (neurogenic claudication) or
with peripheral vascular disease (vascu-
lar claudication). Less commonly, spinal
dural arteriovenous fistulas may be
associated with exertional worsening
due to increased venous congestion.
The Uhthoff sign of worsening demye-
linating disease symptoms due to heat
may be interpreted as exertional wors-
ening. Lesions at the cervicomedullary
junction can manifest with an unusual
pattern of weakness owing to the
sequential decussation of upper and
lower extremity pyramidal fibers from
one side before the other. High- to
midcervical lesions can sometimes
cause a lower motor neuron pattern
several levels caudal to the lesion,
presumably due to venous congestion
below the lesion. A numb clumsy hand
syndrome can occur with compressive
lesions that compromise the central
border zone between superficial and
deep arterial supply in the lower cervi-
cal cord. Patients have a glove distribu-
tion of sensory loss with only mild
motor findings.
Knowledge of the syndromes de-
scribed in this article can refine cord
localization and point toward specific
etiologies. NeuroimagingValmost al-
ways MRIVshould be used to confirm
localization and better delineate the
degree of involvement. Other studies
such as brain MRI, CSF examination,
and neurophysiology studies are often
necessary to further characterize the
nature and extent of the process.
Targeted testing for specific diseases
KEY POINT
h In a spinal cord lesion,
reflexes typically will be
preserved or increased,
but reflexes may be
depressed or absent
(spinal shock) early in
the injury.

Vol 21.1_Spinal Cord Disorders.2015.pdf

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