Veterinary Neuroanatomy and Clinical Neurology

515 Pages·2008·53.84 MB·English

by  Alexander de Lahunta DVM PhD

11830 Westline Industrial Drive
St. Louis, Missouri 63146
VETERINARY NEUROANATOMY AND CLINICAL ISBN: 978-0-7216-6706-5
NEUROLOGY
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Neither the Publisher nor the Authors assume any responsibility for any loss or injury and/or
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expertise and knowledge of the patient, to determine the best treatment and method of
application for the patient.
The Publisher
Library of Congress Cataloging-in-Publication Data
DeLahunta, Alexander, 1932-
Veterinary neuroanatomy and clinical neurology / Alexander de Lahunta, Eric Glass.—
3rd ed.
p. ; cm.
Includes bibliographical references and index.
ISBN 978-0-7216-6706-5 (hardcover : alk. paper) 1. Veterinary neurology. 2. Veterinary
anatomy. 3. Neuroanatomy. I. Glass, Eric. II. Title.
[DNLM: 1. Anatomy, Veterinary. 2. Nervous System Diseases—veterinary. 3. Nervous
System—anatomy & histology. SF 895 D278v 2009]
SF895. D44 2009
636.089’18—dc22
978-0-7216-6706-5
Vice President and Publisher: Linda Duncan
Publisher: Penny Rudolph
Developmental Editor: Shelly Stringer
Publishing Services Manager: Julie Eddy
Project Manager: Laura Loveall
Designer: Teresa McBryan
Printed in China.
Last digit is the print number: 9 8 7 6 5 4 3 2
F
oreword
It is my profound privilege to write this foreword to the interpret MRIs of the brain and spinal cord, a technique that
third edition of Veterinary Neuroanatomy and Clinical came to the forefront of the specialty during the last decade
Neurology, a remarkable collaboration between Drs. of his career. As his resident, I had the unique opportunity
Alexander de Lahunta and Eric Glass. This anxiously antic- to observe Dr. de Lahunta develop an immediate and nat-
ipated textbook recaptures and updates the multifaceted ural mastery of MR imaging, which undoubtedly evolved
aspects of veterinary neurology, advanced neurodiagnos- from his vast experience studying gross and histopathologic
tics, neuroanatomy, and neuropathology, many aspects specimens from clinical cases. In the third edition, Dr. de
of which Dr. de Lahunta himself defined during his dis- Lahunta’s unique appreciation for the complexities of the
tinguished career at Cornell University. The third edition diseased nervous system, combined with Dr. Glass’ clinical
undoubtedly will withstand the test of time as an invaluable perspective derived from an immense caseload in specialty
contribution to the disciplines of veterinary internal medi- practice, seamlessly merge the disciplines of neuroanatomy
cine, neurology, and neurosurgery. and neuropathology together with clinical neurology and
The emphasis of the third edition remains the neuroana- state of the art neurodiagnostics.
tomic diagnosis, and this is accomplished elegantly in par- A foreword to this textbook would be remiss to ignore
allel with descriptions of key differential diagnoses and Dr. de Lahunta’s warmth, selflessness, and humanistic qual-
current diagnostic techniques. The textbook is referenced ities. Dr. de Lahunta has always found time to answer innu-
meticulously, providing the reader the opportunity to fur- merable formal and informal consultation requests from all
ther explore individual neurologic disorders. Hundreds of over the world, help students with their studies and proj-
color illustrations, case photographs, and web-based case ects, and mentor interns and residents, all the while mak-
videos are utilized to provide an invaluable resource for ing landmark contributions to the discipline of veterinary
the student, general practitioner, or specialist wishing to neurology. He has set the bar incredibly high for academic
develop or expand their understanding of neuroanatomy neurologists. We should all aspire to share of our time and
and clinical neurology. experiences with others as Dr. de Lahunta has done so grace-
Those who have been taught by or worked with Dr. de fully for over four decades.
Lahunta invariably conclude that he is one of the greatest In closing, the third edition of Veterinary Neuroanatomy
veterinary teachers of the past several generations. Dr. de and Clinical Neurology provides the critical building blocks
Lahunta’s innumerable college, national, and international necessary to gain competence in the discipline of veter-
teaching awards recognize his tremendous contributions to inary neurology. On behalf of neurologists world wide,
veterinary education. His inherent ability to teach such a I would like to thank Drs. de Lahunta and Glass for col-
complex topic is largely due to his steadfast commitment laborating on this new edition which promises to be the
to a vertically integrated learning process whereby neuro- new treatise of neuroanatomic localization and clinical
embryology, neuroanatomy, clinical neurology, and neu- neurology.
ropathology are taught as a continuum. For 42 years, Dr. Congratulations and please accept our sincere gratitude
de Lahunta preached that a basic understanding of neuro- for all of the time, energy, and wisdom you have shared
anatomy is indispensible for one to determine the anatomic with all of us through the years.
localization and, in turn, to generate the correct differen-
tial diagnosis in neurological patients. Dr. de Lahunta rec-
ognized early in his career that neuroanatomy and clinical
neurology are inseparable, and the third edition is a testa-
ment to this philosophy.
The inseparability of neuroanatomy and clinical neurol- Scott J. Schatzberg, DVM, PhD, DACVIM (Neurology)
ogy may be best epitomized by Dr. de Lahunta’s ability to University of Georgia College of Veterinary Medicine
vvii
P
reface
This third edition is a revision based on my 42 years of The emphasis of this third edition is the anatomic ­diagnosis,
experience in teaching a vertically integrated course which is the basis for the successful practice of clinical
in veterinary neuroanatomy and clinical neurology neurology and is presented in the form of case examples.
to first year veterinary students at the Cornell University Disease descriptions are presented in the form of differen­
College of Veterinary Medicine. The clinical information tial diagnoses of individual case examples. Although many
evolved from my experience as a consultant to the Teaching neurological disorders will be described, this revision makes
Hospital that received patients with neurological disorders, no attempt to present a complete synopsis of the veterinary
consulting with veterinary practitioners, and my involve­ neurological literature. This has been adequately covered in
ment with the neuropathological studies of hospital patients other textbooks of veterinary neurology. A unique feature of
and specimens sent to me by veterinary practitioners and this text is the linking of the case descriptions to videos of
pathologists. My studies were greatly enhanced by my these patients which are available on a website that is orga­
interaction with Drs. John Cummings and Brian Summers. nized by the chapters of this text. There are 380 videotapes
I consider these two colleagues as close friends and brilliant on this website that show most of the neurological disor­
veterinary scientists. ders that are described in this text. This can be accessed at:
When I first organized a course in neuroanatomy for the www.neurovideos.vet.cornell.edu.
veterinary curriculum at Cornell University in 1963, I was My coauthor, Dr. Eric Glass, is a former student of mine
strongly influenced by two outstanding veterinary patholo­ who graduated from the College of Veterinary Medicine at
gists who in 1956 and 1965 published their experiences in Cornell University in 1995. He is the senior neurologist at
correlating neurological signs with the location of lesions Red Bank Veterinary Hospital, a very active specialty prac­
in the nervous system.1,2 These were Dr. Jack McGrath at tice in Tinton Falls, New Jersey, where he has ten years of
the University of Pennsylvania and Dr. Tony Palmer at practice experience. Eric brings a clinician’s perspective to
Cambridge University. They set a standard that I wanted to the understanding of neuroanatomy. I am honored to have
pursue. I felt strongly that teaching neuroanatomy solely his contributions to this textbook. Eric and I have agreed
for the sake of the anatomical training was not a useful on most areas of controversy in clinical neurology and have
expenditure of the student’s limited time or that of the busy presented our combined opinions in this text. We present
teacher. It is the one system that needs to be closely cor­ these controversies as well as differences of opinion as chal­
related with the study of the clinical signs to be useful to lenges for the present and future veterinary neurologists to
the student as a veterinary practitioner. The teaching of support or deny.
clinical veterinary medicine is the primary objective of the Alexander de Lahunta
curriculum at Cornell University. Drs. McGrath and Palmer
set this standard that became the basis for my entire profes­
sional career and the correlated course that I taught to first
year veterinary students for 42 years. This course provided
all the useful neuroanatomy and clinical neurology simul­
taneously. This has been an exciting experience for me that
1. McGrath, JT: Neurologic ­examination ­of ­the ­dog ­with ­clini­
has been rewarded by observing the success of my students
copathologic ­observations, 1956, Philadelphia, PA, Lea and
in this clinical specialty and by observing the satisfaction Febiger.
expressed by the students who have mastered the ability to 2. Palmer, AC: Introduction ­to ­animal ­neurology, 1965, Phila­
diagnose neurological disorders. delphia, PA, F.A. Davis.
vii
C h a p t e r
1
I
ntroductIon
OBJECTIVE FUNCTIONAL SYSTEMS Proprioception
General Proprioception
ACCURATE DIAGNOSIS SENSORY (AFFERENT)
Special Proprioception
Malformations Somatic Afferent
Inflammations General Somatic Afferent MOTOR (EFFERENT)
Injuries Special Somatic Afferent General Somatic Efferent
Neoplasias Visceral Afferent General Visceral Efferent
Degenerations General Visceral Afferent
Special Visceral Afferent FURTHER READING
NEURON
Objective should first attempt to determine whether all the clinical
signs can be explained by a lesion at one site in the nervous
This book was written primarily for the veterinary student system, a focal lesion, because they are more common than
and secondarily for the veterinary practitioner. It is orga- multifocal or diffuse disorders. Based on this anatomic diag-
nized to provide the veterinary student with an anatomic nosis, you will next establish a list of disorders that must
basis and sufficient information about the development, be able to affect the anatomic location of the lesion. This
organization, and function of the nervous system to be able is the differential diagnosis. You will learn various ways to
to understand and diagnose the more common disorders of remind yourself of the disorders to consider. One way is the
the nervous system of domestic animals. For the most part, MIIND system (malformation, injury, inflammation, neo-
these disorders are described in the chapter that discusses plasia, and degeneration).
the functional system primarily affected by the disorder.
Malformations
AccurAte DiAgnOsis Malformations are the disorders that result from abnormal
development of the nervous system.
The major objective of this book is to teach enough of the
morphologic and physiologic features of the nervous sys-
inflammations
tem to enable the student to make an accurate localization
of the lesion in the nervous system. This is the anatomic Inflammations involve a pathologic process and a reaction
diagnosis. The differential diagnosis is totally dependent of blood vessels and tissues to physical, chemical, and bio-
on the anatomic diagnosis and that, in turn, determines logic agents—the reaction of a tissue to an irritant. In the
the ancillary procedures that will be prioritized to arrive at nervous system, this commonly refers to the tissues’ reac-
the most accurate presumptive clinical diagnosis and the tion to a microorganism or an immune system abnormality.
subsequent selection of treatment. Suppurative inflammation is characterized by a neutrophilic
The diagnosis of clinical neurologic disorders starts with response and the products of necrosis of tissue and inflam-
recognition of the problem—the clinical signs exhibited by matory cells usually caused by a bacterium, protozoa, or
the patient and your neurologic examination. This visual fungus. Nonsuppurative inflammation is characterized by
and hands-on experience is difficult to learn by reading a lymphocytic or monocytic response and is usually caused
text descriptions. Direct contact with the affected patient by a viral agent or an immune system abnormality.
is the ideal teaching model but is impractical in a teaching
environment. The most effective alternative is to visualize
injuries
the clinical signs using video technology. This third edition
includes linkage to a website consisting of 381 videos that Injuries occur when nervous tissue undergoes traumatic
provide the student with the classical appearance of the com- disturbance deriving from external or internal sources.
mon disorders of the nervous system of domestic animals. These cause acute or chronic displacements and disruptions
The anatomic diagnosis is determined by the nature of the or vascular impairment of the nervous tissue, which may
problem; that is, clinical signs that you have observed. You result in hemorrhage, edema, or parenchymal necrosis.

 VeterInary neuroanatomy and clInIcal neurology
neoplasias a stimulus from the internal or external environment is
converted into an impulse in the neuron. The axon is the
Neoplasias are uncontrolled growth of cells. Primary cen-
cell process composed of neurofilaments that course from
tral nervous system (CNS) neoplasias include the uncon-
the dendritic zone to the telodendron. The telodendron
trolled growth of nervous tissue cells—neurons, glia, and
is the termination of the neuron where the impulse leaves
ependyma. Metastatic neoplasia of the nervous system is
the neuron. It is often referred to as the synapse. This syn-
the spread of primary neoplasms in other body tissues to
apse may lie at an effector organ or at another neuron. The
the nervous system.
cell body consists of the nucleus and the major organelles
necessary for the neuron to function and may be located
anywhere along the axon.
Degenerations
For example, a sensory neuron in the peripheral nervous
Degenerations include the deterioration of cells due to lack system for general proprioception may have its dendritic
of blood supply (ischemia), abnormal cellular metabolism zone in a neuromuscular spindle in a skeletal muscle where
caused by an inherited cellular defect, exposure to exoge- it is stimulated by a stretching of the muscle. The axon
nous toxins, and abnormalities in other body systems (renal courses toward the spinal cord through a specific periph-
disorders with uremia, diffuse liver disorders with hyper- eral nerve, then through the dorsal or ventral branch of one
ammonemia, cardiorespiratory disorders with hypoxia). of the spinal nerves and into its dorsal root. It then enters
Abiotrophy is cell degeneration due to an intrinsic defect the spinal cord and passes into the dorsal gray column of
in the essential metabolism necessary for the survival and that spinal cord segment to synapse on a second neuron
function of that cell, the neuron. in a nucleus within that gray column. The telodendron is
Do not forget to consider the breed of your patient and the nerve ending at the synapse on another neuron in that
the possible inherited disorders that must be considered. nucleus. The neuronal cell body is located in the spinal gan-
You will prioritize these disorders in your differential on glion associated with the dorsal root that the axon coursed
the basis of signalment, history, and course of the clinical through to reach the spinal cord. It is actually intercalated
signs and the characteristics of the various disorders being in the axon at this point (Fig. 1-1).
considered. The dendritic zone and cell body of a motor neuron in
Based on this ranking of the differential diagnosis, the the peripheral nervous system that is innervating a skel-
most useful ancillary procedures will be selected to further etal muscle are closely associated and are located in the
confirm or deny the diagnosis under consideration. This ventral gray column of a segment of the spinal cord. The
selection is especially critical now that neuroimaging by axon leaves the cell body in that gray column and courses
computed tomography and magnetic resonance are avail- through the white matter of that segment to enter the
able to veterinarians. These procedures require general ventral root of that segment. It continues into the spinal
anesthesia and the costs to the owner of the patient are con- nerve of that segment and its dorsal or ventral branch
siderable. Therefore, it is crucial that the correct anatomic and then travels in a specific peripheral nerve to reach
diagnosis be made prior to the selection of the ancillary pro- the skeletal muscle cells being innervated. Here the axon
cedures. Your knowledge of the characteristics of the disor- ends in a telodendron at the neuromuscular ending in a
ders of the nervous system will then permit you to offer a motor end-plate.
therapy where it is appropriate and a prognosis. Within the CNS, a neuron of the dorsal spinocerebel-
lar tract is an example of a sensory or afferent neuron to
the cerebellum. Its dendritic zone and cell body are closely
neurOn associated in a nucleus in the dorsal gray column of the
spinal cord. The impulse is initiated here by a synapse with
The nervous system is composed of primary functional the telodendron of a sensory general proprioceptive neu-
cells—the neurons and supporting cells, which include the ron of the peripheral nervous system. The axon courses
glia and ependyma. In this book the neuron is defined as through the gray matter into the white matter of the lateral
consisting of a dendritic zone, axon, cell body, and telo- funiculus to join other axons in a tract on the dorsal super-
dendron. The dendritic zone is the receptor portion, where ficial surface of the lateral funiculus. This axon continues
DR
C
B
A
Figure 1-1 Diagram of a general somatic afferent (GSA) Skin GSA D
neuron and a general somatic efferent (GSE) neuron in a A
spinal nerve (SN). A, Dendritic zone. B, Cell body. C, Axon. SN B
D, Telodendron. DR, Dorsal root; SM, skeletal muscle;
VR, ventral root. C
GSE VR
D
SM
Introduction 
cranially in this dorsal spinocerebellar tract. It traverses the
tAble 1-1 Functional classification of the
portion of the spinal cord cranial to the spinal cord seg-
nervous system
ment where it originated, then continues into the medulla
where it enters the cerebellum via the caudal cerebellar
peduncle. It courses through the cerebellar medulla and system Function and Anatomic location
into the white matter of a cerebellar folium. It enters the 1. Afferent (A): sensory
adjacent granular layer of the cerebellum and terminates
in a telodendron that synapses with the dendritic zone of a   Somatic (S)
    General (GSA) Temperature, touch, noxious stimuli
granule cell neuron.
All spinal nerves, cranial nerve V
Within the CNS, the Purkinje neuron of the cerebellum
    Special (SSA) Vision: Cranial nerve II
is an example of an efferent neuron in the cerebellar cortex.
Hearing: Cranial nerve VIII
Its dendritic zone consists of a branched structure located in
  Visceral (V)
the molecular layer of the cerebellar cortex on the surface of
    General (GVA) Organ content, distention, chemicals
a folium. Here the telodendria of the granule cell neurons Spinal nerve splanchnic branches
synapse at sites on these branches to initiate the impulse in Cranial nerves VII, IX, X
the Purkinje neuron .The cell body is located in the Purkinje     Special (SVA) Taste: Cranial nerves VII, IX, X
neuronal layer of the cerebellar cortex. The axon arises from Olfaction: Cranial nerve I
this cell body and courses through the granular layer into   Proprioception
and through the white matter of that cerebellar folium and     General (GP) Muscle and joint movement
enters the white matter of the cerebellar medulla. Here All spinal nerves, cranial nerve V
    Special (SP) Vestibular system: Cranial nerve VIII
the axon ends in a telodendron on the dendritic zone of
another efferent neuron located in a nucleus of the cerebel-
2. efferent (e): Motor
lar medulla.
  Somatic (S)
    General (GSE) Striated skeletal muscle
All spinal nerves
FunctiOnAl systeMs Cranial nerves III, IV, V, VI, VII, IX, X, XI, XII
  Visceral (V)
This book is organized primarily by functional systems     General (GVE) Smooth and cardiac muscle and glands
Sympathetic: All spinal nerves, splanchnic 
rather than by regions of the nervous system or by the chief
nerves
clinical neurologic complaint. It is our opinion that for
Parasympathetic: Sacral spinal nerves
teaching purposes, this is the most effective way to learn the
Cranial nerves III, VII, IX, X, XI
organization of the nervous system and provide the basis
for understanding the disorders that affect the various com-
ponents of the nervous system. Most of these functional
systems are derived from a classification of the peripheral
Special Somatic Afferent
nervous system based on its functional components. The
sensory portion has extensive components in the CNS. The The special somatic afferent (SSA) system involves special-
classification is outlined in Table 1-1. ized dendritic zone receptor organs limited to one area
deep to the body surface but stimulated by changes in the
external environment. These include light to the eyeball
(cranial nerve II) and air waves indirectly to the membra-
sensOry (AFFerent) nous labyrinth of the inner ear (cranial nerve VIII, cochlear
division).
The sensory, or afferent, portion of the peripheral nervous
system is classified on the basis of the location of the den-
dritic zone in the body. This is the site of the origin of the
visceral Afferent
impulse.
The visceral afferent system has its dendritic zone in the
wall of the various viscera of the body. This is tissue derived
somatic Afferent
mostly from splanchnopleura and is stimulated by changes
The somatic afferent system has its dendritic zone on or in the internal environment.
near the surface of the body derived from the somatopleura,
where it receives the various stimuli from the external
environment.
General Visceral Afferent
The general visceral afferent (GVA) system is composed of
General Somatic Afferent
neurons distributed by the seventh, ninth, and tenth cranial
The general somatic afferent (GSA) system comprises the nerves to visceral structures in the head and by the tenth
neurons distributed primarily by the fifth cranial nerve cranial nerve and spinal nerves to the viscera of the body
to the surface of the head and all the spinal nerves to cavities and blood vessels throughout the neck, trunk, and
the surface of body and limbs that are sensitive to touch, limbs. This widely distributed system is stimulated primarily
temperature, and noxious stimuli. by the distention of visceral walls and chemical changes.
 VeterInary neuroanatomy and clInIcal neurology
Special Visceral Afferent general visceral efferent
The special visceral afferent (SVA) system contains the neu- The general visceral efferent (GVE) system has its teloden-
rons in the seventh, ninth, and tenth cranial nerves, whose dria in involuntary smooth muscle of viscera derived from
dendritic zones are limited to the specialized receptors for splanchnic mesoderm as well as blood vessels, cardiac mus-
taste, and the first cranial nerve, whose dendritic zones are cle, and glands. This system is the LMN of the autonomic
localized in the caudal nasal mucosa for olfaction. nervous system, which has components in all segments
of the brain and spinal cord. In some books, the GVE sys-
tem is considered to be the entire autonomic system; we
Proprioception
believe that to be an inappropriate concept that defies the
The modality of general proprioception is sometimes true functional totality of this autonomic system, which
included in the GSA system. In this book we consider it includes peripheral afferent components and a plethora of
as a separate system because of its clinical significance. nuclei and tracts at all levels of the CNS.
Disorders that affect this system express clinical signs dif- The GVE system, unlike the GSE system, is a two-neuron
ferent from those that affect the GSA system as we have system in that there are two neurons between the CNS and
classified it. Proprioception is the system responsible for the target organ. A synapse occurs in a peripheral ganglion
detecting changes in the position of the head, neck, trunk, between these two neurons. There are two divisions of this
and limbs. system: sympathetic and parasympathetic. They are further
described in Chapter 7, which is devoted to the GVE sys-
tem. These GVE neurons are distributed in the third, sev-
General Proprioception
enth, ninth, tenth, and eleventh cranial nerves and all the
The general proprioception (GP) system has its dendritic spinal nerves.
zones widely distributed in receptor organs located in In previous editions of this book and in older books of
muscles, tendons, and joints deep to the body surface. developmental anatomy, a special visceral efferent system
It is distributed widely throughout all the spinal nerves was described for the innervation of striated skeletal muscle
and the fifth cranial nerve. The receptors are sensitive in the head derived from branchial arch mesoderm. This
to changes in the lengths and positions of the structures classification has now been deleted because there is no dif-
they innervate. ference between this head skeletal muscle and the muscles
in the rest of the body. All this muscle is now considered to
be innervated by the GSE system.
Special Proprioception
The special proprioception (SP) system’s dendritic zones are
limited to receptors specialized to respond to positions and Further reADing
movements of the head. They are located in a portion of the
membranous labyrinth of the inner ear. These neurons con- For further reading, the following list of textbooks is highly
cerned with the orientation of the head in space are in the recommended. For all aspects of canine neuroanatomy,
vestibular division of the vestibulocochlear nerve (cranial the most extensive and thorough descriptions are found in
nerve VIII). Miller’s Anatomy of the Dog by Howard Evans. From our per-
spective, this should be considered the gold standard. The
text by Tom Jenkins, Functional Mammalian Neuroanatomy,
MOtOr (eFFerent) is an easy read, has many simplified line drawings of vari-
ous neurologic concepts, and is based primarily on the dog.
The motor, or efferent, portion of the peripheral nervous For the study of brain sections in all three planes, The Brain
system is classified on the basis of where the motor neuron of the Dog in Section by Marcus Singer is unsurpassed. This is
terminates, which is the site of the telodendron. This periph- a superb text for correlation with MR images.
eral motor system is also referred to as the lower motor neu- For further reading in veterinary clinical neurology, the
ron (LMN) because it is the final neuron to innervate the six texts listed are all well written and provide thorough
muscle cell. There are somatic and visceral components of coverage of their areas of concern. Cheryl Chrisman’s text
the efferent system. is limited to small animals and is usefully organized by the
patient’s problem, the chief complaint. Kyle Braund’s text
is organized like a dictionary and is useful for looking up
general somatic efferent
short, succinct reviews of any domestic animal’s neurologic
In the general somatic efferent (GSE) system, the teloden- problem. All species are included in the handbook written
dron is located in striated skeletal muscle throughout the by Mike Lorenz and Joe Kornegay, although their personal
entire body derived from somatic mesoderm, somites, and experience is mostly with small animals. The only text in
head somitomeres. The cell body and dendritic zone of these veterinary neurology that is limited to large animals is that
GSE neurons are in the spinal cord ventral gray column and written by Joe Mayhew. This is a superb book that represents
in nuclei in the brainstem. Their axons are in the ventral his extensive personal experience. The original textbook
root and spinal nerves or in cranial nerves, and they course of veterinary neurology written by Ben Hoerlein, which
through various named peripheral nerves to terminate in a included an extensive section on surgical and medical treat-
muscle cell at the neuromuscular ending (junction). These ment, was revised by John Oliver and Joe Mayhew and was
GSE neurons are found in all the spinal nerves and in all the expanded to include some large-animal neurology. In our
cranial nerves except cranial nerves I, II, and VIII. opinion the most current and most inclusive veterinary
Introduction 
neurology text for small animals is the text published in Lorenz MD, Kornegay JN: Handbook of veterinary neurology, ed 4,
2003 and edited by Curtis Dewey. For spinal surgery, the Philadelphia, 2004, Saunders.
textbook by Nick Sharp and Simon Wheeler details the Mayhew IG: Large animal neurology, Philadelphia, 1989, Lea &
Febiger.
contemporary aspects of spinal surgery for small animals.
Oliver JE, Hoerlein BF, Mayhew IG: Veterinary neurology,
This text is supported by excellent diagrams and photos.
Philadelphia, 1987, Saunders.
The only textbook devoted to veterinary neuropathology is
Platt SR, Olby NJ: BSAVA manual of canine and feline neurology,
the one written by Brian Summers with the help of John
ed 3, Gloucester, UK, 2004, British Small Animal Veterinary
Cummings and myself (Alexander de Lahunta). In addi- Association.
tion to the descriptive neuropathology, this text includes Sharp NJ, Wheeler SJ: Small animal spinal disorders: diagnosis and
considerable clinical correlations as well as descriptions of surgery, ed 2, Philadelphia, 2005, Elsevier.
pathogenesis.
Veterinary neuropathology
S u g g e S t e d r e a d i n g S Summers BA, Cummings JF, de Lahunta A: Veterinary
neuropathology, New York, 1995, Mosby.
domestic animal neuroanatomy
Jenkins TW: Functional mammalian neuroanatomy, ed 2, Other references
Philadelphia, 1978, Lea & Febiger. Crosby EC, Humphrey T, Lauer EW: Correlative anatomy of the
Evans HE: Miller’s anatomy of the dog, ed 3, Philadelphia, 1993, nervous system, New York, 1962, Macmillan.
Saunders. Fankhauser R, Luginbuhl H: Pathologische Anatomie des zentralen
Singer M: The brain of the dog in section, Philadelphia, 1962, und peripheren Nervensystem der Haustiere, Berlin, Germany,
Saunders. 1968, Verlag Paul Perey.
Frauchiger E, Fankhauser R: Neuropathologie des Menschen and
Veterinary Clinical neurology der Tiere, Berlin, Germany, 1957, Springer-Verlag.
Braund KG: Clinical syndromes in veterinary neurology, ed 2, Innes JRM, Saunders LZ: Comparative neuropathology, New York,
St Louis, 1994, Mosby. 1962, Academic Press.
Chrisman CL: Problems in small animal neurology, ed 2, Nickle R, Schummer A: Seiferle E: Lehrbuch der Anatomie der
Philadelphia, 1991, Lea & Febiger. Haustiere, Band IV, Nervensystem, Sinnesorgane, Endokrine
Chrisman CL, et al: Neurology for the small animal practitioner, Drusen, Berlin, Germany, 1975, Verlag Paul Perey.
Jackson, WY, 2003, Teton NewMedia. Papez JW: Comparative neurology, New York, 1929, TY Crowell.
Dewey CW: A practical guide to canine and feline neurology, Ames,
IO, 2003, Iowa State Press.
C h a p t e r
2
N D
euroaNatomy by issectioN
TRANSVERSE BRAIN SECTIONS
The neuroanatomic components of this textbook are with Figs. 2-2 through 2-17. The images are 2 mm thick, but to
based on and complement the dissection of the ner- select those that best demonstrate the anatomic features, the
vous system described in Guide to the Dissection of the intervals between images vary.
Dog by H. E. Evans and A. de Lahunta (ed 6, Philadelphia,
2004, Elsevier). The peripheral nerves are described and
dissected along with the regions of the body in which they
are found. The dissection of the brain and spinal cord is
found in the last section, titled “Nervous System.” The
split head of the embalmed dog used for the dissection of 2 3 45 67 8 910111213 1415 1617
the entire dog is also used to demonstrate the blood ves-
sels and meninges. A separate entire preserved dog brain
is provided to each group of students for the dissection.
The spinal cord can be dissected on the embalmed dogs
or presented as prosections. On completion of the brain
dissection, an additional preserved domestic animal brain
is provided to each group for the study of the transverse
sections.
In the Cornell curriculum this dissection is performed
simultaneously with lectures and discussions of nervous sys-
tem development, cerebrospinal fluid, and malformations,
including hydrocephalus, which are the subjects of Chapters
3 and 4 of this book.
The nomenclature used in this third edition, as in Guide
to the Dissection of the Dog, adheres to that published in the 2 3 45 67 8 910111213 1415 1617
fifth edition of Nomina Anatomica Veterinaria in 2005, unless
otherwise stated.
Transverse Brain secTions
The following transverse brain sections in Figs. 2-2 through
2-17 are arranged from rostral to caudal through the brain
at irregular intervals, as indicated on the drawings in Fig.
2-1. In these sections the white matter has been stained
and appears black, whereas the gray matter is relatively
unstained.
Figs. 2-18 through 2-33 are transverse plane (axial) pro- Figure 2-1 Dorsal and left lateral views of the brainstem, indicating the
ton density MR images of a normal adult dog for comparison approximate levels of the following transverse sections.