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Thomas A. Woolsey
George H. and Ethel R. Bishop Scholar in Neuroscience
Professor of Experimental Neurological Surgery,
of Experimental Neurology, of Anatomy and
Neurobiology, of Cell Biology and Physiology
and of Biomedical Engineering
Washington University School of Medicine
St. Louis, Missouri
Joseph Hanaway
Clinical Assistant Professor of Neurology
Washington University School of Medicine
Attending Neurologist
St. Mary’s Health Center
St. Louis, Missouri
Mokhtar H. Gado
Professor of Radiology
Mallinckrodt Institute of Radiology
Washington University School of Medicine
St. Louis, Missouri
A John Wiley & Sons, Inc., Publication
Contents
Preface . .
. . . . . . . . . . . . . . . . . . . . . . . .
Acknowledgments. .
. . . . . . . . . . . . . . . . . .
xi
1
PA R T I I
The CNS and Its
Blood Vessels
PA R T I
Introduction
Overview.................................................... 4
The Nervous System..................................... 5
Cells........................................................... 5
Gray Matter/White Matter............................. 5
Connections................................................. 7
CNS/PNS.................................................... 7
Constitution of the CNS................................ 7
Principal Divisions of the Brain....................... 8
Cranial Nerves and Spinal Segments................. 8
Cerebral Hemisphere and Brain Stem; .
Sulci and Gyri—Lateral Aspect..................... 20
Cortical Areas............................................ 10
Cerebral Hemisphere and Brain Stem .
Arteries; Arteries of the Insula and Lateral
Sulcus; Arterial Territories—Lateral Aspect..... 22
Using This Book......................................... 10
Cerebral Hemisphere and Brain Stem; .
Sulci and Gyri—Mesial Aspect...................... 24
Cerebrospinal Fluid and Its Circulation ............ 9
Terminology............................................... 10
Terms of Relation—The Special Case .
of the Human Head.................................... 12
Labels....................................................... 12
Image Groups............................................ 14
Pathways................................................... 14
Navigation................................................ 14
Materials and Methods............................... 14
Subjects..................................................... 14
Brain Specimens.......................................... 15
Radiological Imaging................................... 16
References................................................ 17
vi
Brain........................................................ 20
Cerebral Hemisphere and Brain Stem .
Arteries; Arterial Territories—.
Mesial Aspect............................................. 26
Cerebral Hemisphere and Brain Stem Arteries; .
by Conventional Angiography; by MRA—.
Lateral Projection....................................... 28
Dural Venous Sinuses and Folds .
(Diagrammatic); by Conventional .
Angiography; by MRV—Lateral Projection..... 30
Cerebral Hemispheres, Brain Stem and .
Arteries; by MRA—Anterior Aspect............... 32
Cerebral Hemisphere and Brain Stem .
Arteries and Veins by Conventional .
Angiography and Veins by MRV—
Anteroposterior Projections.......................... 34
Cerebral Hemispheres and Brain Stem; .
Sulci and Gyri–—Inferior Aspect................... 36
Cerebral Hemispheres and Brain Stem: .
Arteries and Cranial Nerves; Arterial .
Territories; Axial MRA—Inferior Aspect........ 38
PA R T I I I
Brain Slices
Brain Stem................................................ 40
Brain Stem, Diencephalon, Basal Ganglia, .
and Cerebellum—Anterolateral Aspect........... 40
Brain Stem, Diencephalon, Basal Ganglia, .
and Cerebellum; Arteries and Cranial .
Nerves —Anterolateral Aspect....................... 41
Brain Stem, Diencephalon, Basal Ganglia, .
and Cerebellum; Arterial Territories —
Anterolateral Aspect.................................... 42
Brain Stem, Thalamus, and Striatum—.
Anterior Aspect.......................................... 43
Brain Stem, Thalamus, and Striatum—.
Posterior Aspect.......................................... 44
Brain Stem, Thalamus, and Striatum—.
Lateral Aspect............................................ 45
Cerebellum............................................... 46
Cerebellum—Superior Surface....................... 46
Cerebellum—Inferior Surface........................ 47
Coronal Sections........................................ 54
Coronal Section Through Rostral Wall .
of Lateral Ventricle with Vessel Territories....... 54
Coronal Section Through Anterior Limit .
of Putamen with MRI.................................. 56
Coronal Section Through Head of Caudate
Nucleus and Putamen with MRI.................... 58
Coronal Section Through Anterior .
Limit of Amygdala with Vessel Territories....... 60
Coronal Section Through Tuber Cinereum .
with MRI.................................................. 62
Arteries to Spinal Cord (Diagrammatic).......... 48
Coronal Section Through Interventricular
Foramen (Foramen of Monro) with Vessel
Territories.................................................. 64
Segmental Arterial Supply of Spinal Cord
(Diagrammatic).......................................... 49
Coronal Section Through Anterior Nucleus .
of Thalamus with MRI................................ 66
Fiber Bundles............................................ 50
Coronal Section Through Mamillothalamic .
Tract (Fasciculus) with Vessel Territories......... 68
Spinal Cord............................................... 48
Principal Fiber Bundles in Cerebral .
Hemisphere and Brain Stem .
(Semi-Schematic)—Lateral and .
Mesial Aspects........................................... 50
Coronal Section Through Subthalamic .
Nucleus with Vessel Territories...................... 72
Coronal Section Through Posterior .
Limit of Interpeduncular Fossa with MRI....... 74
Contents
Principal Fiber Bundles in Coronal, .
Axial, and Sagittal Brain Sections .
(Semi-Schematic)......................................... 51
Coronal Section Through Mamillary .
Bodies with MRI........................................ 70
vii
Coronal Section Through Posterior .
Commissure with Vessel Territories................ 76
Sagittal Section Through Cerebral .
Aqueduct (Aqueduct of Sylvius) with MRI.... 110
Coronal Section Through Commissure .
of Superior Colliculi with MRI...................... 78
Axial Sections.......................................... 112
Coronal Section Through Quadrigeminal .
Plate with Vessel Territories.......................... 80
Coronal Section Through Fourth .
Ventricle (IV) with MRI............................... 82
Axial Section Through Superior Putamen .
with MRI................................................ 116
Coronal Section Through Posterior .
Horns of Lateral Ventricles with MRI............. 86
Axial Section Through Putamen with .
Vessel Territories....................................... 118
Sagittal Sections......................................... 88
Axial Section Through Frontoparietal .
Opercula with MRI................................... 120
Sagittal Section Through Superior, .
Middle, and Inferior Temporal Gyri .
with Vessel Territories.................................. 88
Axial Section Through Midlevel .
Diencephalon with Vessel Territories............ 122
Sagittal Section Through Claustrum .
and Lateral Putamen with Vessel .
Territories.................................................. 92
Sagittal Section Through Lateral .
Putamen with MRI..................................... 94
Axial Section Through Anterior .
Commissure with MRI.............................. 124
Axial Section Through Habenular .
Commissure with Vessel Territories.............. 126
Axial Section Through Superior .
Colliculi with MRI.................................... 128
Sagittal Section Through Termination .
of Optic Tract with MRI.............................. 96
Axial Section Through Anterior .
Perforated Substance with Vessel .
Territories................................................ 130
Sagittal Section Through Pulvinar .
with Vessel Territories.................................. 98
Axial Section Through Inferior .
Colliculi with MRI.................................... 132
Sagittal Section Through Ambient .
Cistern with MRI...................................... 100
Sagittal Section Through Olfactory .
Tract with Vessel Territories........................ 102
Sagittal Section Through Inferior .
Cerebellar Peduncle (Restiform Body) .
with Vessel Territories.............................. 104
Contents
Axial Section Through Inferior Corpus .
Callosum with Vessel Territories.................. 114
Coronal Section Through Posterior Limit .
of Hippocampus with Vessel Territories.......... 84
Sagittal Section Through Insula .
with MRI.................................................. 90
viii
Axial Section Through Superior .
Caudate Nucleus with MRI........................ 112
Sagittal Section Through Superior .
Cerebellar Peduncle (Brachium Conjunctivum)
with MRI................................................ 106
Sagittal Section Through Red Nucleus .
with Vessel Territories................................ 108
Spinal Cord............................................. 150
Transverse Section Through Upper .
Cervical Level with Vessel Territories............ 150
Transverse Section Through Cervical
Enlargement with MRI.............................. 151
PA R T I V
Histological Sections
Cerebellum............................................. 136
Transverse Section Through Thoracic .
Level with Vessel Territories........................ 152
Transverse Section Through Lumbar .
Enlargement with Vessel Territories.............. 153
Transverse Section Through Sacral Level....... 154
Horizontal Section Through .
Fastigial Nucleus...................................... 136
Basal Ganglia and Thalamus...................... 155
Horizontal Section Through .
Dentate Nucleus....................................... 137
Coronal Section Through .
Nucleus Accumbens.................................. 155
Brain Stem.............................................. 138
Transverse Section Through Superior .
Colliculus with Vessel Territories................. 138
Transverse Section Through .
Oculomotor Nucleus................................. 139
Transverse Section Through Inferior .
Colliculus with Vessel Territories................. 140
Transverse Section Through Superior .
Pons and Isthmus...................................... 141
Transverse Section Through Middle Pons .
with Vessel Territories................................ 142
Transverse Section Through Facial Genu .
with MRI................................................ 143
Transverse Section Through Vestibulocochlear
Nerve Root with Vessel Territories............... 144
Transverse Section Through Glossopharyngeal
Nerve Root with Vessel Territories............... 145
Transverse Section Through Fourth .
Ventricle with Vessel Territories................... 146
Transverse Section Through Hypoglossal .
Nucleus with MRI.................................... 147
Transverse Section Through Decussation .
of Pyramids............................................. 149
Coronal Section Through Anterior .
Commisure.............................................. 157
Coronal Section Through Anterior .
Thalamic Tubercle..................................... 158
Coronal Section Through .
Mamillothalamic Tract.............................. 159
Coronal Section Through H Fields of Forel... 160
Coronal sSection Through Dorsal Lateral
Geniculate Nucleus................................... 161
Coronal Section Through Pulvinar............... 162
Hypothalamus......................................... 163
Coronal Section Through Optic Chiasm; .
Coronal Section Through Pituitary Stalk....... 163
Coronal Section Through Interthalamic .
Adhesion; Coronal Section Through .
Mamillary Bodies...................................... 164
Basal Forebrain....................................... 165
Coronal Section Through Olfactory .
Trigone and Nucleus Basalis....................... 165
Hippocampus........................................... 166
Coronal Section Through Body .
of Hippocampus....................................... 166
Contents
Transverse Section Through Inferior Olive .
with Vessel Territories................................ 148
Coronal Section Through Optic Chiasm........ 156
ix
Sensory/Motor Systems............................ 198
Vestibular Pathways.................................. 198
Motor Systems......................................... 200
Corticospinal (Pyramidal) and .
Corticobulbar Pathways............................. 200
Rubrospinal and Tectospinal Pathways......... 202
Reticulospinal Pathways............................. 204
Cerebellum............................................. 206
Cerebellar Pathways: Somatic Afferents........ 206
PA R T V
Pathways
Brain Stem.............................................. 170
General Organization of Spinal Cord .
Gray Matter............................................. 170
General Organization of Cranial Nerve .
Gray Matter............................................. 172
Sensory Cranial Nerves and Nuclei.............. 174
Motor Cranial Nerves and Nuclei................ 175
Organization of Cranial Nerve Nuclei into
Columns—Posterior Aspect........................ 176
Organization of Cranial Nerve Nuclei into
Columns—Anterior Aspect......................... 177
Thalamus................................................ 178
Hypothalamus......................................... 180
Sensory Systems...................................... 182
Touch and Position Sense Pathways: Posterior
(Dorsal) Column/Medial Lemniscus and
Trigeminal Main Sensory Nucleus................ 182
Touch Pathways: Anterior and Lateral
Spinothalamic Tracts and Trigeminal .
Spinal Nucleus......................................... 184
Pain Pathways.......................................... 186
Touch Pathways: Head and Face................. 188
Contents
Taste Pathways......................................... 190
Visual Pathways....................................... 192
Olfactory Pathways................................... 194
Auditory Pathways.................................... 196
Cerebellar Pathways: Afferents .
(Non-Somatic).......................................... 208
Cerebellar Pathways: Efferents.................... 210
Basal Ganglia.......................................... 212
Basal Ganglia Pathways............................. 212
Arousal and Sleep.................................... 214
Arousal and Sleep Pathways....................... 214
Hippocampus........................................... 216
Hippocampal Pathways: Afferents............... 216
Hippocampal Pathways: Efferents................ 218
Amygdala................................................ 220
Amygdalar Pathways: Afferents................... 220
Amygdalar Pathways: Efferents................... 222
Hypothalamus......................................... 224
Hypothalamic Pathways: Afferents............... 224
Hypothalamic Pathways: Efferents............... 226
Autonomic Systems.................................. 228
Autonomic Pathways: Afferents................... 228
Autonomic Pathways: Sympathetic .
Efferents.................................................. 230
Autonomic Pathways: Parasympathetic .
Efferents.................................................. 232
Modulatory Systems................................. 234
Cholinergic and Dopaminergic Pathways...... 234
Noradrenergic and Serotoninergic .
Pathways................................................. 236
Index...................................................... 239
PA R T I
PART I is an illustrated overview of The Brain Atlas.
The main features of the central nervous system and the
organization of this book are described. Sources of the
specimens and the methods by which they were prepared
and photographed are detailed. Key aspects of the various
radiological techniques for the images included are outlined.
Selected references are listed at the end.
Introduction
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The Nervous System. . . . . . . . . . . . . . . . . . . 5–10
Using This Book. . . . . . . . . . . . . . . . . . . . . . . 10–14
Materials and Methods . . . . . . . . . . . . . . . 14–17
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Introduction
Introduction
Overview
The human nervous system is complex and sophisticated.
It is the most remarkable system in biology. A major challenge for neuroscience, psychology, medicine, and, indeed,
for civilization is to understand the nervous system at the
same fundamental levels at which we now understand
other organ systems. Early in the 21st century, only 50
years after the discovery of the genetic “alphabet,” the
complete human genome has been mapped. Likewise, new
knowledge about the brain and diseases that afflict the nervous system is exploding. One goal for future work on the
human brain is to reach a level of detailed understanding
similar to that now possible for the genome.
An anchor in this quest is information about the
structure and organization of the central nervous system
(CNS). The Brain Atlas: A Visual Guide to the Human
Central Nervous System was prepared to help students and
professionals understand the normal human brain and
guide interpretation of clinical and experimental work.
Clear charts and maps of biological structures have
been teaching aids from the earliest times. In the biological sciences, the first detailed and illustrated text based on
direct observation was the De Fabrica Humani Corporis
(1543) and its synoptic Epitome (1543) by Andreas Vesalius
(1514–1564). Those books have been said to “mark the
beginning of modern science.” Publication of the Fabrica
also was a major landmark in book publishing. The highly
popular Epitome was intended as a primer but served very
much as a modern day atlas. Such works have evolved and
today are used in the same way maps are used to plan travel
and understand geographic relationships.
In the mid to late 19th century, instructional programs
in universities and medical schools were developed to
teach students to make accurate observations from specimens. This skill enables students to generate and retain
mental conceptualizations of complex three-dimensional
(3D) structures in the body. In part, this was to prepare
students to interpret observations that could be made
only at the surfaces of living organisms. Experience
with these teaching aids was so positive that, even today,
instruction at nearly every level now uses charts and
atlases to aid the study of gross anatomy, embryology,
histology, and neuroscience. Atlases have been developed
for a wide range of other related disciplines, such as
pathology, radiology, and surgery. These books support
varied and flexible learning plans, styles, and objectives.
At their best, such works are ready references for efficient
recall and lifelong study—rapidly accessible sources of
information. The Brain Atlas is intended to be such a
work: a reference serving different needs for students
learning about the human brain and a resource for rapid
clarification in self-directed study, in the classroom, in
the laboratory, and in the clinic.
Because of recent stunning advances in imaging, the
information included in The Brain Altas is more crucial
than ever for medical practice, human and animal brain
research, and certain branches of psychology. For example,
strokes (brain attacks) resulting from insufficient blood
supply to parts of the CNS are the leading cause of disability in adults and the third leading cause of death in the
United States. Intense efforts are now directed at reducing
risk and improving therapy for this disease. The quick
access to information on the brain and its blood supply in
The Brain Atlas is crucial for such efforts. Other forms of
“brain disease,” such as mental illness, dementia, substance
abuse, and a host of genetic syndromes, can be investigated
and understood only by reference to the detailed organization of the human brain. Alterations in brain function,
such as learning difficulties or speech problems, have also
now been directly linked to altered brain structures. In the
future, access to basic information about brain structure
will be even more essential for evaluating patients at risk
for specific diseases and for monitoring and assessing the
effects of therapeutic interventions.
New imaging and other innovative techniques have
spurred a revolution in the study of the way in which the
brain works. Functional imaging of healthy individuals
at all ages provides a wide range of new and compelling
information on how the brain executes different tasks,
from speaking different languages to reacting to pain. Such
imaging promises to reveal, for example, the ways in which
the brains of individuals with special talents may differ.
The human brain is no longer a “black box” from which
one only rarely and fortuitously records activity. Instead,
the precise locations in the brain associated with many
uniquely human tasks can be specified. Therefore, ready
anatomical reference works are crucial for cognitive psychologists and research scientists.
The Brain Atlas is divided into five parts, with key features
summarized at the beginning of each. This introduction
(Part I) summarizes several general aspects of the brain
to help the novice get started or refresh the knowledge of
advanced students and practicing professionals. The balance
of this overview outlines terminology used in this volume,
as well as special features designed to assist in identification, study, and navigation. Information on the sources and
preparation of the anatomical images that appear in this
book is provided. The main parts of the volume (Parts II–V)
are designed to flow logically and progressively, from overall
surface anatomy of the CNS (Part II), through cross-sectional gross anatomy (Part III) and selected regional histology (Part IV), and ending with diagrams of the major neuronal systems that are responsible for the brain’s magnificent
array of functions (Part V). Because each part illustrates
a different aspect of the structure and organization of the
CNS, the book is arranged so that users can navigate easily
between topics for efficient learning and comprehension.
The Nervous System
Cells
The cells of the nervous system are of two principal types:
nerve cells or neurons, which are directly responsible
for conveying and processing information; and glial cells
(Gr., glia, glue), that support the neurons and make them
more efficient and effective. Neurons exhibit a wide range
of shapes, sizes, functional characteristics, and chemical
attributes. Most neurons are not visible without magnification. Neurons differ from all other cells in that they
have numerous microscopic processes extending for great
distances from the cell body (soma; Fig. 1). All neurons are
polarized, that is, different parts are specialized to receive
or send information. For most nerve cells, these functions are segregated in two different classes of processes.
Dendrites, shorter processes (~1 mm or less) that are
tapered and branched much like limbs on a tree, receive
and integrate incoming information. Most neurons have
several dendrites. Axons (usually only one per neuron)
have a relatively uniform diameter, can be highly branched,
and extend for considerable distances, up to almost 2 m in
tall people. Axons distribute signals to other cells (neurons,
muscle cells, secretory cells, etc.) without attenuation. The
principal mode of communication between neurons and
from neurons to other tissues, such as muscle, is through
specialized contacts called synapses (Gr., syn + haptein,
clasp). Synapses are small and require magnification
under a microscope to be seen. Axons convey information
through synapses throughout the brain to activate specific
targets.
Gray Matter/White Matter
Different parts of the brain and spinal cord have distinctive appearances. These anatomical distinctions can be
correlated almost without exception to specific functional
attributes, such as the sense of touch, language understanding, or the ability to execute complex movements
such as dancing. Because of the appearance of fresh brain
tissue, areas rich in neurons, synapses and glia are called
gray matter, and areas containing mainly axons and glia
are called white matter (Figs. 1 and 2). This distinction is
Figure 1 Schematic illustration of major elements of the central ner-
dendrite
soma
neuron
rWhite
White
matter
matter
myelin
Mm
100 Mm
axon
1 Mm
Gray
matter
(nucleus)
synapse
Introduction
vous system that are sources and targets of connections that facilitate
different functions. Gray matter is rich in neurons, connecting axons,
and contact points called synapses. For example, a gray matter area, the
cerebral cortex, connects to a gray matter nucleus via a myelinated axon
of a nerve cell. The full extent of the axon is not shown (//) but could
extend for more than 1 m. One synapse is enlarged. Some but not all of
the neurons in the gray matter are diagrammed as they would appear
with cell body stains (blue circles and triangles; see pp. 165 and 166).
Note the scale bars for the gray matter and the enlarged depiction of a
synapse. These can be compared with actual images of gray and white
matter in Figure 2.
Gray
matter
(area)
Stained slice
White matter
Ventricle
Gray matter
MRI
White matter
Ventricle
Gray matter
Stained section
White matter
Ventricle
Gray matter
Figure 2 Differences between gray matter (regions that are neuron
Introduction
and synapse rich) and white matter (regions rich in myelinated axons
and surrounding glia) are shown with three different methods used to
useful in understanding anatomical studies from normal
or autopsy specimens and, increasingly, from images of
living individuals.
Signals are processed within the gray matter by groups
of neurons that have similar functions, appearance, inputs,
and outputs. Such groups are termed nuclei (e.g., hypoglossal nucleus), areas (e.g., dorsal tegmentum), or were
named because of a fancied resemblance to specific objects
(e.g., Gr., hippokampos, seahorse = hippocampus). Detailed
maps of the locations, identities, connections, and functions of these different gray matter structures are provided
in this book.
prepare materials for The Brain Atlas. All images (from pp. 58, 59, and
155) are in the coronal plane and are reproduced at life size.
Longer connections through axons of neurons having
similar functions travel and conduct signals from one area
to another (for example, from the top of the brain to the
bottom of the spinal cord), grouped together as fascicles
and/or tracts. Many, but not all, axons are wrapped by
myelin, the membranes of a specific class of glia (oligodendrocytes), effectively serving as electrical insulation for
the axons. Myelin greatly speeds the conduction of impulses along axons while allowing them to be smaller, more
densely packed, and much more economical to maintain.
In fresh brain tissue, regions of the brain lacking neuronal
cell bodies but rich in axons and their myelin covers or
sheaths have an ivory/white appearance that differentiates
white matter from gray matter. The Brain Atlas provides a
convenient map of the locations, identities, connections,
and functions conducted in different white matter structures (Fig. 2). Images of brains prepared or visualized in
several standard ways illustrate the different regions of the
brain and the characteristics and functional attributes of
both gray and white matter.
Gray
matter
(area)
Connections
Several schemata have been devised to indicate the connections between different neurons and regions of the
nervous system. This was originally accomplished with
artists’ drawings of slices or sections through the brain.
Correlations are more direct in this book, because the
actual photographic and radiographic images of the external and internal organization of the CNS in Parts II–IV
are used to construct diagrams of its pathways in Part
V. The convention shown in Figure 3 represents a group
of neuron cell bodies (without dendrites) and synapses
they make with other cells in and out of the CNS. In such
diagrams, the direction of information transfer always
goes away from the neuron cell body (•), along its axon to
the synapse (-<), and then to the next cell body axon and
synapse to complete the neural pathway. Part V depicts
pathways in the diagrams and summarizes them in the
accompanying text.
neuron
CNS/PNS
The nervous system has two main divisions: the CNS and
the peripheral nervous system (PNS). This book focuses
on the CNS (Fig. 4), those parts of the nervous system
that are protected in the cranial cavity of the skull and in
the spinal canal formed by the vertebrae and their neural
arches. The PNS consists of spinal and cranial nerves, collections of neurons (ganglia), and neurons scattered in
different organs of the body, such as the gut, heart, and
urinary bladder.
Constitution of the CNS
The adult brain weighs between 1250 and 1450 g and
occupies ~1400 cc. The adult spinal cord is approximately
50 cm long and occupies ~150 cc. The weight of the CNS
therefore constitutes nearly 3% of the total body weight
1 used to illustrate brain pathways in Part V (Fig. 11). Solid circles represent neurons and their dendrites; colored lines represent the course of
the axons; and the “Y” represents presynaptic endings on neurons in the
target nucleus. Arrowheads indicate projections to distant targets not
illustrated directly.
axon
Gray
matter
(nucleus)
synapse
Introduction
Figure 3 The red shows the conventions based on the sketch in Figure
White
matter
of a 50-kg woman and slightly more than 2% of that of
a 70-kg man. In spite of its relatively small size, the brain
receives about 15% of the output of the heart, utilizes
about 20% of the body’s oxygen, and metabolizes a similar
percentage of body glucose, regardless of whether an individual is alert or sleeping. Its upkeep is therefore expensive.
Half of all human genes (currently estimated at 30,000) are
expressed uniquely in the nervous system; of the remaining half, 70% are expressed in the brain as well as elsewhere
in the body. It has been estimated that the CNS contains
about 100 billion neurons that make more synaptic connections in each individual than the number of stars, planets, and all other known objects in the universe. Neurons,
their processes, and the synapses they make are supported
by approximately a trillion glial cells.
Skull
Brain
C1
C1 C1
T1
T1 T1
Spinal
column
(vertebrae)
Spinal
cord
Principal Divisions of the Brain
In early development, the brain and spinal cord arise from
the neural tube, which greatly expands in the front end
of the embryo to form the main divisions of the brain
(Fig. 5, Table 1). The adult brain consists of: the telencephalon, which includes the cerebral cortex, basal ganglia,
and olfactory bulbs; the diencephalon, which includes the
thalamus, hypothalamus, and epithalamus; the mesencephalon or midbrain, which includes structures around
the cerebral aqueduct, the superior and inferior colliculi,
and the cerebral peduncles; the metencephalon, which
includes the pons and cerebellum; and the myelencephalon, which includes the open and closed medulla.
Introduction
Cranial Nerves and Spinal Segments
This book focuses on the brain and the organization of
connections within it. Communication between the brain
and the outside world (such as that occurring while reading this book) depends on connections between the brain
and the PNS, either directly through the 12 pairs of cranial
nerves numbered I–XII (CN I–CN XII) or from the spinal
cord via 31 pairs of spinal nerves. The cranial nerves traverse openings in the skull (principally foramina) while
the spinal nerves exit between adjacent vertebrae.
The spinal cord and spinal roots are organized segmentally. The different segments of the spinal cord and related
segmental spinal nerves connecting it with the periphery
are pertinent to understanding the organization of specific neural pathways. Spinal segments are defined by their
proximity to specific bones that form the spinal column.
The spinal column consists of 33 vertebrae: 7 in the neck
(cervical, C1–C7), 12 in the thorax (T1–T12), 5 in the
abdomen (lumbar, L1–L5), 5 in the pelvis (sacral, S1–S5),
and 4 in the diminutive “tail” (coccygeal, Co1–Co4). The
spinal cord lies within the bony spinal canal of the spinal
column and consists of 31 segments: 8 cervical (neck), 12
L1
S1
L1
L1
S1
S1
Figure 4 Schematic drawing of the central nervous system (CNS) in
the midsagittal plane. The CNS is within skeletal elements. The brain
(darker green) is surrounded by the skull (darker gray), and the spinal
cord (lighter green) is surrounded by 33 vertebrae that make up the
spinal (vertebral) column. The spinal cord is divided into segments in
relation to the labeled vertebrae (black; C1, T1, etc.). The spinal nerves
(yellow) course between and are labeled in relation to the vertebrae
(C1, T1, etc.). The intersection of the spinal nerves with the spinal cord
defines the segment (red) of the spinal cord (C1, T1, etc.). Some spinal
nerves have an extended intraspinal course from their (superior) spinal
segment before exiting below a vertebra (compare S1 with T1).
thoracic (chest), 5 lumbar (back), 5 sacral (pelvis), and 1
coccygeal (“tail”), each giving rise to a pair (right and left)
of spinal nerves (C1, T1, L1, S1, Co1, etc.) (Fig. 4).
Each pair of spinal nerves exits the spinal canal between
two adjacent vertebrae, except superiorly (above), where
the first pair exits between the skull and C1. Each cervical root is numbered by the vertebra below its exit. The
lowest cervical nerve, C8, exits between vertebrae C7 and
T1. Below C8, each spinal nerve, including T1, is labeled
with the same number as the vertebra above its point
of exit. The spinal nerves define segments of the spinal
cord. In the upper cervical region, a spinal cord segment
A
Corpus callosum,
anterior commissure,
fornix and septum pellucidum
11
Figure 5 The main divisions of the brain and lobes
of the cerebral cortex are
colored and labeled in midsagittal A and lateral B views
of the brain from images in
Part II (0.6X). The relation
of these divisions to the brain
stem and cerebrum are summarized in Table 1. The table
also indicates the embryonic
origins of the different parts
of the central nervous system
to which many of these divisions correspond.
Parietal lobe
1
Frontal lobe 10
2 Midbrain
Hypothalamus,
thalamus, habenula
and pineal gland
9
Occipital
3 lobe
Temporal lobe
8
4 Cerebellum
Pons 7
6
Medulla oblongata
B
Frontal lobe 19
5 Spinal cord
12 Parietal lobe
13 Occipital lobe
List for A and B
Temporal lobe 18
14 Cerebellum
Pons 17
Medulla oblongata 16
the spinal canal, where they constitute the cauda equina
(“horse tail”).
Cerebrospinal Fluid and Its Circulation
The lumen (hollow center) of the embryonic neural
tube persists in the fully formed spinal cord and closed
Introduction
lies at approximately the same level as the corresponding
vertebra. Inferiorly (or below), spinal cord segments lie at
progressively more superior levels than the corresponding
vertebrae. The adult spinal cord ends at the level of the first
lumbar vertebra (L1). The discrepancy between the cord
and vertebral levels is a result of differences in the growth
of the spine and spinal cord. Below L1, nerve roots occupy
15 Spinal cord
Cerebellum 4, 14
Corpus callosum, anterior commissure,
fornix and septum pellucidum 11
Frontal lobe 10, 19
Hypothalamus, thalamus, habenula and
pineal gland (diencephalon) 9
Medulla oblongata (myelencephalon) 6, 16
Midbrain (mesencephalon) 2
Occipital lobe 3, 13
Parietal lobe 1, 12
Pons 7, 17
Spinal cord 5, 15
Temporal lobe 8, 18
Table 1. Ontogenesis of the CNS
CENTRAL NERVOUS SYSTEM – CNS
(Neuraxis)
Spinal Primordium
(Neural Tube)
Rhombencephalic
Vesicle
SPINAL CORD
Myelecephalic Vescicle
Metenecephalic
Vescicle
Mesencephalic Vesicle
Medulla
Pons
Cerebellum *
Brain Stem
Midbrain
Diencephalic Vescicle
BRAIN
Diencephalon
Prosencephalic Vesicle
Cerebrum
Telencephalic Vescicle
Telencephalon
* The cerebellum is considered part of the brain stem, although, technically, it is a separate structure.
medulla as the central canal. In the rest of the brain, it
expands with the cerebral vesicles into the ventricular
system. The brain and spinal cord are filled and bathed
by ~150 cc cerebrospinal fluid (CSF), which fills the
ventricles, the central canal, and the subarachnoid space
between the pia on the brain surface and the arachnoidal
membrane just deep to the dura. Widened regions of
the subarachnoid space are called cisterns. The choroid
plexus, a specialized secretory epithelium found in each
ventricle (Fig. 6A and 6B), actively generates CSF that
continuously bathes and cushions the brain. The ~700 cc
CSF secreted per day (4+ fresh baths every 24 hours) circulates from the ventricles, exiting below the cerebellum
and through the subarachnoid space, eventually draining
into the venous system.
Introduction
Cortical Areas
10
In this volume, descriptive anatomical names are used
for structures depicted at different levels of resolution.
However, a widely accepted system of numbering the different regions of the well-developed human cerebral cortex
is frequently used also. These regions were defined based
on microscopic patterns of nerve cell bodies (cytoarchitectonics) or myelin (myeloarchitectonics). The most widely
used of these is based on numbers published by Korbinian
Brodmann (1868–1918) in 1909. This system divides the
mammalian cortex into “Brodmann’s areas” (indicated in
Fig. 7A and 7B by circled numbers), many of which correspond surprisingly closely to known, separable, brain
functions and to patterns of connections.
Using this Book
Terminology
Correct names and terms for structures in the brain are
essential for clear communication but are constantly changing as more is learned about the brain. Use of terms based
on the spoken language of students and faculty is a worldwide trend that has been recognized by the International
Federation of Associations of Anatomists (IFAA). The latest revised terminology, Terminologia Anatomica (referred
to here as Terminologia), is used in The Brain Atlas. Terms
are provided in English (for example, part for pars) or as
taken from the older Latin, Greek, and Egyptian terms of
anatomy and medicine that are now part of the English
language (for example, substantia nigra—black substance).
Because not everyone has adopted the Terminologia terms,
this book provides the common usage followed by the
Terminologia equivalent, for example, gyrus rectus (straight
gyrus). Common synonyms and eponyms are also used:
corticospinal (pyramidal) tract; basal vein (basal vein of
Rosenthal).
A
Arachnoid
granulations
Figure 6 Midsagittal A and
Superior
sagittal sinus
20
1
2 Interventricular foramen
Corpus callosum 19
3 Interthalamic adhesion
Fornix 18
4 Third ventricle
Septum
pellucidum 17
Frontal pole
Cerebral
5 aqueduct
6
16
Straight
sinus
lateral B views of the brain
from Part II are the basis for
these schematics (0.6X). The
brain is bathed in cerebrospinal fluid (CSF) that is continuously produced, circulated,
and absorbed. The location of
the choroid plexus (red), which
makes CSF, is shown in all
four brain ventricles. The CSF
(green) circulates through the
ventricular system and over the
brain in the direction shown by
the arrows. It ultimately returns
to the venous system (blue).
In the head, this transfer is
through special structures, the
arachnoid granulations.
Occipital
7 pole
Pituitary gland 15
8
Midbrain 14
Cerebellum,
vermis
Cerebellum,
9 hemisphere
Pons 13
Medulla oblongata 12
10 Fourth ventricle
11
Fourth ventricle,
median aperture
B
Central sulcus
Lateral ventricle, body
Third ventricle
Interventricular
foramen
Lateral
ventricle,
frontal horn
21
40
39
Choroid plexus
22 of lateral ventricle
23 Lateral sulcus
38
Lateral
24 ventricle,
trigone
37
Lateral
ventricle,
25 occipital
horn
Frontal pole 36
Choroid
plexus of
lateral
ventricle,
temporal horn
Lateral
ventricle,
26 temporal
horn
35
Fourth
27 ventricle
Cerebral
aqueduct 34
Cerebellum,
Pons 33
Fourth ventricle,
lateral aperture 32
Choroid plexus of
29 fourth ventricle
31
Medulla
oblongata
30
Fourth ventricle,
median aperture
Introduction
28 hemisphere
List for A and B
Arachnoid granulations 20
Central sulcus (fissure of Rolando) 21
Cerebellum, hemisphere 9, 28
Cerebellum, vermis 8
Cerebral aqueduct (aqueduct of Sylvius) 5, 34
Choroid plexus of fourth ventricle (IV) 29
Choroid plexus of lateral ventricle 22
Choroid plexus of lateral ventricle, temporal
(inferior) horn 35
Corpus callosum 19
Fornix 18
Fourth ventricle (IV) 10, 27
Fourth ventricle (IV), lateral aperture (foramen
of Luschka) 32
Fourth ventricle (IV), median aperture
(foramen of Magendie) 11, 30
Frontal pole 16, 36
Interthalamic adhesion (massa intermedia) 3
Interventricular foramen (foramen of
Monro) 2, 38
Lateral sulcus (Sylvian fissure) 23
Lateral ventricle, body 40
Lateral ventricle, frontal (anterior) horn 37
Lateral ventricle, occipital (posterior) horn 25
Lateral ventricle, temporal (inferior) horn 26
Lateral ventricle, trigone (atrium) 24
Medulla oblongata 12, 31
Midbrain 14
Occipital pole 7
Pituitary gland 15
Pons 13, 33
Septum pellucidum 17
Straight sinus 6
Superior sagittal sinus 1
Third ventricle (III) 4, 39
11
3
A
1
4
6
8
24
23
26
29
33
10
28
38
36
3
6
8
1
5
7
40
39
41
42
22
47
13
2
18
45
10
11
19
4
9
44
17
27
35
B
12
18
37
20
Terms of Relation—The Special Case of the
Human Head
19
36
25
14
31
30
34
46
7
5
9
32
geminal (CN V); abducent nucleus (CN VI). The third and
fourth ventricles are indicated with capital Roman numerals: fourth ventricle (IV).
2
21
38
19
37
18
17
20
43
Introduction
Figure 7 Areas of the cerebral cortex differ consistently in their microscopic structure. The structural differences reflect, in part, connections
within an area and to and from other parts of the central nervous system. Brodmann’s system of numbers identifies different cortical areas.
These have been transposed to the midsagittal A and lateral B views on
specimens depicted in Part II. Numbered areas have frequently been
shown to correspond to known functions. Notable examples are area
4 for control of fine movements, area 41 for audition, and area 17 for
vision. This and other similar systems of identification are widely used,
especially when a specific functional/connectional correlation has been
established for an area of the cerebral cortex.
12
To identify structures consisting of several parts, the principal structure is followed by the specific part(s), separated by a comma: hippocampus, CA3, pyramidal layer;
thalamus, centromedian nucleus (CM); fourth ventricle
(IV), median aperture (foramen of Magendie). Terms for
nuclei in the thalamus include an abbreviation in parentheses: centromedian nucleus (CM); ventral posteromedial
nucleus (VPMm), medial part; thalamus, pulvinar (Pul).
Cranial nerves and associated structures are numbered
with capital Roman numerals: vagal (CN X) trigone; tri-
Adjectives describing anatomical relations are thoroughly
discussed in textbooks of anatomy. Here, adjectives from
the Terminologia are used, but commonly used synonyms that describe position or relation are included
in parentheses: posterior (dorsal) horn; anterior (ventral) cochlear nucleus (CN VIII). In particular, terms of
comparison related to humans (bipeds) and four-legged
animals (quadrupeds) (Fig. 8) are confounded because
in humans and other primates, the axis of the forebrain
and skull is at nearly 90° to the axis of the spinal cord and
body. This is in contrast to the dog and other commonly
studied animals where the axis of the forebrain and skull
is the same as the axis of the spinal cord and body (Fig.
8). Accordingly, homologous structures in the brains of
humans versus cats and dogs can have different relations
to the principal body axes. For instance, structures within
the human brain that are nearer to the back of the head are
often named posterior (dorsal) with respect to the principal body axis. An example is the occipital (posterior) horn
of the human lateral ventricle. In dogs, however, the same
structure is oriented toward the tail (caudal) rather than
to the back (dorsal). The coronal plane of section (paralleling the coronal suture of the skull) is across the skull in
both humans and dogs. In dogs this plane is perpendicular
to the long axis of the body crossing from dorsal (posterior) to ventral (anterior); in people it is parallel to the
long axis of the body from superior to inferior (Fig. 8). In
the Terminologia this distinction is now made clearer. For
instance, in the Terminologia, pontine reticular formation,
superior part, is preferred over the traditional usage, rostral reticular formation. In The Brain Atlas, lists give the
preferred term with the synonym in parentheses: anterior
(ventral) horn; posterior (dorsal) spinocerebellar tract. In
some instances, the use of quadruped terms of relation,
unfortunately, cannot be avoided: dorsal supraoptic commissure—not superior.
Labels
Structures in The Brain Atlas are indicated by leaders
(numbered tags), for precise identification of features.
These are arranged vertically top down or clockwise,
beginning at the top of the image (12 (24) o’clock). The
colored numbers are accompanied by the short version
of the term identifying the item (for example, median
aperture). All terms are listed in full (for example, median
aperture [foramen of Magendie]) and in alphabetical order
and hierarchically (for example Globus pallidus, inter-
Figure 8 Terms of comparison as applied to a human (biped) and
Posterior
(dorsal)
a dog (quadruped). For the human brain, superior and inferior are
preferred in many instances to dorsal and ventral. Although corresponding to structures that are dorsal in quadrupeds, the potential
confusion in describing structures in the human head that is at right
angles rather than parallel to the long axis of the body complicates
clear communications about anatomy. Image taken from a photograph
of Harvey Cushing, MD (1869–1939) who was a pioneer in American
brain surgery and was particularly interested in the work of Andreas
Vesalius. (Reproduced with permission from the American Association
of Neurological Surgeons. A Bibliography of the Writings of Harvey
Cushing, Third Edition, Revised 1993.)
Superior
(cranial)
nal (medial) segment (GPi)) on the same or facing page
opposite the labeled image followed by the appropriate
number(s) in color. After looking up the structures in the
index, the entry can be found in the list of terms and then
located by its number around the “clock face.” The system
offers two options: tracing the leader from a structure to
identify it quickly; or from the index to the list on the page
from which the pointer(s) is identified by number without
an extensive search of the image to find a specific symbol,
abbreviation, or other term against the background of a
structure (Fig. 9). When several illustrations are grouped
on a page, term 1 is related to the image nearest the top of
the page. Because of the number of items on each page, all
are not labeled in every picture. In particular, larger structures (for example, caudate nucleus, lateral ventricle) that
appear in adjacent sections have been labeled on alternate
plates. Students are encouraged to try to identify unlabeled
structures for self-testing.
Anterior cerebral artery
39
Anterior cerebral artery territory
Anterior
(ventral)
Inferior
(caudal)
Dorsal
Ventral
Caudal
28
Cranial
(rostral)
21
Anterior cerebral artery
Cerebral Hemispheres and Brain Stem: Arteries
and Cranial Nerves (1X); Arterial Territories
(0.6X); Axial MRA (0.5X)–Inferior Aspect
Anterior communicating artery
Optic chiasm 41
Olfactory tract 40
Anterior cerebral artery 39
Middle cerebral artery,
orbital branches 38
Internal carotid artery
42
1 Olfactory bulb
2 Anterior cerebral artery, frontopolar branch
3 Anterior cerebral artery, orbital branch
5 Infundiblulum
37
Insula 36
Middle cerebral artery,
branches on insula
Middle cerebral
artery, stem
33
Oculomotor nerve
32
Posterior
cerebral artery
31
Superior
cerebellar artery
6
35
Posterior
4 Posterior cerebral artery territory
5 Superior cerebellar artery territory
Basilar artery, lateral branches territory 24
Labels are
numbered
clockwise
9 Trochlear nerve
10 Pons
Anterior inferior
Vertebral artery territory 23
6 cerebellar artery territory
Anterior spinal artery territory 22
7 cerebellar artery territory
Posterior inferior
Trigeminal nerve,
11 sensory root
12
13
28
Anterior inferior
cerebellar artery
14
27
Posterior cerebral artery,
posterior temporal branches
15
Anterior and
posterior inferior
cerebellar arteries
Vestibulocochlear
nerve
Facial nerve
Glossopharyngeal
nerve
16 Vagus nerve
26
Posterior inferior cerebellar artery
17 Hypoglossal nerve
25
18 Accessory nerve
Abducent nerve 24
Vertebral artery 23
19 Basilar artery
Posterior cerebral artery, 22
20 Spinal nerve
21
calcarine branch Anterior spinal
artery
Hypoglossal nerve (CN XII) 17
Infundiblulum 5
Insula 36
Internal carotid artery 37
Middle cerebellar peduncle, cut edge 28
Middle cerebral artery, branches on insula 35
Middle cerebral artery, orbital branches 38
Middle cerebral artery, stem 34
Middle cerebral artery, temporopolar branches 6
Oculomotor nerve (CN III) 32
Olfactory bulb 1
Olfactory tract 40
Optic chiasm 41
Optic nerve (CN II) 4
Pons 10
Posterior cerebral artery 31
Posterior cerebral artery, calcarine branch 22
Posterior cerebral artery, posterior temporal
branches 26
Posterior communicating artery 8
Posterior inferior cerebellar artery 25
Spinal nerve (C3) 20
Superior cerebellar artery 30
Temporal lobe, cut surfaces 33
Trigeminal nerve (CN V), sensory root 11
Trochlear nerve (CN IV) 9
Vagus nerve (CN X) 16
Vertebral artery 23
Vestibulocochlear nerve (CN VIII) 13
8 pericallosal arteries
Middle cerebral artery, stem 20
9 Internal carotid artery, carotid siphon
Posterior cerebral artery 19
10 branches on hemispheric convexity
Middle cerebral artery,
branches on insula
Internal carotid artery,
Anterior inferior cerebellar artery 17
12 intrapetrous part
Posterior cerebral artery,
16
posterior temporal branches
13 Superior cerebellar artery
Vertebral arteries 15
14 Posterior inferior cerebellar artery
MRA
Anterior cerebral arteries, pericallosal arteries 8
Anterior cerebral artery 21
Anterior cerebral artery territory 28
Anterior choroidal artery territory 2
Anterior inferior cerebellar artery 17
Anterior inferior cerebellar artery territory 6
Anterior spinal artery territory 22
Basilar artery 18
Basilar artery, lateral branches territory 24
Basilar artery, medial branches territory 25
Internal carotid artery, carotid siphon
(intracavernous part) 9
Internal carotid artery, intrapetrous part 12
Internal carotid artery territory 27
Middle cerebral artery, branches on hemispheric
convexity 10
Middle cerebral artery, branches on insula 11
Middle cerebral artery, stem 20
Middle cerebral artery territory 3
Ophthalmic artery territory 1
Posterior cerebral artery 19
Posterior cerebral artery, posterior temporal
branches 16
Posterior cerebral artery territory 4
Posterior communicating artery territory 26
Posterior inferior cerebellar artery 14
Posterior inferior cerebellar artery territory 7
Superior cerebellar artery 13
Superior cerebellar artery territory 5
Vertebral arteries 15
Vertebral artery territory 23
22
Anterior and posterior inferior cerebellar arteries
(common origin) 12
Anterior cerebral artery 39
Anterior cerebral artery, frontopolar branch 2
Figure 9 Leaders point to structures identified by the
11 Middle cerebral artery,
Basilar artery 18
23
Anterior cerebral artery 21
Anterior cerebral artery territory
28
“short” version of the term. Terms are numbered sequentially in color, starting at 12 (24) o’clock. Depending on
the exact layout, terms are numbered in sequence around
more than one object as shown for the right-hand page
here or circling individual objects on a page starting with
the object nearest the top of the page. Terms are enlarged
at the top of this figure. Each is listed alphabetically in
full, usually on the same page (bottom of this figure).
Occasionally, the lists are on the facing page or a fold
out (see pp. 38–39).
Introduction
Abducent nerve (CN VI) 24
Accessory nerve (CN XI) 18
Anterior and posterior inferior cerebellar arteries
(common origin) 12
Anterior cerebral artery 39
Anterior cerebral artery, frontopolar branch 2
Anterior cerebral artery, orbital branch 3
Anterior choroidal artery 7
Anterior communicating artery 42
Anterior inferior cerebellar artery 27
Anterior spinal artery 21
Basilar artery 19
Basilar artery, lateral branches 29
Facial nerve (CN VII) 14
Glossopharyngeal nerve (CN IX) 15
Anterior cerebral arteries,
Anterior cerebral artery 21
3 Middle cerebral artery territory
Basilar artery, medial branches territory 25
8 communicating artery
29
Middle cerebellar
peduncle, cut edge
2 Anterior choroidal artery territory
7 Anterior choroidal artery
30
Basilar artery,
lateral branches
1 Ophthalmic artery territory
Posterior communicating artery territory 26
Middle cerebral artery,
temporopolar branches
34
Temporal lobe,
cut surfaces
Anterior cerebral artery territory 28
Internal carotid artery territory 27
4 Optic nerve
13
sacral cord is enlarged more that of the midbrain to clearly
illustrate its internal structure. The pathways shown are simplified from the highly detailed information now available
from humans and primates (see, for example, Paxinos and
Mai, 2004). In some cases, such as the hypothalamospinal
tract, data from non-primates has been transposed when it
is consistent with clinical observation in humans as in the
lateral medullary syndrome. A short synopsis accompanies
each pathway diagram, summarizing its function(s) and the
connected structures.
Image Groups
The images in each section of The Brain Altas are grouped
together to facilitate correlation of different classes
of information from different sources. For example,
images of the brain and its blood vessels are juxtaposed
directly with those mapping vascular territories and those
obtained by radiological methods. Examples are shown
in Figures 9 and 10. In Figure 9, the base of the brain–
–illustrating its parts, the cranial nerves, and the major
blood vessels––can be compared directly with the map
of the brain territories supplied by those blood vessels
and their radiology on the opposite page. Part III images
are on facing pages and are interleaved by kind (Fig. 10).
The layout permits rapid “scanning” or "scrolling" of the
images from front to back, up and down, and side to
middle to develop a true 3D appreciation of the brain.
Navigation
The Brain Atlas has a number of features to assist in rapid
location of pertinent figures and facilitate navigation (Fig.
10). Color-coded and labeled page edges distinguish different parts of the book. Icons in the upper outside corner of all pages in Parts II–V locate the part of the brain
depicted. In parts III–V, the lines on these icons show the
location and orientation of the slice/section. This context
is especially useful in conjunction with locator images now
common in clinical imaging. The corners can be flipped
through quickly to find an approximate location for a specific section or region (for example, spinal cord and blood Part I
Figure 10
supply of the cerebellum).
Pathways
Neural pathways are depicted in two ways: they are drawn on
the specimens (Fig. 11, left) or on “stacks” of selected images
(specimens, slices, and histological sections) in a threequarter view, as if seen from the left front (Fig. 11, right).
This perspective was chosen because it gives a sense of three
dimensions, as if the viewer was sitting across from a living person, and is a modification of the elegant and widely
imitated illustration style published by A. T. Rasmussen
(1883–1955) in 1932. To obtain these views, images of the
sections were rotated and “extruded” to create a sense of
perspective. They are aligned with respect to the central
canal of the spinal cord and closed medulla, the median
longitudinal fissure of the fourth ventricle, and the cerebral
aqueduct. Section images were adjusted so that relative sizes
are preserved: spinal cord < medulla < pons < thalamus.
True sizes vary, however. For example, the section of the
Materials and Methods
Subjects
The images in this volume are from living adults or from
specimens obtained at autopsy. None had a history of an
abnormal clinical neurological examination and none
suffered from neurological disease. The brains and spinal
cords, their coverings, and their blood vessels are grossly
within normal limits. The brain slices and histological sec-
Coronal Section Through Fourth Ventricle (IV)
(1X) with MRI (0.7X)
Pineal
gland
Fornix, crus
Caudate nucleus, tail
Choroid plexus
of lateral ventricle
31
30
Corpus
callosum,
splenium
32
Callosal
sulcus
1
Precentral
gyrus
2
3 Postcentral gyrus
29
Corpus callosum,
4 forceps major
28
Lateral ventricle,
5 trigone
Hippocampus,
fimbria
27
1 Anterior cerebral artery territory
6 Tapetum
2 Middle cerebral artery territory
Calcarine
fissure
26
Middle
temporal
gyrus
25
7
3 Choroidal arteries territory
8 Hippocampus
9
14
Lateral
occipitotemporal
gyrus
Superior cerebellar
peduncle
6
12 Middle cerebellar peduncle
21
13
20
Fourth ventricle, lateral recess
32
5
Medial
occipitotemporal
gyrus
11 Collateral sulcus
Superior medullary velum
Brain Slices–Coronal Sections
brain slices on facing pages in Part III. Adjacent brain
slices are matched to outlines of the territories supplied
by their arteries. These images are arranged in the three
series of slices (coronal, axial, and sagittal) to develop a
three-dimensional appreciation of the internal structure
of the brain and its blood supply that may be compared
with other images (see pp. 82–83, 85).
10
23
Cerebellum, vermis,
22
central lobule
Posterior cerebral
4 artery territory
Inferior
longitudinal
fasciculus
19
18
17
16
Medullary
Vagal Hypoglossal
striae of
trigone
trigone
fourth ventricle
Calcarine fissure 26
Callosal sulcus 1
Caudate nucleus, tail 29
Cerebellum, vermis, central lobule 22
Choroid plexus of lateral ventricle 28
Collateral sulcus 11
Corpus callosum, forceps major 4
Corpus callosum, splenium 32
Facial colliculus 14
Fornix, crus 30
Fourth ventricle (IV) 13
Fourth ventricle (IV), lateral recess 19
Hippocampus 8
Hippocampus, fimbria 27
Hypoglossal (CN XII) trigone 16
Inferior colliculus 24
Inferior longitudinal fasciculus 9
Lateral occipitotemporal (fusiform) gyrus 23
Lateral ventricle, trigone (atrium) 5
Medial occipitotemporal (lingual) gyrus 10
Medullary striae of fourth ventricle (IV) 18
Middle cerebellar peduncle (brachium pontis) 12
15
14
7
Superior cerebellar
artery territory
Anterior inferior cerebellar
artery territory
Posterior inferior cerebellar
artery territory
Fourth ventricle
8 Posterior spinal artery territory
Facial colliculus
Sulcus
limitans
Middle temporal gyrus 25
Optic radiation 7
Pineal gland 31
Postcentral gyrus 3
Precentral gyrus 2
Sulcus limitans 15
Superior cerebellar peduncle (brachium
conjunctivum) 21
Superior medullary velum 20
Tapetum 6
Vagal (CN X) trigone 17
Anterior cerebral artery territory 1
Anterior inferior cerebellar artery territory 6
Choroidal arteries territory 3
Middle cerebral artery territory 2
Posterior cerebral artery territory 4
Posterior inferior cerebellar artery territory 7
Posterior spinal artery territory 8
Superior cerebellar artery territory 5
Brain Slices–Coronal Sections
Introduction
Inferior
colliculus 24
Figure 10 Magnetic resonance images are matched to
Optic
radiation
35
Label
lists
Figure 11 Brain pathways are drawn on the brain surface (left) or on the sections from other parts of the atlas
(see page numbers to left of the section enlarged below
the open atlas). The drawings show the main connections of each pathway as summarized in the text on the
facing page. The synopsis gives the main function(s) of
a pathway. As with all other plates, terms and structures
can be identified alphabetically from the label lists (see
pp. 232–233).
Synopsis
Text
Page 141
tions are within normal limits. The specimen depicted in
most of the plates in Part II is from a 78-year-old woman
who died from pneumonia. For Part III, the coronal slices
are from a 22-year-old who died from a retroperitoneal
hemangioendothelioma. The sagittal slices are from a
35-year-old woman who died from chronic renal failure,
and the axial slices are from a 58-year-old man who died
from a renal adenocarcinoma.
Brain Specimens
Dissection The skull and vertebral arches were removed
carefully to expose the dura. The dura was opened, and
the brain and spinal cord were removed. The blood vessels
Planes of Sectioning A standard frame of reference is
useful in comparing different planes of imaging or sections
and images from different individuals. Most modern imaging studies and data bases follow a convention described by
J. Talairach and P. Tournoux (1988). Images and sections of
the brain are perpendicular to and/or parallel to the midsagittal plane and to the line between the superior border
of anterior commissure (AC) and the inferior aspect of the
posterior commissure (PC), known as the AC/PC line.
Brain Slices Before slicing, fixed brains were trimmed
(blocked) for correct orientation using a brain knife. For
the coronal plane, the frontal poles were removed by slicing perpendicular to the AC/PC line; for the axial plane,
the vertex was removed by slicing parallel to the AC/PC
line. For the sagittal plane, the brain was bisected along the
interhemispheric fissue. The oriented brains were sliced
serially at 4 mm with the rotary blade of a Hobart Model
410 commercial meat slicer. The slices were stacked in
order, each separated by a sheet of filter paper.
Histological Sections Carefully oriented blocks of tissue were embedded in celloidin and cut on a microtome
at 40 µm in axial (spinal cord, brain stem, and cerebellum) or coronal (basal ganglia, thalamus, hypothalamus,
hippocampus, and basal forebrain) planes. Section planes
through brain stem structures were varied slightly to illustrate certain features (see locator icons in Part V). Sections
of the forebrain, from the Yakovlev–Haleem Collection
Introduction
Fixation All specimens were preserved in formaldehyde.
For the specimens in Part II, both common carotid arteries
and vertebral arteries were exposed in the neck and clamped
proximally. The jugular veins were transected. After flushing
with 0.9% NaCl, all vessels were perfused simultaneously
with 16% paraformaldehyde in buffered normal saline from
a reservoir 45 cm above the head. The head was removed
after 2 hours, when the neck was stiff, and the soft tissues
were dissected away from the skull. The top (vertex) of the
skull was removed, and the head was stored for 3–4 weeks
in 16% paraformaldehyde. For specimens in Part III, the
vertebral and carotid arteries were perfused with 50 mL 40%
formaldehyde as soon as the brains were collected. These
brains were suspended from a string around the basilar
artery in 10% formaldehyde for 2–4 weeks to complete fixation. The specimens used for histology were preserved by
immersion in 40% formaldehyde.
were defined and later removed from brain by carefully
peeling the pia from the brain surface (Part II).
15
at the National Museum of Health and Medicine/Armed
Forces Institute of Pathology (Washington, DC; http://
brainatlas.msu.edu/databases/yakovlevcomparative/index.
html), were chosen from many normal specimens to illustrate appropriate levels of the CNS.
Staining Brain slices were stained with a modified copper
sulfate technique (Mulligan, 1931). After washing the slices
in cold running tap water for 30 minutes, each was immersed
in 1.5 L staining solution (CuSO4 • 5H2O, 5 gm; phenol, 50
gm; 37.5% HCl, 1 mL in 1 L dH2O) at 60°C in a Pyrex baking dish for 6 minutes. Each section was then washed for
7 minutes in cold tap water and placed in 1.5 L fresh 1.5%
K4Fe(CN)6 • 3H2O for 30–60 seconds, until the gray matter
turned red-brown and the white matter remained unstained.
After washing for 6 minutes under running tap water, the
sections were stored in 10% formalin (up to several months
without fading). Spinal cord and brain stem sections were
stained by the Loyez method for myelin. Sections in the
Yakovlev–Haleem Collection were stained by the Weigert
hematoxylin method for myelin (basal ganglia, thalamus,
hypothalamus, and cerebellum) and a Nissl method (cresyl
violet) for cell bodies (basal forebrain and hippocampus).
For a general discussion of classical histological methods for
the brain, see Gabe, 1976.
Photography For Part II, complete sets of photographs
were taken on 4 x 5-in negatives as the brains were dissected. Brain slice surfaces in Part III were photographed
against an illuminated background through a green filter
(Wratten #58 to enhance contrast of the red-brown stain)
on 5 x 7-in negatives. Final prints were made at ~1.2x
enlargement. Histological sections were photographed
with macro optics on 4 x 5-in negatives. Black-and-white
radiological films and photographic negatives and prints
were digitized on a flatbed scanner.
Introduction
Radiological Imaging
16
Cerebral Angiography Angiography shows blood vessels in living persons. Conventional cerebral angiography,
illustrated in Part II, uses X-rays to image the blood vessels
of the brain as they are filled by intravascular injection
of radiopaque contrast material (dye) that subsequently
washes through the body with the circulating blood.
Images are collected in rapid succession for approximately
10 seconds, beginning just before the dye is injected. Each
image of the head and neck shows the skull, soft tissues,
and contrast-filled blood vessels. An image of the skull
and soft tissues (skin, fat, muscle) without contrast material is subtracted digitally to “remove” the skull and other
tissues to show the blood vessels in isolation. The contrast
material circulates first into the cerebral arteries (arterial
phase) and collects several seconds later in the cerebral
veins (venous phase). The sequence of images over time
constitutes a cerebral angiogram and is specified by the
artery into which the contrast material was injected (for
example, a right carotid angiogram). Images reproduced
in this book were recorded with an image intensifier from
which each frame was digitized on-line.
Cerebral angiograms are obtained in views or projections
indicating the path of X-rays through the head. In the lateral
(“side”) view, X-rays cross from one side of the head to the
other, perpendicular to the midsagittal plane (see pp. 28, 29,
and 31). In the anteroposterior (“frontal”) view (pp. 34–35),
X-rays pass parallel to the midsagittal plane from the back
(posterior) to the front (anterior). A modification of the
postero-anterior view is used to visualize the blood vessels
that are filled in a vertebral angiogram. The X-ray source is
positioned to view the head as if - the chin were tilted down
(Towne projection) to minimize the overlap of the brain
and the base of the skull on the projected image (p. 34). The
lateral view of a carotid angiogram contains blood vessels on
both sides of a hemisphere as well as those within it deep to
the surface, all superimposed. Likewise, in a vertebral angiogram that fills the basilar artery, the cerebellar arteries and
the posterior cerebral arteries of both sides of the brain are
superimposed in the lateral projection.
Magnetic Resonance Imaging Magnetic resonance imaging (MRI) shows “slices” of the brain and surrounding
tissues in living persons (Part III). MRI scanners have
a strong magnet, a radio frequency (RF) transmitter, a
receiver (antenna), and a computer for processing the
received signal. In strong magnetic fields, nuclei of hydrogen atoms (protons) act as little magnets that align in
relation to the direction of the magnetic field. Magnetized
hydrogen atoms absorb the energy of a brief RF pulse,
which perturbs their alignment. After the pulse, hydrogen
atoms restore their magnetic alignment and broadcast an
RF signal that is proton- and magnetic-field-strength specific. The signal is received by the antenna encircling the
head and is processed to determine its source and strength,
from which the images are reconstructed. Signal intensity
from a specific location in the slice is represented by shades
of gray on a black-and-white image. In medical imaging,
stronger signals are assigned lighter (brighter) shades while
weaker signals are assigned darker shades.
The energy of and time interval between RF pulses and
time delays before receiving the signal can be selected and
constitute the pulse sequence. Signal intensity depends on
three inherent properties of the tissue: water content in a
unit volume of tissue (proton density) and two important
magnetic characteristics of the tissue known as relaxation
times, T1 (relaxation time 1) and T2 (relaxation time 2).
Although greater water content yields stronger (brighter)
signals, the water content signal is greatly modulated by
the opposing effects of the tissue-dependent relaxation
times T1 and T2. The relaxation times can be selectively
emphasized, i.e., “weighted,” by the pulse sequence used.
T1-weighted images show higher (brighter) signals in
white matter than in gray matter and resemble anatomic
brain slices. The CSF in T1-weighted images has a low
(dark) signal. In T2-weighted images, the signal is low
(dark) in white matter, resembling a myelin stain, whereas
the signal in the CSF is high (bright), emphasizing the
ventricles, cisterns, and subarachnoid space.
A set of parallel images can be made in either a twodimensional (2D) or three-dimensional (3D) modes. In
the 2D mode, the RF pulse is delivered to individual slices
in rapid succession, and the signal is acquired one slice at
a time. The process is repeated, typically 192–250 times. A
2D acquisition typically has 20 slices, 5 mm thick. In the
3D mode, the RF pulse is delivered to the entire volume.
Likewise the signal is emitted from the entire volume. The
slice thickness can be as narrow as 1 mm without significant
loss of signal to noise. The MRI images in The Brain Atlas
were obtained in a 1.5 Tesla magnet with T1-weighted pulse
sequences. Coronal and axial images were obtained with 2D
“inversion recovery” sequences, while sagittal images were
obtained with 3D “magnetization preparation” (MPRAGE
sequence by Siemens Corp., Erlangen, Germany). Both
“inversion recovery” and “magnetization preparation” provide heavy T1 weighting that makes the MRIs similar to the
stained brain slices in Part III. Differences between the brain
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17