neuroanatomy - University of Toledo

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Atlas of
Neuroanatomy and
Neurophysiology
Selections from the Netter Collection of Medical Illustrations
Illustrations by
Frank H. Netter, MD
John A. Craig, MD
James Perkins, MS, MFA
Text by
John T. Hansen, PhD
Bruce M. Koeppen, MD, PhD
Atlas of Neuroanatomy and Neurophysiology
Selections from the Netter Collection of Medical Illustrations
Copyright ©2002 Icon Custom Communications. All rights reserved.
The contents of this book may not be reproduced in any form without written
authorization from Icon Custom Communications. Requests for permission
should be addressed to Permissions Department, Icon Custom Communications,
295 North St., Teterboro NJ 07608, or can be made at www. Netterart.com.
NOTICE
Every effort has been taken to confirm the accuracy of the information presented.
Neither the publisher nor the authors can be held responsible for errors or for any
consequences arising from the use of the information contained herein, and make
no warranty, expressed or implied, with respect to the contents of the publication.
Printed in U.S.A.
Foreword
Frank Netter: The Physician, The Artist, The Art
This selection of the art of Dr. Frank H. Netter on neuroanatomy and neurophysiology is drawn
from the Atlas of Human Anatomy and Netter’s Atlas of Human Physiology. Viewing these pictures
again prompts reflection on Dr. Netter’s work and his roles as physician and artist.
Frank H. Netter was born in 1906 in New York City. He pursued his artistic muse at the Sorbonne,
the Art Student’s League, and the National Academy of Design before entering medical school at
New York University, where he received his M.D. degree in 1931. During his student years, Dr.
Netter’s notebook sketches attracted the attention of the medical faculty and other physicians, allowing him to augment his income by illustrating articles and textbooks. He continued illustrating as a
sideline after establishing a surgical practice in 1933, but ultimately opted to give up his practice in
favor of a full-time commitment to art. After service in the United States Army during the Second
World War, Dr. Netter began his long collaboration with the CIBA Pharmaceutical Company (now
Novartis Pharmaceuticals). This 45-year partnership resulted in the production of the extraordinary
collection of medical art so familiar to physicians and other medical professionals worldwide.
When Dr. Netter’s work is discussed, attention is focused primarily on Netter the artist and only
secondarily on Netter the physician. As a student of Dr. Netter’s work for more than forty years, I can
say that the true strength of a Netter illustration was always established well before brush was laid to
paper. In that respect each plate is more of an intellectual than an artistic or aesthetic exercise. It is
easy to appreciate the aesthetic qualities of Dr. Netter’s work, but to overlook its intellectual qualities is to miss the real strength and intent of the art. This intellectual process requires thorough understanding of the topic, as Dr. Netter wrote: “Strange as it may seem, the hardest part of making a medical picture is not the drawing at all. It is the planning, the conception, the determination of point of
view and the approach which will best clarify the subject which takes the most effort.”
Years before the inception of “the integrated curriculum,” Netter the physician realized that a
good medical illustration can include clinical information and physiologic functions as well as anatomy. In pursuit of this principle Dr. Netter often integrates pertinent basic and clinical science elements in his anatomic interpretations. Although he was chided for this heresy by a prominent
European anatomy professor, many generations of students training to be physicians rather than
anatomists have appreciated Dr. Netter’s concept.
The integration of physiology and clinical medicine with anatomy has led Dr. Netter to another,
more subtle, choice in his art. Many texts and atlases published during the period of Dr. Netter’s
career depict anatomy clearly based on cadaver specimens with renderings of shrunken and shriveled tissues and organs. Netter the physician chose to render “live” versions of these structures—not
shriveled, colorless, formaldehyde-soaked tissues, but plump, robust organs, glowing with color!
The value of Dr. Netter’s approach is clearly demonstrated by the plates in this selection.
John A. Craig, MD
Austin, Texas
This volume brings together two distinct but related aspects of the work of Frank
H. Netter, MD, and associated artists. Netter is best known as the creator of the
Atlas of Human Anatomy, a comprehensive textbook of gross anatomy that has
become the standard atlas for students of the subject. But Netter’s work included
far more than anatomical art. In the pages of Clinical Symposia, a series of monographs published over a period of more than 50 years, and in The Netter Collection
of Medical Illustrations, this premier medical artist created superb illustrations of
biological and physiological processes, disease pathology, clinical presentations,
and medical procedures.
As a service to the medical community, Novartis Pharmaceuticals has commissioned this special edition of Netter’s work, which includes his beautiful and
instructive illustrations of nervous system anatomy as well as his depictions of
neurophysiological concepts and functions. We hope that readers will find Dr.
Netter’s renderings of neurological form and function interesting and useful.
Click any title below to link to that plate.
Part 1 Neuroanatomy
Cerebrum—Medial Views . . . . . . . . . . . . . . . . . 2
Cerebrum—Inferior View. . . . . . . . . . . . . . . . . . 3
Basal Nuclei (Ganglia). . . . . . . . . . . . . . . . . . . . 4
Thalamus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cerebellum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Brainstem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Fourth Ventricle and Cerebellum . . . . . . . . . . . 8
Accessory Nerve (XI) . . . . . . . . . . . . . . . . . . . . 9
Arteries to Brain and Meninges . . . . . . . . . . . 10
Arteries to Brain: Schema . . . . . . . . . . . . . . . . 11
Oculomotor (III), Trochlear (IV)
and Abducent (VI) Nerves: Schema. . . . . . . 27
Trigeminal Nerve (V): Schema . . . . . . . . . . . . 28
Facial Nerve (VII): Schema . . . . . . . . . . . . . . . 29
Vestibulocochlear Nerve (VIII): Schema. . . . . 30
Glossopharyngeal Nerve (IX): Schema . . . . . . 31
Vagus Nerve (X): Schema . . . . . . . . . . . . . . . . 32
Accessory Nerve (XI): Schema . . . . . . . . . . . . 33
Hypoglossal Nerve (XII): Schema . . . . . . . . . . 34
Nerves of Heart . . . . . . . . . . . . . . . . . . . . . . . . 35
Arteries of Brain: Inferior Views . . . . . . . . . . . 12
Autonomic Nerves
and Ganglia of Abdomen. . . . . . . . . . . . . . . 36
Cerebral Arterial Circle (Willis) . . . . . . . . . . . 13
Nerves of Stomach and Duodenum . . . . . . . . 37
Arteries of Brain: Frontal View and Section . . 14
Nerves of Stomach
and Duodenum (continued) . . . . . . . . . . . . 38
Arteries of Brain:
Lateral and Medial Views . . . . . . . . . . . . . . . 15
Nerves of Small Intestine . . . . . . . . . . . . . . . . 39
Arteries of Posterior Cranial Fossa . . . . . . . . . 16
Nerves of Large Intestine . . . . . . . . . . . . . . . . 40
Veins of Posterior Cranial Fossa . . . . . . . . . . . 17
Deep Veins of Brain. . . . . . . . . . . . . . . . . . . . . 18
Nerves of Kidneys,
Ureters and Urinary Bladder . . . . . . . . . . . . 41
Subependymal Veins of Brain . . . . . . . . . . . . . 19
Nerves of Pelvic Viscera: Male . . . . . . . . . . . . 42
Hypothalamus and Hypophysis . . . . . . . . . . . 20
Nerves of Pelvic Viscera: Female . . . . . . . . . . 43
Arteries and Veins
of Hypothalamus and Hypophysis . . . . . . . . 21
Median Nerve . . . . . . . . . . . . . . . . . . . . . . . . . 44
Relation of Spinal Nerve Roots to Vertebrae . . . 22
Radial Nerve in Arm
and Nerves of Posterior Shoulder . . . . . . . . 46
Autonomic Nervous System:
General Topography. . . . . . . . . . . . . . . . . . . 23
Spinal Nerve Origin: Cross Sections. . . . . . . . 24
Olfactory Nerve (I): Schema . . . . . . . . . . . . . . 25
Optic Nerve (II)
(Visual Pathway): Schema . . . . . . . . . . . . . . 26
Ulnar Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Radial Nerve in Forearm . . . . . . . . . . . . . . . . . 47
Sciatic Nerve and Posterior
Cutaneous Nerve of Thigh . . . . . . . . . . . . . . 48
Tibial Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Common Fibular (Peroneal) Nerve. . . . . . . . . 50
NEUROANATOMY
Sagittal section of
brain in situ
Cingulate gyrus
Cingulate sulcus
Medial frontal gyrus
Sulcus of corpus callosum
Fornix
Septum pellucidum
Interventricular
foramen (Monro)
Interthalamic
adhesion
Thalamus and
3rd ventricle
Subcallosal
(parolfactory)
area
Anterior
commissure
Subcallosal
gyrus
Hypothalamic
sulcus
Lamina
terminalis
Supraoptic
recess
Optic chiasm
Tuber cinereum
Hypophysis (pituitary gland)
Mammillary body
Cerebral peduncle
Pons
Medial surface of cerebral
hemisphere: brainstem excised
Cingulate gyrus
Mammillothalamic
fasciculus
Mammillary body
Cerebrum: Medial Views
Paracentral sulcus
Central sulcus (Rolando)
Paracentral lobule
Marginal sulcus
Corpus callosum
Precuneus
Superior sagittal sinus
Choroid plexus
of 3rd ventricle
Stria medullaris
of thalamus
Parietooccipital
sulcus
Cuneus
Habenular
commissure
Pineal body
Posterior
commissure
Calcarine
sulcus
Straight sinus
in tentorium
cerebelli
Cerebral aqueduct
(Sylvius)
Great cerebral vein
(Galen)
Superior colliculus
Inferior colliculus
Tectal (quadrigeminal) plate
Cerebellum
Superior medullary velum
4th ventricle and choroid plexus
Inferior medullary velum
Medulla oblongata
Genu
Rostrum
Trunk
Splenium
of
corpus callosum
Isthmus of cingulate gyrus
Parietooccipital sulcus
Cuneus
Uncus
Calcarine sulcus
Optic nerve (II)
Lingual gyrus
Olfactory tract
Crus
Body
Column
Collateral sulcus
Rhinal sulcus
Medial occipitotemporal gyrus
Occipitotemporal sulcus
Lateral occipitotemporal gyrus
2
of fornix
Fimbria of hippocampus
Dentate gyrus
Parahippocampal gyrus
NEUROANATOMY
Cerebrum: Inferior View
Sectioned brainstem
Frontal pole of cerebrum
Straight gyrus
Olfactory sulcus
Orbital sulci
Longitudinal cerebral fissure
Genu of corpus callosum
Lamina terminalis
Olfactory bulb
Olfactory tract
Orbital gyri
Optic chiasm
Temporal pole
Optic nerve (II) (cut)
Lateral sulcus (Sylvius)
Hypophysis
(pituitary gland)
Inferior temporal sulcus
Inferior temporal gyrus
Anterior
perforated substance
Optic tract
Tuber cinereum
Mammillary body
Inferior (inferolateral) margin
of cerebrum
Posterior perforated
substance (in
interpeduncular
fossa)
Rhinal sulcus
Cerebral crus
Uncus
Lateral geniculate
body
Inferior
temporal gyrus
Substantia nigra
Medial geniculate
body
Occipitotemporal
sulcus
Red nucleus
Lateral occipitotemporal gyrus
Pulvinar of thalamus
Superior colliculus (of
corpora quadrigemina)
Collateral sulcus
Cerebral aqueduct
Splenium of corpus callosum
Medial occipitotemporal gyrus
Calcarine sulcus
Apex of cuneus
Occipital pole of cerebrum
Isthmus of cingulate gyrus
3
NEUROANATOMY
Horizontal sections
through cerebrum
Basal Nuclei (Ganglia)
A
B
Head of caudate nucleus
Lateral ventricle
Anterior limb
of internal
capsule
Genu
Septum pellucidum
Posterior limb
Column of fornix
Putamen
Globus pallidus
Insula
(island of Reil)
Lentiform
nucleus
3rd ventricle
Interthalamic
adhesion
External capsule
Thalamus
Claustrum
Crus of fornix
Retrolenticular part
of internal capsule
Choroid plexus
of lateral ventricle
Tail of caudate nucleus
Hippocampus and fimbria
Splenium of
corpus callosum
Occipital (posterior) horn
Habenula
Organization of
basal nuclei (ganglia)
A
B
Caudate Putamen Globus
nucleus
pallidus
Striatum
Lentiform
nucleus
Corpus
striatum
Basal nuclei
(ganglia)
Pineal body
Cleft for internal capsule
Caudate
nucleus
Levels of
sections
above
Body
Head
A
B
Thalamus
A
B
Pulvinar
Lentiform nucleus
(globus pallidus medial
to putamen)
Amygdaloid body
Medial geniculate body
Lateral geniculate body
Tail of caudate nucleus
Interrelationship of thalamus, lentiform nucleus, caudate
nucleus and amygdaloid body (schema): left lateral view
4
NEUROANATOMY
Thalamus
Corpus callosum (cut)
Interventricular foramen (Monro)
Tela choroidea (cut edge)
of 3rd ventricle
Septum pellucidum
3rd ventricle
Columns of fornix
Choroid plexus
Anterior tubercle
Superior thalamostriate vein
Stria terminalis
Pes hippocampi
Interthalamic adhesion
Temporal (inferior) horn
Lamina affixa
Internal cerebral vein
Stria medullaris
Dentate gyrus
Habenular trigone
Collateral eminence
Pulvinar (retracted)
Hippocampus
Posterior commissure
Brachium of superior colliculus
Habenular commissure
Brachium of inferior colliculus
Pineal body
Collateral trigone
Superior colliculus
Calcar avis
Inferior colliculus
Cerebellum
Calcarine sulcus
3rd ventricle
Internal
medullary
lamina
Interthalamic
adhesion
a
Pulvinar
rio
r
MD
LP
M
Intralaminar
nuclei
Inte
LP
3rd ventricle
VPL
M
External
medullary
lamina
VP
Median nuclei
Schematic section
through thalamus
(at level of broken
line shown in figure
at right)
Thalamic nuclei
CM
LD
LP
M
MD
VA
VI
VL
VP
VPL
VPM
Centromedian
Lateral dorsal
Lateral posterior
Medial
Medial dorsal
Ventral anterior
Ventral intermedial
Ventral lateral
Ventral posterior
Ventral posterolateral
Ventral posteromedial
VL
VP
Reticular nucleus
VP
CM
rn
L
VA
La
m
in
n
te
An
dia
Me ial
d
na
Me llar y lami
u
d
D
e
L
al m
VP
M
VI
Pulvinar
Schematic representation of thalamus
(external medullary lamina and
reticular nuclei removed)
Lateral nuclei
Medial nuclei
Anterior nuclei
5
NEUROANATOMY
Cerebellum
Superior surface
Anterior cerebellar notch
Anterior lobe
Quadrangular lobule (H IV-V)
Central lobule (II & III)
Primary fissure
Horizontal fissure
Culmen (IV & V)
Simple lobule (H VI)
Superior
vermis
Posterior lobe
Declive (VI)
Postlunate fissure
Folium (VII A)
Superior semilunar
(anseriform) lobule (H VII A)
Horizontal fissure
Inferior semilunar
(caudal) lobule (H VII B)
Posterior cerebellar notch
Central lobule
Superior vermis
Anterior lobe
Inferior surface
Wing of central lobule
Lingula (I)
Superior
Middle
Inferior
Flocculus (H X)
Flocculonodular lobe
4th ventricle
Posterolateral (dorsolateral)
fissure
Retrotonsillar fissure
Nodule (X)
Inferior
vermis
Cerebellar peduncles
Posterior lobe
Uvula (IX)
Pyramid (VIII)
Tuber (VII B)
Posterior cerebellar notch
Decussation of
superior cerebellar peduncles
Tonsil
Biventer lobule (H VIII)
Secondary (postpyramidal)
fissure
Horizontal fissure
Inferior semilunar
(caudal) lobule (H VII B)
Cerebral crus
Medial longitudinal fasciculus
4th ventricle
Nuclear layer of
medulla oblongata
Fastigial
Cerebellar
nuclei
Superior cerebellar
peduncle
Globose
Lingula (I)
Dentate
Vermis
Emboliform
Section in plane of superior cerebellar peduncle
6
NEUROANATOMY
Brainstem
Thalamus (cut surface)
Posterolateral view
Optic tract
Pulvinars of thalami
Pineal body
Superior colliculi
Brachia of superior and inferior colliculi
Inferior colliculi
Cerebral crus
Trochlear nerve (IV)
Pons
Trigeminal nerve (V)
Superior cerebellar peduncle
Middle cerebellar peduncle
Rhomboid fossa of
4th ventricle
Vestibulocochlear nerve (VIII)
Facial nerve (VII)
Glossopharyngeal (IX) and
vagus (X) nerves
Inferior cerebellar peduncle
Cuneate tubercle
Hypoglossal nerve (XII)
Gracile tubercle
Accessory nerve (XI)
Dorsal roots of
1st spinal nerve (C1)
Cuneate fasciculus
Gracile fasciculus
Olfactory tract
Anterior view
Anterior perforated substance
Infundibulum (pituitary stalk)
Optic chiasm
Mammillary bodies
Optic tract
Temporal lobe (cut surface)
Oculomotor nerve (III)
Tuber cinereum
Cerebral crus
Abducent nerve (VI)
Facial nerve (VII) and
intermediate nerve
Posterior perforated substance
Vestibulocochlear nerve (VIII)
Pons
Flocculus of cerebellum
Olive
Choroid plexus of 4th
ventricle
Glossopharyngeal nerve (IX)
Pyramid
Ventral roots of 1st spinal nerve (C1)
Decussation of pyramids
Vagus nerve (X)
Accessory nerve (XI)
7
NEUROANATOMY
Fourth Ventricle and Cerebellum
Habenular trigone
Posterior view
Medial
Lateral
3rd ventricle
Geniculate bodies
Dorsal median sulcus
Pineal body
Locus ceruleus
Superior colliculus
Medial eminence
Inferior colliculus
Facial colliculus
Vestibular area
Dentate nucleus
of cerebellum
Superior
Middle
Inferior
Cerebellar peduncles
Striae medullares
Lateral recess
Tenia of 4th ventricle
Superior fovea
Cuneate tubercle
Sulcus limitans
Gracile tubercle
Inferior fovea
Dorsal median sulcus
Trigeminal tubercle
Lateral funiculus
Hypoglossal trigone
Vagal trigone
Cuneate fasciculus
Gracile fasciculus
Obex
Median sagittal section
Posterior commissure
Body of fornix
Habenular commissure
Thalamus (in
3rd ventricle)
Pineal body
Interventricular
foramen (Monro)
Great cerebral vein (Galen)
Anterior commissure
Lamina terminalis
Lingula (I)
Central lobule (II-III)
Culmen (IV-V)
Declive (VI)
Folium (VII A)
Hypothalamic sulcus
Cerebral peduncle
Cerebral aqueduct (Sylvius)
Superior colliculus
Tectal (quadrigeminal) plate
Inferior colliculus
Pons
Medial longitudinal fasciculus
Tuber (VII B)
4th ventricle
Pyramid (VIII)
Choroid plexus of 4th ventricle
Uvula (IX)
Nodulus (X)
Medulla oblongata
Median aperture (foramen of Magendie)
Decussation of pyramids
Central canal of spinal cord
8
Vermis of
cerebellum
Tonsil of cerebellum
Vermis of
cerebellum
NEUROANATOMY
Accessory Nerve (XI): Schema
Nucleus ambiguus
Vagus nerve (X)
Cranial root of accessory nerve (joins vagus nerve
and via recurrent laryngeal nerve supplies muscles of
larynx, except cricothyroid)*
Spinal root of
accessory nerve
Foramen
magnum
Jugular foramen
Superior ganglion
of vagus nerve
Accessory nerve (XI)*
Inferior ganglion
of vagus nerve
C1 spinal nerve
C2 spinal nerve
Accessory nerve
(to sternocleidomastoid
and trapezius muscles)
Sternocleidomastoid muscle (cut)
C3 spinal nerve
C4 spinal nerve
Trapezius muscle
Efferent fibers
Proprioceptive fibers
*Recent evidence suggests that the accessory nerve lacks a cranial root and has no connection to the vagus nerve.
Verification of this finding awaits further investigation.
9
NEUROANATOMY
Left middle meningeal artery
Posterior cerebral artery
Superior cerebellar artery
Basilar artery
Arteries to Brain and Meninges
Middle cerebral artery
Anterior cerebral artery
Anterior communicating artery
Ophthalmic artery
Left labyrinthine
(internal acoustic) artery
Posterior
communicating
artery
Mastoid branch of
left occipital artery
Cavernous sinus
Anterior inferior
cerebellar artery
Middle
meningeal
artery
Posterior meningeal
branch of left ascending
pharyngeal artery
Posterior inferior
cerebellar artery
Left and right
vertebral arteries
(intracranial part)
Maxillary
artery
Superficial
temporal
artery
Posterior meningeal
branch of vertebral
artery
External
carotid
artery
Anterior meningeal
branch of vertebral artery
Posterior auricular artery
Facial artery
Occipital artery
Internal carotid artery
Carotid sinus
Carotid body
Vertebral artery
(cervical part)
Transverse process of C6
Deep cervical artery
Supreme intercostal
artery
Costocervical trunk
Subclavian artery
10
Lingual artery
Ascending pharyngeal artery
Superior laryngeal artery
Superior thyroid artery
Common carotid artery
Ascending cervical artery (cut)
Inferior thyroid artery
Thyrocervical trunk
Brachiocephalic trunk
Internal thoracic artery
NEUROANATOMY
Arteries to Brain: Schema
1
Ophthalmic artery
Supraorbital artery
Posterior communicating artery
Supratrochlear artery
Caroticotympanic branch
of internal carotid artery
3
3
2
3
Lacrimal artery
1
Dorsal nasal artery
Middle meningeal artery
3
Angular artery
Anterior tympanic artery
Superficial temporal artery
1
1
Middle meningeal artery
Posterior auricular artery
4
Facial artery
Maxillary artery
Basilar artery
5
4
5
Occipital artery
Lingual artery
Anterior inferior
cerebellar artery
5
Posterior inferior
cerebellar artery
5
Ascending pharyngeal artery
Anterior spinal artery
5
External carotid artery
Spinal segmental
medullary branches
5
Vertebral artery
5
Superior thyroid artery
Deep cervical artery
5
Transverse cervical artery
Suprascapular artery
Vertebral artery
Supreme intercostal artery
Ascending cervical artery
Costocervical trunk
Thyrocervical trunk
Subclavian artery
Subclavian artery
Internal thoracic artery
Brachiocephalic trunk
Arch
Aorta
Descending
Ascending
Anastomoses
1
2
3
4
5
Right–Left
Carotid–Vertebral
Internal carotid–External carotid
Subclavian–Carotid
Subclavian–Vertebral
11
NEUROANATOMY
Arteries of Brain: Inferior Views
Medial frontobasal (orbitofrontal) artery
Distal medial striate artery
(recurrent artery of Heubner)
Anterolateral central (lenticulostriate) arteries
Lateral frontobasal (orbitofrontal) artery
Prefrontal artery
Anterior choroidal artery
Basilar artery
Pontine arteries
Labyrinthine (internal acoustic) artery
Anterior inferior cerebellar artery
Vertebral artery
Posterior inferior cerebellar artery (PICA) (cut)
Posterior spinal artery
Optic tract
Cerebral crus
Posterior medial choroidal artery
Posterior lateral choroidal artery
Choroid plexus of lateral ventricle
Lateral ventricle
12
Cerebral arterial
circle (Willis)
(broken line)
NEUROANATOMY
Cerebral Arterial Circle (Willis)
Vessels dissected out: inferior view
(A2 segment)
Anteromedial central (perforating)
arteries
(A1 segment)
Hypothalamic artery
Anterolateral central
(lenticulostriate) arteries
Ophthalmic artery
Superior hypophyseal artery
Inferior hypophyseal artery
(P2 segment)
(P1 segment)
Basilar artery
Pontine arteries
Thalamotuberal
(premammillary) artery
Posteromedial central
(perforating) arteries
Thalamoperforating artery
(paramedian) arteries
Vertebral artery
Vessels in situ: inferior view
Hypothalamic artery
Optic chiasm
Cavernous sinus
Superior hypophyseal artery
and long hypophyseal portal veins
Adenohypophysis (anterior
lobe of pituitary gland)
Neurohypophysis (posterior
lobe of pituitary gland)
(perforating) arteries
Efferent hypophyseal veins
Basilar artery
13
NEUROANATOMY
Corpus callosum
Arteries of Brain: Frontal View and Section
Paracentral artery
Medial frontal branches
Pericallosal artery
Lateral frontobasal
(orbitofrontal) artery
Callosomarginal artery
Polar frontal artery
Prefrontal artery
Anterior cerebral
arteries
Precentral (pre-rolandic)
and central (rolandic)
sulcal arteries
Medial frontobasal
Anterior parietal
(postcentral sulcal)
artery
Distal medial striate
artery (recurrent
artery of Heubner)
Posterior parietal
artery
Internal carotid
artery
Branch to
angular gyrus
Anterior choroidal
artery
Temporal branches
(anterior, middle
and posterior)
Posterior cerebral
artery
and branches
(deep in lateral cerebral
[sylvian] sulcus)
Basilar and pontine arteries
Labyrinthine (internal
acoustic) artery
Vertebral artery
Posterior inferior cerebellar artery
Posterior spinal artery
Falx cerebri
Corpus striatum
(caudate and lentiform nuclei)
Insula (island of Reil)
Limen of insula
Precentral (pre-rolandic),
central (rolandic) sulcal
and parietal arteries
Lateral cerebral (sylvian) sulcus
Temporal branches of
middle cerebral artery
Temporal lobe
14
Callosomarginal arteries
and
Pericallosal arteries
(branches of anterior
cerebral arteries)
Trunk of corpus callosum
Internal capsule
Septum pellucidum
Rostrum of corpus callosum
Anterior cerebral arteries
Optic chiasm
NEUROANATOMY
Arteries of Brain: Lateral and Medial Views
Anterior parietal (postcentral sulcal) artery
Posterior parietal artery
Central (rolandic) sulcal artery
Branch to angular gyrus
Precentral (pre-rolandic) sulcal artery
Terminal branches
of posterior
cerebral artery
Prefrontal sulcal
artery
Terminal branches of
anterior cerebral
artery
Lateral frontobasal
Left middle
cerebral artery
Left anterior
cerebral artery
Occipitotemporal
branches
Posterior temporal branch
Right anterior cerebral artery
Middle temporal branch
Left internal carotid artery
Polar temporal artery
Medial
frontal
branches
Posterior
Intermediate
Anterior
Pericallosal artery
Superior and inferior terminal branches (trunks)
Anterior temporal branch
Paracentral artery
Cingular branches
Right posterior cerebral artery
Precuneal artery
Callosomarginal
artery
Polar frontal artery
Dorsal branch
to corpus callosum
Parietooccipital branch
Calcarine branch
Right anterior
cerebral artery
Medial frontobasal (orbitofrontal) artery
Anterior
communicating artery (cut)
Medial occipital artery
Posterior temporal branch
Anterior temporal branch
Right internal carotid artery
Note: Anterior parietal (postcentral sulcal) artery also occurs as separate anterior parietal and postcentral sulcal arteries
15
NEUROANATOMY
Arteries of Posterior Cranial Fossa
Thalamogeniculate arteries
Lateral and medial geniculate bodies of left thalamus
Choroid plexuses of lateral ventricles
Pulvinars of left and right thalami
Crura of fornix
Occipital (posterior) horn of right lateral ventricle
Right dorsal branch to corpus callosum
(posterior pericallosal artery)
Heads of caudate nuclei
Septum pellucidum
Parietooccipital
Corpus callosum
Calcarine
Branches of
right posterior
cerebral artery
Anterior
cerebral arteries
Longitudinal
cerebral
fissure
Superior
colliculi
Superior
vermian
branch
Optic nerve (II)
IV
Ophthalmic artery
III
Posterior medial
choroidal artery
to choroid plexus
of 3rd ventricle
V
Anterior
cerebral artery
Middle
cerebral artery
VIII
Posterior
communicating artery
VII
Posterior lateral
choroidal artery
VI
Lateral (marginal) branch
IX
X
Thalamoperforating arteries
Inferior vermian artery
(phantom)
Left internal carotid artery
XI
Basilar artery
Choroidal branch to 4th ventricle
(phantom) and
Cerebellar tonsillar branch
of posterior inferior cerebellar artery
Pontine arteries
Outline of 4th ventricle (broken line)
Posterior meningeal branch of vertebral artery
Posterior inferior cerebellar artery (PICA)
Anterior meningeal branch of vertebral artery
Temporal branches of posterior cerebral artery
16
Left posterior spinal artery
Left vertebral artery
NEUROANATOMY
Veins of Posterior Cranial Fossa
Left superior and inferior colliculi
Left pulvinar
Basal vein (Rosenthal)
Right pulvinar
Internal cerebral veins
Posterior mesencephalic vein
Lateral
mesencephalic vein
Dorsal vein of corpus callosum
Inferior sagittal sinus
Left thalamus
(cut surface)
Straight sinus
Falx cerebri
Optic tract
Confluence of sinuses
Tentorium
cerebelli (cut)
Inferior thalamostriate veins
Left transverse
sinus (cut)
Deep middle
cerebral
vein (cut)
Superior
sagittal
sinus
Anterior
cerebral
vein
Optic
nerve (II)
C
C
CL
D
F
TU
L
N
Superior
vermian
vein
P
U
Anterior pontomesencephalic vein
Inferior
vermian vein
Falx cerebelli (cut)
and occipital sinus
T
Inferior cerebellar
hemispheric veins
Transverse pontine vein
Intraculminate vein
Superior cerebellar vein (inconstant)
Petrosal vein (draining
to superior petrosal sinus)
Preculminate vein
Lateral pontine vein
Precentral cerebellar vein
Superior retrotonsillar vein
Anteromedian medullary vein
Vein of lateral recess of 4th ventricle
Superior, middle and
inferior cerebellar peduncles
Anterior spinal vein
(Inferior retrotonsillar)
vein of cerebellomedullary
cistern
Posterior spinal vein
4th ventricle
Parts of cerebellum
L
CL
C
D
F
Lingula
Central lobule
Culmen
Declive
Folium
TU Tuber
P Pyramid
U Uvula
N Nodule
T Tonsil
17
NEUROANATOMY
Deep Veins of Brain
Anterior cerebral veins
Rostrum of corpus callosum
Septum pellucidum
Anterior vein of septum pellucidum
Anterior vein of caudate nucleus
Transverse veins of caudate nucleus
Interventricular foramen (Monro)
Columns of fornix
Superior choroid vein and
choroid plexus of lateral ventricle
Thalamus
Tela choroidea of 3rd ventricle
Lateral direct vein
Posterior vein of caudate nucleus
Internal cerebral veins
Inferior sagittal sinus
Straight sinus
Tentorium cerebelli
Transverse sinus
Confluence of sinuses
Dissection: superior view
Uncal vein
Anterior cerebral vein
Superficial middle cerebral vein
(draining to sphenoparietal sinus)
Optic chiasm
Deep middle cerebral vein
Cerebral crus
Inferior
cerebral
veins
Dissection: inferior view
18
Inferior
anastomotic
vein (Labbé)
NEUROANATOMY
Subependymal Veins of Brain
Posterior veins of septum pellucidum
Superior thalamic veins
Superior choroid vein
Lateral direct vein
Posterior terminal vein of caudate nucleus
(posterior part of thalamostriate vein)
Internal cerebral veins (right and left)
Transverse veins of caudate nucleus
Medial (atrial) vein of lateral ventricle
Lateral (atrial) vein of lateral ventricle
Lateral ventricle
Anterior vein of
caudate nucleus
Great cerebral vein
(Galen)
Anterior vein of
septum pellucidum
Dorsal vein of corpus
callosum
Genu of
corpus
callosum
Inferior sagittal
sinus
Internal
occipital vein
Straight sinus
Occipital
(posterior)
horn of
lateral
ventricle
Interventricular
foramen (Monro)
Anterior commissure
Anterior cerebral vein
Optic chiasm
Cerebellum
3rd ventricle
Deep middle cerebral vein
Inferior thalamostriate veins
Temporal (inferior) horn of lateral ventricle
Posterior mesencephalic vein
Superior vermian vein
Hippocampal and inferior ventricular veins
Cerebral aqueduct
4th ventricle
Lateral and median apertures of 4th ventricle
Veins on lateral wall of ventricle
Veins on medial wall and floor of ventricle
All other veins
19
NEUROANATOMY
Hypothalamus and Hypophysis
Septum pellucidum
Thalamus
Fornix
Hypothalamic sulcus
Anterior commissure
Paraventricular
Posterior
Dorsomedial
Principal
nuclei of
hypothalamus
Supraoptic
Ventromedial
Arcuate
(infundibular)
Mammillary
Mammillothalamic tract
Optic chiasm
Dorsal longitudinal
fasciculus and other
descending pathways
Hypophysis (pituitary gland)
Lamina terminalis
Hypothalamic
sulcus
Paraventricular hypothalamic nucleus
Supraoptic hypothalamic nucleus
Supraopticohypophyseal tract
Tuberohypophyseal tract
Mammillary
body
Hypothalamohypophyseal tract
Arcuate (infundibular) nucleus
Pars tuberalis
Adenohypophysis
(anterior lobe of
pituitary gland)
Fibrous trabecula
Median eminence
of tuber cinereum
Infundibular
stem
Pars intermedia
Pars distalis
Infundibular
process
Cleft
20
Neurohypophysis
(posterior lobe
of pituitary gland)
Arteries and Veins of Hypothalamus and Hypophysis
NEUROANATOMY
Hypothalamic vessels
Primary plexus of
hypophyseal portal system
Superior
hypophyseal
artery
Long hypophyseal portal veins
Artery of trabecula
Short hypophyseal portal veins
Trabecula (fibrous tissue)
Efferent hypophyseal vein
to cavernous sinus
Secondary plexus
of hypophyseal
portal system
Adenohypophysis
(anterior lobe of
pituitary gland)
to cavernous sinus
Neurohypophysis
(posterior lobe of
pituitary gland)
Capillary plexus of
infundibular process
to cavernous sinus
Efferent hypophyseal
veins to cavernous sinus
21
NEUROANATOMY
Relation of Spinal Nerve Roots to Vertebrae
C1
C2
C2
C3
C3
C4
C4
C5
C5
C6
C6 C7
C7
C8
T1
T1
T2
T2
T3
T3
T4
T4
T5
T5
T6
T6
T7
T7
T8
T8
T9
T9
T10
T10
T11
T11
T12
T12
L1
Base
of skull
Cervical
enlargement
Lumbar
enlargement
L4
C1 spinal nerve exits
above C1 vertebra
C1
L4
L5
C8 spinal nerve
exits below
C7 vertebra
(there are 8 cervical
nerves but only
7 cervical vertebrae)
L5
S1
S2
Lumbar disc protrusion does not usually affect
nerve exiting above disc. Lateral protrusion
at disc level L4–5 affects L5 spinal nerve, not
L4 spinal nerve. Protrusion at disc level L5–S1
affects S1 spinal nerve, not L5 spinal nerve
L4
Conus medullaris
(termination of
spinal cord)
L1
L4
L2
L2
L5
L3
L3
Internal terminal
filum (pial part)
L5
Cauda equina
L4
L4
S1
L5
L5
Sacrum
External
terminal filum
(dural part)
S2
S1
S3
Termination of
dural sac
S4
S5
Coccygeal nerve
Coccyx
Cervical nerves
Thoracic nerves
Lumbar nerves
Sacral and coccygeal nerves
22
S2
S3
S4
S5
Coccygeal nerve
Medial protrusion at disc level L4–5 rarely affects
L4 spinal nerve but may affect L5 spinal nerve
and sometimes S1–4 spinal nerves
Autonomic Nervous System: General Topography
Facial nerve (VII)
Vagus nerve (X)
Internal carotid nerve and plexus
Superior cervical sympathetic ganglion
C4 spinal nerve
Middle cervical sympathetic ganglion
Vertebral ganglion
Cervicothoracic (stellate) ganglion
Sympathetic trunk
Cervical (sympathetic)
cardiac nerves
Superior
Middle
Inferior
Thoracic (sympathetic) cardiac nerves
6th intercostal nerve
(ventral ramus of T6
spinal nerve)
Sympathetic trunk
6th thoracic sympathetic ganglion
Gray and white rami communicantes
Greater splanchnic nerve
Lesser splanchnic nerve
Least splanchnic nerve
Aorticorenal ganglion
Lumbar splanchnic nerves (sympathetic)
Gray rami communicantes
Sacral splanchnic nerves (sympathetic)
Pelvic splanchnic nerves
(sacral parasympathetic
outflow)
Sciatic nerve
Inferior hypogastric
(pelvic) plexus
NEUROANATOMY
Ciliary ganglion
Pterygopalatine ganglion
Otic ganglion
Chorda tympani nerve
Lingual nerve
Submandibular ganglion
Pharyngeal and superior laryngeal branches
of vagus nerve
Recurrent laryngeal branch of vagus nerve
Superior cervical
Inferior cervical
Thoracic
Cardiac branches
of vagus nerve
Cardiac plexus
Anterior
Posterior
Pulmonary plexuses
Esophageal plexus
Thoracic aortic plexus
Anterior vagal trunk
Posterior vagal trunk
Celiac ganglion
Celiac trunk and plexus
Superior mesenteric ganglion
Superior mesenteric artery
and plexus
Intermesenteric
(abdominal aortic) plexus
Inferior mesenteric ganglion
Inferior mesenteric artery
and plexus
Superior hypogastric plexus
Parasympathetic branch from
inferior hypogastric plexus to
descending colon
Hypogastric nerves
Rectal plexus
Vesical plexus
Sympathetic fibers
Parasympathetic fibers
Prostatic plexus
23
NEUROANATOMY
Spinal Nerve Origin: Cross Sections
Section through thoracic vertebra
Aorta
Body of vertebra
Fat in epidural space
Dura mater
Sympathetic ganglion
Arachnoid mater*
Ventral root
Subarachnoid space
White and gray rami
communicantes
Pia mater*
Recurrent
meningeal
branches of
spinal nerve
Spinal nerve
Ventral ramus
(intercostal nerve)
Dorsal ramus
Pleura
Lung
Spinal sensory
(dorsal root) ganglion
Dorsal root
Lateral horn of
gray matter of spinal cord
Section through lumbar vertebra
Lateral branch
Sympathetic
ganglion
Medial branch
Dura mater
Arachnoid mater
Gray ramus
communicans
Internal vertebral
(epidural) venous plexus
Ventral root
Fat in
epidural
space
Spinal nerve
Ventral ramus (contributes to lumbar plexus)
Dorsal ramus
Dorsal and ventral
roots of lumbar and
sacral spinal nerves
forming cauda equina
Spinal sensory (dorsal root) ganglion
Dorsal root
Conus medullaris
*Leptomeninges
24
of dorsal
ramus
of spinal
nerve
NEUROANATOMY
Olfactory Nerve (I): Schema
Subcallosal (parolfactory) area
Septal area and nuclei
Olfactory bulb cells: schema
Fibers from
Fibers to
Efferent fibers to
olfactory bulb
Afferent fibers from bulb
to central connections
and contralateral bulb
Contralateral
olfactory bulb
Anterior commissure
Medial
olfactory stria
Granule cell (excited by
and inhibiting to mitral
and tufted cells)
Mitral cell
Recurrent process
Tufted cell
Periglomerular
cell
Glomerulus
Olfactory
nerve fibers
Olfactory cells
Olfactory mucosa
Olfactory tract
Olfactory trigone
and olfactory tubercle
Olfactory nerves (I)
Lateral olfactory stria
Uncus
Olfactory bulb
Lateral olfactory tract nucleus
Cribriform plate of ethmoid bone
Anterior perforated substance
Anterior olfactory nucleus
Amygdaloid body (phantom)
Piriform lobe
Hippocampal
fimbria
Dentate gyrus
25
NEUROANATOMY
Optic Nerve (II) (Visual Pathway): Schema
G
Central darker
circle represents
macular zone
G
A
B
A
Overlapping
visual fields
Lighter shades
represent
monocular fields
B
Each quadrant
a different color
H
H
R RC
P
Projection on
right retina
Projection on
left retina
C
P
Choroid
Choroid
Periphery
Macula
Optic nerves (II)
Optic chiasm
Structure of retina: schema
A
B
C
G
H
P
R
Amacrine cells
Bipolar cells
Cones
Ganglion cells
Horizontal cells
Pigment cells
Rods
Projection on left
dorsal lateral
geniculate nucleus
Optic tracts
Projection on right
dorsal lateral
geniculate nucleus
Lateral
geniculate
bodies
Optic radiation
Optic radiation
Calcarine
sulcus
Calcarine
sulcus
Projection on left
occipital lobe
26
Projection on right
occipital lobe
NEUROANATOMY
Oculomotor (III), Trochlear (IV) and Abducent (VI) Nerves: Schema
Long ciliary nerve
Short ciliary nerves
Anterior ethmoidal nerve
Superior oblique muscle
Levator palpebrae
superioris muscle
Superior
rectus muscle
Ciliary ganglion
Posterior ethmoidal nerve
Abducent nucleus
Sensory root of ciliary ganglion
Trochlear nucleus
Sympathetic root of ciliary ganglion
Oculomotor nucleus
Superior division of
oculomotor nerve
Accessory oculomotor
(Edinger-Westphal)
nucleus (parasympathetic)
Frontal nerve (cut)
Lacrimal nerve (cut)
Nasociliary nerve
Ophthalmic nerve (V1)
Abducent
nerve (VI)
Infraorbital nerve
Zygomatic nerve (cut)
Inferior oblique muscle
Ciliary muscle
Pterygopalatine
ganglion
Inferior division of
oculomotor nerve
Dilator muscle of pupil
Sphincter muscle of pupil
Medial rectus muscle
Inferior rectus muscle
Efferent fibers
Afferent fibers
Sympathetic fibers
Parasympathetic root
of ciliary ganglion
Mandibular nerve (V3)
and nerve plexus
Maxillary nerve (V2)
Lateral rectus muscle and
abducent nerve (turned back)
Cavernous plexus
Common tendinous ring
27
NEUROANATOMY
Efferent fibers
Afferent fibers
Sympathetic fibers
Trigeminal Nerve (V): Schema
Ophthalmic nerve (V1)
Tentorial (meningeal) branch
Nasociliary nerve
Lacrimal nerve
Sensory root of
ciliary ganglion
Frontal nerve
Ciliary ganglion
Posterior ethmoidal nerve
Long ciliary nerve
Short ciliary nerves
Anterior ethmoidal nerve
Supraorbital nerve
Supratrochlear nerve
Infratrochlear nerve
Internal nasal branches
and
External nasal branches
of anterior ethmoidal nerve
Trigeminal nerve (V) ganglion and nuclei
Motor nucleus
Mesencephalic nucleus
Principal sensory nucleus
Spinal tract and nucleus
Maxillary nerve (V2)
Meningeal branch
Zygomaticotemporal
nerve
Zygomaticofacial nerve
Zygomatic nerve
Infraorbital nerve
Pterygopalatine
ganglion
Superior
alveolar
branches of
infraorbital nerve
Nasal branches
(posterior superior
lateral, nasopalatine
and posterior
superior medial)
Facial nerve (VII)
Chorda
tympani nerve
Nerve (vidian) of
pterygoid canal
(from facial nerve [VII]
and carotid plexus)
Pharyngeal branch
Greater and lesser
palatine nerves
Deep temporal nerves
(to temporalis muscle)
Lateral pterygoid
and masseteric nerves
Tensor veli palatini and
medial pterygoid nerves
Buccal nerve
Mental nerve
Inferior dental plexus
Lingual nerve
28
Superficial
temporal branches
Articular branch
and anterior
auricular nerves
Auriculotemporal nerve
Submandibular
ganglion
Mylohyoid nerve
Inferior
alveolar nerve
Otic ganglion
Mandibular nerve (V3) Tensor tympani nerve
Parotid branches
Meningeal branch
Lesser petrosal nerve (from
glossopharyngeal nerve [IX])
NEUROANATOMY
Facial Nerve (VII): Schema
Facial nerve (VII)
Greater petrosal nerve
Internal acoustic meatus
Geniculate ganglion
Deep petrosal nerve (from internal carotid plexus)
Intermediate nerve
Motor nucleus of facial nerve
Internal carotid plexus
(on internal carotid artery)
Lesser petrosal nerve
Nerve (vidian) of pterygoid canal
Superior salivatory nucleus
Solitary tract nucleus
Otic ganglion
Facial muscles
Frontal belly (frontalis)
of occipitofrontalis
Orbicularis oculi
Corrugator supercilii
Zygomaticus major
Zygomaticus minor
che
Temporal bran
Procerus
Levator labii
superioris
Levator labii
superioris
alaeque nasi
s
Levator
anguli oris
Nasalis
Depressor
septi nasi
Orbicularis
oris
Zygomatic bra
nch
es
anterior 2⁄3
Taste: tongue
of
Buccal
branches
Occipital
branch of
posterior
auricular
nerve
al br
anc
h
Depressor
anguli oris
Cer vic
Depressor labii
inferioris
Mentalis
(Risorius)
(not shown)
al
Margin ular
ib
d
man
branch
Buccinator
Occipital
belly
(occipitalis) of
occipitofrontalis
muscle
Branches to auricular muscles
Posterior auricular nerve
Nerve to stapedius muscle
Stylomastoid foramen
Tympanic plexus
Platysma
Tympanic nerve (Jacobson)
(from glossopharyngeal nerve)
Sublingual gland
Efferent fibers
Afferent fibers
Sympathetic fibers
Submandibular gland
Lingual nerve (from trigeminal nerve)
Digastric muscle (posterior belly)
Stylohyoid muscle
Caroticotympanic nerve (from internal carotid plexus)
29
NEUROANATOMY
Vestibulocochlear Nerve (VIII): Schema
Afferent fibers
Facial canal
Tympanic cavity
Geniculum of facial nerve
(site of geniculate ganglion)
Head of malleus
Cochlear (spiral) ganglion
Incus
Vestibular nerve
Cochlear nerve
Motor root of facial nerve
and intermediate nerve
Vestibulocochlear
nerve (VIII)
Medulla oblongata
(cross section)
Ampulla of lateral
semicircular duct
Internal
acoustic
meatus
Medial
Vestibular
nuclei
(diagrammatic)
Ampulla of superior
semicircular duct
Superior
Anterior
Inferior
Posterior
Utricle
Cochlear
nuclei
Ampulla of posterior
semicircular duct
Lateral
Inferior cerebellar
peduncle (to cerebellum)
Vestibular ganglion
Saccule
Superior division
Inferior division
30
of vestibular nerve
NEUROANATOMY
Glossopharyngeal Nerve (IX): Schema
Spinal tract and spinal nucleus of trigeminal nerve
Efferent fibers
Afferent fibers
Solitary tract nucleus
Tympanic nerve (Jacobson)
Tympanic cavity and plexus
Stylomastoid foramen
Caroticotympanic nerve (from internal carotid plexus)
Nucleus ambiguus
Inferior salivatory nucleus
Geniculate ganglion
of facial nerve
Deep petrosal nerve
Nerve (vidian) of pterygoid canal
Lesser petrosal nerve
Mandibular nerve (V3)
Otic ganglion
Auriculotemporal nerve
Parotid gland
Tubal branch of tympanic plexus
Pharyngotympanic (auditory)
tube and pharyngeal opening
Glossopharyngeal
nerve (IX)
Stylopharyngeus muscle (and branch
from glossopharyngeal nerve)
Jugular foramen
Communication to auricular
branch of vagus nerve
Superior and
Inferior ganglia of
Glossopharyngeal nerve
Communication to facial nerve (VII)
Taste and
somatic
sensation:
posterior
1
⁄3 of tongue
Vagus nerve (X)
Superior cervical
sympathetic ganglion
Sympathetic trunk
Carotid branch of
glossopharyngeal nerve
Pharyngeal plexus
Carotid sinus
Pharyngeal, tonsillar and lingual
branches of glossopharyngeal nerve
Carotid body
Pharyngeal branch of vagus nerve
External carotid artery
31
NEUROANATOMY
SEE ALSO PLATE 160
Vagus Nerve (X): Schema
Posterior nucleus of vagus
nerve (parasympathetic
and visceral afferent)
Solitary tract nucleus (visceral
afferents including taste)
Meningeal branch of vagus nerve
Auricular branch of vagus nerve
Spinal tract and spinal
nucleus of trigeminal nerve
(somatic afferent)
Pharyngotympanic (auditory) tube
Levator veli
palatini muscle
Nucleus ambiguus
(motor to pharyngeal
and laryngeal muscles)
Salpingopharyngeus
muscle
Cranial root of
accessory nerve*
(see next plate)
Palatoglossus muscle
Vagus nerve (X)
Palatopharyngeus
muscle
Jugular foramen
Superior pharyngeal
constrictor muscle
Superior ganglion of vagus nerve
Inferior ganglion of vagus nerve
Stylopharyngeus muscle
Middle pharyngeal constrictor muscle
Pharyngeal branch of vagus nerve (motor to muscles of
palate and lower pharynx; sensory to lower pharynx)
Inferior pharyngeal constrictor muscle
Cricothyroid muscle
Trachea
Esophagus
Right subclavian artery
Right recurrent laryngeal nerve
Heart
Hepatic branch of anterior
vagal trunk (in lesser omentum)
Celiac branches from anterior
and posterior vagal trunks
to celiac plexus
Celiac and superior mesenteric
ganglia and celiac plexus
Hepatic plexus
Gallbladder
and bile ducts
Liver
Pyloric branch
from hepatic plexus
Pancreas
Duodenum
Ascending colon
Cecum
Appendix
32
Communicating branch of vagus nerve to
carotid branch of glossopharyngeal nerve
Pharyngeal plexus
Superior laryngeal nerve:
Internal branch (sensory and parasympathetic)
External branch (motor to cricothyroid muscle)
Superior cervical cardiac branch of vagus nerve
Inferior cervical cardiac branch of vagus nerve
Thoracic cardiac branch of vagus nerve
Left recurrent laryngeal nerve (motor to muscles of larynx
except cricothyroid; sensory and parasympathetic to
larynx below vocal folds; parasympathetic, efferent and
afferent to upper esophagus and trachea)
Pulmonary plexus
Cardiac plexus
Esophageal plexus
Gastric branches of anterior vagal trunk
(branches from posterior trunk behind stomach)
Vagal branches (parasympathetic motor,
secretomotor and afferent fibers) accompany
superior mesenteric artery and its branches
usually as far as left colic (splenic) flexure
Small intestine
Efferent fibers
Afferent fibers
NEUROANATOMY
Accessory Nerve (XI): Schema
SEE ALSO PLATE 28
Nucleus ambiguus
Vagus nerve (X)
Cranial root of accessory nerve (joins vagus nerve
and via recurrent laryngeal nerve supplies muscles of
larynx, except cricothyroid)*
Spinal root of
accessory nerve
Foramen
magnum
Jugular foramen
Superior ganglion
of vagus nerve
Accessory nerve (XI)*
Inferior ganglion
of vagus nerve
C1 spinal nerve
C2 spinal nerve
Accessory nerve
(to sternocleidomastoid
and trapezius muscles)
Sternocleidomastoid muscle (cut)
C3 spinal nerve
C4 spinal nerve
Trapezius muscle
Efferent fibers
*Recent evidence suggests that the accessory nerve lacks a cranial root and has no connection to the vagus nerve.
Verification of this finding awaits further investigation.
33
NEUROANATOMY
Hypoglossal Nerve (XII): Schema
(in hypoglossal canal)
Hypoglossal nucleus
Superior
longitudinal
Intrinsic
muscles
of tongue
Transverse
and vertical
Inferior
longitudinal
Meningeal branch
Styloglossus
muscle
Occipital condyle
Inferior ganglion of
vagus nerve
Ventral rami of
C1, 2, 3 form
ansa cervicalis
of cervical plexus
Superior cervical
sympathetic
ganglion
Superior root of
ansa cervicalis
Genioglossus
muscle
Geniohyoid muscle
Hyoglossus muscle
Thyrohyoid muscle
Omohyoid muscle
(superior belly)
Sternohyoid muscle
Inferior root of ansa cervicalis
Ansa cervicalis
Internal jugular vein
Sternothyroid muscle
Omohyoid muscle (inferior belly)
Efferent fibers
Afferent fibers
34
NEUROANATOMY
Nerves of Heart
Superior cervical
Vagus nerve (X)
(Conjoined sympathetic and
vagal) superior cervical cardiac nerves
Middle cervical
Middle cervical
(sympathetic) cardiac nerve
Phrenic nerve
Inferior cervical
(vagal) cardiac nerve
Vertebral ganglion
Vertebral artery
Cervicothoracic
(stellate) ganglion
Ansa subclavia
Superior cervical
Vagus nerve (X)
Superior cervical
Superior cervical
Middle cervical
Phrenic nerve
Middle cervical
Inferior cervical
Vertebral ganglion
Cervicothoracic
(stellate) ganglion
Inferior cervical
sympathetic
cardiac nerves
Recurrent
laryngeal nerve
Inferior cervical
(sympathetic) cardiac nerves
Thoracic cardiac branch
of vagus nerve
4th thoracic
Thoracic (sympathetic)
cardiac branches
Cardiac plexus
3rd thoracic
Thoracic (sympathetic)
cardiac branches
Thoracic cardiac
branch of
vagus nerve
Recurrent laryngeal
nerve
Phrenic nerve (cut)
35
NEUROANATOMY
Right sympathetic trunk
Thoracic duct
Autonomic Nerves and Ganglia of Abdomen
Anterior,
Posterior
vagal trunks
Right greater
and lesser
splanchnic
nerves
Left gastric artery
and plexus
Right phrenic nerve
Left greater
splanchnic nerve
Inferior phrenic
arteries and plexuses
Left lesser
splanchnic nerve
Right greater
and lesser
splanchnic
nerves
Splenic artery
and plexus
Right suprarenal
plexus
Celiac ganglia
Common hepatic
artery and plexus
Superior mesenteric
ganglion and plexus
Right aorticorenal ganglion
Left aorticorenal
ganglion
Right least
splanchnic nerve
Left sympathetic
trunk
Right renal
artery and plexus
Intermesenteric
(aortic) plexus
Right
sympathetic trunk
Inferior mesenteric
ganglion
White and gray
rami communicantes
Left colic artery
and plexus
Cisterna chyli
Inferior mesenteric
artery and plexus
Gray ramus communicans
3rd lumbar ganglion
of sympathetic trunk
2nd and 3rd lumbar
splanchnic nerves
Right ureter and plexus
Right testicular (ovarian)
artery and plexus
4th lumbar splanchnic nerve
1st sacral ganglion
of sympathetic trunk
Left common iliac
artery and plexus
Superior rectal
artery and plexus
Superior hypogastric
plexus
Internal and external
iliac arteries and
plexuses
Right and left
hypogastric nerves
to inferior hypogastric (pelvic) plexus
Left sacral plexus
Pelvic splanchnic
nerves
36
NEUROANATOMY
Nerves of Stomach and Duodenum
Right and left inferior phrenic arteries and plexuses
Anterior and posterior layers of lesser omentum
Branch from hepatic plexus to
cardia via lesser omentum
Right greater splanchnic
nerve
Hepatic branch of anterior vagal trunk
Celiac branch of posterior vagal trunk
Celiac branch of anterior vagal trunk
Left gastric artery and plexus
Vagal
branch
from
hepatic
plexus
to
pyloric
part of
stomach
Hepatic plexus
Right gastric
artery and plexus
Anterior gastric
branch of anterior
vagal trunk
Left greater splanchnic
nerve
Left lesser splanchnic
nerve
Splenic artery and plexus
Celiac ganglia and plexus
Plexus on gastro-omental
(gastroepiploic) arteries
Superior mesenteric artery and plexus
Plexus on inferior pancreaticoduodenal artery
Plexus on first jejunal artery
Plexus on anterior superior and anterior
inferior pancreaticoduodenal arteries
(posterior pancreaticoduodenal arteries
and plexuses not visible in this view)
37
NEUROANATOMY
Nerves of Stomach and Duodenum (continued)
Posterior gastric branch of posterior vagal trunk
Plexus on gastro-omental
(gastroepiploic) arteries
Hepatic branch of anterior vagal trunk via lesser omentum
Hepatic plexus
Branch from hepatic plexus to cardia via lesser omentum
Right gastric
artery and
plexus
Right inferior phrenic artery and plexus
Celiac branch of posterior vagal trunk
Celiac branch of anterior vagal trunk
Left inferior phrenic artery and plexus
Greater, lesser and least
splanchnic nerves
Aorticorenal ganglia
Splenic artery and plexus
Right phrenic nerve
Phrenic ganglion
Greater,
Lesser,
Least
splanchnic
nerves
Branch from right inferior phrenic
plexus to cardia of stomach
Right and left inferior phrenic
View
with
stomach
reflected
cephalad
Plexus on
anterior superior
and anterior inferior
pancreaticoduodenal arteries
Right greater,
lesser
and least
splanchnic nerves
Plexus on gastroduodenal artery
Plexus on posterior superior
and posterior inferior
pancreaticoduodenal arteries
Celiac ganglia
Superior mesenteric ganglion and plexus
Superior mesenteric ganglion and plexus
38
Celiac branches
of anterior
and posterior
vagal trunks
Left gastric
artery and plexus
Left greater,
lesser and least
splanchnic nerves
Left aorticorenal ganglion
Nerves of Small Intestine
NEUROANATOMY
Recurrent branch of left inferior phrenic
artery and plexus to esophagus
Hepatic branch of anterior
vagal trunk (courses in lesser
omentum, removed here)
Celiac branches of anterior
Inferior phrenic arteries and plexuses
Hepatic plexus
Greater splanchnic nerves
Right gastric artery and plexus (cut)
Gastroduodenal artery and plexus
Lesser splanchnic nerves
Least splanchnic nerves
Aorticorenal ganglia
Intermesenteric (aortic) plexus
Inferior pancreaticoduodenal
Superior mesenteric
artery and plexus
Middle colic artery and plexus (cut)
Right colic artery and plexus
Ileocolic artery and plexus
Superior mesenteric
artery and plexus
Peritoneum (cut edge)
Mesenteric branches
Mesoappendix (contains
appendicular artery and
nerve plexus)
39
NEUROANATOMY
Nerves of Large Intestine
Anterior vagal trunk and hepatic branch
Celiac branches of anterior
Right inferior phrenic artery and plexus
Right greater
splanchnic nerve
Marginal artery and plexus
Esophagus
Left inferior phrenic
artery and plexus
Left gastric artery
and plexus
Left greater
splanchnic
nerve
Left suprarenal
plexus
Right lesser and
least splanchnic
nerves
Left lesser and
least splanchnic
nerves
Left aorticorenal
ganglion
Superior
mesenteric
ganglion
Left renal artery
and plexus
Middle colic
artery
and plexus
1st left lumbar
splanchnic nerve
Inferior
pancreaticoduodenal
arteries
and plexuses
Left lumbar
sympathetic trunk
Right colic
artery
and plexus
Left colic artery
and plexus
Intermesenteric
(aortic) plexus
Inferior
mesenteric
ganglion, artery
and plexus
Ileocolic
artery
and plexus
Sigmoid
arteries
and plexuses
Cecal and
appendicular
arteries
and plexuses
Superior
hypogastric
plexus
Right internal
iliac artery
and plexus (cut)
Superior
rectal
artery
and plexus
Sacral sympathetic trunk
Right sacral plexus
Right and left
hypogastric
nerves
Middle rectal artery and plexus
Right inferior hypogastric
(pelvic) plexus
Vesical plexus
Rectal plexus
Urinary bladder
40
Rectosigmoid
artery and
plexus
Nerves from inferior hypogastric (pelvic)
plexuses to sigmoid colon, descending
colon and left colic (splenic) flexure
Nerves of Kidneys, Ureters and Urinary Bladder
NEUROANATOMY
Greater splanchnic nerve
Lesser splanchnic nerve
Least splanchnic nerve
Renal plexus and ganglion
2nd lumbar splanchnic nerve
Renal and upper ureteric branches
from intermesenteric plexus
Testicular (ovarian) artery and plexus
Inferior mesenteric ganglion
Sympathetic trunk and ganglion
Middle ureteric branch
Sacral splanchnic nerves
(branches from upper sacral
sympathetic ganglia to
hypogastric plexus)
Gray ramus communicans
Hypogastric nerves
Sacral plexus
Pudendal nerve
Inferior hypogastric (pelvic) plexus
with periureteric loops and
branches to lower ureter
Rectal plexus
Vesical plexus
Prostatic plexus
41
NEUROANATOMY
Nerves of Pelvic Viscera: Male
T10 spinal nerve (anterior ramus)
and
Celiac branch
White and gray rami communicantes
Greater
Lesser
Least
Inferior phrenic arteries and plexuses
Left gastric artery and gastric plexus
Diaphragm
Celiac ganglia, plexus and trunk
Left renal artery
and plexus
Left aorticorenal ganglion
L1 spinal nerve
(anterior ramus)
Superior mesenteric artery and plexus
Gray
White
Inferior mesenteric ganglion,
artery and plexus
Splanchnic
nerves
Rami
communicantes
1st, 2nd, 3rd lumbar splanchnic nerves
Ureter and ureteric plexus
Sympathetic trunk and ganglia
Superior rectal artery and plexus
Hypogastric nerves
5th lumbar splanchnic nerve
L5 spinal nerve (anterior ramus)
Lumbosacral trunk
Nerve from inferior
hypogastric plexus
to sigmoid and descending
colon (parasympathetic)
S1 spinal nerve
(anterior ramus)
Sacral splanchnic nerves
(sympathetic)
Pelvic splanchnic
nerves
(parasympathetic)
Inferior hypogastric
(pelvic) plexus
Sacral plexus
Obturator nerve
and artery
Piriformis muscle
Ductus deferens
and plexus
Gluteus maximus
muscle and sacro tuberous ligament
Vesical plexus
Rectal plexus
(Ischio-)coccygeus
muscle and
sacrospinous ligament
Prostatic plexus
Cavernous nerves
of penis
Pudendal nerve
Levator ani muscle
Inferior anal (rectal) nerve
Perineal nerve
Dorsal nerve of penis
Posterior scrotal nerves
42
NEUROANATOMY
Nerves of Pelvic Viscera: Female
Peritoneum
Abdominal aorta
Sympathetic trunk
and L2 ganglion
Inferior vena cava
Extraperitoneal
(subserous)
fascia
White and
gray rami
communicantes
Common
iliac vessels
and plexus
Lumbar
splanchnic
nerves
Ureter
Intermesenteric
(aortic) plexus
Ovarian artery
and plexus
Gray rami
communicantes
Superior
hypogastric
plexus
L5 spinal
nerve
Sacral
promontory
Superior
hypogastric
plexus
Right
hypogastric
nerve (cut)
Common
iliac artery
and plexus
Right and
left sacral
sympathetic
trunks and
ganglia
Ureter
Internal
iliac artery
and plexus
S1
Piriformis
muscle
S2
Sigmoid
colon
External
iliac artery
and plexus
Right and left
hypogastric nerves
Uterus
Right sympathetic trunk
S3
Sacral
splanchnic
nerves
(sympathetic)
S4
S5
Pudendal
nerve
Left hypogastric nerve
Inferior hypogastric (pelvic) plexus
Uterine (fallopian) tube
Ovary
Pelvic
splanchnic
nerves
(parasympathetic)
Symphyseal surface of pubis
Urinary bladder
Vesical plexus
(Ischio-)coccygeus muscle
Rectal plexus
Uterovaginal plexus
Uterus (retracted)
Rectum (retracted)
43
NEUROANATOMY
Median Nerve
Anterior view
Note: Only muscles innervated by median nerve shown
Musculocutaneous nerve
Median nerve (C5, 6, 7, 8, T1)
Medial
Posterior
Lateral
Inconstant contribution
Cords of
brachial
plexus
Pronator teres muscle (humeral head)
Medial cutaneous
nerve of arm
Articular branch
Medial cutaneous
nerve of forearm
Flexor carpi radialis muscle
Axillary nerve
Palmaris longus muscle
Radial nerve
Pronator teres muscle (ulnar head)
Ulnar nerve
Flexor digitorum superficialis muscle
(turned up)
Flexor digitorum profundus muscle
(lateral part supplied by median
[anterior interosseous] nerve;
medial part supplied by ulnar nerve)
Anterior interosseous nerve
Flexor pollicis longus muscle
Pronator quadratus muscle
Cutaneous
innervation
Palmar branch of median nerve
Thenar
muscles
Abductor pollicis brevis
Opponens pollicis
Superficial head of
flexor pollicis brevis
(deep head
supplied by
ulnar nerve)
1st and 2nd
lumbrical muscles
Palmar view
Communicating branch
of median nerve with
ulnar nerve
Common palmar
digital nerves
Proper palmar
digital nerves
Dorsal branches to
dorsum of middle and
distal phalanges
Posterior (dorsal) view
44
NEUROANATOMY
Ulnar Nerve
Anterior view
Note: Only muscles innervated
by ulnar nerve shown
Ulnar nerve (C7, 8, T1)
(no branches above elbow)
Medial epicondyle
Articular branch
(behind condyle)
Cutaneous
innervation
Flexor digitorum profundus
muscle (medial part only;
lateral part supplied by
anterior interosseous
branch of median nerve)
Palmar view
Flexor carpi ulnaris muscle
(drawn aside)
Dorsal branch of ulnar nerve
Posterior
(dorsal) view
Flexor pollicis brevis muscle
(deep head only; superficial
head and other thenar muscles
supplied by median nerve)
Adductor pollicis muscle
Palmar branch
Superficial branch
Deep branch
Palmaris brevis
Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
Hypothenar muscles
Common palmar digital nerve
Communicating branch of median nerve with
ulnar nerve
Palmar and dorsal interosseous muscles
3rd and 4th lumbrical muscles (turned down)
Proper palmar digital nerves
(dorsal digital nerves are from dorsal branch)
Dorsal branches to dorsum of middle and distal phalanges
45
NEUROANATOMY
Radial Nerve in Arm and Nerves of Posterior Shoulder
Dorsal scapular nerve (C5)
Posterior view
Supraspinatus muscle
Suprascapular nerve (C5, 6)
Levator scapulae
muscle (supplied
also by branches
from C3 and C4)
Deltoid muscle
Teres minor muscle
Axillary nerve (C5, 6)
Superior lateral
cutaneous nerve of arm
Rhomboid
minor muscle
Radial nerve
(C5, 6, 7, 8, T1)
Rhomboid
major muscle
Inferior lateral
cutaneous nerve of arm
Posterior cutaneous
nerve of forearm
Infraspinatus muscle
Teres major muscle
Lower subscapular nerve (C5, 6)
Posterior cutaneous nerve of arm
(branch of radial nerve in axilla)
Long head
Triceps brachii muscle
Lateral intermuscular
septum
Brachialis muscle (lateral
part; remainder of muscle
supplied by musculocutaneous nerve)
Lateral head
Medial head
Brachioradialis muscle
Triceps brachii tendon
Medial epicondyle
Extensor carpi radialis
longus muscle
Olecranon
Anconeus muscle
Extensor digitorum muscle
Extensor carpi ulnaris muscle
46
Extensor carpi
radialis brevis
muscle
NEUROANATOMY
Radial Nerve in Forearm
Radial nerve (C5, 6, 7, 8, T1)
Superficial (terminal) branch
Deep (terminal) branch
Posterior view
Lateral epicondyle
Anconeus muscle
Brachioradialis muscle
Extensor carpi radialis longus muscle
Supinator muscle
Extensor carpi radialis brevis muscle
Extensor carpi ulnaris muscle
Extensor- supinator
group of muscles
Extensor digitorum muscle and
extensor digiti minimi muscle
Extensor indicis muscle
Extensor pollicis longus muscle
Abductor pollicis longus muscle
Extensor pollicis brevis muscle
Posterior interosseous nerve
(continuation of deep branch of
radial nerve distal to supinator muscle)
Superficial branch of radial nerve
From axillary nerve
Superior lateral
cutaneous nerve
of arm
Inferior lateral
cutaneous nerve
of arm
Posterior cutaneous
nerve of arm
From radial nerve
Posterior cutaneous
nerve of forearm
Superficial branch of
radial nerve and dorsal
digital branches
Dorsal digital nerves
Cutaneous innervation from
radial and axillary nerves
47
NEUROANATOMY
Sciatic Nerve and Posterior Cutaneous Nerve of Thigh
Posterior cutaneous
nerve of thigh
(S1, 2, 3)
Greater sciatic foramen
Inferior cluneal nerves
Sciatic nerve (L4, 5, S1, 2, 3)
Perineal branches
Common fibular (peroneal)
division of sciatic nerve
Tibial division
of sciatic nerve
Long head (cut) of
biceps femoris muscle
Short head of
biceps femoris muscle
Adductor magnus muscle
(also partially supplied
by obturator nerve)
Cutaneous innervation
Long head (cut)
of biceps femoris
muscle
Semitendinosus muscle
Semimembranosus muscle
Tibial nerve
Common fibular
(peroneal) nerve
Articular
branch
Posterior
cutaneous nerve
of thigh
Articular branch
Plantaris muscle
Medial sural
cutaneous nerve
Lateral sural
cutaneous nerve
Sural
communicating
branch
Gastrocnemius muscle
Common fibular
(peroneal) nerve
via lateral sural
cutaneous nerve
Sural nerve
Medial sural
cutaneous nerve
Soleus muscle
From sciatic
nerve
Tibial nerve
Medial
calcaneal branches
Medial and lateral
plantar nerves
48
Superficial fibular
(peroneal) nerve
Sural nerve
Lateral calcaneal
branches
Lateral dorsal
cutaneous nerve
Tibial nerve
via medial
calcaneal
branches
NEUROANATOMY
Tibial Nerve
Common fibular (peroneal) nerve
Tibial nerve
(L4, 5, S1, 2, 3)
Articular branch
Lateral sural cutaneous nerve (cut)
Medial sural
cutaneous nerve (cut)
Medial calcaneal
branches
(S1, 2)
Articular branches
Medial
plantar nerve
(L4, 5)
From
tibial nerve
Plantaris muscle
Lateral
plantar nerve
(S1, 2)
Gastrocnemius
muscle (cut)
Saphenous nerve
(L3, 4)
Sural nerve
(S1, 2) via
lateral calcaneal
and lateral dorsal
cutaneous
branches
Nerve to popliteus muscle
Popliteus muscle
Cutaneous innervation of sole
Interosseous nerve of leg
Soleus muscle (cut and
partly retracted)
Flexor digitorum
longus muscle
Tibialis posterior muscle
Flexor hallucis
longus muscle
Sural nerve (cut)
Lateral calcaneal branch
Medial
calcaneal branch
Flexor retinaculum (cut)
Flexor
retinaculum
(cut)
Tibial
nerve
Medial
calcaneal
branch
Medial plantar
nerve
Flexor digitorum
brevis muscle
and nerve
Abductor hallucis
muscle and nerve
Flexor hallucis
brevis muscle
and nerve
1st lumbrical
muscle and
nerve
Common
plantar
digital
nerves
Proper
plantar
digital
nerves
Lateral calcaneal
branch of sural nerve
Lateral plantar
nerve
Nerve to abductor
digiti minimi muscle
Quadratus plantae
muscle and nerve
Abductor digiti
minimi muscle
Deep branch to
interosseous
muscles,
2nd, 3rd and 4th
lumbrical muscles
and
Adductor hallucis
muscle
Superficial
branch to
4th interosseous
muscle
and
Flexor digiti minimi
brevis muscle
Common and
Proper plantar
digital nerves
Lateral dorsal
cutaneous nerve
Note: Articular branches not shown
49
NEUROANATOMY
Common fibular
(peroneal) nerve
(phantom)
Common Fibular (Peroneal) Nerve
Lateral sural cutaneous nerve (phantom)
Articular branches
Biceps femoris tendon
Recurrent articular nerve
Common fibular (peroneal)
nerve (L4, 5, S1, 2)
Extensor digitorum longus muscle (cut)
Head of fibula
Deep fibular (peroneal) nerve
Fibularis (peroneus)
longus muscle (cut)
Tibialis anterior muscle
Cutaneous innervation
Superficial fibular
(peroneal) nerve
Branches of lateral
sural cutaneous nerve
longus muscle
Extensor digitorum
longus muscle
Extensor hallucis
longus muscle
brevis muscle
Lateral sural
cutaneous nerve
Medial dorsal cutaneous nerve
Intermediate dorsal
cutaneous nerve
Inferior extensor
retinaculum (partially cut)
Lateral dorsal cutaneous nerve
(branch of sural nerve)
Dorsal digital nerves
50
Superficial fibular
(peroneal) nerve
Lateral branch of
deep fibular
(peroneal) nerve to
Extensor hallucis brevis
and
Extensor digitorum brevis
muscles
Medial branch of
deep fibular
(peroneal) nerve
Deep
fibular
(peroneal)
nerve
Sural nerve
via lateral dorsal
cutaneous branch
Click any title below to link to that plate.
Part 2 Neurophysiology
Organization of the Brain: Cerebrum. . . . . . . 52
The Cerebral Cortex . . . . . . . . . . . . . . . . . . . . 70
Organization of the Brain: Cell Types. . . . . . . 53
Descending Motor Pathways . . . . . . . . . . . . . 71
Blood-Brain Barrier . . . . . . . . . . . . . . . . . . . . . 54
Cerebellum: Afferent Pathways. . . . . . . . . . . . 72
Synaptic Transmission:
Morphology of Synapses . . . . . . . . . . . . . . . 55
Cerebellum: Efferent Pathways . . . . . . . . . . . . 73
Neuromuscular Junction . . . . . . . . . . . . . . . 56
Visceral Efferent Endings . . . . . . . . . . . . . . . 57
Cutaneous Sensory Receptors . . . . . . . . . . . . . 74
Cutaneous Receptors:
Pacinian Corpuscle. . . . . . . . . . . . . . . . . . . . 75
Proprioception and Reflex Pathways: I . . . . . . 76
Inhibitory Mechanisms . . . . . . . . . . . . . . . . 58
Proprioception and Reflex Pathways: II . . . . . 77
Chemical Synaptic Transmission . . . . . . . . . 59
Proprioception and Reflex Pathways: IV. . . . . 79
Temporal and Spatial Summation . . . . . . . . 60
Cerebrospinal Fluid (CSF):
Brain Ventricles and CSF Composition . . . . 61
Cerebrospinal Fluid (CSF):
Circulation of CSF . . . . . . . . . . . . . . . . . . . . 62
Spinal Cord: Ventral Rami. . . . . . . . . . . . . . . . 63
Spinal Cord: Membranes and Nerve Roots . . 64
Peripheral Nervous System . . . . . . . . . . . . . . . 65
Autonomic Nervous System: Schema . . . . . . . 66
Autonomic Nervous System:
Cholinergic and Adrenergic Synapses . . . . . 67
Proprioception and Reflex Pathways: III . . . . 78
Sensory Pathways: I . . . . . . . . . . . . . . . . . . . . . 80
Sensory Pathways: II . . . . . . . . . . . . . . . . . . . . 81
Sensory Pathways: III. . . . . . . . . . . . . . . . . . . . 82
Visual System: Receptors. . . . . . . . . . . . . . . . . 83
Visual System: Visual Pathway . . . . . . . . . . . . 84
Auditory System: Cochlea . . . . . . . . . . . . . . . . 85
Auditory System: Pathways . . . . . . . . . . . . . . . 86
Vestibular System: Receptors . . . . . . . . . . . . . 87
Vestibular System: Vestibulospinal Tracts. . . . 88
Gustatory (Taste) System: Receptors . . . . . . . 89
Gustatory (Taste) System: Pathways . . . . . . . . 90
Hypothalamus . . . . . . . . . . . . . . . . . . . . . . . . . 68
Olfactory System: Receptors . . . . . . . . . . . . . . 91
Limbic System . . . . . . . . . . . . . . . . . . . . . . . . . 69
Olfactory System: Pathway . . . . . . . . . . . . . . . 92
NEUROPHYSIOLOGY
Organization of the Brain: Cerebrum
Postcentral gyrus
Central sulcus (Rolando)
Precentral gyrus
Postcentral sulcus
Precentral sulcus
Superior parietal lobule
Inferior parietal lobule
Supramarginal gyrus
Angular gyrus
Parietooccipital
sulcus
Occipital pole
Frontal pole
Calcarine sulcus
Lateral sulcus
(Sylvius)
Temporal pole
Superior temporal gyrus
Inferior temporal gyrus
Middle temporal gyrus
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Insula (island of Reil)
©
FIGURE 2.1 ORGANIZATION
OF THE
BRAIN: CEREBRUM•
The cerebral cortex represents the highest center for sensory and
motor processing. In general, the frontal lobe processes motor,
visual, speech, and personality modalities. The parietal lobe
processes sensory information; the temporal lobe, auditory and
memory modalities; and the occipital lobe, vision. The cerebellum
52
coordinates smooth motor activities and processes muscle position.
The brainstem (medulla, pons, midbrain) conveys motor and sensory
information and mediates important autonomic functions. The spinal
cord receives sensory input from the body and conveys somatic and
autonomic motor information to peripheral targets (muscles, viscera).
NEUROPHYSIOLOGY
Organization of the Brain: Cell Types
Bipolar cell of cranial n.
Multipolar (pyramidal)
cell of cerebral
motor cortex
Unipolar cell of
sensory ganglia of
cranial nn.
Satellite cells
Schwann cell
Astrocyte
Interneurons
Blood vessel
Striated
(somatic)
muscle
Motor
endplate
Multipolar somatic
motor cell of nuclei
of cranial nn.
Multipolar cell
of lower brain
motor centers
Specialized ending
Muscle spindle
Unipolar sensory cell
of dorsal spinal
root ganglion
Satellite cells
Interneuron
Oligodendrocyte
Astrocyte
Corticospinal
(pyramidal) fiber
Myelinated afferent
fiber of spinal nerve
Multipolar visceral
motor (autonomic)
cell of spinal cord
Axodendritic ending
Axosomatic ending
Myelin sheath
Axoaxonic ending
Multipolar somatic
motor cell of
anterior horn
of spinal cord
Autonomic preganglionic
(sympathetic or parasympathetic) nerve fiber
Myelin sheath
Autonomic postganglionic
neuron of sympathetic or
parasympathetic ganglion
Satellite cells
Unmyelinated nerve fiber
Schwann cells
Collateral
Renshaw interneuron
(feedback)
Myelinated somatic motor
fiber of spinal nerve
Myelin sheath
Red:
Blue:
Purple:
Gray:
Motor neuron
Sensory neuron
Interneuron
Glial and
neurilemmal cells
and myelin
Note: Cerebellar cells
not shown here
Schwann cells
Motor endplate with
Schwann cell cap
Endings on
cardiac muscle
or nodal cells
Striated
(voluntary)
muscle
FIGURE 2.2 ORGANIZATION
Free nerve endings
(unmyelinated fibers)
Encapsulated ending
Unmyelinated fibers
Free nerve endings
Beaded
varicosities
and endings on
smooth muscle
and gland cells
OF THE
Encapsulated ending
Muscle spindle
©
BRAIN: CELL TYPES•
Neurons form the functional cellular units responsible for
communication, and throughout the nervous system, they are
characterized by their distinctive size and shapes (e.g., bipolar,
unipolar, multipolar). Supporting cells include the neuroglia
(e.g., astrocytes, oligodendrocytes), satellite cells, and other specialized cells that optimize neuronal function, provide maintenance functions, or protect the nervous system.
53
NEUROPHYSIOLOGY
Blood-Brain Barrier
Cell
membrane
Basement
membrane
Tight
junction
proteins
Cytoplasm
Red
blood
cell
Astrocyte
foot processes
Capillary
lumen
Tight
junction
Capillary
endothelial
cell
Astrocyte
©
FIGURE 2.3 BLOOD-BRAIN BARRIER•
The blood-brain barrier (BBB) is the cellular interface between the
blood and the central nervous system (CNS; brain and spinal cord).
It serves to maintain the interstitial fluid environment to ensure
optimal functionality of the neurons. This barrier consists of the
capillary endothelial cells with an elaborate network of tight junctions and astrocytic foot processes that abut the endothelium and
its basement membrane. The movement of large molecules and
54
other substances (including many drugs) from the blood to the
interstitial space of the CNS is restricted by the BBB. CNS endothelial cells also exhibit a low level of pinocytotic activity across the
cell, so specific carrier systems for the transport of essential substrates of energy and amino acid metabolism are characteristic of
these cells. The astrocytes help transfer important metabolites from
the blood to the neurons and also remove excess K⫹ and neurotransmitters from the interstitial fluid.
NEUROPHYSIOLOGY
Synaptic Transmission: Morphology of Synapses
Dendrite
Node
Dendrites
Axon
Myelin sheath
Numerous boutons (synaptic knobs)
of presynaptic neurons terminating
on a motor neuron and its dendrites
Enlarged section
of bouton
Axon (axoplasm)
Axolemma
Mitochondria
Glial process
Synaptic vesicles
Synaptic cleft
Presynaptic membrane
(densely staining)
Postsynaptic membrane
(densely staining)
Postsynaptic cell
©
FIGURE 2.4 MORPHOLOGY OF SYNAPSES•
Neurons communicate with each other and with effector targets at
specialized regions called synapses. The top figure shows a typical
motor neuron that receives numerous synaptic contacts on its cell
body and associated dendrites. Incoming axons lose their myelin
sheaths, exhibit extensive branching, and terminate as synaptic
boutons (synaptic terminals or knobs) on the motor neuron. The
lower figure shows an enlargement of one such synaptic bouton.
Chemical neurotransmitters are contained in synaptic vesicles,
which can fuse with the presynaptic membrane, release the transmitters into the synaptic cleft, and then bind to receptors situated
in the postsynaptic membrane. This synaptic transmission results in
excitatory, inhibitory, or modulatory effects on the target cell.
55
NEUROPHYSIOLOGY
Synaptic Transmission: Neuromuscular Junction
Structure of Neuromuscular Junction
Active zone
Myelin sheath
Neurilemma
Schwann cell process
Axoplasm
Acetylcholine
receptor sites
Schwann cell
Mitochondria
Basement membrane
Nucleus of Schwann cell
Presynaptic membrane
Active zone
Synaptic vesicles
Synaptic trough
Basement membrane
Sarcolemma
Nucleus of
muscle cell
Myofibrils
Synaptic cleft
Postsynaptic
membrane
Junctional fold
Sarcoplasm
Acetylcholine receptor sites
©
FIGURE 2.5 STRUCTURE
OF THE
NEUROMUSCULAR JUNCTION•
Motor axons that synapse on skeletal muscle form expanded terminals called neuromuscular junctions (motor endplates). The motor
axon loses its myelin sheath and expands into a Schwann
cell–invested synaptic terminal that resides within a trough in the
muscle fiber. Acetylcholine-containing synaptic vesicles accumulate adjacent to the presynaptic membrane and, when appropri-
56
ately stimulated, release their neurotransmitter into the synaptic
cleft. The transmitter then binds to receptors that mediate depolarization of the muscle sarcolemma and initiate a muscle action
potential. A single muscle fiber has only one neuromuscular junction, but a motor axon can innervate multiple muscle fibers.
NEUROPHYSIOLOGY
Synaptic Transmission: Visceral Efferent Endings
Visceral Efferent Endings
B. Gland (submandibular)





















A. Smooth muscle
C. Neurosecretory
(posterior pituitary)
Sympathetic terminal
ending
Smooth muscle cells (cut)
Schwann cell cap enclosing
nerve axons
Mucous cells
Schwann cell
cap enclosing
nerve axons
Varicosity
Pituicyte processes
Axon
Axon
Schwann
cell cap
Fibroblast
Schwann cell cap
Serous cells
Smooth muscle cells
Varicosities
Terminal endings
Parasympathetic
terminal ending
Schwann cell
cap enclosing
nerve axons
Capillary
Endothelium
Mast cell
Varicosity
Neurosecretory
vesicles
Collagen space
Basement membrane
©
FIGURE 2.6 VISCERAL EFFERENT ENDINGS•
Neuronal efferent endings on smooth muscle (A) and glands (B
and C) exhibit unique endings unlike the presynaptic and postsynaptic terminals observed in neuronal and neuromuscular junction synapses. Rather, neurotransmitter substances are released
into interstitial spaces (A and B) or into the bloodstream (C, neu-
rosecretion) from expanded nerve terminal endings. This arrangement allows for the stimulation of numerous target cells over a
wide area. Not all smooth muscle cells are innervated. They are
connected to adjacent cells by gap junctions and can therefore
contract together with the innervated cells.
57
NEUROPHYSIOLOGY
Synaptic Transmission: Inhibitory Mechanisms
I
(Inhibitory
fiber)
E
(Excitatory
fiber)
Motor
neuron
E
(Excitatory
fiber)
Motor
neuron
I
(Inhibitory
fiber)
Axon
mV
⫹20
A. Only E fires
90-mV spike
in E terminal
EPSP in
motor neuron
B. Only I fires
Long-lasting
partial
depolarization
in E terminal
No response in
motor neuron
C. I fires before E
Partial
depolarization
of E terminal
reduces spike
to 80 mV, thus
releasing less
transmitter
substance
Smaller EPSP in
motor neuron
Axon
mV
90 mV
A′. Only E fires
EPSP in
motor
neuron
⫺70
⫺60
⫺70
⫺60
⫺70
B′. Only I fires
Motor
neuron
hyperpolarized
⫺60
⫺70
⫺70
⫺70
⫺80
C′. I fires before E
⫹20
80 mV
Depolarization of motor
neuron less
than if only
E fires
⫺60
⫺70
⫺80
⫺70
⫺60
⫺70
©
FIGURE 2.7 SYNAPTIC INHIBITORY MECHANISMS•
Inhibitory synapses modulate neuronal activity. Illustrated here is presynaptic inhibition (left panel) and postsynaptic inhibition (right
panel) at a motor neuron.
58
NEUROPHYSIOLOGY
Synaptic Transmission: Chemical Synaptic Transmission














Inhibitory
Excitatory
Synaptic
vesicles
in synaptic
bouton
Presynaptic
membrane
Na
K
Transmitter
substances
Synaptic cleft
Postsynaptic
membrane
When impulse reaches excitatory synaptic
bouton, it causes release of a transmitter
substance into synaptic cleft. This increases
permeability of postsynaptic membrane to
Na and K. More Na moves into postsynaptic cell than K moves out, due to greater electrochemical gradient
Cl
At inhibitory synapse, transmitter substance released by an impulse increases permeability of
the postsynaptic membrane to Cl. K moves
out of post-synaptic cell but no net flow of Cl
occurs at resting membrane potential
Synaptic bouton
Potential (mV)
Current
65
70
Potential
0
Resultant ionic current flow is in direction that tends to
hyperpolarize postsynaptic cell. This makes depolarization by excitatory synapses more difficult—more depolarization is required to reach threshold
msec
0
4
8
12
16
70
Potential (mV)
Resultant net ionic current flow is in a direction that tends to depolarize postsynaptic cell.
If depolarization reaches firing threshold, an
impulse is generated in postsynaptic cell
8
12
16
msec
Current flow and potential change
Potential
75
Current
4
Current flow and potential change
©
FIGURE 2.8 CHEMICAL SYNAPTIC TRANSMISSION•
Chemical synaptic transmission between neurons may be excitatory or inhibitory. During excitation (left column), a net increase in
the inward flow of Na compared with the outward flow of K
results in a depolarizing potential change (excitatory postsynaptic
potential [EPSP]) that drives the postsynaptic cell closer to its
threshold for an action potential. During inhibition (right column),
the opening of K and Cl channels drives the membrane potential
away from threshold (hyperpolarization) and decreases the probability that the neuron will reach threshold (inhibitory postsynaptic
potential [IPSP]) for an action potential.
59
NEUROPHYSIOLOGY
Synaptic Transmission: Temporal and Spatial Summation
Temporal and Spatial Summation
of Excitation and Inhibition
Excitatory fibers
mV
mV
Excitatory fibers
–70
–70
Axon
Axon
Inhibitory fibers
Inhibitory fibers
A. Resting state: motor nerve cell shown with synaptic boutons of
excitatory and inhibitory nerve fibers ending close to it
B. Partial depolarization: impulse from one excitatory fiber has
caused partial (below firing threshold) depolarization of motor
neuron
mV
Excitatory fibers
mV
Excitatory fibers
–70
–70
Axon
Axon
Inhibitory fibers
Inhibitory fibers
C. Temporal excitatory summation: a series of impulses in one
excitatory fiber together produce a suprathreshold depolarization
that triggers an action potential
mV
Excitatory fibers
D. Spatial excitatory summation: impulses in two excitatory fibers
cause two synaptic depolarizations that together reach firing
threshold triggering an action potential
mV
Excitatory fibers
–70
–70
Axon
Axon
Inhibitory fibers
Inhibitory fibers
E. Spatial excitatory summation with inhibition: impulses from
two excitatory fibers reach motor neuron but impulses from
inhibitory fiber prevent depolarization from reaching threshold
E. (continued): motor neuron now receives additional excitatory
impulses and reaches firing threshold despite a simultaneous
inhibitory impulse; additional inhibitory impulses might still
prevent firing
©
CHART 2.1 SUMMARY OF SOME NEUROTRANSMITTERS AND WHERE WITHIN THE CENTRAL AND PERIPHERAL NERVOUS
SYSTEM THEY ARE FOUND
Transmitter
Acetylcholine
Biogenic amines
Norepinephrine
Dopamine
Serotonin
Amino acids
␥-Aminobutyric
acid (GABA)
Glutamate
Purines
Adenosine
Adenosine
triphosphate (ATP)
Location
Neuromuscular junction, autonomic endings and ganglia, CNS
Sympathetic endings, CNS
CNS
CNS, GI tract
CNS
CNS
CNS
CNS
Transmitter
Gas
Nitric oxide
Peptides
␤-Endorphins
Enkephalins
Antidiuretic
hormone
Pituitary-releasing
hormones
Somatostatin
Neuropeptide Y
Vasoactive
intestinal peptide
Location
CNS, GI tract
CNS, GI tract
CNS
CNS (hypothalamus/posterior
pituitary)
CNS (hypothalamus/anterior
pituitary)
CNS, GI tract
CNS
CNS, GI tract
CNS, Central nervous system; GI, gastrointestinal.
FIGURE 2.9 TEMPORAL
AND
SPATIAL SUMMATION •
Neurons receive multiple excitatory and inhibitory inputs. Temporal summation occurs when a series of subthreshold impulses in
one excitatory fiber produces an action potential in the postsynaptic cell (panel C). Spatial summation occurs when subthreshold
impulses from two or more different fibers trigger an action poten-
60
tial (panel D). Both temporal and spatial summation can be modulated by simultaneous inhibitory input (panel E). Inhibitory and
excitatory neurons use a wide variety of neurotransmitters, some of
which are summarized here.
Cerebrospinal Fluid (CSF): Brain Ventricles and CSF Composition
NEUROPHYSIOLOGY
Left lateral phantom view
Frontal (anterior) horn
Right lateral ventricle
Central part
Temporal (inferior) horn
Left
lateral
ventricle
4th ventricle
Left lateral aperture
(foramen of Luschka)
Left lateral recess
Left interventricular
foramen (Monro)
Median aperture
(foramen of Magendie)
3rd ventricle
©
CHART 2.2 CSF COMPOSITION
Na⫹ (mEq/L)
K⫹ (mEq/L)
Cl− (mEq/L)
HCO3− (mEq/L)
Glucose (mg/dL)
Protein (g/dL)
pH
FIGURE 2.10 BRAIN VENTRICLES
AND
CSF
140–145
3
115–120
20
50–75
0.05–0.07
7.3
Blood Plasma
135–147
3.5–5.0
95–105
22–28
70–110
6.0–7.8
7.35–7.45
CSF COMPOSITION•
CSF circulates through the four brain ventricles (two lateral ventricles and a third and fourth ventricle) and in the subarachnoid
space surrounding the brain and spinal cord. The electrolyte composition of the CSF is regulated by the choroid plexus, which
secretes the CSF. Importantly, the CSF has a lower [HCO3⫺] than
plasma and therefore a lower pH. This allows small changes in
blood PCO2 to cause changes in CSF pH, which in turn regulates
the rate of respiration (see Chapter 5).
61
NEUROPHYSIOLOGY
Cerebrospinal Fluid (CSF): Circulation of CSF
Choroid plexus of lateral
ventricle (phantom)
Subarachnoid space
Cistern of corpus callosum
Arachnoid granulations
Dura mater
Arachnoid
Interventricular
foramen (Monro)
Choroid plexus of 3rd ventricle
Lateral aperture (foramen of Luschka)
Dura mater
Median aperture
(foramen of Magendie)
Arachnoid
Subarachnoid space
©
FIGURE 2.11 CIRCULATION
OF
CEREBROSPINAL FLUID•
CSF circulates through the four brain ventricles (two lateral ventricles and a third and fourth ventricle) and in the subarachnoid
space surrounding the brain and spinal cord. Most of the CSF is
62
reabsorbed into the venous system through the arachnoid granulations and through the walls of the capillaries of the central nervous
system and pia mater.
NEUROPHYSIOLOGY
Spinal Cord: Ventral Rami
Base of skull
C1 vertebra (atlas)
C1 spinal nerve
Cervical plexus
C8 spinal nerve
Brachial plexus
T1 spinal nerve
Spinal dura mater
1st rib
Filaments
of spinal
nerve roots
(T7 and T8)
Intercostal
nerves
T12 spinal
nerve
L1
vertebra
12th rib
Conus medullaris
Lumbar plexus
L1 spinal nerve
L5 vertebra
Cauda equina
S1 spinal nerve
Sacral plexus
Sacrum (cut away)
Termination of
dural sac
Sciatic nerve
Coccygeal nerve
Coccyx
©
FIGURE 2.12 SPINAL CORD
AND
VENTRAL RAMI IN SITU•
The spinal cord gives rise to 31 pairs of spinal nerves that distribute
segmentally to the body. These nerves are organized into plexuses
that distribute to the neck (cervical plexus), upper limb (brachial
plexus), and pelvis and lower limb (lumbosacral plexus). Motor
fibers of these spinal nerves innervate skeletal muscle, and sensory
fibers convey information back to the central nervous system from
the skin, skeletal muscles, and joints.
63
NEUROPHYSIOLOGY
Spinal Cord: Membranes and Nerve Roots
Posterior view
Ventral root of spinal nerve
Dorsal root of spinal nerve
Spinal sensory (dorsal root) ganglion
Ventral ramus of spinal nerve
Dorsal ramus of spinal nerve
Dura mater
Arachnoid mater
Subarachnoid space
Pia mater overlying spinal cord
Filaments of dorsal root
Membranes removed: anterior view
(greatly magnified)
Gray matter
White matter
Filaments of dorsal root
Dorsal root of spinal nerve
Filaments of ventral root
Spinal sensory (dorsal
root) ganglion
Dorsal ramus of
spinal nerve
Ventral ramus of
spinal nerve
Ventral root of spinal nerve
Spinal nerve
Gray and white rami
communicantes
©
FIGURE 2.13 SPINAL MEMBRANES
AND
NERVE ROOTS•
The spinal cord gives rise to 31 pairs of spinal nerves that distribute
segmentally to the body. Motor fibers of these spinal nerves innervate skeletal muscle, and sensory fibers convey information back
to the central nervous system from the skin, skeletal muscles, and
joints.
64
The spinal cord is ensheathed in three meningeal coverings: the
outer, tough dura mater; the arachnoid mater; and the pia mater,
which intimately ensheaths the cord itself. CSF bathes the cord and
is found in the subarachnoid space.
NEUROPHYSIOLOGY
Peripheral Nervous System
Posterior horn
Dorsal root ganglion
Sensory neuron cell body
Dorsal root
Anterior horn
Motor neuron cell body
Ventral root
Peripheral nerve
Axon
Myelin sheath
Motor neuron
Sensory neuron
Neuromuscular
junction
Skin
Muscle
with
©
FIGURE 2.14 PERIPHERAL NERVOUS SYSTEM•
The peripheral nervous system (PNS) consists of all of the neural
elements outside of the CNS (brain and spinal cord) and provides
the connections between the CNS and all other body organ systems. The PNS consists of somatic and autonomic components. The
somatic component innervates skeletal muscle and skin and is
shown here (see Figure 2.15 for the autonomic nervous system).
The somatic component of the peripheral nerves contains both
motor and sensory axons. Cell bodies of the motor neurons are
found in the anterior horn gray matter, whereas the cell bodies of
sensory neurons are located in the dorsal root ganglia.
65
NEUROPHYSIOLOGY
Autonomic Nervous System: Schema
Intracranial vessels
Facial nerve (VII)
Medulla oblongata
Vagus nerve (X)
Lacrimal glands
Otic ganglion
Parotid glands
mi
Gray ra ntes
nica
u
m
m
o
c
C1
C2
C3
C4
C5
C6
C7
C8
Sweat
gland
Ciliary ganglion
Eye
Sublingual and
submandibular glands
Peripheral cranial
and facial vessels
Larynx
Trachea
Bronchi
Lungs
T1
Gray and white rami communican
tes
Peripheral
blood vessel
Pulmonary plexus
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
Heart
Greater  Splanchnic
Lesser  nerves
Least 
Celiac ganglion
Stomach
Lumbar
splanchnic
nerves
Pancreas
Suprarenal glands
Kidneys
m uni
cantes
Intestines
L5
Inferior mesenteric
ganglion
Superior hypogastric
plexus
Sigmoid colon
Rectum
Urinary bladder
a mi
ay r
S2
S3
S4
S5
Coccygeal
Superior mesenteric
ganglion
Descending colon
co m
S1
Gr
Note: Blue-shaded
areas indicate zones of
parasympathetic
outflow from CNS
Liver
Gallbladder
Bile ducts
Arrector (smooth)
T12
muscle of hair follicle
Note: Above three
L1
structures are shown at
L2
only one level but
occur at all levels
L3
L4
Cardiac plexus
Pelvic
splanchnic
nerves
Inferior
hypogastric
plexus
Prostate
External genitalia
©
Sympathetic
fibers
Presynaptic
Postsynaptic
Parasympathetic
fibers
Presynaptic
Postsynaptic
Antidromic
conduction
FIGURE 2.15 AUTONOMIC NERVOUS SYSTEM: SCHEMA•
The autonomic nervous system is composed of two divisions: the
parasympathetic division derived from four of the cranial nerves
(CN III, VII, IX, and X) and the S2-S4 sacral spinal cord levels, and the
sympathetic division associated with the thoracic and upper lumbar
spinal cord levels (T1-L2). The autonomic nervous system is a twoneuron chain, with the preganglionic neuron arising from the central
nervous system and synapsing on a postganglionic neuron located in
66
a peripheral autonomic ganglion. Postganglionic axons of the autonomic nervous system innervate smooth muscle, cardiac muscle, and
glands. Basically, the sympathetic division mobilizes our body (“fight
or flight”) while the parasympathetic division regulates digestive and
homeostatic functions. Normally, both divisions work in concert to
regulate visceral activity (respiration, cardiovascular function, digestion, and associated glandular activity).
Autonomic Nervous System: Cholinergic and Adrenergic Synapses
Parotid
gland
Glossopharyngeal
nerve (IX)
Medulla
oblongata
NEUROPHYSIOLOGY
Internal carotid nerve
Vagus nerve (X)
Larynx
Trachea
Bronchi
Lungs
Heart
Cervical
sympathetic
ganglia
Striated muscle
Sweat glands
White ramus
communicans
Gray ramus
communicans
Thoracic
part of
spinal cord
Celiac
ganglion
Peripheral arteries
Superior
mesenteric
ganglion
Upper
lumbar
part of
spinal cord
(L1-2 [3])
Hair follicles
Visceral
arteries
Gastrointestinal
tract
Suprarenal
gland
Inferior
mesenteric ganglion
Sacral
part of
spinal cord
Urinary bladder
Urethra
Prostate
C Cholinergic synapses
A Adrenergic synapses
Sympathetic
fibers
Presynaptic
Parasympathetic
fibers
Postsynaptic
Presynaptic
Postsynaptic
Somatic fibers
Antidromic conduction
FIGURE 2.16 CHOLINERGIC
AND
©
ADRENERGIC SYNAPSES: SCHEMA•
The autonomic nervous system (ANS) is a two-neuron chain, with
the preganglionic neuron arising from the central nervous system
and synapsing on a postganglionic neuron located in a peripheral
autonomic ganglion. Acetylcholine is the neurotransmitter in both
the sympathetic and parasympathetic ganglia. The parasympathetic
division of the ANS releases acetylcholine at its postganglionic
synapses and is characterized as having cholinergic (C) effects,
whereas the sympathetic division releases predominantly noradren-
aline (norepinephrine) at its postganglionic synapses, causing
adrenergic (A) effects (except on sweat glands, where acetylcholine
is released). Although acetylcholine and noradrenaline are the
chief transmitter substances, other neuroactive peptides often are
colocalized with them and include such substances as gammaaminobutyric acid (GABA), substance P, enkephalins, histamine,
glutamic acid, neuropeptide Y, and others.
67
NEUROPHYSIOLOGY
Hypothalamus
Corpus callosum
Septum
pellucidum
Fornix
Lateral
ventricle
From
hippocampal
formation
Thalamus
Interthalamic
Lateral
adhesion
hypothalamic area
Paraventricular nucleus
Medial
Anterior hypothalamic area
Anterior
forebrain commissure
Dorsal hypothalamic area
bundle
Dorsomedial nucleus
Mamillothalamic tract
Posterior area
Lateral
Periventricular
preoptic Medial
nucleus
nucleus preoptic
Nucleus
intercalatus
nucleus
Olfactory
tract
Optic (II)
nerve
Optic chiasm
Fornix
Red nucleus
Ventromedial
Mamillary
nucleus
complex
Tuberohypophyseal tract
Oculomotor (III) nerve
Supraoptic nucleus
Supraopticohypophyseal
tract
Posterior lobe of pituitary
Anterior
lobe of
pituitary
Cerebral
peduncle
Dorsal
longitudinal
fasciculus
Descending
hypothalamic
connections
Pons
Reticular
formation
©
CHART 2.3 MAJOR FUNCTIONS OF THE HYPOTHALAMUS
Hypothalamic Area
Preoptic and anterior
Posterior
Lateral
Ventromedial
Supraoptic (subfornical organ and organum vasculosum)
Paraventricular
Periventricular
Major Functions*
Heat loss center: cutaneous vasodilation and sweating
Heat conservation center: cutaneous vasoconstriction and shivering
Feeding center: eating behavior
Satiety center: inhibits eating behavior
ADH and oxytocin secretion (sensation of thirst)
ADH and oxytocin secretion
Releasing hormones for the anterior pituitary
*Stimulation of the center causes the responses listed.
FIGURE 2.17 SCHEMATIC RECONSTRUCTION
OF THE
HYPOTHALAMUS•
The hypothalamus, part of the diencephalon, controls a number of
important homeostatic systems within the body, including temperature regulation, food intake, water intake, many of the endocrine
systems (see Chapter 8), motivation, and emotional behavior. It
receives inputs from the reticular formation (sleep/wake cycle
68
information), the thalamus (pain), the limbic system (emotion, fear,
anger, smell), the medulla oblongata (blood pressure and heart
rate), and the optic system, and it integrates these inputs for regulation of the functions listed.
NEUROPHYSIOLOGY
Limbic System
Columns of fornix
Body of fornix
Thalamus
Uncus
Crura of fornix
Hippocampus
Commissure of fornix
Lateral ventricle
Body of fornix
Columns
of fornix
Commissure
of fornix
Crura of fornix
Mamillary
bodies
Amygdaloid bodies
FIGURE 2.18 HIPPOCAMPUS
AND
Hippocampus
with fimbria
©
FORNIX•
The limbic system includes the hypothalamus and a collection of
interconnected structures in the telencephalon (cingulate, parahippocampal, and subcallosal gyri), as well as the amygdala and hip-
pocampal formation. The limbic system functions in linking emotion and motivation (amygdala), learning and memory (hippocampal formation), and sexual behavior (hypothalamus).
69
NEUROPHYSIOLOGY
The Cerebral Cortex
Motor
Premotor; orientation;
eye and head
movements
Sm I
Sensory
Sm II
Ms I
Ms II
Sensory
analysis
Prefrontal;
inhibitory control
of behavior;
higher
intelligence
Visual III
Visual II
Visual I
Language;
reading; speech
Auditory I
Motor control
of speech
Auditory II
Motor
Sm I
Sensory
Sm III
?
Ms I
Ms II
Premotor
Prefrontal;
inhibitory control
of behavior;
higher
intelligence
Visual III
Visual II
Visual I
Cingulate gyrus
(emotional behavior)
and cingulum
©
Corpus callosum
Hippocampal commissure
Olfactory
FIGURE 2.19 CEREBRAL CORTEX: LOCALIZATION
Anterior commissure
OF
FUNCTION
The cerebral cortex is organized into functional regions. In addition to specific areas devoted to sensory and motor functions, there
are areas that integrate information from multiple sources. The
cerebral cortex participates in advanced intellectual functions,
70
AND
ASSOCIATION PATHWAYS•
including aspects of memory storage and recall, language, higher
cognitive functions, conscious perception, sensory integration, and
planning/execution of complex motor activity. General cortical
areas associated with these functions are illustrated.
NEUROPHYSIOLOGY
Hip
Knee
Ankle
Motor
cortex
Internal
capsule
Trunk
Shoulder
Elbow
W
Fin rist
ge
rs
Descending Motor Pathways
b
um
Th eck
N
Browd
Eyeli
Nares
Lips
Tongue
Larynx
Toes
Lateral aspect of
cerebral cortex to show
topographic projection
of motor centers on
precentral gyrus
Midbrain
Basis
pedunculi
Pons
Motor system
Fibers originate in motor cortex and
descend via posterior limb of internal
capsule to basis pedunculi of midbrain
Longitudinal bundles branch upon
entering basis pontis and rejoin to
enter pyramids of medulla
Basis
pontis
Medulla
Pyramids
Medulla
Decussation
of pyramids
At lower medulla, bulk of fibers cross
median plane to form lateral
corticospinal tract; some fibers
continue downward in ipsilateral
lateral corticospinal tract; others
descending ipsilateral anterior
corticospinal tract
Synapse occurs at spinal level: Lateral
corticospinal fibers synapse on
ipsilateral anterior horn cells; anterior
corticospinal fibers synapse on
contralateral anterior horn cells
Above midthoracic
level
Spinal
cord
Below midthoracic
level
Motor
endplate
Anterior corticospinal tract
Lateral corticospinal tract
Motor
endplate
©
FIGURE 2.20 CORTICOSPINAL TRACTS•
The corticospinal, or pyramidal, tract is the major motor tract that
controls voluntary movement of the skeletal muscles, especially
skilled movements of distal muscles of the limbs. All structures
from the cerebral cortex to the anterior horn cells in the spinal
cord constitute the upper portion of the system (upper motor neuron). The anterior horn cells and their associated axons constitute
the lower portion of the system (lower motor neuron).
71
NEUROPHYSIOLOGY
Cerebellum: Afferent Pathways
To contralateral cerebellar cortex
Cortical input
Leg
Nucleus
reticularis
tegmenti
pontis
Arm
Fac
e
Primary fissure
Pontine nuclei
(contralateral)
Spinal input
Inferior olive
Upper part
of medulla
oblongata
Spinal input
Vestibular nerve
and ganglion
Lower part
of medulla
oblongata
Cortical input
Lateral reticular
nucleus
Spinal input
Cervical part
of spinal cord
Motor interneuron
Rostral
spinocerebellar
tract
Spinal border cells
Motor interneuron
Lumbar part
of spinal cord
Clarke’s column
Ventral spinocerebellar tract
Vestibular
nuclei
To nodule and flocculus
Reticulocerebellar
tract
Cuneocerebellar
tract
Gracile nucleus
Main cuneate
nucleus (relay
for cutaneous
information)
External cuneate nucleus
(relay for proprioceptive
information)
From skin (touch
and pressure)
From muscle (spindles
and Golgi tendon organs)
From skin and
deep tissues
(pain and Golgi
tendon organs)
From skin (touch
and pressure)
and from muscle
(spindles and
Golgi tendon
organs)
Dorsal spinocerebellar tract
Functional Subdivisions of Cerebellum
Hemisphere Vermis
InterLateral mediate
part part
Anterior lobe
Leg zone
Primary
Arm zone
fissure
Face zone
Middle
(posterior)
lobe
2nd spinal
projection
area (gracile
lobule)
ArchiLingula
cerebellum
Flocculus
(vestibulocerebellum) Nodule
Paleocerebellum Uvula
(spinocerebellum) Pyramid
Vermis
Neocerebellum
Middle vermis
(pontocerebellum) Hemisphere
Posterolateral
fissure
Flocculonodular lobe
Schema of
theoretical
“unfolding”
of cerebellar
surface in
derivation of
above diagram
©
FIGURE 2.21 CEREBELLAR AFFERENT PATHWAYS•
The cerebellum plays an important role in coordinating movement. It
receives sensory information and then influences descending motor
pathways to produce fine, smooth, and coordinated motion. The
cerebellum is divided into three general areas: archicerebellum (also
called vestibulocerebellum) paleocerebellum (also called spinocerebellum) and the neocerebellum (also called the cerebrocerebellum).
The archicerebellum is primarily involved in controlling posture and
balance, as well as the movement of the head and eyes. It receives
afferent signals from the vestibular apparatus and then sends efferent
fibers to the appropriate descending motor pathways. The paleocere-
72
bellum primarily controls movement of the proximal portions of the
limbs. It receives sensory information on limb position and muscle
tone and then modifies and coordinates these movements through
efferent pathways to the appropriate descending motor pathways. The
neocerebellum is the largest portion of the cerebellum, and it coordinates the movement of the distal portions of the limbs. It receives
input from the cerebral cortex and thus helps in the planning of
motor activity (e.g., seeing a pencil and then planning and executing
the movement of the arm and hand to pick it up).
NEUROPHYSIOLOGY
Cerebellum: Efferent Pathways
Excitatory
endings
Motor and
premotor
cerebral
cortex
Inhibitory
endings of
Purkinje
cells
Internal capsule
Ventral anterior and
ventral lateral nuclei
of thalamus
Cerebral peduncle
Mesencephalic reticular formation
Red nucleus
Fastigial nucleus
Globose nuclei
Decussation of superior
cerebellar peduncles
Descending fibers from
superior cerebellar
peduncles
Hook bundle of Russell
Emboliform nucleus
Dentate nucleus
Section
A–B
viewed
from
below
Cerebellar
cortex
Section
B–C
viewed
from
above
Vestibular
nuclei
Inferior cerebellar
peduncle
Inferior olive
Lateral reticular nucleus
Medulla oblongata
Pontomedullary reticular formation
A
Planes of
section:
red arrows
indicate
C
direction
of view
B
©
FIGURE 2.22 CEREBELLAR EFFERENT PATHWAYS•
The cerebellum plays an important role in coordinating movement.
It influences descending motor pathways to produce fine, smooth,
and coordinated motion. The archicerebellum is primarily involved
in controlling posture and balance and movement of the head and
eyes. It sends efferent fibers to the appropriate descending motor
pathways. The paleocerebellum primarily controls movement of
the proximal portions of the limbs. It modifies and coordinates
these movements through efferent pathways to the appropriate
descending motor pathways. The neocerebellum coordinates the
movement of the distal portions of the limbs. It helps in the planning of motor activity (e.g., seeing a pencil and then planning and
executing the movement of the arm and hand to pick it up).
73
NEUROPHYSIOLOGY
Cutaneous Sensory Receptors
Free nerve endings
Hair shaft
Meissner’s corpuscle
Pore of sweat gland
Stratum
granulosum
Stratum
spinosum
Stratum
basale
Internal sheath
Hair follicle
Epidermis
Melanocyte
Arrector muscle of hair
Sebaceous gland
Cuticle
Stratum corneum
Stratum
lucidum
External sheath
Glassy
membrane
Connective
tissue layer
Dermis
Dermal
papilla
(of papillary
layer)
Reticular
layer
Hair cuticle
Sweat gland
Subcutaneous tissue
Hair matrix
Papilla of hair follicle
Pacinian
corpuscle
Artery
Subcutaneous
artery and vein
Vein
Sensory nerves
Elastic fibers
Detail of Merkel’s disc
Basal
epithelial
cells
Skin ligaments
(retinacula cutis)
Desmosomes
Motor
(autonomic)
nerve
Cross section
Lobulated
nucleus
Mitochondria
Granulated
vesicles
Expanded
axon terminal
Schwann
cell
AND
Axon
©
Schwann cells
Detail of free nerve ending
CUTANEOUS RECEPTORS•
Cutaneous receptors respond to touch (mechanoreceptors), pain
(nociceptors), and temperature (thermoreceptors). Several different
types of receptors are present in skin. Meissner’s corpuscles have
small receptive fields and respond best to stimuli that are applied
at low frequency (i.e., flutter). The pacinian corpuscles are located
in the subcutaneous tissue and have large receptive fields. They
74
Cutaneous
nerve
Merkel
cell
Cytoplasmic
protrusion
FIGURE 2.23 SKIN
Basement membrane
Axon terminal
Mitochondrion
Schwann cell
respond best to high-frequency stimulation (i.e., vibration).
Merkel’s discs have small receptive fields and respond to touch and
pressure (i.e., indenting the skin). Ruffini’s corpuscles have large
receptive fields, and they also respond to touch and pressure. Free
nerve endings respond to pain and temperature.
NEUROPHYSIOLOGY
Cutaneous Receptors: Pacinian Corpuscle
Pacinian Corpuscle
as Pressure Transducer
Pressure
To amplifier
Generator potential
Action potential
A. Sharp “on and off” changes in pressure at start and end
of pulse applied to lamellated capsule are transmitted to
central axon and provoke generator potentials, which in
turn may trigger action potentials; there is no response to a
slow change in pressure gradient. Pressure at central core
and, accordingly, generator potentials are rapidly dissipated
by viscoelastic properties of capsule (Action potentials may
be blocked by pressure at a node or by drugs)
1st node
Myelin sheath
Lamellated capsule
Central core
Unmyelinated axon terminal
Pressure
To amplifier
Generator potential
B. In absence of capsule, axon responds to slow as well
as to rapid changes in pressure. Generator potential
dissipates slowly, and there is no “off” response
Na+
Pressure
ⴙ
ⴙ
ⴚ
ⴚ
Action potential
ⴚ ⴙ
ⴚ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴙ
Pressure applied to axon terminal directly or
via capsule causes increased permeability of
membrane to Na+, thus setting up ionic
generator current through 1st node
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴙ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
ⴙ
ⴙ
ⴙ
ⴙ
ⴚ
ⴚ
ⴚ
ⴚ
ⴚ
If resultant depolarization at 1st node is great
enough to reach threshold, an action potential
appears which is propagated along nerve fiber
©
FIGURE 2.24 PACINIAN CORPUSCLE•
Pacinian corpuscles are mechanoreceptors that transduce mechanical forces (displacement, pressure, vibration) into action potentials
that are conveyed centrally by afferent nerve fibers. As the viscoelastic lamellae are displaced, the unmyelinated axon terminal
membrane’s ionic permeability is increased until it is capable of
producing a “generator potential.” As demonstrated in the figure,
pacinian corpuscles respond to the beginning and end of a
mechanical force while the concentric lamellae dissipate slow
changes in pressure. In the absence of the capsule, the generator
potential decays slowly and yields only a single action potential.
75
NEUROPHYSIOLOGY
Proprioception and Reflex Pathways: I
Spinal Effector Mechanisms
Dorsal horn
interneuron
From motor neuron
From
cutaneous
receptor
Dorsal horn interneuron
From
muscle
spindle
Flexor reflex interneuron
Dorsal horn interneuron
Dorsal root
ganglion
To motor neuron
Ventral root
To motor neuron
␣ motor axon
Schematic representation of motor neurons
E xt e
r
n so
s
Fl e x o
rs
o rs
so
Flex
In lumbar
enlargement
of spinal cord
rs
In cervical
enlargement of
spinal cord
Ext e
n
©
FIGURE 2.25 PROPRIOCEPTION: SPINAL EFFECTOR MECHANISM•
Position sense or proprioception involves input from cutaneous
mechanoreceptors, Golgi tendon organs, and muscle spindles
(middle figure of upper panel). Both monosynaptic reflex pathways
(middle figure of upper panel) and polysynaptic pathways involving several spinal cord segments (top and bottom figures of upper
76
panel) initiate muscle contraction reflexes. The lower panel shows
the somatotopic distribution of the motor neuron cell bodies in the
ventral horn of the spinal cord that innervate limb muscles (flexor
and extensor muscles of upper and lower limbs).
NEUROPHYSIOLOGY
Proprioception and Reflex Pathways: II
Alpha motor neurons to extrafusal
striated muscle end plates
Gamma motor neurons to intrafusal
striated muscle end plates
Ia (A␣) fibers from annulospiral
endings (proprioception)
II (A␤) fibers from flower spray
endings (proprioception);
from paciniform corpuscles (pressure)
and pacinian corpuscles (pressure)
III (A␦) fibers from free nerve endings
and from some specialized endings
(pain and some pressure)
IV (unmyelinated) fibers from free
nerve endings (pain)
Ib (A␣) fibers from Golgi tendon
organs (proprioception)
A␣ fibers from
Golgi-type
endings
A␤ fibers from
paciniform corpuscles
and Ruffini terminals
Alpha motor neuron to extrafusal
muscle fiber end plates
A␦ and C fibers
from free nerve
endings
Gamma motor neuron to intrafusal
muscle fiber and plates
II (A␤) fiber from flower spray endings
Extrafusal
muscle fiber
Ia (A␣) fiber from annulospiral endings
Intrafusal
muscle fibers
Sheath
Lymph space
Nuclear bag fiber
Nuclear chain fiber
Detail of
muscle spindle
FIGURE 2.26 MUSCLE
AND JOINT
©
Efferent fibers
Afferent fibers
RECEPTORS•
Muscle spindles and Golgi tendon organs send afferent signals to
the brain to convey the position of limbs and help coordinate muscle movement. Muscle spindles convey information on muscle tension and contraction (dynamic forces) and muscle length (static
forces). The nuclear bag fibers respond to both dynamic and static
forces, whereas the nuclear chain fibers respond to static forces.
Intrafusal fibers maintain appropriate tension on the nuclear bag
and nuclear chain fibers. If the muscle tension is too great (e.g.,
overstretching of muscle or too heavy a load), activation of the
Golgi tendon organ causes a reflex relaxation of the muscle.
77
NEUROPHYSIOLOGY
Proprioception and Reflex Pathways: III
Ib fibers
Ia fibers ⫹⫹⫹⫹
Extrafusal muscle fiber
Intrafusal muscle fiber
Alpha motor neurons ⫹⫹⫹
Gamma motor neurons
Golgi
tendon
organ
A. Passive stretch. Both intrafusal and extrafusal muscle fibers stretched;
spindles activated. Reflex via Ia fibers and alpha motor neurons causes
secondary contraction (basis of stretch reflexes, such as knee jerk).
Stretch is too weak to activate Golgi tendon organs
Ib fibers ⫹⫹
Alpha activation
from brain
Ia fibers
Inhibitory interneuron
Alpha motor neurons ⫹⫹
Gamma motor neurons
Golgi
tendon
organ
B. Active contraction. Central excitation of alpha motor neurons
only causes contraction of extrafusal muscle fibers with consequent
relaxation of intrafusal fibers; spindles not activated. Tension is low;
does not adjust to increased resistance. Tendon organ activated,
causing relaxation
Alpha and
gamma
Ib fibers ⫹⫹⫹
activation
from brain
Ia fibers ⫹⫹⫹⫹
Alpha motor neurons ⫹⫹⫹⫹
Gamma motor neurons ⫹⫹⫹⫹
Golgi
tendon
organ
C. Active contraction with gamma coactivation. Intrafusal as well as
extrafusal fibers contract; spindles activated, reinforcing contraction
stimulus via Ia fibers in accord with resistance. Tendon organ
activated, causing relaxation if load is too great
FIGURE 2.27 PROPRIOCEPTIVE REFLEX CONTROL
OF
©
MUSCLE TENSION•
Interaction of the muscle spindle and Golgi tendon organ during passive stretch of a muscle (panel A) and during a contraction (panels B
and C).
78
NEUROPHYSIOLOGY
Proprioception and Reflex Pathways: IV
B. Stretch reflex
(reciprocal inhibition)
A. Afferent inhibition
From extensor spindle
receptor (Ia, II fibers)
From extensor spindle
receptor (Ia, II fibers)
From flexor spindle
(Ia, II fibers)
Axosomatic or
axodendritic
inhibitory
synapse
Axoaxonic presynaptic
inhibitory synapse
Excitatory
synapse
To extensors
To extensors
To flexors
C. Recurrent inhibition
D. Tendon organ reflex
From extensor tendon
organ (Ib fibers)
Inhibitory synapse
Renshaw cells
Excitatory synapse
Collaterals
To extensors
To synergistic
muscles
To flexors
E. Flexor withdrawal reflex
Nociceptive fibers
Ipsilateral
flexion
Contralateral
extension
Inhibitory synapse
Excitatory synapse
Excitatory synapse
Inhibitory synapse
To extensors
To flexors
To extensors
To flexors
©
FIGURE 2.28 SPINAL REFLEX PATHWAYS•
Summary of the spinal reflex pathways.
79
NEUROPHYSIOLOGY
Sensory Pathways: I
Cerebral cortex:
postcentral gyrus
Posterior limb of
internal capsule
Ventral posterolateral
(VPL) nucleus of
thalamus
Mesencephalon
(cerebral peduncles)
Medial lemniscus
Gracile nucleus
Spinothalamic tract
Cuneate nucleus
Lower part of
medulla oblongata
Fasciculus gracilis
Fasciculus cuneatus
Reticular formation
Dorsal (posterior) spinal
root ganglion
Proprioception,
position
Cervical part
of spinal cord
Touch,
pressure,
vibration
Lateral
spinothalamic tract:
pain, temperature
Pain,
temperature
Spinocervical tract
Lumbar part
of spinal cord
©
OF THE
BODY•
Pain, temperature, and pressure sensations below the head ultimately are conveyed to the primary somatosensory cortex (postcentral gyrus) by the anterolateral system (spinothalamic and spinoreticular tracts). The fasciculus gracilis and cuneatus of the spinal
lemniscal system convey proprioceptive, vibratory, and tactile sen-
80
Small
myelinated
and unmyelinated fibers
Lateral cervical nucleus
Ventral (anterior)
spinothalamic tract:
touch, pressure
FIGURE 2.29 SOMESTHETIC SYSTEM
Large
myelinated
fibers
sations to the thalamus (ventral posterolateral nucleus), whereas
the lateral cervical system mediates some touch, vibratory, and
proprioceptive sensations (blue and purple lines show these dual
pathways). Ultimately, these fibers ascend as parallel pathways to
the thalamus, synapse, and ascend to the cortex.
NEUROPHYSIOLOGY
Sensory Pathways: II
Cerebral cortex:
postcentral gyrus
Ventral posteromedial (VPM)
nucleus of thalamus
Internal capsule
Midbrain
(cerebral
peduncles)
Dorsal trigeminal lemniscus
Trigeminal mesencephalic nucleus
Trigeminal motor nucleus
Principal sensory trigeminal nucleus
Touch, pressure
Pain, temperature
Proprioception
Ventral
trigeminal
lemniscus
Pontine
reticular
formation
Trigeminal (semilunar) ganglion
Ophthalmic n.
Maxillary n.
Pons
Sensory root
and
Motor root of mandibular n.
Medullary
reticular
formation
Spinal
trigeminal
tract
Spinal
trigeminal
nucleus
Cervical
part of
spinal
cord
Facial (VII) n.
Vagus (X) n.
Dorsolateral fasciculus (of Lissauer)
Substantia gelatinosa (Iamina II)
FIGURE 2.30 SOMESTHETIC SYSTEM
OF THE
©
HEAD•
Nerve cells bodies for touch, pressure, pain, and temperature in
the head are in the trigeminal (semilunar) ganglion of the trigeminal (CN V) nerve (blue and red lines in figure). Neuronal cell bodies mediating proprioception reside in the mesencephalic nucleus
of CN V (purple fibers). Most relay neurons project to the contralateral VPM nucleus of the thalamus and thence to the postcentral gyrus of the cerebral cortex, where they are somatotopically
represented.
81
NEUROPHYSIOLOGY
Sensory Pathways: III
Schematic demarcation of
dermatomes shown as distinct
segments. There is actually
considerable overlap between
any two adjacent dermatomes
C2
C3
C4
C5
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
C2
C3
C4
C5
C6
C7
C8
C6
C6
T1
C5
C8
C7
C6
C8
C7
C7
S2, 3 L2
C8
S3
S4
S5
L3
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
L2
L3
L4
L5
S1
S2
S1
S2
L5
L1
L4
L2
L3
L5
S1 S2
L4
S1
S1
L5
L5
L4
L4
Levels of principal dermatomes
Clavicles
C5
C5, 6, 7 Lateral parts of upper limbs
Medial sides of upper limbs
C8, T1
Thumb
C6
C6, 7, 8 Hand
Ring and little fingers
C8
Level of nipples
T4
T10
T12
L1, 2, 3, 4
L4, 5, S1
L4
S1, 2, L5
S1
S2, 3, 4
Level of umbilicus
Inguinal or groin regions
Anterior and inner surfaces of lower limbs
Foot
Medial side of great toe
Posterior and outer surfaces of lower limbs
Lateral margin of foot and little toe
Perineum
©
FIGURE 2.31 DERMATOMES•
Sensory information below the head is localized to specific areas
of the body, which reflect the distribution of peripheral sensory
fibers that convey sensations to the spinal cord through the dorsal
roots (sensory nerve cell bodies reside in the corresponding dorsal
root ganglion). The area of skin subserved by afferent fibers of one
82
dorsal root is called a dermatome. This figure shows the dermatome segments and lists key dermatome levels used by clinicians. Variability and overlap occur, so all dermatome segments
are only approximations.
NEUROPHYSIOLOGY
Visual System: Receptors
B. Section
through retina
A. Eyeball
Iris
Lens
Axons at surface
of retina passing
via optic nerve,
chiasm, and tract
to lateral
geniculate body
Cornea
Suspensory
ligament
Ciliary
body
Anterior
chamber
Inner limiting
membrane
Ganglion cell
Posterior
chamber
Müller cell
(supporting glial
cell)
Amacrine cell
Bipolar cell
Horizontal cell
Rod
Cone
Pigment cells
of choroid
Ora
containing
serrata aqueous humor
Vitreous humor
Retina
Choroid
Sclera
Fovea
Optic nerve
Synaptic
ending
fully
polarized
Synaptic
ending
depolarized
C. Rod in dark
D. Rod in light
Photons
of light
Rhodopsin
Metabolic
energy
Current
flow
Na+
permeability
increased
Retinene
+
Opsin
Vitamin A
Synaptic bar
Nucleus
Lumirhodopsin
Metarhodopsin
Retinene
+
Opsin
Vitamin A
Centriole
(basal body)
Na+
permeability
decreased
Circulation
©
FIGURE 2.32 VISUAL RECEPTORS•
The rods and cones of the retina transduce light into electrical signals. As illustrated for the rod, light is absorbed by rhodopsin, and
through the second messenger cGMP (not shown), Na⫹ channels
in the membrane close and the cell hyperpolarizes. Thus, in the
dark the cell is depolarized, but it is hyperpolarized in the light.
This electrical response to light is distinct from other receptor
responses, in which the response to a stimulus results in a depolarization of the receptor cell membrane.
83
NEUROPHYSIOLOGY
Visual System: Visual Pathway
Central
darker
circle
represents
macular
zone
G
G
Overlapping
visual fields
A
Lightest
shades
represent
monocular
fields
A
B
B
H
H
Each
quadrant
a different
color
R RC
P
Choroid
C
Projection on
left retina
Projection on
right retina
Optic
(II) nerves
Optic chiasm
P
Choroid
Periphery
Macula
Structure of retina (schematic):
Projection on left
A Amacrine cells
dorsal lateral
B Bipolar cells
geniculate nucleus
C Cones
G Ganglion cells
H Horizontal cells
P Pigment cells
R Rods
Optic tracts
Projection on right
dorsal lateral
geniculate nucleus
Lateral
geniculate
bodies
Calcarine
fissure
Projection
on left
occipital lobe
Projection
on right
occipital lobe
©
FIGURE 2.33 RETINOGENICULOSTRIATE VISUAL PATHWAY•
The retina has two types of photoreceptors: cones that mediate
color vision and rods that mediate light perception but with low
acuity. The greatest acuity is found in the region of the macula of
the retina, where only cones are found (upper left panel). Visual
signals are conveyed by the ganglion cells whose axons course in
the optic nerves. Visual signals from the nasal retina cross in the
84
optic chiasm while information from the temporal retina remains in
the ipsilateral optic tract. Fibers synapse in the lateral geniculate
nucleus (visual field is topographically represented here and
inverted), and signals are conveyed to the visual cortex on the
medial surface of the occipital lobe.
NEUROPHYSIOLOGY
Auditory System: Cochlea
Cochlear nerve
A. Membranous
labyrinth within
bony labyrinth
(path of sound
waves)
Semicircular
canals
Utricle
Saccule
Scala vestibuli
Cochlear duct
(scala media)
Scala tympani
B. Section
through turn
of cochlea
Round window
Scala vestibuli
(perilymph);
weakly
+80 mV
positive
Efferent
nerve fibers
Oval window and stapes
Vestibular (Reissner’s)
membrane
Cochlear duct (scala media;
endolymph)
Tectorial membrane
Spiral ligament
Bone
Outer hair cells; ⫺60 mV
Scala tympani
(perilymph); 0 mV
Afferent
nerve fibers
Basilar membrane
Spiral ganglion
C. Spiral organ
of Corti
Inner hair cell; ⫺60 mV
Hair cells
Inner Outer
Tectorial membrane
Stereocilia
Rods
and
tunnel
of Corti
Basilar membrane
Supporting cells
Afferent nerve fibers
Spiral lamina
Spiral ganglion
Efferent nerve fibers
As basilar membrane moves up, hairs are deflected outward, causing
depolarization of hair cells and increased firing of afferent nerve fibers
©
FIGURE 2.34 COCHLEAR RECEPTORS•
The cochlea transduces sound into electrical signals. This is
accomplished by the hair cells, which depolarize in response to
vibration of the basilar membrane. The basilar membrane moves in
response to pressure changes imparted on the oval window of the
cochlea in response to vibrations of the tympanic membrane.
85
NEUROPHYSIOLOGY
Auditory System: Pathways
Acoustic area of
temporal lobe cortex
Brachium of
inferior
colliculus
Inferior
colliculus
Midbrain
Lateral
lemnisci
Nuclei of
lateral
lemnisci
Medulla
oblongata
Correspondence
between cochlea
and acoustic area
of cortex:
Low tones
Middle tones
High tones
Dorsal cochlear nucleus
Ventral cochlear nucleus
Cochlear division of
vestibulocochlear nerve
Dorsal
acoustic stria
Reticular formation
Trapezoid body
Intermediate acoustic stria
Superior olivary complex
Inner
Outer
Spiral ganglion Hair cells
©
FIGURE 2.35 AUDITORY PATHWAYS•
The cochlea transduces sound into electrical signals. Axons convey
these signals to the dorsal and ventral cochlear nuclei, where it is
tonotopically organized. Following a series of integrated relay
pathways, the ascending pathway projects to the thalamus (medial
86
geniculate bodies) and then the acoustic cortex in the transverse
gyrus of the temporal lobe, where information is tonotopically represented (low, middle, and high tones).
NEUROPHYSIOLOGY
Vestibular System: Receptors
A. Membranous labyrinth
Vestibular ganglion
Superior semicircular canal
Vestibular
and cochlear
divisions of
vestibulocochlear n.
Maculae
Saccule
Utricle
Cristae within
ampullae
Horizontal semicircular canal
Posterior semicircular canal
Cochlear duct
(scala media)
B. Section of crista
Opposite wall
of ampulla
Gelatinous cupula
Hair tufts
C. Section of macula
Otoconia
Gelatinous otolithic
membrane
Hair tuft
Hair cells
Supporting cells
Basement membrane
Nerve fibers
Hair cells
Nerve fibers
Basement
membrane
Excitation
D. Structure and innervation
of hair cells
Inhibition
Kinocilium
Kinocilium
Stereocilia
Basal body
Cuticle
Cuticle
Stereocilia
Basal body
Hair cell (type I)
Hair cell (type II)
Supporting cells
Supporting cell
Afferent nerve
calyx
Efferent nerve
endings
Efferent nerve
ending
Afferent nerve
endings
Basement
membrane
Myelin sheath
Myelin sheath
©
FIGURE 2.36 VESTIBULAR RECEPTORS•
The vestibular apparatus detects movement of the head in the form
of linear and angular acceleration. This information is important for
the control of eye movements so that the retina can be provided
with a stable visual image. It is also important for the control of
posture. The utricle and saccule respond to linear acceleration,
such as the pull of gravity. The three semicircular canals are
aligned so that the angular movement of the head can be sensed in
all planes. The sensory hair cells are located in the maculae of the
utricle and saccule and in the cristae within each ampullae.
87
NEUROPHYSIOLOGY
Vestibular System: Vestibulospinal Tracts
Excitatory
endings
Inhibitory
endings
Superior
Medial
Lateral
Inferior
Ascending fibers in medial
longitudinal fasciculi
Vestibular nuclei
Rostral
Upper
limb
Trunk
Ventral
Dorsal
To
cerebellum
Lower
limb
Caudal
Somatotopical
pattern in lateral
vestibular nucleus
Vestibular
ganglion
and
nerve
Motor neuron
(controlling
neck muscles)
Medial vestibulospinal fibers in medial
longitudinal fasciculi
Lateral
vestibulospinal
tract
Excitatory
interneuron
Excitatory
endings
to back
muscles
?
Inhibitory
interneuron
?
Lower
part of
cervical
spinal cord
Fibers from maculae
(gravitational stimuli)
To flexor muscles
To extensor muscles
?
To axial
muscles
Fibers from cristae
(rotational stimuli)
Inhibitory ending
?
To axial muscles
Inhibitory
ending
Lumbar part of
spinal cord
Excitatory ending
Lateral vestibulospinal tract
Inhibitory interneuron
Excitatory synapse
To flexor muscles
To extensor muscles
©
FIGURE 2.37 VESTIBULOSPINAL TRACTS•
Sensory input from the vestibular apparatus is used to maintain stability of the head and to maintain balance and posture. Axons convey vestibular information to the vestibular nuclei in the pons, and
then secondary axons distribute this information to five sites: spinal
88
cord (muscle control), cerebellum (vermis), reticular formation
(vomiting center), extraocular muscles, and cortex (conscious perception). This figure shows only the spinal cord pathways.
NEUROPHYSIOLOGY
Gustatory (Taste) System: Receptors
A. Tongue
Foliate
papillae
B. Section
through
vallate
papilla
Taste buds
Duct of
gustatory
(Ebner’s)
gland
C. Taste bud
Epithelium
Fungiform
papillae
Vallate papillae
Basement membrane
Nerve plexus
Microvilli
Taste pore
Nerve fibers
emerging from
taste buds
Taste cells
Desmosomes
Epithelium
Large nerve fiber
Fibroblast
Basement membrane
Granules
Schwann cell
Small nerve fiber
Collagen
Intercellular space Large nerve fiber
Microvilli
D. Detail of taste pore
E. Detail of base of receptor cells
©
FIGURE 2.38 TASTE RECEPTORS•
Taste buds on the tongue respond to various chemical stimuli. Taste
cells, like neurons, normally have a net negative charge internally
and are depolarized by stimuli, thus releasing transmitters that depo-
larize neurons connected to the taste cells. A single taste bud can
respond to more than one stimulus. The four traditional taste qualities
that are sensed are sweet, salty, sour, and bitter.
89
NEUROPHYSIOLOGY
Gustatory (Taste) System: Pathways
Ventral posteromedial (VPM)
nucleus of thalamus
Sensory cortex (just below
face area)
Lateral hypothalamic area
Amygdala
Mesencephalic
nucleus
and
Motor nucleus
of trigeminal n.
Pontine taste area
Trigeminal (V) n.
Maxillary n.
Mandibular n.
Pons
Pterygopalatine
ganglion
Greater petrosal n.
Geniculate ganglion
Facial (VII) n.
and
Nervus inermedius
Rostral part of nucleus
of solitary tract
Otic
ganglion
Lingual n.
Chorda
tympani
Glossopharyngeal (IX) n.
Fungiform papillae
Foliate papillae
Lower
part of
medulla
oblongata
Valiate papillae
Petrosal (inferior)
ganglion of
glossopharyngeal n.
Nodose (inferior)
ganglion of vagus n.
Vagus (X) n.
Epiglottis
Larynx
Superior laryngeal n.
©
FIGURE 2.39 TASTE PATHWAYS•
Depicted here are the afferent pathways leading from the taste receptors to the brainstem and, ultimately, to the sensory cortex in the
postcentral gyrus.
90
NEUROPHYSIOLOGY
Olfactory System: Receptors
Olfactory
bulb
Lateral nasal wall
A. Distribution
of olfactory
epithelium
(blue area)
Cribriform plate
of ethmoid bone
Septum
B. Schema of
section through
olfactory mucosa
Cribriform plate
Schwann cell
Olfactory gland
Unmyelinated
olfactory axons
Basement
membrane
Sustentacular
cells
Endoplasmic
reticulum
Nucleus
Olfactory cells
Dendrites
Terminal bars
(desmosomes)
Olfactory rod
(vesicle)
Villi
Cilia
Mucus
©
FIGURE 2.40 OLFACTORY RECEPTORS•
The sensory cells that make up the olfactory epithelium respond to
odorants by depolarizing. Like taste buds, an olfactory cell can
respond to more than one odorant. There are six general odor
qualities that can be sensed: floral, ethereal (e.g., pears), musky,
camphor (e.g., eucalyptus), putrid, and pungent (e.g., vinegar, peppermint).
91
NEUROPHYSIOLOGY
Olfactory System: Pathway
Efferent fibers
Afferent fibers
Granule cell (excited by
and inhibiting to mitral
and tufted cells)
Mitral cell
Recurrent process
Fibers from contralateral olfactory bulb
Fibers to contralateral olfactory bulb
Anterior commissure
Tufted cell
Medial olfactory stria
Periglomerular cell
Olfactory trigone and
olfactory tubercle
Glomerulus
Olfactory
nerve fibers
Anterior perforated
substance
Lateral olfactory
stria
Lateral olfactory
tract nucleus
Piriform lobe
Uncus
Amygdala
(in phantom)
Entorhinal area
Olfactory epithelium
Olfactory nerves
Olfactory bulb
Olfactory tract
Anterior olfactory nucleus
Cribriform plate of ethmoid bone
©
FIGURE 2.41 OLFACTORY PATHWAY•
Olfactory stimuli are detected by the nerve fibers of the olfactory
epithelium and conveyed to the olfactory bulb (detailed local circuitry shown in upper left panel). Integrated signals pass along the
olfactory tract and centrally diverge to pass to the anterior commis-
92
sure (some efferent projections course to the contralateral olfactory
bulb, blue lines) or terminate in the ipsilateral olfactory trigone
(olfactory tubercle). Axons then project to the primary olfactory
cortex (piriform cortex), entorhinal cortex, and amygdala.
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neuroanatomy - University of Toledo

Transcription

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