netter's atlas of neurology
TRANSCRIPT
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 NeurophysiologySelections 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 anyconsequences 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 drawnfrom the Atlas of Human Anatomy and Netter’s Atlas of Human Physiology. Viewing these picturesagain 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 atNew 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, allow-ing him to augment his income by illustrating articles and textbooks. He continued illustrating as asideline after establishing a surgical practice in 1933, but ultimately opted to give up his practice infavor of a full-time commitment to art. After service in the United States Army during the SecondWorld War, Dr. Netter began his long collaboration with the CIBA Pharmaceutical Company (nowNovartis Pharmaceuticals). This 45-year partnership resulted in the production of the extraordinarycollection 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 onlysecondarily on Netter the physician. As a student of Dr. Netter’s work for more than forty years, I cansay that the true strength of a Netter illustration was always established well before brush was laid topaper. In that respect each plate is more of an intellectual than an artistic or aesthetic exercise. It iseasy to appreciate the aesthetic qualities of Dr. Netter’s work, but to overlook its intellectual quali-ties is to miss the real strength and intent of the art. This intellectual process requires thorough under-standing of the topic, as Dr. Netter wrote: “Strange as it may seem, the hardest part of making a med-ical picture is not the drawing at all. It is the planning, the conception, the determination of point ofview 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 agood medical illustration can include clinical information and physiologic functions as well as anato-my. In pursuit of this principle Dr. Netter often integrates pertinent basic and clinical science ele-ments in his anatomic interpretations. Although he was chided for this heresy by a prominentEuropean anatomy professor, many generations of students training to be physicians rather thananatomists 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’scareer depict anatomy clearly based on cadaver specimens with renderings of shrunken and shriv-eled tissues and organs. Netter the physician chose to render “live” versions of these structures—notshriveled, 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, MDAustin, 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 mono-
graphs 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 commis-
sioned 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.
Part 1 NeuroanatomyCerebrum—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
Arteries of Brain: Inferior Views . . . . . . . . . . . 12
Cerebral Arterial Circle (Willis) . . . . . . . . . . . 13
Arteries of Brain: Frontal View and Section . . 14
Arteries of Brain: Lateral and Medial Views. . . . . . . . . . . . . . . 15
Arteries of Posterior Cranial Fossa . . . . . . . . . 16
Veins of Posterior Cranial Fossa . . . . . . . . . . . 17
Deep Veins of Brain. . . . . . . . . . . . . . . . . . . . . 18
Subependymal Veins of Brain . . . . . . . . . . . . . 19
Hypothalamus and Hypophysis . . . . . . . . . . . 20
Arteries and Veins of Hypothalamus and Hypophysis . . . . . . . . 21
Relation of Spinal Nerve Roots to Vertebrae . . . 22
Autonomic Nervous System: General Topography. . . . . . . . . . . . . . . . . . . 23
Spinal Nerve Origin: Cross Sections. . . . . . . . 24
Olfactory Nerve (I): Schema . . . . . . . . . . . . . . 25
Optic Nerve (II)
(Visual Pathway): Schema . . . . . . . . . . . . . . 26
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
Autonomic Nerves and Ganglia of Abdomen. . . . . . . . . . . . . . . 36
Nerves of Stomach and Duodenum . . . . . . . . 37
Nerves of Stomach and Duodenum (continued) . . . . . . . . . . . . 38
Nerves of Small Intestine . . . . . . . . . . . . . . . . 39
Nerves of Large Intestine . . . . . . . . . . . . . . . . 40
Nerves of Kidneys, Ureters and Urinary Bladder . . . . . . . . . . . . 41
Nerves of Pelvic Viscera: Male . . . . . . . . . . . . 42
Nerves of Pelvic Viscera: Female . . . . . . . . . . 43
Median Nerve . . . . . . . . . . . . . . . . . . . . . . . . . 44
Ulnar Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Radial Nerve in Arm and Nerves of Posterior Shoulder . . . . . . . . 46
Radial Nerve in Forearm . . . . . . . . . . . . . . . . . 47
Sciatic Nerve and Posterior Cutaneous Nerve of Thigh . . . . . . . . . . . . . . 48
Tibial Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Common Fibular (Peroneal) Nerve. . . . . . . . . 50
2
NEUROANATOMY Cerebrum: Medial Views
Cingulate gyrus
Cingulate sulcus
Medial frontal gyrus
Sulcus of corpus callosum
Fornix
Septum pellucidum
Central sulcus (Rolando)
Sagittal section of brain in situ
Interventricularforamen (Monro)
Interthalamicadhesion
Thalamus and3rd ventricle
Subcallosal(parolfactory)area
Anterior commissure
Subcallosalgyrus
Hypothalamicsulcus
Laminaterminalis
Supra- optic recess
Paracentral sulcus
Paracentral lobule
Corpus callosum
Precuneus
Superior sagittal sinus
Choroid plexusof 3rd ventricle
Stria medullarisof thalamus
Parietooccipitalsulcus
Habenularcommissure
Cuneus
Pineal body
Posteriorcommissure
Calcarinesulcus
Straight sinusin tentoriumcerebelli
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
Hypophysis (pituitary gland)
Mammillary body
Cerebral peduncle
Pons Cerebral aqueduct (Sylvius)
GenuRostrumTrunkSplenium
ofcorpus callosum
Isthmus of cingulate gyrus
Parietooccipital sulcus
Cuneus
Calcarine sulcus
Lingual gyrus
CrusBodyColumn
of fornix
Fimbria of hippocampus
Dentate gyrus
Parahippocampal gyrusLateral occipitotemporal gyrus
Occipitotemporal sulcus
Medial occipitotemporal gyrus
Rhinal sulcus
Collateral sulcus
Olfactory tract
Optic nerve (II)
Uncus
Mammillary body
Mammillothalamicfasciculus
Cingulate gyrus
Medial surface of cerebralhemisphere: brainstem excised
Tuber cinereum
Optic chiasm
Marginal sulcus
3
NEUROANATOMYCerebrum: Inferior View
Sectioned brainstem Frontal pole of cerebrum
Straight gyrus
Olfactory sulcus
Orbital sulci
Orbital gyri
Temporal pole
Lateral sulcus (Sylvius)
Inferior temporal sulcus
Inferior temporal gyrus
Rhinal sulcus
Uncus
Collateral sulcus
Parahippocampal gyrus
Medial occipitotemporal gyrus
Calcarine sulcus
Isthmus of cingulate gyrus
Longitudinal cerebral fissure
Occipital pole of cerebrum
Apex of cuneus
Splenium of corpus callosum
Cerebral aqueduct
Pulvinar of thalamus
Red nucleus
Substantia nigra
Cerebral crus
Mammillary body
Tuber cinereum
Optic tract
Optic nerve (II) (cut)
Optic chiasm
Longitudinal cerebral fissure
Genu of corpus callosum
Lamina terminalis
Olfactory bulb
Olfactory tract
Posterior perforated substance (in interpeduncular fossa)
Inferior (infero-lateral) marginof cerebrum
Hypophysis (pituitary gland)
Anterior perforated substance
Superior colliculus (of corpora quadrigemina)
Medial geniculate body
Lateral geniculate body
Inferiortemporal gyrus
Occipitotemporal sulcus
Lateral occipito-temporal gyrus
4
NEUROANATOMY Basal Nuclei (Ganglia)
Horizontal sections through cerebrum
Genu of corpus callosum
Lateral ventricle
Septum pellucidum
Column of fornix
Insula(island of Reil)
Interthalamicadhesion
Thalamus
Crus of fornix
Choroid plexusof lateral ventricle
Splenium of corpus callosum
Head of caudate nucleus
Anterior limb
Genu
Posterior limb
Putamen
Globus pallidus
3rd ventricle
External capsule
Claustrum
Retrolenticular partof internal capsule
Tail of caudate nucleus
Hippocampus and fimbria
Occipital (posterior) hornof lateral ventricle
Habenula
Pineal body
Cleft for internal capsule
Organization ofbasal nuclei (ganglia)
Caudatenucleus
Putamen Globuspallidus
StriatumLentiformnucleus
Corpus striatum
Basal nuclei(ganglia)
Caudatenucleus
Levels ofsectionsabove
Body
Head
Lentiform nucleus(globus pallidus medialto putamen)
Thalamus
Pulvinar
Medial geniculate body
Lateral geniculate body
Tail of caudate nucleusAmygdaloid body
A
Interrelationship of thalamus, lentiform nucleus, caudatenucleus and amygdaloid body (schema): left lateral view
B
A B
A B
of internalcapsule
Lentiformnucleus
A
B
5
NEUROANATOMYThalamus
Interventricular foramen (Monro)
3rd ventricle
Corpus callosum (cut)
Head of caudate nucleus
Septum pellucidum
Columns of fornix
Anterior tubercle
Stria terminalis
Interthalamic adhesion
Lamina affixa
Stria medullaris
Habenular trigone
Pulvinar (retracted)
Lateral geniculate body
Medial geniculate body
Brachium of superior colliculus
Brachium of inferior colliculus
Choroid plexus
Superior thalamostriate vein
Pes hippocampi
Internal cerebral vein
Dentate gyrus
Collateral eminence
Hippocampus
Fimbria of hippocampus
Posterior commissure
Habenular commissure
Pineal body
Collateral trigone
Calcar avis
Tela choroidea (cut edge)of 3rd ventricle
Temporal (inferior) hornof lateral ventricle
Occipital (posterior) hornof lateral ventricle
Calcarine sulcus
Superior colliculus
Inferior colliculus
Cerebellum
Pulvinar
Reticular nucleus
Median nuclei
3rd ventricle
Pulvinar
Lateral geniculate body
Medial geniculate body
3rd ventricleInterthalamicadhesion
Intralaminarnuclei
Externalmedullarylamina
Internalmedullarylamina
Schematic sectionthrough thalamus
(at level of brokenline shown in figureat right)
Thalamic nuclei
CM CentromedianLD Lateral dorsalLP Lateral posteriorM MedialMD Medial dorsalVA Ventral anteriorVI Ventral intermedialVL Ventral lateralVP Ventral posteriorVPL Ventral posterolateralVPM Ventral posteromedial
Lateral nuclei
Medial nuclei
Anterior nuclei
Schematic representation of thalamus
(external medullary lamina andreticular nuclei removed)
MD
M
CM
VPL
VPM
LP
LP
LD
VP
VPLVPM
VI
VL
VAMedian
Medial
lamina
medullary
Internal
Anterior
Lam
ina
6
NEUROANATOMY Cerebellum
Anterior cerebellar notch
Central lobule (II & III)
Culmen (IV & V)
Declive (VI)
Folium (VII A)
Superior vermis
Posterior cerebellar notch
Superior surface
Superiorvermis
Inferior surfaceCentral lobule
Lingula (I)
Superior medullary velum
Flocculus (H X)
4th ventricle
Inferior medullary velum
Nodule (X)
Uvula (IX)
Pyramid (VIII)
Tuber (VII B)
Posterior cerebellar notch
Inferiorvermis
4th ventricle
Superior medullary velum
Fastigial
Globose
Dentate
Emboliform
Decussation ofsuperior cerebellar peduncles
Cerebellarnuclei
Section in plane of superior cerebellar peduncle
Cerebral crus
Medial longitudinal fasciculus
Lingula (I)
Vermis
Nuclear layer ofmedulla oblongata
Superior cerebellarpeduncle
Secondary (postpyramidal)fissure
Posterolateral (dorsolateral)fissure
Flocculonodular lobe
Posterior lobe
Retrotonsillar fissure
Tonsil
Biventer lobule (H VIII)
Horizontal fissure
Inferior semilunar (caudal) lobule (H VII B)
Anterior lobe
Wing of central lobule
Superior
Middle
InferiorCerebellar peduncles
Anterior lobe
Quadrangular lobule (H IV-V)
Primary fissure
Horizontal fissure
Simple lobule (H VI)
Posterior lobe
Postlunate fissure
Horizontal fissure
Superior semilunar(anseriform) lobule (H VII A)
Inferior semilunar (caudal) lobule (H VII B)
7
NEUROANATOMYBrainstem
Pulvinars of thalami
Posterolateral view
Pineal body
Superior colliculi
Inferior colliculi
Trochlear nerve (IV)
Superior medullary velum
Superior cerebellar peduncle
Cuneate tubercle
Gracile tubercle
Cuneate fasciculus
Gracile fasciculus
Rhomboid fossa of4th ventricle
Glossopharyngeal (IX) andvagus (X) nerves
Dorsal roots of1st spinal nerve (C1)
Anterior view
Optic chiasm
Optic tract
Tuber cinereum
Cerebral crus
Lateral geniculate body
Pons
Olive
Pyramid
Ventral roots of 1st spinal nerve (C1)
Decussation of pyramids
Middle cerebellar peduncle
Posterior perforated substance
Olfactory tract
Anterior perforated substance
Infundibulum (pituitary stalk)
Mammillary bodies
Temporal lobe (cut surface)
Oculomotor nerve (III)
Trochlear nerve (IV)
Trigeminal nerve (V)
Abducent nerve (VI)
Vestibulocochlear nerve (VIII)
Flocculus of cerebellum
Glossopharyngeal nerve (IX)
Vagus nerve (X)
Hypoglossal nerve (XII)
Accessory nerve (XI)
Facial nerve (VII) andintermediate nerve
Choroid plexus of 4thventricle
Thalamus (cut surface)
Lateral geniculate body
Optic tract
Medial geniculate body
Brachia of superior and inferior colliculi
Cerebral crus
Pons
Trigeminal nerve (V)
Middle cerebellar peduncle
Vestibulocochlear nerve (VIII)
Facial nerve (VII)
Inferior cerebellar peduncle
Hypoglossal nerve (XII)
Accessory nerve (XI)
8
NEUROANATOMY Fourth Ventricle and Cerebellum
Posterior view
3rd ventricle
Pulvinar of thalamus
Pineal body
Superior colliculus
Inferior colliculus
Trochlear nerve (IV)
Superior medullary velum
Cerebellar peduncles
Lateral recess
Superior fovea
Sulcus limitans
Inferior fovea
Trigeminal tubercle
Hypoglossal trigone
Vagal trigone
Obex
Gracile fasciculus
Interthalamic adhesion
Posterior commissure
Habenular commissure
Pineal body
Splenium of corpus callosum
Great cerebral vein (Galen)
Cuneate fasciculus
Lateral funiculus
Dorsal median sulcus
Gracile tubercle
Habenular trigone
Geniculate bodies
Dorsal median sulcus
Superior cerebellar peduncle
Locus ceruleus
Medial eminence
Facial colliculus
Vestibular area
Striae medullares
Tenia of 4th ventricle
Cuneate tubercle
SuperiorMiddleInferior
MedialLateral
Dentate nucleusof cerebellum
Lingula (I)
Central lobule (II-III)
Culmen (IV-V)
Declive (VI)
Folium (VII A)
Tuber (VII B)
Pyramid (VIII)
Uvula (IX)
Nodulus (X)
Choroid plexus of 4th ventricle
Tonsil of cerebellumCentral canal of spinal cord
Medulla oblongata
Choroid plexus of 4th ventricle
4th ventricle
Medial longitudinal fasciculus
Pons
Inferior colliculus
Tectal (quadrigeminal) plate
Superior colliculus
Cerebral aqueduct (Sylvius)
Cerebral peduncle
Hypothalamic sulcus
Lamina terminalis
Anterior commissure
Body of fornix
Decussation of pyramids
Median aperture (foramen of Magendie)
Superior medullary velum
Inferior medullary velum
Vermis ofcerebellum
Vermis ofcerebellum
Interventricularforamen (Monro)
Thalamus (in3rd ventricle)
Median sagittal section
9
NEUROANATOMYAccessory Nerve (XI): Schema
Nucleus ambiguus
Vagus nerve (X)
Cranial root of accessory nerve (joins vagus nerveand via recurrent laryngeal nerve supplies muscles oflarynx, except cricothyroid)*
Spinal root ofaccessory nerve
Foramenmagnum
Jugular foramen
Superior ganglionof vagus nerve
Accessory nerve (XI)*
Inferior ganglionof vagus nerve
C1 spinal nerve
C2 spinal nerve
Accessory nerve(to sternocleidomastoidand 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.
10
NEUROANATOMY Arteries to Brain and Meninges
Left middle meningeal artery
Posterior cerebral artery
Superior cerebellar artery
Basilar artery
Left labyrinthine(internal acoustic) artery
Mastoid branch ofleft occipital artery
Anterior inferiorcerebellar artery
Posterior inferiorcerebellar artery
Posterior meningealbranch of left ascendingpharyngeal artery
Left and rightvertebral arteries(intracranial part)
Posterior meningealbranch of vertebralartery
Anterior meningealbranch of vertebral artery
Posterior auricular artery
Occipital artery
Internal carotid artery
Carotid sinus
Carotid body
Vertebral artery(cervical part)
Transverse process of C6
Deep cervical artery
Supreme intercostalartery
Costocervical trunk
Subclavian artery
Middle cerebral artery
Anterior cerebral artery
Anterior communicating artery
Ophthalmic artery
Posteriorcommunicatingartery
Cavernous sinus
Middle meningealartery
Maxillaryartery
Superficialtemporalartery
Externalcarotidartery
Facial artery
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
11
NEUROANATOMYArteries to Brain: Schema
Ophthalmic artery
Supraorbital artery
Supratrochlear artery
Lacrimal artery
Dorsal nasal artery
Middle meningeal artery
Angular artery
Superficial temporal artery
Posterior auricular artery
Facial artery
Occipital artery
Lingual artery
Ascending pharyngeal artery
Anterior spinal artery
Spinal segmental medullary branches
Vertebral artery
Common carotid artery
Deep cervical artery
Transverse cervical artery
Subclavian artery
Internal thoracic artery
Suprascapular artery
Supreme intercostal artery
Costocervical trunk
Anterior communicating artery
Anastomoses
1 Right–Left
2 Carotid–Vertebral
3 Internal carotid–External carotid
4 Subclavian–Carotid
5 Subclavian–Vertebral
Vertebral artery
Ascending cervical artery
Inferior thyroid artery
Thyrocervical trunk
Subclavian artery
Brachiocephalic trunk
Aorta
Arch
Descending
Ascending
Middle meningeal artery
Anterior tympanic artery
Superior cerebellar artery
Posterior cerebral artery
Middle cerebral artery
Posterior communicating artery
Anterior cerebral artery
Maxillary artery
Basilar artery
External carotid artery
Internal carotid artery
Superior thyroid artery
Common carotid artery
Anterior inferiorcerebellar artery
Posterior inferiorcerebellar artery
5
5
5
5
55
54
4
33
3
3
1
1
2
5
11
Caroticotympanic branchof internal carotid artery
12
NEUROANATOMY Arteries of Brain: Inferior Views
Medial frontobasal (orbitofrontal) artery
Anterior communicating artery
Anterior cerebral artery
Distal medial striate artery (recurrent artery of Heubner)
Internal carotid artery
Anterolateral central (lenticulostriate) arteries
Middle cerebral artery
Lateral frontobasal (orbitofrontal) artery
Prefrontal artery
Anterior choroidal artery
Posterior communicating artery
Posterior cerebral artery
Superior cerebellar artery
Basilar artery
Pontine arteries
Labyrinthine (internal acoustic) artery
Anterior inferior cerebellar artery
Vertebral artery
Anterior spinal artery
Posterior inferior cerebellar artery (PICA) (cut)
Posterior spinal artery
Cerebral arterialcircle (Willis)(broken line)
Anterior communicating artery
Distal medial striate artery(recurrent artery of Heubner)
Anterior cerebral artery
Middle cerebral artery
Posterior communicating artery
Anterior choroidal artery
Optic tract
Posterior cerebral artery
Cerebral crus
Lateral geniculate body
Posterior medial choroidal artery
Posterior lateral choroidal artery
Choroid plexus of lateral ventricle
Medial geniculate body
Pulvinar of thalamus
Lateral ventricle
13
NEUROANATOMYCerebral Arterial Circle (Willis)
Vessels dissected out: inferior view
Anterior cerebral artery (A2 segment)
Anterior communicating artery
Anterior cerebral artery (A1 segment)
Ophthalmic artery
Internal carotid artery
Middle cerebral artery
Posterior communicating artery
Posterior cerebral artery (P2 segment)(P1 segment)
Superior cerebellar artery
Basilar artery
Pontine arteries
Anterior inferior cerebellar artery
Anteromedial central (perforating)arteries
Hypothalamic artery
Distal medial striate artery (recurrent artery of Heubner)
Anterolateral central(lenticulostriate) arteries
Superior hypophyseal artery
Inferior hypophyseal artery
Anterior choroidal artery
Thalamotuberal(premammillary) artery
Posteromedial central (perforating) arteries
Thalamoperforating artery
Posteromedial central (paramedian) arteries
Labyrinthine (internal acoustic) artery
Vertebral artery
Vessels in situ: inferior view
Anterior cerebral artery
Hypothalamic artery
Internal carotid artery
Superior hypophyseal artery
Middle cerebral artery
Inferior hypophyseal artery
Posterior communicating artery
Efferent hypophyseal veins
Posterior cerebral artery
Anterior communicating artery
Optic chiasm
Cavernous sinus
Infundibulum (pituitary stalk) and long hypophyseal portal veins
Adenohypophysis (anterior lobe of pituitary gland)
Neurohypophysis (posterior lobe of pituitary gland)
Posteromedial central (perforating) arteries
Superior cerebellar artery
Basilar artery
14
NEUROANATOMY Arteries of Brain: Frontal View and Section
Corpus callosum
Prefrontal artery
Anterolateral central(lenticulostriate) arteries
Lateral frontobasal(orbitofrontal) artery
Anterior parietal(postcentral sulcal) artery
Precentral (pre-rolandic) and central (rolandic) sulcal arteries
Posterior parietal artery
Branch to angular gyrus
Anterior communicating artery
Temporal branches(anterior, middleand posterior)
Middle cerebral arteryand branches(deep in lateral cerebral[sylvian] sulcus)
Posterior communicating artery
Anterior inferior cerebellar artery
Posterior spinal artery
Corpus striatum (caudate and lentiform nuclei)
Anterolateral central(lenticulostriate) arteries
Insula (island of Reil)
Limen of insula
Precentral (pre-rolandic),central (rolandic) sulcaland parietal arteries
Lateral cerebral (sylvian) sulcus
Temporal branches ofmiddle cerebral artery
Temporal lobe
Middle cerebral artery
Internal carotid artery
Paracentral artery
Medial frontal branches
Pericallosal artery
Callosomarginal artery
Polar frontal artery
Anterior cerebralarteries
Medial frontobasal(orbitofrontal) artery
Distal medial striateartery (recurrent artery of Heubner)
Internal carotid artery
Anterior choroidalartery
Posterior cerebralartery
Superior cerebellar artery
Basilar and pontine arteries
Labyrinthine (internalacoustic) artery
Vertebral artery
Posterior inferior cerebellar artery
Anterior spinal artery
Falx cerebri
Callosomarginal arteriesandPericallosal arteries(branches of anteriorcerebral arteries)
Trunk of corpus callosum
Internal capsule
Septum pellucidum
Rostrum of corpus callosum
Anterior cerebral arteries
Distal medial striate artery (recurrent artery of Heubner)
Anterior communicating artery
Optic chiasm
15
NEUROANATOMYArteries of Brain: Lateral and Medial Views
Anterior parietal (postcentral sulcal) artery
Central (rolandic) sulcal artery
Precentral (pre-rolandic) sulcal artery
Prefrontal sulcalartery
Terminal branches ofanterior cerebralartery
Lateral frontobasal(orbitofrontal) artery
Left middlecerebral artery
Left anteriorcerebral artery
Anterior communicating artery
Right anterior cerebral artery
Left internal carotid artery
Pericallosal arteryPosterior
Intermediate
Anterior
Medialfrontalbranches
Callosomarginalartery
Polar frontal artery
Right anteriorcerebral artery
Medial fronto-basal (orbito-frontal) artery
Anterior communicating artery (cut)
Distal medial striate artery(recurrent artery of Heubner)
Right internal carotid artery
Posterior parietal artery
Branch to angular gyrus
Terminal branchesof posteriorcerebral artery
Posterior temporal branch
Middle temporal branch
Superior and inferior terminal branches (trunks)
Anterior temporal branch
Paracentral artery
Cingular branches
Right posterior cerebral artery
Precuneal artery
Dorsal branch to corpus callosum
Parietooccipital branch
Calcarine branch
Posterior temporal branch
Anterior temporal branch
Posterior communicating artery
Polar temporal artery
Medial occipital artery
Occipitotemporalbranches
Note: Anterior parietal (postcentral sulcal) artery also occurs as separate anterior parietal and postcentral sulcal arteries
16
NEUROANATOMY Arteries of Posterior Cranial Fossa
Thalamogeniculate arteries
Anterior choroidal artery
Crura of fornix
Anterolateral central(lenticulostriate) arteries
Heads of caudate nuclei
Septum pellucidum
Corpus callosum
Anteriorcerebral arteries
Longitudinalcerebralfissure
Lateral and medial geniculate bodies of left thalamus
Choroid plexuses of lateral ventricles
Pulvinars of left and right thalami
Splenium of corpus callosum
Occipital (posterior) horn of right lateral ventricle
Right dorsal branch to corpus callosum(posterior pericallosal artery)
Parietooccipital
Calcarine
Branches ofright posteriorcerebral artery
Optic nerve (II)
Ophthalmic artery
Thalamoperforating arteries
Anteriorcerebral artery
Middlecerebral artery
Posteriorcommunicating artery
Left internal carotid artery
Basilar artery
Pontine arteries
Labyrinthine (internal acoustic) artery
Posterior cerebral artery
Superior cerebellar artery
Anterior meningeal branch of vertebral artery
Anterior inferior cerebellar artery
Temporal branches of posterior cerebral artery
Anterior spinal artery
Superiorcolliculi
Posterior medialchoroidal arteryto choroid plexusof 3rd ventricle
Posterior lateralchoroidal artery
Lateral (marginal) branch
Inferior vermian artery(phantom)
Choroidal branch to 4th ventricle(phantom) andCerebellar tonsillar branchof posterior inferior cerebellar artery
Outline of 4th ventricle (broken line)
Posterior meningeal branch of vertebral artery
Posterior inferior cerebellar artery (PICA)
Left posterior spinal artery
Left vertebral artery
IIIIV
V
VIII
VII
VIIX
X
XI
Superiorvermianbranch
17
NEUROANATOMYVeins of Posterior Cranial Fossa
Parts of cerebellum
L Lingula TU TuberCL Central lobule P PyramidC Culmen U UvulaD Declive N NoduleF Folium T Tonsil
Left superior and inferior colliculi
Basal vein (Rosenthal)
Posterior mesencephalic vein
Medial geniculate body
Lateral geniculate body
Optic tract
Left thalamus(cut surface)
Inferior thalamo-striate veins
Optic nerve (II)
Lateralmesencephalic vein
Deep middlecerebralvein (cut)
Anteriorcerebralvein
Anterior ponto-mesencephalic vein
Petrosal vein (drainingto superior petrosal sinus)
Superior, middle andinferior cerebellar peduncles
Trigeminal nerve (V)
Transverse pontine vein
Lateral pontine vein
Anteromedian medullary vein
Vein of lateral recess of 4th ventricle
Anterior spinal vein 4th ventricle
Confluence of sinuses
Left transversesinus (cut)
Superiorsagittalsinus
Left pulvinar
Right pulvinar
Internal cerebral veins
Dorsal vein of corpus callosum
Inferior sagittal sinus
Straight sinus
Falx cerebri
Splenium of corpus callosum
Great cerebral vein (Galen)
Tentoriumcerebelli (cut)
CC
D
F
TU
P
U
T
CL
L
N
Superiorvermianvein
Inferiorvermian vein
Falx cerebelli (cut)and occipital sinus
Inferior cerebellarhemispheric veins
Posterior spinal vein
Precentral cerebellar vein
Preculminate vein
Intraculminate vein
Superior cerebellar vein (inconstant)
(Inferior retrotonsillar) vein of cerebellomedullarycistern
Superior retrotonsillar vein
18
NEUROANATOMY Deep Veins of Brain
Longitudinal cerebral fissure
Anterior cerebral veins
Septum pellucidum
Anterior vein of septum pellucidum
Head of caudate nucleus
Anterior vein of caudate nucleus
Transverse veins of caudate nucleus
Interventricular foramen (Monro)
Columns of fornix
Superior thalamostriate vein
Rostrum of corpus callosum
Superior choroid vein andchoroid plexus of lateral ventricle
Thalamus
Tela choroidea of 3rd ventricle
Lateral direct vein
Posterior vein of caudate nucleus
Internal cerebral veins
Basal vein (Rosenthal)
Great cerebral vein (Galen)
Inferior sagittal sinus
Straight sinus
Tentorium cerebelli
Transverse sinus
Confluence of sinuses
Superior sagittal sinus
Dissection: superior view
Dissection: inferior view
Uncal vein
Optic chiasm
Inferiorcerebralveins
Inferioranastomoticvein (Labbé)
Anterior cerebral vein
Deep middle cerebral vein
Cerebral crus
Basal vein (Rosenthal)
Lateral geniculate body
Medial geniculate body
Pulvinar of thalamus
Splenium of corpus callosum
Great cerebral vein (Galen)
Superficial middle cerebral vein(draining to sphenoparietal sinus)
19
NEUROANATOMYSubependymal Veins of Brain
Lateral direct vein
Superior thalamic veins
Posterior veins of septum pellucidum
Superior choroid vein
Transverse veins of caudate nucleus
Superior thalamostriate vein
Lateral ventricle
Anterior vein ofcaudate nucleus
Anterior vein ofseptum pellucidum
Genu ofcorpuscallosum
Interventricularforamen (Monro)
Anterior commissure
Interthalamic adhesion
Anterior cerebral vein
Optic chiasm
3rd ventricle
Deep middle cerebral vein
Inferior thalamostriate veins
Basal vein (Rosenthal)
Temporal (inferior) horn of lateral ventricle
Posterior mesencephalic 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
Cerebellum
Posterior terminal vein of caudate nucleus(posterior part of thalamostriate vein)
Internal cerebral veins (right and left)
Medial (atrial) vein of lateral ventricle
Lateral (atrial) vein of lateral ventricle
Splenium of corpus callosum
Great cerebral vein(Galen)
Dorsal vein of corpuscallosum
Inferior sagittalsinus
Internaloccipital vein
Straight sinus
Occipital(posterior)horn oflateralventricle
Superior vermian vein
20
NEUROANATOMY Hypothalamus and Hypophysis
Septum pellucidum
Thalamus
Fornix
Hypothalamic sulcus
Anterior commissure
Paraventricular
Posterior
Dorsomedial
Supraoptic
VentromedialArcuate(infundibular)
Mammillary
Principalnuclei ofhypothalamus
Optic chiasm
Infundibulum (pituitary stalk)
Hypophysis (pituitary gland)
Mammillothalamic tract
Dorsal longitudinalfasciculus and otherdescending pathways
Lamina terminalis
Paraventricular hypothalamic nucleus
Supraoptic hypothalamic nucleus
Supraopticohypophyseal tract
Tuberohypophyseal tract
Hypothalamohypophyseal tract
Infundibulum (pituitary stalk)
Fibrous trabecula
Pars intermedia
Pars distalis
Cleft
Pars tuberalis
Adenohypophysis(anterior lobe ofpituitary gland)
Hypothalamicsulcus
Mammillarybody
Arcuate (infundibular) nucleus
Median eminenceof tuber cinereum
Infundibularstem
Infundibularprocess
Neurohypophysis(posterior lobeof pituitary gland)
21
NEUROANATOMYArteries and Veins of Hypothalamus and Hypophysis
Primary plexus ofhypophyseal portal system
Efferent hypophyseal veinto cavernous sinus
Capillary plexus ofinfundibular process
Efferent hypophyseal veinto cavernous sinus
Long hypophyseal portal veins
Artery of trabecula
Trabecula (fibrous tissue)
Short hypophyseal portal veins
Neurohypophysis(posterior lobe ofpituitary gland)
Superiorhypophysealartery
Secondary plexusof hypophysealportal system
Hypothalamic vessels
Efferent hypophysealveins to cavernous sinus
Efferent hypophyseal veinto cavernous sinus
Adenohypophysis(anterior lobe ofpituitary gland)
Inferior hypophyseal artery
22
NEUROANATOMY Relation of Spinal Nerve Roots to Vertebrae
C1 spinal nerve exitsabove C1 vertebra
Cervicalenlargement
Base of skull
C8 spinal nerveexits belowC7 vertebra(there are 8 cervicalnerves but only7 cervical vertebrae)
Lumbar disc protrusion does not usually affectnerve exiting above disc. Lateral protrusionat disc level L4–5 affects L5 spinal nerve, notL4 spinal nerve. Protrusion at disc level L5–S1affects S1 spinal nerve, not L5 spinal nerve
Lumbarenlargement
Conus medullaris(termination ofspinal cord)
Internal terminal filum (pial part)
External terminal filum (dural part) Termination of
dural sac
Cauda equina
Coccygeal nerve
Coccyx Coccygeal nerve
Cervical nerves
Thoracic nerves
Lumbar nerves
Sacral and coccygeal nerves
Medial protrusion at disc level L4–5 rarely affectsL4 spinal nerve but may affect L5 spinal nerveand sometimes S1–4 spinal nerves
C1
C2
C3
C4
C5
C6
C7
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
C1
C2
C3
C4
C5C6
C7
C8
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
L2L2
L3
L5
L3
L4
L4
L5
Sacrum
S1S2
S3
S4
S5
S2
L4
L4
L5
L5
S1
L4
L4
L5
L5
S1
S2
S3
S4
S5
23
NEUROANATOMYAutonomic Nervous System: General Topography
Oculomotor nerve (III)
Facial nerve (VII)
Glossopharyngeal nerve (IX)
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 T6spinal 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 parasympatheticoutflow)
Sciatic nerve
Inferior hypogastric(pelvic) plexus
Sympathetic fibers
Parasympathetic fibers
Ciliary ganglion
Pterygopalatine ganglion
Otic ganglion
Chorda tympani nerve
Lingual nerve
Submandibular ganglion
Pharyngeal and superior laryngeal branchesof vagus nerve
Recurrent laryngeal branch of vagus nerve
Superior cervicalInferior cervicalThoracic
Cardiac branchesof vagus nerve
Cardiac plexus
AnteriorPosterior
Pulmonary plexuses
Esophageal plexus
Thoracic aortic plexus
Anterior vagal trunk
Posterior vagal trunk
Celiac ganglion
Celiac trunk and plexus
Superior mesenteric ganglion
Superior mesenteric arteryand plexus
Intermesenteric(abdominal aortic) plexus
Inferior mesenteric ganglion
Inferior mesenteric arteryand plexus
Superior hypogastric plexus
Parasympathetic branch frominferior hypogastric plexus todescending colon
Hypogastric nerves
Rectal plexus
Vesical plexus
Prostatic plexus
24
NEUROANATOMY Spinal Nerve Origin: Cross Sections
Section through thoracic vertebra
Fat in epidural space
Sympathetic ganglion
Ventral root
White and gray ramicommunicantes
Spinal nerve
Ventral ramus(intercostal nerve)
Dorsal ramus
Aorta
Dura mater
Subarachnoid space
Arachnoid mater*
Pia mater*
Recurrentmeningealbranches ofspinal nerve
Pleura
Lung
Spinal sensory (dorsal root) ganglion
Dorsal root
Dura mater
Arachnoid mater
Ventral root
Spinal nerve
Ventral ramus (contributes to lumbar plexus)
Dorsal ramus
Spinal sensory (dorsal root) ganglion
Dorsal root
Conus medullaris
*Leptomeninges
Dorsal and ventralroots of lumbar andsacral spinal nervesforming cauda equina
Gray ramuscommunicans
Fat inepiduralspace
Sympatheticganglion
Section through lumbar vertebra
Lateral branch
Medial branch
of dorsal ramus of spinal nerve
Lateral horn of gray matter of spinal cord
Body of vertebra
Internal vertebral (epidural) venous plexus
25
NEUROANATOMYOlfactory Nerve (I): Schema
Olfactory bulb cells: schema
Efferent fibers toolfactory bulb
Afferent fibers from bulbto central connectionsand contralateral bulb
Granule cell (excited byand inhibiting to mitraland tufted cells)
Mitral cell
Recurrent process
Tufted cell
Periglomerularcell
Glomerulus
Subcallosal (parolfactory) area
Olfactorynerve fibers
Septal area and nuclei
Fibers from
Fibers to
Contralateralolfactory bulb
Anterior commissure
Medial olfactory stria
Olfactory cells
Olfactory mucosa
Olfactory nerves (I)
Olfactory bulb
Cribriform plate of ethmoid bone
Anterior olfactory nucleus
Olfactory tract
Olfactory trigoneand olfactory tubercle
Lateral olfactory stria
Lateral olfactory tract nucleus
Anterior perforated substance
Amygdaloid body (phantom)
Piriform lobe
Uncus
Hippocampalfimbria
Dentate gyrus
Parahippocampal gyrus
26
NEUROANATOMY Optic Nerve (II) (Visual Pathway): Schema
Overlappingvisual fields
Projection onleft retina
Choroid Choroid
Periphery Macula
Projection onright retina
Central darkercircle representsmacular zone
Lighter shadesrepresentmonocular fields
Each quadranta different color
Projection on rightdorsal lateralgeniculate nucleus
Optic nerves (II)
Optic chiasm
Optic tracts
Projection on leftdorsal lateralgeniculate nucleus
Lateralgeniculatebodies
Optic radiation Optic radiation
Calcarinesulcus
Calcarinesulcus
Projection on leftoccipital lobe
Projection on rightoccipital lobe
Structure of retina: schema
A Amacrine cellsB Bipolar cellsC ConesG Ganglion cellsH Horizontal cellsP Pigment cellsR Rods
G
G
A
B
H
A
B
H
R R C C
P P
27
NEUROANATOMYOculomotor (III), Trochlear (IV) and Abducent (VI) Nerves: Schema
Long ciliary nerve
Short ciliary nerves
Anterior ethmoidal nerve
Superior oblique muscle
Levator palpebraesuperioris muscle
Superior rectus muscle
Ciliary ganglion
Posterior ethmoidal nerve
Sensory root of ciliary ganglion
Sympathetic root of ciliary ganglion
Superior division ofoculomotor nerve
Frontal nerve (cut)
Lacrimal nerve (cut)
Nasociliary nerve
Abducent nucleus
Trochlear nucleus
Oculomotor nucleus
Accessory oculomotor(Edinger-Westphal)nucleus (parasympathetic)
Trochlear nerve (IV)
Oculomotor nerve (III)
Ophthalmic nerve (V1)
Infraorbital nerve
Zygomatic nerve (cut)
Inferior oblique muscle
Ciliary muscle
Dilator muscle of pupil
Sphincter muscle of pupil
Pterygopalatineganglion
Inferior division ofoculomotor nerve
Medial rectus muscle
Inferior rectus muscle
Parasympathetic rootof ciliary ganglion
Efferent fibers
Afferent fibers
Sympathetic fibers
Parasympathetic fibers
Abducentnerve (VI)
Mandibular nerve (V3)
Maxillary nerve (V2)
Internal carotid arteryand nerve plexus
Lateral rectus muscle andabducent nerve (turned back)
Cavernous plexus
Common tendinous ring
28
NEUROANATOMY Trigeminal Nerve (V): Schema
Efferent fibers
Afferent fibers
Proprioceptive fibers
Parasympathetic fibers
Sympathetic fibers
Ophthalmic nerve (V1)
Tentorial (meningeal) branch
Nasociliary nerve
Lacrimal nerve
Frontal nerve
Sensory root ofciliary ganglion
Ciliary ganglion
Posterior ethmoidal nerve
Long ciliary nerve
Short ciliary nerves
Anterior ethmoidal nerve
Supraorbital nerve
Supratrochlear nerve
Infratrochlear nerve
Internal nasal branchesandExternal nasal branchesof anterior ethmoidal nerve
Maxillary nerve (V2)
Meningeal branch
Zygomaticotemporalnerve
Zygomaticofacial nerve
Zygomatic nerve
Infraorbital nerve
Pterygopalatineganglion
Superioralveolarbranches ofinfraorbital nerve
Nasal branches(posterior superiorlateral, nasopalatineand posteriorsuperior medial)
Nerve (vidian) ofpterygoid canal(from facial nerve [VII]and carotid plexus)
Pharyngeal branch
Greater and lesserpalatine nerves
Deep temporal nerves(to temporalis muscle)
Lateral pterygoidand masseteric nerves
Tensor veli palatini andmedial pterygoid nerves
Buccal nerve
Mental nerve
Inferior dental plexus
Lingual nerve
Submandibularganglion
Mylohyoid nerve
Mandibular nerve (V3)
Inferioralveolar nerve
Otic ganglion
Tensor tympani nerve
Chordatympani nerve
Superficial temporal branches
Articular branch and anterior auricular nerves
Auriculotemporal nerve
Parotid branches
Meningeal branch
Lesser petrosal nerve (fromglossopharyngeal nerve [IX])
Facial nerve (VII)
Trigeminal nerve (V) ganglion and nuclei
Motor nucleusMesencephalic nucleus
Principal sensory nucleusSpinal tract and nucleus
29
NEUROANATOMYFacial Nerve (VII): Schema
Greater petrosal nerve
Deep petrosal nerve (from internal carotid plexus)
Lesser petrosal nerve
Nerve (vidian) of pterygoid canal
Otic ganglion
Pterygopalatine ganglion
Facial muscles
Orbicularis oculi
Frontal belly (frontalis)of occipitofrontalis
Corrugator supercilii
Zygomaticus major
Zygomaticus minor
Procerus
Nasalis
Facial nerve (VII)
Levator labiisuperioris
Levatoranguli oris
Levator labiisuperiorisalaeque nasi
Tem
po
ral
bra
nc
he
s
Zygomatic
Mentalis
Depressorsepti nasi
Orbicularisoris
Depressoranguli oris
Depressor labiiinferioris
(Risorius)(not shown)
Buccinator
Platysma
Buccalbranches
Marginal
mandibular
branch
anterior 2⁄3tongueTaste:
of
Efferent fibers
Afferent fibers
Parasympathetic fibers
Sympathetic fibers
Sublingual gland
Submandibular gland
Submandibular ganglion
Lingual nerve (from trigeminal nerve)
Chorda tympani nerve Caroticotympanic nerve (from internal carotid plexus)
Stylohyoid muscle
Digastric muscle (posterior belly)
Glossopharyngeal nerve (IX)
Tympanic nerve (Jacobson)(from glossopharyngeal nerve)
Tympanic plexus
Stylomastoid foramen
Nerve to stapedius muscle
Posterior auricular nerve
Branches to auricular muscles
Occipitalbranch ofposteriorauricularnerve
Ce
rvic
al b
ran
ch
Geniculate ganglion
Internal carotid plexus (on internal carotid artery)
Internal acoustic meatus
Intermediate nerve
Motor nucleus of facial nerve
Superior salivatory nucleus
Solitary tract nucleus
Occipitalbelly(occipitalis) ofoccipitofrontalismuscle
branches
30
NEUROANATOMY Vestibulocochlear Nerve (VIII): Schema
Afferent fibers
Geniculum of facial nerve(site of geniculate ganglion)
Facial canal
Greater petrosal nerve
Cochlear (spiral) ganglion
Vestibular nerve
Cochlear nerve
Tympanic cavity
Chorda tympani nerve
Motor root of facial nerveand intermediate nerve
Vestibulocochlearnerve (VIII)
Medulla oblongata(cross section)
Internal acousticmeatus
Medial
Superior
Inferior
Lateral
Vestibularnuclei(diagrammatic)
Anterior
Posterior
Cochlearnuclei
Inferior cerebellarpeduncle (to cerebellum)
Vestibular ganglionInferior division
Superior division
Saccule
Ampulla of posteriorsemicircular duct
Utricle
Ampulla of superiorsemicircular duct
Ampulla of lateralsemicircular duct
of vestibular nerve
Head of malleus
Incus
31
NEUROANATOMYGlossopharyngeal Nerve (IX): Schema
Efferent fibers
Afferent fibers
Parasympathetic fibers Tympanic nerve (Jacobson)
Tympanic cavity and plexus
Stylomastoid foramen
Caroticotympanic nerve (from internal carotid plexus)
Greater petrosal nerve
Deep petrosal nerve
Nerve (vidian) of pterygoid canal
Lesser petrosal nerve
Pterygopalatine ganglion
Mandibular nerve (V3)
Otic ganglion
Auriculotemporal nerve
Parotid gland
Tubal branch of tympanic plexus
Pharyngotympanic (auditory) tube and pharyngeal opening
Stylopharyngeus muscle (and branch from glossopharyngeal nerve)
Spinal tract and spinal nucleus of trigeminal nerve
Solitary tract nucleus
Nucleus ambiguus
Inferior salivatory nucleus
Geniculate ganglionof facial nerve
Glossopharyngealnerve (IX)
Jugular foramen
Communication to auricularbranch of vagus nerve
Superior andInferior ganglia ofGlossopharyngeal nerve
Communication to facial nerve (VII)
Vagus nerve (X)
Superior cervicalsympathetic ganglion
Sympathetic trunk
Carotid branch ofglossopharyngeal nerve
Internal carotid artery
Carotid sinus
Carotid body
Common carotid artery
External carotid artery
Taste and somaticsensation:posterior1⁄3 of tongue
Pharyngeal plexus
Pharyngeal, tonsillar and lingualbranches of glossopharyngeal nerve
Pharyngeal branch of vagus nerve
32
NEUROANATOMY Vagus Nerve (X): Schema
SEE ALSO PLATE 160Glossopharyngeal nerve (IX)
Meningeal branch of vagus nerve
Auricular branch of vagus nerve
Pharyngotympanic (auditory) tube
Levator velipalatini muscle
Salpingopharyngeusmuscle
Palatoglossus muscle
Palatopharyngeusmuscle
Superior pharyngealconstrictor muscle
Stylopharyngeus muscle
Middle pharyngeal constrictor muscle
Inferior pharyngeal constrictor muscle
Cricothyroid muscle
Trachea
Esophagus
Right subclavian artery
Right recurrent laryngeal nerve
Heart
Cranial root ofaccessory nerve* (see next plate)
Posterior nucleus of vagus nerve (parasympathetic and visceral afferent)
Spinal tract and spinalnucleus of trigeminal nerve(somatic afferent)
Solitary tract nucleus (visceralafferents including taste)
Nucleus ambiguus(motor to pharyngealand laryngeal muscles)
Vagus nerve (X)
Jugular foramen
Superior ganglion of vagus nerve
Inferior ganglion of vagus nerve
Pharyngeal branch of vagus nerve (motor to muscles ofpalate and lower pharynx; sensory to lower pharynx)
Communicating branch of vagus nerve tocarotid 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 larynxexcept cricothyroid; sensory and parasympathetic tolarynx below vocal folds; parasympathetic, efferent andafferent to upper esophagus and trachea)
Pulmonary plexus
Hepatic branch of anteriorvagal trunk (in lesser omentum)
Celiac branches from anteriorand posterior vagal trunksto celiac plexus
Celiac and superior mesentericganglia and celiac plexus
Hepatic plexusCardiac plexus
Esophageal plexusGallbladderand bile ducts
Liver
Pyloric branchfrom hepatic plexus
Pancreas
Anterior vagal trunk
Gastric branches of anterior vagal trunk(branches from posterior trunk behind stomach)
Duodenum
Ascending colon
Vagal branches (parasympathetic motor,secretomotor and afferent fibers) accompanysuperior mesenteric artery and its branchesusually as far as left colic (splenic) flexure
Small intestine
Cecum
Appendix
Efferent fibers
Afferent fibers
Parasympathetic fibers
33
NEUROANATOMYAccessory Nerve (XI): Schema
SEE ALSO PLATE 28
Nucleus ambiguus
Vagus nerve (X)
Cranial root of accessory nerve (joins vagus nerveand via recurrent laryngeal nerve supplies muscles oflarynx, except cricothyroid)*
Spinal root ofaccessory nerve
Foramenmagnum
Jugular foramen
Superior ganglionof vagus nerve
Accessory nerve (XI)*
Inferior ganglionof vagus nerve
C1 spinal nerve
C2 spinal nerve
Accessory nerve(to sternocleidomastoidand 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.
34
NEUROANATOMY Hypoglossal Nerve (XII): Schema
Intrinsicmusclesof tongue
Superior longitudinal
Transverseand vertical
Inferiorlongitudinal
Styloglossusmuscle
Meningeal branch
Hypoglossal nucleus
Occipital condyle
Inferior ganglion ofvagus nerve
Hypoglossal nerve (XII)(in hypoglossal canal)
Ventral rami ofC1, 2, 3 formansa cervicalisof cervical plexus
Superior cervicalsympatheticganglion
Superior root ofansa cervicalis
Internal carotid artery
Inferior root of ansa cervicalis
Ansa cervicalis
Internal jugular vein
Common carotid artery
Sternothyroid muscle
Sternohyoid muscle
Omohyoid muscle(superior belly)
Genioglossusmuscle
Geniohyoid muscle
Hyoglossus muscle
Thyrohyoid muscle
Omohyoid muscle (inferior belly) Efferent fibers
Afferent fibers
35
NEUROANATOMYNerves of Heart
Vagus nerve (X)
Superior cervicalsympathetic ganglion
(Conjoined sympathetic andvagal) superior cervical cardiac nerves
Middle cervicalsympathetic ganglion
Middle cervical(sympathetic) cardiac nerve
Phrenic nerve
Inferior cervical(vagal) cardiac nerve
Vertebral ganglion
Inferior thyroid artery
Vertebral artery
Cervicothoracic(stellate) ganglion
Ansa subclavia
Recurrentlaryngeal nerve
Inferior cervical(sympathetic) cardiac nerves
Thoracic cardiac branchof vagus nerve
4th thoracicsympathetic ganglion
Thoracic (sympathetic)cardiac branches
Cardiac plexus
Phrenic nerve (cut)
Superior cervicalsympathetic ganglion
Vagus nerve (X)
Superior cervical(sympathetic) cardiac nerve
Superior cervical(vagal) cardiac nerve
Middle cervicalsympathetic ganglion
Phrenic nerve
Middle cervical(sympathetic) cardiac nerve
Inferior cervical(vagal) cardiac nerve
Vertebral ganglion
Cervicothoracic(stellate) ganglion
Inferior cervicalsympatheticcardiac nerves
3rd thoracicsympathetic ganglion
Thoracic (sympathetic)cardiac branches
Thoracic cardiacbranch ofvagus nerve
Recurrent laryngealnerve
36
NEUROANATOMY Autonomic Nerves and Ganglia of Abdomen
Right sympathetic trunk
Thoracic duct
Right greaterand lessersplanchnicnerves
Right phrenic nerve
Inferior phrenicarteries and plexuses
Right greaterand lessersplanchnicnerves
Right suprarenalplexus
Right aortico-renal ganglion
Right leastsplanchnic nerve
Right renalartery and plexus
Rightsympathetic trunk
White and grayrami communicantes
Cisterna chyli
Gray ramus communicans
3rd lumbar ganglionof sympathetic trunk
2nd and 3rd lumbarsplanchnic nerves
Right ureter and plexus
Right testicular (ovarian)artery and plexus
4th lumbar splanchnic nerve
1st sacral ganglion of sympathetic trunk
Gray rami communicantes
Anterior,Posteriorvagal trunks
Left gastric arteryand plexus
Celiac ganglia
Left greater splanchnic nerve
Left lesser splanchnic nerve
Splenic arteryand plexus
Common hepaticartery and plexus
Superior mesentericganglion and plexus
Left aorticorenalganglion
Left sympathetictrunk
Intermesenteric(aortic) plexus
Inferior mesentericganglion
Left colic arteryand plexus
Inferior mesentericartery and plexus
Left common iliacartery and plexus
Superior rectalartery and plexus
Superior hypogastricplexus
Internal and externaliliac arteries andplexuses
Right and lefthypogastric nervesto inferior hypo-gastric (pelvic) plexus
Left sacral plexus
Pelvic splanchnicnerves
37
NEUROANATOMYNerves of Stomach and Duodenum
Right and left inferior phrenic arteries and plexuses
Anterior and posterior layers of lesser omentum
Branch from hepatic plexus tocardia via lesser omentum
Right greater splanchnicnerve
Hepatic branch of anterior vagal trunk
Anterior vagal trunk
Celiac branch of posterior vagal trunk
Celiac branch of anterior vagal trunk
Left gastric artery and plexus
Anterior gastric branch of anteriorvagal trunk
Left greater splanchnic nerve
Left lesser splanchnicnerve
Splenic artery and plexus
Celiac ganglia and plexus
Plexus on gastro-omental(gastroepiploic) arteries
Plexus on inferior pancreaticoduodenal artery
Superior mesenteric artery and plexus
Plexus on first jejunal artery
Plexus on anterior superior and anteriorinferior pancreaticoduodenal arteries(posterior pancreaticoduodenal arteries and plexuses not visible in this view)
Right gastricartery and plexus
Hepatic plexus
Vagalbranchfrom hepaticplexustopyloricpart ofstomach
38
NEUROANATOMY Nerves of Stomach and Duodenum (continued)
Plexus on gastro-omental (gastroepiploic) arteries
Hepatic plexus
Right gastricartery andplexus
Posterior gastric branch of posterior vagal trunk
Hepatic branch of anterior vagal trunk via lesser omentum
Branch from hepatic plexus to cardia via lesser omentum
Right inferior phrenic artery and plexus
Posterior vagal trunk
Celiac branch of posterior vagal trunk
Celiac branch of anterior vagal trunk
Left gastric artery and plexus
Greater, lesser and leastsplanchnic nerves
Left inferior phrenic artery and plexus
Celiac ganglia and plexus
Aorticorenal ganglia
Splenic artery and plexus
Right phrenic nerve
Phrenic ganglion
Branch from right inferior phrenicplexus to cardia of stomach
Right and left inferior phrenicarteries and plexuses
Anterior vagal trunk
Posterior vagal trunk
Greater,Lesser,Leastsplanchnicnerves
Viewwithstomachreflectedcephalad
Plexus onanterior superiorand anterior inferiorpancreatico-duodenal arteries
Plexus on gastroduodenal artery
Plexus on posterior superiorand posterior inferiorpancreaticoduodenal arteries
Superior mesenteric ganglion and plexus
Superior mesenteric ganglion and plexus
Right greater,lesserand leastsplanchnic nerves
Celiac ganglia
Right aortico-renal ganglion
Left aorticorenal ganglion
Left greater, lesser and leastsplanchnic nerves
Celiac branchesof anteriorand posteriorvagal trunks
Left gastricartery and plexus
39
NEUROANATOMYNerves of Small Intestine
Recurrent branch of left inferior phrenicartery and plexus to esophagus
Anterior vagal trunk
Posterior vagal trunk
Hepatic branch of anteriorvagal trunk (courses in lesseromentum, removed here)
Celiac branches of anteriorand posterior vagal trunks
Inferior phrenic arteries and plexuses
Left gastric artery and plexus
Hepatic plexus
Greater splanchnic nerves
Right gastric artery and plexus (cut)
Celiac ganglia and plexus
Gastroduodenal artery and plexus
Lesser splanchnic nerves
Least splanchnic nerves
Aorticorenal ganglia
Superior mesenteric ganglion
Intermesenteric (aortic) plexus
Inferior pancreaticoduodenalarteries and plexuses
Superior mesentericartery and plexus
Middle colic artery and plexus (cut)
Right colic artery and plexus
Superior mesentericartery and plexus
Peritoneum (cut edge)
Mesenteric branches
Mesoappendix (containsappendicular artery andnerve plexus)
Ileocolic artery and plexus
40
NEUROANATOMY Nerves of Large Intestine
Anterior vagal trunk and hepatic branch
Posterior vagal trunk
Celiac branches of anteriorand posterior vagal trunks
Right inferior phrenic artery and plexus
Right greater splanchnic nerve
Celiac ganglia and plexus
Right lesser andleast splanchnic nerves
Right aortico-renal ganglion
Superiormesentericganglion
Middle colicarteryand plexus
Inferiorpancreatico-duodenalarteriesand plexuses
Right colicarteryand plexus
Ileocolicarteryand plexus
Cecal andappendiculararteriesand plexuses
Right internaliliac arteryand plexus (cut)
Sacral sympathetic trunk
Right sacral plexus
Middle rectal artery and plexus
Right inferior hypogastric(pelvic) plexus
Vesical plexus
Rectal plexus
Urinary bladder
Marginal artery and plexus
Esophagus
Left inferior phrenicartery and plexus
Left gastric arteryand plexus
Left greatersplanchnic nerve
Left suprarenalplexus
Left lesser andleast splanchnicnerves
Left aorticorenalganglion
Left renal arteryand plexus
1st left lumbarsplanchnic nerve
Left lumbarsympathetic trunk
Intermesenteric(aortic) plexus
Left colic arteryand plexus
Inferiormesentericganglion, arteryand plexus
Sigmoidarteriesand plexuses
Superiorhypogastricplexus
Superiorrectalarteryand plexus
Right and lefthypogastricnerves
Rectosigmoidartery andplexus
Nerves from inferior hypogastric (pelvic)plexuses to sigmoid colon, descendingcolon and left colic (splenic) flexure
Pelvic splanchnic nerves
41
NEUROANATOMYNerves of Kidneys, Ureters and Urinary Bladder
Anterior vagal trunk
Posterior vagal trunk
Greater splanchnic nerve
Celiac ganglia and plexus
Lesser splanchnic nerve
Superior mesenteric ganglion
Least splanchnic nerve
Aorticorenal ganglion
Renal plexus and ganglion
2nd lumbar splanchnic nerve
Renal and upper ureteric branchesfrom intermesenteric plexus
Intermesenteric (aortic) plexus
Testicular (ovarian) artery and plexus
Inferior mesenteric ganglion
Sympathetic trunk and ganglion
Middle ureteric branch
Superior hypogastric plexus
Sacral splanchnic nerves(branches from upper sacral sympathetic ganglia to hypogastric plexus)
Gray ramus communicans
Hypogastric nerves
Sacral plexus
Pudendal nerve
Pelvic splanchnic nerves
Inferior hypogastric (pelvic) plexuswith periureteric loops andbranches to lower ureter
Rectal plexus
Vesical plexus
Prostatic plexus
42
NEUROANATOMY Nerves of Pelvic Viscera: Male
Anterior vagal trunk
Posterior vagal trunkandCeliac branch
Inferior phrenic arteries and plexuses
Left gastric artery and gastric plexus
Celiac ganglia, plexus and trunk
Left aorticorenal ganglion
Superior mesenteric ganglion
Superior mesenteric artery and plexus
Intermesenteric (aortic) plexus
Inferior mesenteric ganglion,artery and plexus
Ureter and ureteric plexus
Superior hypogastric plexus
Superior rectal artery and plexus
Hypogastric nerves
Nerve from inferiorhypogastric plexusto sigmoid and descendingcolon (parasympathetic)
Sacral splanchnic nerves(sympathetic)
Inferior hypogastric(pelvic) plexus
Obturator nerveand artery
Ductus deferensand plexus
Vesical plexus
Rectal plexus
Prostatic plexus
Cavernous nervesof penis
Posterior scrotal nerves
Dorsal nerve of penis
Perineal nerve
Inferior anal (rectal) nerve
Levator ani muscle
Pudendal nerve
(Ischio-)coccygeusmuscle andsacrospinous ligament
Gluteus maximusmuscle and sacro -tuberous ligament
Piriformis muscle
Sacral plexus
Pelvic splanchnicnerves(parasympathetic)
S1 spinal nerve(anterior ramus)
Gray rami communicantes
Lumbosacral trunk
L5 spinal nerve (anterior ramus)
5th lumbar splanchnic nerve
Sympathetic trunk and ganglia
Gray rami communicantes
1st, 2nd, 3rd lumbar splanchnic nerves
GrayWhite
Ramicommunicantes
L1 spinal nerve(anterior ramus)
Left renal arteryand plexus
Diaphragm
GreaterLesserLeast
Splanchnicnerves
White and gray rami communicantes
T10 spinal nerve (anterior ramus)
43
NEUROANATOMYNerves of Pelvic Viscera: Female
Sympathetic trunk and L2 ganglion
White andgray ramicommunicantes
Lumbarsplanchnicnerves
Gray ramicommunicantes
L5 spinalnerve
Righthypogastricnerve (cut)
Right andleft sacralsympathetictrunks andganglia
Piriformismuscle
Sacralsplanchnicnerves(sympathetic)
Pudendalnerve
S5
S4
S3
S2
S1
Pelvicsplanchnicnerves(parasympathetic)
(Ischio-)coccygeus muscle
Rectal plexus
Rectum (retracted)
Uterus (retracted)
Uterovaginal plexus
Vesical plexus
Urinary bladder
Symphyseal surface of pubis
Ovary
Uterine (fallopian) tube
Inferior hypogastric (pelvic) plexus
Left hypogastric nerve
Right sympathetic trunk
Uterus
Right and lefthypogastric nerves
Sigmoidcolon
Externaliliac arteryand plexus
Internaliliac arteryand plexus
Commoniliac arteryand plexus
Superiorhypogastricplexus
Superiorhypogastricplexus
Ureter
Sacralpromontory
Ovarian arteryand plexus
Intermesenteric(aortic) plexus
Ureter
Commoniliac vesselsand plexus
Extraperitoneal(subserous)fascia
Abdominal aorta
Inferior vena cava
Peritoneum
44
NEUROANATOMY Median Nerve
Anterior view Note: Only muscles innervated by median nerve shown
Musculocutaneous nerve
Median nerve (C5, 6, 7, 8, T1)
Inconstant contribution
Pronator teres muscle (humeral head)
Articular branch
Flexor carpi radialis muscle
Palmaris longus muscle
Pronator teres muscle (ulnar head)
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
Palmar branch of median nerve
Abductor pollicis brevis
Opponens pollicis
Superficial head offlexor pollicis brevis(deep head supplied byulnar nerve)
Thenarmuscles
1st and 2ndlumbrical muscles
Dorsal branches todorsum of middle anddistal phalanges
Medial
PosteriorLateral
Cords ofbrachialplexus
Medial cutaneousnerve of arm
Medial cutaneousnerve of forearm
Axillary nerve
Radial nerve
Ulnar nerve
Cutaneous innervation
Palmar view
Posterior (dorsal) view
Proper palmar digital nerves
Common palmar digital nerves
Communicating branchof median nerve withulnar nerve
45
NEUROANATOMYUlnar Nerve
Ulnar nerve (C7, 8, T1)(no branches above elbow)
Inconstant contribution
Medial epicondyle
Articular branch(behind condyle)
Flexor digitorum profundusmuscle (medial part only;lateral part supplied byanterior interosseousbranch of median nerve)
Dorsal branch of ulnar nerve
Flexor carpi ulnaris muscle(drawn aside)
Palmar branch
Superficial branch
Deep branch
Palmaris brevis
Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
Hypothenar muscles
Common palmar digital nerve
Palmar and dorsal interosseous muscles
Communicating branch of median nerve withulnar nerve
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
Adductor pollicis muscle
Posterior(dorsal) view
Flexor pollicis brevis muscle(deep head only; superficialhead and other thenar musclessupplied by median nerve)
Palmar view
Cutaneousinnervation
Anterior view Note: Only muscles innervated by ulnar nerve shown
46
NEUROANATOMY Radial Nerve in Arm and Nerves of Posterior Shoulder
Posterior view
Suprascapular nerve (C5, 6)
Dorsal scapular nerve (C5)
Supraspinatus muscle
Levator scapulaemuscle (suppliedalso by branchesfrom C3 and C4)
Rhomboidminor muscle
Rhomboidmajor muscle
Infraspinatus muscle
Teres major muscle
Lower subscapular nerve (C5, 6)
Posterior cutaneous nerve of arm(branch of radial nerve in axilla)
Triceps brachii muscle
Long head
Lateral head
Medial head
Triceps brachii tendon
Medial epicondyle
Olecranon
Anconeus muscle
Extensor digitorum muscle
Extensor carpi ulnaris muscle
Extensor carpiradialis brevismuscle
Extensor carpi radialislongus muscle
Brachioradialis muscle
Brachialis muscle (lateralpart; remainder of musclesupplied by musculo-cutaneous nerve)
Lateral intermuscularseptum
Posterior cutaneousnerve of forearm
Inferior lateralcutaneous nerve of arm
Deltoid muscle
Teres minor muscle
Axillary nerve (C5, 6)
Superior lateralcutaneous nerve of arm
Radial nerve(C5, 6, 7, 8, T1)
Inconstant contribution
47
NEUROANATOMYRadial Nerve in Forearm
Posterior view
Radial nerve (C5, 6, 7, 8, T1) Inconstant contribution
Superficial (terminal) branch
Deep (terminal) branch
Lateral epicondyle
Anconeus muscle
Brachioradialis muscle
Extensor carpi radialis longus muscle
Supinator muscle
Extensor carpi radialis brevis muscle
Extensor carpi ulnaris muscle Extensor- supinatorgroup of muscles
Extensor digitorum muscle andextensor 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 nerveSuperior lateralcutaneous nerveof arm
From radial nerve
Inferior lateralcutaneous nerveof arm
Superficial branch ofradial nerve and dorsaldigital branches
Posterior cutaneous nerve of arm
Posterior cutaneous nerve of forearm
Cutaneous innervation fromradial and axillary nerves
Dorsal digital nerves
48
NEUROANATOMY Sciatic Nerve and Posterior Cutaneous Nerve of Thigh
Posterior cutaneous nerve of thigh (S1, 2, 3)
Inferior cluneal nerves
Perineal branches
Tibial divisionof sciatic nerve
Long head (cut) of biceps femoris muscle
Adductor magnus muscle(also partially suppliedby obturator nerve)
Semitendinosus muscle
Semimembranosus muscle
Tibial nerve
Articular branch
Plantaris muscle
Medial suralcutaneous nerve
Gastrocnemius muscle
Sural nerve
Soleus muscle
Tibial nerve
Medial calcaneal branches
Medial and lateralplantar nerves
Greater sciatic foramen
Sciatic nerve (L4, 5, S1, 2, 3)
Common fibular (peroneal) division of sciatic nerve
Short head of biceps femoris muscle
Cutaneous innervation
Long head (cut)of biceps femorismuscle
Common fibular(peroneal) nerve
Articular branch
Lateral suralcutaneous nerve
Suralcommunicatingbranch
Posteriorcutaneous nerveof thigh
From sciatic nerve
Lateral calcanealbranches
Lateral dorsalcutaneous nerve
Common fibular(peroneal) nerve via lateral suralcutaneous nerve
Medial suralcutaneous nerve
Superficial fibular(peroneal) nerve
Sural nerve
Tibial nervevia medialcalcanealbranches
49
NEUROANATOMYTibial Nerve
Tibial nerve(L4, 5, S1, 2, 3)
Medial suralcutaneous nerve (cut)
Articular branches
Plantaris muscle
Gastrocnemiusmuscle (cut)
Nerve to popliteus muscle
Popliteus muscle
Interosseous nerve of leg
Soleus muscle (cut andpartly retracted)
Flexor digitorumlongus muscle
Tibialis posterior muscle
Flexor hallucis longus muscle
Sural nerve (cut)
Lateral calcaneal branch
Medial calcaneal branch
Flexor retinaculum (cut)
Lateral dorsalcutaneous nerve
Common fibular (peroneal) nerve
Lateral sural cutaneous nerve (cut)
Medial calcaneal branches(S1, 2)
Medialplantar nerve(L4, 5)
Lateral plantar nerve(S1, 2)
Fromtibial nerve
Saphenous nerve(L3, 4)
Sural nerve (S1, 2) via lateral calcaneal and lateral dorsalcutaneous branches
Cutaneous innervation of sole
Flexor retinaculum(cut)
Tibialnerve
Medialcalcanealbranch
Medial plantarnerve
Flexor digitorumbrevis muscleand nerve
Abductor hallucismuscle and nerve
Flexor hallucisbrevis muscleand nerve
1st lumbricalmuscle andnerve
Commonplantardigital nerves
Properplantardigitalnerves
Lateral calcaneal branch of sural nerve
Lateral plantarnerve
Quadratus plantaemuscle and nerve
Nerve to abductor digiti minimi muscle
Abductor digitiminimi muscle
Deep branch to interosseousmuscles, 2nd, 3rd and 4thlumbrical musclesandAdductor hallucis muscle
Superficial branch to4th interosseousmuscleandFlexor digiti minimibrevis muscle
Common andProper plantardigital nerves
Note: Articular branches not shown
Articular branch
50
NEUROANATOMY Common Fibular (Peroneal) Nerve
Common fibular (peroneal) nerve (phantom)
Biceps femoris tendon
Common fibular (peroneal) nerve (L4, 5, S1, 2)
Head of fibula
Fibularis (peroneus) longus muscle (cut)
Superficial fibular(peroneal) nerve
Branches of lateralsural cutaneous nerve
Fibularis (peroneus) longus muscle
Fibularis (peroneus) brevis muscle
Medial dorsal cutaneous nerve
Intermediate dorsalcutaneous nerve
Inferior extensorretinaculum (partially cut)
Lateral dorsal cutaneous nerve(branch of sural nerve)
Dorsal digital nerves
Lateral sural cutaneous nerve (phantom)
Articular branches
Recurrent articular nerve
Extensor digitorum longus muscle (cut)
Deep fibular (peroneal) nerve
Tibialis anterior muscle
Cutaneous innervation
Extensor digitorumlongus muscle
Extensor hallucislongus muscle
Lateral sural cutaneous nerve
Superficial fibular (peroneal) nerve
Lateral branch ofdeep fibular (peroneal) nerve toExtensor hallucis brevisandExtensor digitorum brevismuscles
Medial branch ofdeep fibular(peroneal) nerve
Deepfibular(peroneal)nerve
Sural nervevia lateral dorsalcutaneous branch
Part 2 Neurophysiology
Organization of the Brain: Cerebrum. . . . . . . 52
Organization of the Brain: Cell Types. . . . . . . 53
Blood-Brain Barrier . . . . . . . . . . . . . . . . . . . . . 54
Synaptic Transmission: Morphology of Synapses . . . . . . . . . . . . . . . 55
Synaptic Transmission: Neuromuscular Junction . . . . . . . . . . . . . . . 56
Synaptic Transmission: Visceral Efferent Endings . . . . . . . . . . . . . . . 57
Synaptic Transmission: Inhibitory Mechanisms . . . . . . . . . . . . . . . . 58
Synaptic Transmission: Chemical Synaptic Transmission . . . . . . . . . 59
Synaptic Transmission: 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
Hypothalamus . . . . . . . . . . . . . . . . . . . . . . . . . 68
Limbic System . . . . . . . . . . . . . . . . . . . . . . . . . 69
The Cerebral Cortex . . . . . . . . . . . . . . . . . . . . 70
Descending Motor Pathways . . . . . . . . . . . . . 71
Cerebellum: Afferent Pathways. . . . . . . . . . . . 72
Cerebellum: Efferent Pathways . . . . . . . . . . . . 73
Cutaneous Sensory Receptors . . . . . . . . . . . . . 74
Cutaneous Receptors: Pacinian Corpuscle. . . . . . . . . . . . . . . . . . . . 75
Proprioception and Reflex Pathways: I . . . . . . 76
Proprioception and Reflex Pathways: II . . . . . 77
Proprioception and Reflex Pathways: III . . . . 78
Proprioception and Reflex Pathways: IV. . . . . 79
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
Olfactory System: Receptors . . . . . . . . . . . . . . 91
Olfactory System: Pathway . . . . . . . . . . . . . . . 92
52
NEUROPHYSIOLOGY Organization of the Brain: Cerebrum
Central sulcus (Rolando)
Precentral gyrus
Postcentral gyrus
Postcentral sulcus
Superior parietal lobule
Inferior parietal lobule Supramarginal gyrus Angular gyrus
Parietooccipitalsulcus
Occipital pole
Calcarine sulcus
Inferior temporal gyrus
Middle temporal gyrus
Superior temporal gyrusTemporal pole
Lateral sulcus(Sylvius)
Frontal pole
Precentral sulcus
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 andmotor processing. In general, the frontal lobe processes motor,visual, speech, and personality modalities. The parietal lobeprocesses sensory information; the temporal lobe, auditory andmemory modalities; and the occipital lobe, vision. The cerebellum
coordinates smooth motor activities and processes muscle position.The brainstem (medulla, pons, midbrain) conveys motor and sensoryinformation and mediates important autonomic functions. The spinalcord receives sensory input from the body and conveys somatic andautonomic motor information to peripheral targets (muscles, viscera).
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53
NEUROPHYSIOLOGYOrganization of the Brain: Cell Types
Red:Blue:
Purple:Gray:
Motor neuronSensory neuronInterneuronGlial andneurilemmal cellsand myelin
Multipolar (pyramidal)cell of cerebralmotor cortex
Astrocyte
Multipolar somaticmotor cell of nucleiof cranial nn.
Multipolar cellof lower brain motor centers
Oligodendrocyte
Corticospinal(pyramidal) fiber
Axodendritic ending
Axosomatic ending
Axoaxonic ending
Multipolar somaticmotor cell ofanterior hornof spinal cord
Collateral
Renshaw interneuron(feedback)
Myelinated somatic motorfiber of spinal nerve
Myelin sheath
Motor endplate withSchwann cell cap
Striated(voluntary)muscle
Striated(somatic)muscle
Motorendplate
Interneurons
Interneuron
Astrocyte
Bipolar cell of cranial n.
Unipolar cell ofsensory ganglia ofcranial nn.
Satellite cells
Schwann cell
Free nerve endings(unmyelinated fibers)
Encapsulated ending
Specialized ending
Muscle spindle
Unipolar sensory cellof dorsal spinalroot ganglion
Satellite cells
Myelinated afferentfiber of spinal nerve
Myelin sheath
Schwann cells
Unmyelinated fibers
Free nerve endings
Encapsulated ending
Muscle spindle
Autonomic preganglionic(sympathetic or para-sympathetic) nerve fiber
Myelin sheath
Autonomic postganglionicneuron of sympathetic orparasympathetic ganglion
Satellite cells
Unmyelinated nerve fiber
Schwann cells
Beadedvaricositiesand endings onsmooth muscleand gland cells
Endings oncardiac muscleor nodal cells
Multipolar visceralmotor (autonomic)cell of spinal cord
Blood vessel
Note: Cerebellar cellsnot shown here
FIGURE 2.2 ORGANIZATION OF THE BRAIN: CELL TYPES•Neurons form the functional cellular units responsible for communication, and throughout the nervous system, they arecharacterized by their distinctive size and shapes (e.g., bipolar,unipolar, multipolar). Supporting cells include the neuroglia
(e.g., astrocytes, oligodendrocytes), satellite cells, and other spe-cialized cells that optimize neuronal function, provide mainte-nance functions, or protect the nervous system.
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NEUROPHYSIOLOGY Blood-Brain Barrier
Basementmembrane
Cellmembrane
Cytoplasm
Tightjunctionproteins
Astrocytefoot processes
Astrocyte
Capillaryendothelial
cell
Tightjunction
Capillarylumen
Redbloodcell
FIGURE 2.3 BLOOD-BRAIN BARRIER•The blood-brain barrier (BBB) is the cellular interface between theblood and the central nervous system (CNS; brain and spinal cord).It serves to maintain the interstitial fluid environment to ensureoptimal functionality of the neurons. This barrier consists of thecapillary endothelial cells with an elaborate network of tight junc-tions and astrocytic foot processes that abut the endothelium andits basement membrane. The movement of large molecules and
other substances (including many drugs) from the blood to theinterstitial space of the CNS is restricted by the BBB. CNS endothe-lial cells also exhibit a low level of pinocytotic activity across thecell, so specific carrier systems for the transport of essential sub-strates of energy and amino acid metabolism are characteristic ofthese cells. The astrocytes help transfer important metabolites fromthe blood to the neurons and also remove excess K� and neuro-transmitters from the interstitial fluid.
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NEUROPHYSIOLOGYSynaptic Transmission: Morphology of Synapses
FIGURE 2.4 MORPHOLOGY OF SYNAPSES•Neurons communicate with each other and with effector targets atspecialized regions called synapses. The top figure shows a typicalmotor neuron that receives numerous synaptic contacts on its cellbody and associated dendrites. Incoming axons lose their myelinsheaths, exhibit extensive branching, and terminate as synapticboutons (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 trans-mitters into the synaptic cleft, and then bind to receptors situatedin the postsynaptic membrane. This synaptic transmission results inexcitatory, inhibitory, or modulatory effects on the target cell.
Dendrite
Node Axon
Myelin sheathDendrites
Axolemma
Mitochondria
Postsynaptic cell
Enlarged sectionof bouton
Axon (axoplasm)
Glial process
Synaptic vesicles
Synaptic cleft
Presynaptic membrane (densely staining)
Postsynaptic membrane(densely staining)
Numerous boutons (synaptic knobs) of presynaptic neurons terminating on a motor neuron and its dendrites
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NEUROPHYSIOLOGY Synaptic Transmission: Neuromuscular Junction
Structure of Neuromuscular Junction
Active zone
Schwann cell process
Acetylcholinereceptor sites
Myofibrils
Synaptic cleft
Postsynapticmembrane
Junctional fold
Sarcoplasm
Acetylcholine receptor sites
Myelin sheath
Neurilemma
Axoplasm
Schwann cell
Mitochondria
Basement membrane
Nucleus of Schwann cell
Presynaptic membrane
Active zone
Synaptic vesicles
Synaptic trough
Basement membrane
Sarcolemma
Nucleus ofmuscle cell
FIGURE 2.5 STRUCTURE OF THE NEUROMUSCULAR JUNCTION•Motor axons that synapse on skeletal muscle form expanded termi-nals called neuromuscular junctions (motor endplates). The motoraxon loses its myelin sheath and expands into a Schwanncell–invested synaptic terminal that resides within a trough in themuscle fiber. Acetylcholine-containing synaptic vesicles accumu-late adjacent to the presynaptic membrane and, when appropri-
ately stimulated, release their neurotransmitter into the synapticcleft. The transmitter then binds to receptors that mediate depolar-ization of the muscle sarcolemma and initiate a muscle actionpotential. A single muscle fiber has only one neuromuscular junc-tion, but a motor axon can innervate multiple muscle fibers.
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NEUROPHYSIOLOGYSynaptic Transmission: Visceral Efferent Endings
FIGURE 2.6 VISCERAL EFFERENT ENDINGS•Neuronal efferent endings on smooth muscle (A) and glands (Band C) exhibit unique endings unlike the presynaptic and postsy-naptic terminals observed in neuronal and neuromuscular junc-tion synapses. Rather, neurotransmitter substances are releasedinto interstitial spaces (A and B) or into the bloodstream (C, neu-
rosecretion) from expanded nerve terminal endings. This arrange-ment allows for the stimulation of numerous target cells over awide area. Not all smooth muscle cells are innervated. They areconnected to adjacent cells by gap junctions and can thereforecontract together with the innervated cells.
Pituicyte processes
� � � � � � �� � � � � � � � � � � � � �
Visceral Efferent Endings
A. Smooth muscle
Smooth muscle cells (cut)
Schwann cell cap enclosingnerve axons
Schwann cell cap
Smooth muscle cells
Varicosities
Terminal endings
B. Gland (submandibular)
Sympathetic terminalending
Varicosity
Schwanncell cap
Schwann cellcap enclosingnerve axons
Mucous cells
Varicosity
Parasympatheticterminal ending
Serous cells Schwann cellcap enclosingnerve axons
C. Neurosecretory(posterior pituitary)
Axon Axon
Fibroblast
Neurosecretoryvesicles
Collagen space
Basement membrane
Mast cell
Endothelium
Capillary
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NEUROPHYSIOLOGY
FIGURE 2.7 SYNAPTIC INHIBITORY MECHANISMS•Inhibitory synapses modulate neuronal activity. Illustrated here is presynaptic inhibition (left panel) and postsynaptic inhibition (rightpanel) at a motor neuron.
Synaptic Transmission: Inhibitory Mechanisms
A. Only E fires 90-mV spike in E terminal
B. Only I fires Long-lasting partial depolarization in E terminal
EPSP inmotor neuron
No response inmotor neuron
C. I fires before E Partial depolarization of E terminal reduces spike to 80 mV, thus releasing less transmitter substance
Smaller EPSP inmotor neuron
E(Excitatoryfiber)
E(Excitatoryfiber)
I(Inhibitoryfiber)
I(Inhibitoryfiber)
Motorneuron
Motorneuron
AxonAxon
�20
�70�60
�70
�60
�70
�20
�70�60
�70
�70
�60�70
mV
mV
80 mV
90 mV A′. Only E fires
EPSP in motor neuron
�70
�80
B′. Only I fires
Motor neuron hyper- polarized
�70
�60
�80
C′. I fires before E
Depolariza- tion of motor neuron less than if only E fires
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NEUROPHYSIOLOGYSynaptic Transmission: Chemical Synaptic Transmission
FIGURE 2.8 CHEMICAL SYNAPTIC TRANSMISSION•Chemical synaptic transmission between neurons may be excita-tory or inhibitory. During excitation (left column), a net increase inthe inward flow of Na� compared with the outward flow of K�
results in a depolarizing potential change (excitatory postsynapticpotential [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 potentialaway from threshold (hyperpolarization) and decreases the proba-bility that the neuron will reach threshold (inhibitory postsynapticpotential [IPSP]) for an action potential.
�������������� Excitatory Inhibitory
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 postsy-naptic cell than K� moves out, due to great-er electrochemical gradient
Resultant net ionic current flow is in a direc-tion that tends to depolarize postsynaptic cell. If depolarization reaches firing threshold, an impulse is generated in postsynaptic cell
At inhibitory synapse, transmitter substance re-leased 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
Resultant ionic current flow is in direction that tends to hyperpolarize postsynaptic cell. This makes depolariza-tion by excitatory synapses more difficult—more depolari-zation is required to reach threshold
Synapticvesicles
in synapticbouton
Presynapticmembrane
Transmittersubstances
Synaptic cleft
Postsynapticmembrane
Synaptic bouton
Cl�K�
�
�
�
��
�
�
�
�
��
�
�
��
�
�
�
�
�Na�
Current
Potential
Po
ten
tia
l (m
V)
�700 4 8
msec
Current flow and potential change
12 16
�65
Current
Potential
Po
ten
tia
l (m
V) �70
0 4 8msec
Current flow and potential change
12 16
�75
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NEUROPHYSIOLOGY Synaptic Transmission: Temporal and Spatial Summation
FIGURE 2.9 TEMPORAL AND SPATIAL SUMMATION •Neurons receive multiple excitatory and inhibitory inputs. Tempo-ral summation occurs when a series of subthreshold impulses inone excitatory fiber produces an action potential in the postsynap-tic cell (panel C). Spatial summation occurs when subthresholdimpulses from two or more different fibers trigger an action poten-
tial (panel D). Both temporal and spatial summation can be modu-lated by simultaneous inhibitory input (panel E). Inhibitory andexcitatory neurons use a wide variety of neurotransmitters, some ofwhich are summarized here.
Axon
mV
–70
Axon
mV
–70
Axon
mV
–70
Axon
mV
–70
Axon
mV
–70
Axon
mV
–70
Temporal and Spatial Summationof Excitation and Inhibition
Excitatory fibers
Inhibitory fibers
Excitatory fibers
Inhibitory fibers
Excitatory fibers
Inhibitory fibers
Excitatory fibers
Inhibitory fibers
Excitatory fibers
Inhibitory fibers
Excitatory 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
C. Temporal excitatory summation: a series of impulses in one excitatory fiber together produce a suprathreshold depolarization that triggers an action potential
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
D. Spatial excitatory summation: impulses in two excitatory fibers cause two synaptic depolarizations that together reach firing threshold triggering an action potential
Transmitter LocationAcetylcholine Neuromuscular junction, autonomic end-
ings and ganglia, CNSBiogenic amines
Norepinephrine Sympathetic endings, CNSDopamine CNSSerotonin CNS, GI tract
Amino acids�-Aminobutyric CNSacid (GABA)Glutamate CNS
PurinesAdenosine CNSAdenosine CNStriphosphate (ATP)
Transmitter LocationGas
Nitric oxide CNS, GI tractPeptides
�-Endorphins CNS, GI tractEnkephalins CNSAntidiuretic CNS (hypothalamus/posterior hormone pituitary)Pituitary-releasing CNS (hypothalamus/anterior hormones pituitary)Somatostatin CNS, GI tractNeuropeptide Y CNSVasoactive intestinal peptide CNS, GI tract
CHART 2.1 SUMMARY OF SOME NEUROTRANSMITTERS AND WHERE WITHIN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM THEY ARE FOUND
CNS, Central nervous system; GI, gastrointestinal.
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NEUROPHYSIOLOGY
FIGURE 2.10 BRAIN VENTRICLES AND CSF COMPOSITION•CSF circulates through the four brain ventricles (two lateral ventri-cles and a third and fourth ventricle) and in the subarachnoidspace surrounding the brain and spinal cord. The electrolyte com-position 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 inblood PCO2 to cause changes in CSF pH, which in turn regulatesthe rate of respiration (see Chapter 5).
Cerebrospinal Fluid (CSF): Brain Ventricles and CSF Composition
Left lateral phantom view
Right lateral ventricle
Left interventricularforamen (Monro)
3rd ventricle
Frontal (anterior) horn
Central part
Temporal (inferior) horn
Occipital (posterior) horn
Leftlateralventricle
Cerebral aqueduct (Sylvius)
4th ventricle
Left lateral recess
Central canal of spinal cord
Median aperture(foramen of Magendie)
Left lateral aperture(foramen of Luschka)
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CSF Blood PlasmaNa� (mEq/L) 140–145 135–147K� (mEq/L) 3 3.5–5.0Cl− (mEq/L) 115–120 95–105HCO3
− (mEq/L) 20 22–28Glucose (mg/dL) 50–75 70–110Protein (g/dL) 0.05–0.07 6.0–7.8pH 7.3 7.35–7.45
CHART 2.2 CSF COMPOSITION
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NEUROPHYSIOLOGY Cerebrospinal Fluid (CSF): Circulation of CSF
FIGURE 2.11 CIRCULATION OF CEREBROSPINAL FLUID•CSF circulates through the four brain ventricles (two lateral ventri-cles and a third and fourth ventricle) and in the subarachnoidspace surrounding the brain and spinal cord. Most of the CSF is
reabsorbed into the venous system through the arachnoid granula-tions and through the walls of the capillaries of the central nervoussystem and pia mater.
Interventricularforamen (Monro)
Arachnoid granulations
Superior sagittal sinus
Subarachnoid space
Median aperture(foramen of Magendie)
Central canal of spinal cord
Subarachnoid space
Arachnoid
Arachnoid
Dura mater
Cistern of corpus callosum
Choroid plexus of lateralventricle (phantom)
Dura mater
Choroid plexus of 4th ventricle
Lateral aperture (foramen of Luschka)
Cerebral aqueduct (Sylvius)
Choroid plexus of 3rd ventricle
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NEUROPHYSIOLOGY
FIGURE 2.12 SPINAL CORD AND VENTRAL RAMI IN SITU•The spinal cord gives rise to 31 pairs of spinal nerves that distributesegmentally to the body. These nerves are organized into plexusesthat distribute to the neck (cervical plexus), upper limb (brachialplexus), and pelvis and lower limb (lumbosacral plexus). Motor
fibers of these spinal nerves innervate skeletal muscle, and sensoryfibers convey information back to the central nervous system fromthe skin, skeletal muscles, and joints.
Spinal Cord: Ventral Rami
Lumbar plexus
L5 vertebra
Sacral plexus
Sciatic nerve
Coccyx
Filamentsof spinalnerve roots(T7 and T8)
L1vertebra
Coccygeal nerve
Base of skull
C1 spinal nerve
C8 spinal nerve
T1 spinal nerve
1st rib
12th rib
Intercostalnerves
T12 spinalnerve
Conus medullaris
L1 spinal nerve
Cauda equina
S1 spinal nerve
Sacrum (cut away)
Termination ofdural sac
C1 vertebra (atlas)
Cervical plexus
Brachial plexus
Spinal dura mater
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NEUROPHYSIOLOGY
FIGURE 2.13 SPINAL MEMBRANES AND NERVE ROOTS•The spinal cord gives rise to 31 pairs of spinal nerves that distributesegmentally to the body. Motor fibers of these spinal nerves inner-vate skeletal muscle, and sensory fibers convey information backto the central nervous system from the skin, skeletal muscles, andjoints.
The spinal cord is ensheathed in three meningeal coverings: theouter, tough dura mater; the arachnoid mater; and the pia mater,which intimately ensheaths the cord itself. CSF bathes the cord andis found in the subarachnoid space.
Arachnoid mater
Posterior view
Membranes removed: anterior view(greatly magnified)
Gray and white ramicommunicantes
Gray matterWhite matter
Subarachnoid space
Pia mater overlying spinal cord
Filaments of dorsal root
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
Filaments of dorsal root
Dorsal root of spinal nerve
Filaments of ventral root
Spinal sensory (dorsalroot) ganglion
Dorsal ramus ofspinal nerve
Ventral ramus ofspinal nerve
Ventral root of spinal nerve
Spinal nerve
Spinal Cord: Membranes and Nerve Roots
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NEUROPHYSIOLOGYPeripheral Nervous System
FIGURE 2.14 PERIPHERAL NERVOUS SYSTEM•The peripheral nervous system (PNS) consists of all of the neuralelements outside of the CNS (brain and spinal cord) and providesthe connections between the CNS and all other body organ sys-tems. The PNS consists of somatic and autonomic components. Thesomatic 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 bothmotor and sensory axons. Cell bodies of the motor neurons arefound in the anterior horn gray matter, whereas the cell bodies ofsensory neurons are located in the dorsal root ganglia.
Sensory neuron cell body
Dorsal root ganglion
Dorsal root
Posterior horn
Anterior horn
Motor neuron cell body
Motor neuron
Neuromuscularjunction
Muscle
Skin
Sensory neuron
Ventral root
Peripheral nerve
Axon
Myelin sheath
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66
NEUROPHYSIOLOGY Autonomic Nervous System: Schema
FIGURE 2.15 AUTONOMIC NERVOUS SYSTEM: SCHEMA•The autonomic nervous system is composed of two divisions: theparasympathetic division derived from four of the cranial nerves (CN III, VII, IX, and X) and the S2-S4 sacral spinal cord levels, and thesympathetic division associated with the thoracic and upper lumbarspinal cord levels (T1-L2). The autonomic nervous system is a two-neuron chain, with the preganglionic neuron arising from the centralnervous system and synapsing on a postganglionic neuron located in
a peripheral autonomic ganglion. Postganglionic axons of the auto-nomic nervous system innervate smooth muscle, cardiac muscle, andglands. Basically, the sympathetic division mobilizes our body (“fightor flight”) while the parasympathetic division regulates digestive andhomeostatic functions. Normally, both divisions work in concert toregulate visceral activity (respiration, cardiovascular function, diges-tion, and associated glandular activity).
Intracranial vesselsCiliary ganglion
EyePterygopalatine ganglion
Lacrimal glandsOtic ganglion
Parotid glands
Sublingual andsubmandibular glands
Peripheral cranialand facial vessels
LarynxTracheaBronchiLungs
Heart
Stomach
Pancreas
Suprarenal glands
Kidneys
Intestines
Descending colon
Sigmoid colon
Urinary bladder
Prostate
External genitalia
Rectum
Submandibular ganglion
Pulmonary plexus
Cardiac plexus
Celiac ganglion
Aorticorenal ganglion
Superior mesenteric
ganglion
Inferior mesenteric
ganglion
Superior hypogastric
plexus
Inferior
hypogastric
plexus
Lumbarsplanchnic
nerves
Splanchnicnerves
GreaterLesserLeast
���
Pelvicsplanchnicnerves
Presynaptic
Postsynaptic
Antidromic
conduction
Presynaptic
Postsynaptic
Sympathetic
fibers
Parasympathetic
fibers
Oculomotor nerve (III)
Facial nerve (VII)
Glossopharyngeal nerve (IX)
Medulla oblongata
Vagus nerve (X)
Sweatgland
Peripheralblood vessel
Arrector (smooth) muscle of hair follicle
Note: Above three structures are shown at only one level but occur at all levels
Note: Blue-shaded areas indicate zones of parasympathetic outflow from CNS
Coccygeal
S5
S4S3
S2
S1
L5
L4
L3
L2
L1
T12
T9
T8
T7
T6
T5T4
T3
T2
T1
C8
C7C6
C5
C4
C3
C2
C1
T11
T10
Gra
yra
mico
mm
un
ica
nte
sG
ray
an
dw
hit
era
mi
com
mu
nic
an
tes
Gra
y ra
mi
com
mu
nic
an
tes
Liver
Gallbladder
Bile ducts
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NEUROPHYSIOLOGYAutonomic Nervous System: Cholinergic and Adrenergic Synapses
FIGURE 2.16 CHOLINERGIC AND ADRENERGIC SYNAPSES: SCHEMA•The autonomic nervous system (ANS) is a two-neuron chain, withthe preganglionic neuron arising from the central nervous systemand synapsing on a postganglionic neuron located in a peripheralautonomic ganglion. Acetylcholine is the neurotransmitter in boththe sympathetic and parasympathetic ganglia. The parasympatheticdivision of the ANS releases acetylcholine at its postganglionicsynapses and is characterized as having cholinergic (C) effects,whereas the sympathetic division releases predominantly noradren-
aline (norepinephrine) at its postganglionic synapses, causingadrenergic (A) effects (except on sweat glands, where acetylcholineis released). Although acetylcholine and noradrenaline are thechief transmitter substances, other neuroactive peptides often arecolocalized with them and include such substances as gamma-aminobutyric acid (GABA), substance P, enkephalins, histamine,glutamic acid, neuropeptide Y, and others.
Somatic fibers
Antidromic conduction
Medullaoblongata
Thoracicpart ofspinal cord
Sacralpart ofspinal cord
Upperlumbarpart ofspinal cord(L1-2 [3])
Cervicalsympatheticganglia
Gray ramuscommunicans
Glossopharyngeal
nerve (IX)
Internal carotid nerve
Vagus nerve (X)
White ramuscommunicans
Celiacganglion
Superiormesentericganglion
Inferiormesenteric ganglion
Pelvic splanchnic nerves
C Cholinergic synapses
A Adrenergic synapses
Parotidgland
LarynxTracheaBronchiLungs
Heart
Striated muscle
Sweat glands
Hair follicles
Peripheral arteries
Visceralarteries
Gastrointestinaltract
Urinary bladder
UrethraProstate
Presynaptic
Postsynaptic
Presynaptic
Postsynaptic
Sympatheticfibers
Parasympatheticfibers
Suprarenalgland
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NEUROPHYSIOLOGY Hypothalamus
FIGURE 2.17 SCHEMATIC RECONSTRUCTION OF THE HYPOTHALAMUS•The hypothalamus, part of the diencephalon, controls a number ofimportant homeostatic systems within the body, including tempera-ture regulation, food intake, water intake, many of the endocrinesystems (see Chapter 8), motivation, and emotional behavior. Itreceives inputs from the reticular formation (sleep/wake cycle
information), the thalamus (pain), the limbic system (emotion, fear,anger, smell), the medulla oblongata (blood pressure and heartrate), and the optic system, and it integrates these inputs for regula-tion of the functions listed.
Anteriorlobe ofpituitary
Optic chiasm
Optic (II)nerve
Olfactorytract
Medialpreopticnucleus
Lateralpreopticnucleus
Lateralventricle
Medial forebrainbundle
Anteriorcommissure
Septumpellucidum
Fornix
Corpus callosum
Fromhippocampalformation
Interthalamicadhesion
Thalamus
Lateralhypothalamic area
Paraventricular nucleus
Anterior hypothalamic area
Dorsal hypothalamic area
Dorsomedial nucleus
Mamillothalamic tract
Posterior area
Periventricularnucleus
Nucleusintercalatus
Fornix
Ventromedialnucleus
Tuberohypophyseal tract
Supraoptic nucleus
Supraopticohypophysealtract
Posterior lobe of pituitary
Oculomotor (III) nerve
Mamillarycomplex
Red nucleusCerebralpeduncle
Dorsallongitudinalfasciculus
Descendinghypothalamicconnections
Pons
Reticularformation
Hypothalamic Area Major Functions*Preoptic and anterior Heat loss center: cutaneous vasodilation and sweatingPosterior Heat conservation center: cutaneous vasoconstriction and shiveringLateral Feeding center: eating behaviorVentromedial Satiety center: inhibits eating behaviorSupraoptic (subfornical organ and organum vasculosum) ADH and oxytocin secretion (sensation of thirst)Paraventricular ADH and oxytocin secretionPeriventricular Releasing hormones for the anterior pituitary
CHART 2.3 MAJOR FUNCTIONS OF THE HYPOTHALAMUS
*Stimulation of the center causes the responses listed.
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NEUROPHYSIOLOGYLimbic System
FIGURE 2.18 HIPPOCAMPUS AND FORNIX•The limbic system includes the hypothalamus and a collection ofinterconnected structures in the telencephalon (cingulate, parahip-pocampal, and subcallosal gyri), as well as the amygdala and hip-
pocampal formation. The limbic system functions in linking emo-tion and motivation (amygdala), learning and memory (hippocam-pal formation), and sexual behavior (hypothalamus).
Genu of corpus callosum
Head of caudate nucleus
Columns of fornix
Body of fornix
Thalamus
Uncus
Crura of fornix
Fimbria of hippocampus
Hippocampus
Commissure of fornix
Splenium of corpus callosum
Lateral ventricle
Amygdaloid bodies
Mamillarybodies
Columnsof fornix
Body of fornix
Commissureof fornix
Crura of fornix
Hippocampuswith fimbria ©
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NEUROPHYSIOLOGY The Cerebral Cortex
FIGURE 2.19 CEREBRAL CORTEX: LOCALIZATION OF FUNCTION AND ASSOCIATION PATHWAYS•The cerebral cortex is organized into functional regions. In addi-tion to specific areas devoted to sensory and motor functions, thereare areas that integrate information from multiple sources. Thecerebral cortex participates in advanced intellectual functions,
including aspects of memory storage and recall, language, highercognitive functions, conscious perception, sensory integration, andplanning/execution of complex motor activity. General corticalareas associated with these functions are illustrated.
Motor controlof speech
Prefrontal;inhibitory controlof behavior;higherintelligence
Premotor; orientation;eye and headmovements
MotorMs IMs II
SensorySm ISm II
MotorMs IMs II
SensorySm ISm III ?
Sensoryanalysis
Visual I
Visual II
Visual III
Language;reading; speech
Auditory I
Auditory II
Olfactory
Cingulate gyrus(emotional behavior)and cingulum
Prefrontal;inhibitory controlof behavior;higherintelligence
Premotor
Visual I
Visual II
Visual III
Corpus callosum
Hippocampal commissure
Anterior commissure
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NEUROPHYSIOLOGY
FIGURE 2.20 CORTICOSPINAL TRACTS•The corticospinal, or pyramidal, tract is the major motor tract thatcontrols voluntary movement of the skeletal muscles, especiallyskilled movements of distal muscles of the limbs. All structuresfrom the cerebral cortex to the anterior horn cells in the spinal
cord constitute the upper portion of the system (upper motor neu-ron). The anterior horn cells and their associated axons constitutethe lower portion of the system (lower motor neuron).
Descending Motor Pathways
Basispedunculi
Hip
Tru
nk
Sh
ou
lde
rE
lbo
wW
rist
Finge
rs
Thumb
Neck
Brow
Eyelid
Nares
Lips
Tongue
Larynx
Knee
Ankle
Toes
Basispontis
Pyramids
Midbrain
Internalcapsule
Motorcortex
Pons
Medulla
Medulla
Spinalcord
Above mid-thoraciclevel
Below mid-thoraciclevel
Decussationof pyramids
Anterior corticospinal tract
Lateral corticospinal tract
Motorendplate
Motorendplate
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
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
Lateral aspect of cerebral cortex to show topographic projection of motor centers on precentral gyrus
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NEUROPHYSIOLOGY
FIGURE 2.21 CEREBELLAR AFFERENT PATHWAYS•The cerebellum plays an important role in coordinating movement. Itreceives sensory information and then influences descending motorpathways to produce fine, smooth, and coordinated motion. Thecerebellum is divided into three general areas: archicerebellum (alsocalled vestibulocerebellum) paleocerebellum (also called spinocere-bellum) and the neocerebellum (also called the cerebrocerebellum).The archicerebellum is primarily involved in controlling posture andbalance, as well as the movement of the head and eyes. It receivesafferent signals from the vestibular apparatus and then sends efferentfibers to the appropriate descending motor pathways. The paleocere-
bellum primarily controls movement of the proximal portions of thelimbs. It receives sensory information on limb position and muscletone and then modifies and coordinates these movements throughefferent pathways to the appropriate descending motor pathways. Theneocerebellum is the largest portion of the cerebellum, and it coordi-nates the movement of the distal portions of the limbs. It receivesinput from the cerebral cortex and thus helps in the planning ofmotor activity (e.g., seeing a pencil and then planning and executingthe movement of the arm and hand to pick it up).
Schema oftheoretical“unfolding”of cerebellarsurface inderivation ofabove diagram
Cortical input
Nucleusreticularistegmentipontis
Pontine nuclei(contralateral)
Spinal input
Inferior olive
Upper partof medullaoblongata
Spinal input
Vestibular nerveand ganglion
Lower partof medulla oblongata
Cortical input
Lateral reticularnucleus
Spinal input
Cervical part of spinal cord
Motor interneuron
Rostralspinocerebellartract
Spinal border cells
Motor interneuron
Lumbar partof spinal cord
Clarke’s column
Ventral spino-cerebellar tract
Superior cerebellar peduncle
Middle cerebellar peduncle
To contralateral cerebellar cortex
Primary fissure
LegArm
Face
To nodule and flocculus
Inferior cerebellar peduncleVestibularnuclei
Reticulocerebellartract
Cuneocerebellartract
Gracile nucleus
Main cuneatenucleus (relayfor cutaneousinformation)
External cuneate nucleus(relay for proprioceptive information)
From skin (touchand pressure)
From muscle (spindlesand Golgi tendon organs)
From skin anddeep tissues(pain and Golgitendon organs)
From skin (touchand pressure)and from muscle(spindles andGolgi tendonorgans)
Dorsal spinocerebellar tract
Functional Subdivisions of Cerebellum
Neocerebellum(pontocerebellum)
Middle vermisHemisphere
Paleocerebellum(spinocerebellum)
UvulaPyramidVermis
Archi-cerebellum(vestibulo-cerebellum)
LingulaFlocculusNodule
2nd spinal projectionarea (gracilelobule)
Leg zoneArm zoneFace zone
Hemisphere Vermis
Lateralpart
Inter-mediate part Anterior lobe
Primaryfissure
Middle(posterior)lobe
Posterolateralfissure
Flocculo-nodular lobe
Cerebellum: Afferent Pathways
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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 involvedin controlling posture and balance and movement of the head andeyes. It sends efferent fibers to the appropriate descending motorpathways. The paleocerebellum primarily controls movement of
the proximal portions of the limbs. It modifies and coordinatesthese movements through efferent pathways to the appropriatedescending motor pathways. The neocerebellum coordinates themovement of the distal portions of the limbs. It helps in the plan-ning of motor activity (e.g., seeing a pencil and then planning andexecuting the movement of the arm and hand to pick it up).
Cerebellum: Efferent Pathways
SectionA–Bviewedfrombelow
SectionB–Cviewedfrom above
Planes ofsection:red arrowsindicatedirectionof viewPontomedullary reticular formation
Medulla oblongata
Lateral reticular nucleus
Inferior olive
Inferior cerebellarpeduncle
Vestibularnuclei
Cerebellarcortex
Dentate nucleus
Emboliform nucleus
Globose nuclei
Fastigial nucleus
Red nucleus
Mesencephalic reticular formation
Ventral anterior andventral lateral nuclei of thalamus
Inhibitoryendings ofPurkinjecells
Excitatoryendings
Motor andpremotor cerebralcortex
Internal capsule
Cerebral peduncle
Decussation of superiorcerebellar peduncles
Descending fibers fromsuperior cerebellarpeduncles
Hook bundle of Russell
A
B
C
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FIGURE 2.23 SKIN AND CUTANEOUS RECEPTORS•Cutaneous receptors respond to touch (mechanoreceptors), pain(nociceptors), and temperature (thermoreceptors). Several differenttypes of receptors are present in skin. Meissner’s corpuscles havesmall receptive fields and respond best to stimuli that are appliedat low frequency (i.e., flutter). The pacinian corpuscles are locatedin the subcutaneous tissue and have large receptive fields. They
respond best to high-frequency stimulation (i.e., vibration).Merkel’s discs have small receptive fields and respond to touch andpressure (i.e., indenting the skin). Ruffini’s corpuscles have largereceptive fields, and they also respond to touch and pressure. Freenerve endings respond to pain and temperature.
Subcutaneousartery and vein
Cutaneousnerve
Motor(autonomic)
nerve
Skin ligaments(retinacula cutis)
Elastic fibers
Sensory nerves
Vein
Artery
Paciniancorpuscle
Papilla of hair follicle
Hair matrix
Sweat gland
Hair cuticle
Ha
ir f
olli
cle
Connectivetissue layer
Glassymembrane
External sheath
Internal sheath
Cuticle
Sebaceous gland
Arrector muscle of hair
Melanocyte
Hair shaft
Free nerve endings Meissner’s corpuscle
Pore of sweat gland
Stratum corneumStratumlucidum Stratum
granulosum
Stratumspinosum
Stratumbasale
Dermalpapilla(of papillarylayer)
Reticularlayer
Ep
ide
rmis
De
rmis
Su
bc
uta
ne
ou
s tissue
Cross section
Detail of free nerve ending
Detail of Merkel’s disc
Mitochondria
Basalepithelialcells
Cytoplasmicprotrusion
Lobulatednucleus
Granulatedvesicles
Expandedaxon terminal
Schwanncell
Desmosomes
Merkelcell
Schwann cells
Axon
Basement membrane
Axon terminal
Mitochondrion
Schwann cell
Cutaneous Sensory Receptors
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NEUROPHYSIOLOGY
FIGURE 2.24 PACINIAN CORPUSCLE•Pacinian corpuscles are mechanoreceptors that transduce mechani-cal forces (displacement, pressure, vibration) into action potentialsthat are conveyed centrally by afferent nerve fibers. As the vis-coelastic lamellae are displaced, the unmyelinated axon terminalmembrane’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 amechanical force while the concentric lamellae dissipate slowchanges in pressure. In the absence of the capsule, the generatorpotential decays slowly and yields only a single action potential.
Cutaneous Receptors: Pacinian Corpuscle
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Pressure Na+
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)
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
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
If resultant depolarization at 1st node is great enough to reach threshold, an action potential appears which is propagated along nerve fiber
Pacinian Corpuscleas Pressure Transducer
1st node
Myelin sheath
Lamellated capsule
Central core
Unmyelinated axon terminal
To amplifierPressure
Generator potential
Action potential
To amplifier
Pressure
Generator potential
Action potential
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NEUROPHYSIOLOGY
FIGURE 2.25 PROPRIOCEPTION: SPINAL EFFECTOR MECHANISM•Position sense or proprioception involves input from cutaneousmechanoreceptors, Golgi tendon organs, and muscle spindles(middle figure of upper panel). Both monosynaptic reflex pathways(middle figure of upper panel) and polysynaptic pathways involv-ing several spinal cord segments (top and bottom figures of upper
panel) initiate muscle contraction reflexes. The lower panel showsthe somatotopic distribution of the motor neuron cell bodies in theventral horn of the spinal cord that innervate limb muscles (flexorand extensor muscles of upper and lower limbs).
Proprioception and Reflex Pathways: I
In cervicalenlargement ofspinal cord
In lumbarenlargementof spinal cord
Proprioceptive fibers
Dorsal horn interneuron
Flexor reflex interneuron
Dorsal horn interneuron
Dorsal horninterneuron
Fromcutaneousreceptor
Frommusclespindle
Dorsal rootganglion
Ventral root
� motor axon
From motor neuron
To motor neuron
To motor neuron
Schematic representation of motor neurons
Spinal Effector Mechanisms
Flex ors
Extensors
Fle xors
Exte nsors
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Detail ofmuscle spindle
Efferent fibers
Afferent fibers
A� fibers fromGolgi-typeendings
A� fibers frompaciniform corpusclesand Ruffini terminals
A� and C fibersfrom free nerveendings
Extrafusalmuscle fiber
Intrafusalmuscle fibers
Sheath
Lymph space
Nuclear bag fiber
Nuclear chain fiber
Ib (A�) fibers from Golgi tendonorgans (proprioception)
Alpha motor neuron to extrafusalmuscle fiber end plates
Gamma motor neuron to intrafusalmuscle fiber and plates
II (A�) fiber from flower spray endings
Ia (A�) fiber from annulospiral endings
IV (unmyelinated) fibers from freenerve endings (pain)
III (A�) fibers from free nerve endingsand from some specialized endings(pain and some pressure)
II (A�) fibers from flower sprayendings (proprioception);from paciniform corpuscles (pressure)and pacinian corpuscles (pressure)
Ia (A�) fibers from annulospiralendings (proprioception)
Gamma motor neurons to intrafusalstriated muscle end plates
Alpha motor neurons to extrafusalstriated muscle end plates
Proprioception and Reflex Pathways: II
FIGURE 2.26 MUSCLE AND JOINT RECEPTORS•Muscle spindles and Golgi tendon organs send afferent signals tothe brain to convey the position of limbs and help coordinate mus-cle movement. Muscle spindles convey information on muscle ten-sion and contraction (dynamic forces) and muscle length (staticforces). 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 bagand nuclear chain fibers. If the muscle tension is too great (e.g.,overstretching of muscle or too heavy a load), activation of theGolgi tendon organ causes a reflex relaxation of the muscle.
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NEUROPHYSIOLOGY
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 Band C).
Alpha andgammaactivationfrom brain
Alpha activationfrom brain
Inhibitory interneuron
Golgitendonorgan
Golgitendonorgan
Golgitendonorgan
Extrafusal muscle fiber
Intrafusal muscle fiber
Alpha motor neurons ���
Gamma motor neurons
Ib fibers
Ia fibers ����
Extrafusal muscle fiber
Intrafusal muscle fiber
Alpha motor neurons ��
Gamma motor neurons
Ib fibers ��
Ia fibers
Extrafusal muscle fiber
Intrafusal muscle fiber
Alpha motor neurons ����
Gamma motor neurons ����
Ib fibers ���
Ia fibers ����
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
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
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
Proprioception and Reflex Pathways: III
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NEUROPHYSIOLOGYProprioception and Reflex Pathways: IV
FIGURE 2.28 SPINAL REFLEX PATHWAYS•Summary of the spinal reflex pathways.
Nociceptive fibers
Ipsilateralflexion
Inhibitory synapse
Excitatory synapse
Excitatory synapse
Inhibitory synapse
To extensors
To flexors
To extensors
To flexors
A. Afferent inhibitionB. Stretch reflex
(reciprocal inhibition)
C. Recurrent inhibition
E. Flexor withdrawal reflex
D. Tendon organ reflex
Contralateralextension
From extensor spindlereceptor (Ia, II fibers)
From flexor spindle(Ia, II fibers)
Axoaxonic presynapticinhibitory synapse
To extensors
From extensor spindlereceptor (Ia, II fibers)
Axosomatic oraxodendriticinhibitorysynapse
Excitatorysynapse
To extensors
To flexors
To extensors
To flexors
Renshaw cells
Collaterals
To synergisticmuscles
From extensor tendonorgan (Ib fibers)
Inhibitory synapse
Excitatory synapse
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NEUROPHYSIOLOGY
FIGURE 2.29 SOMESTHETIC SYSTEM OF THE BODY•Pain, temperature, and pressure sensations below the head ulti-mately are conveyed to the primary somatosensory cortex (post-central gyrus) by the anterolateral system (spinothalamic and spin-oreticular tracts). The fasciculus gracilis and cuneatus of the spinallemniscal system convey proprioceptive, vibratory, and tactile sen-
sations to the thalamus (ventral posterolateral nucleus), whereasthe lateral cervical system mediates some touch, vibratory, andproprioceptive sensations (blue and purple lines show these dualpathways). Ultimately, these fibers ascend as parallel pathways tothe thalamus, synapse, and ascend to the cortex.
Cerebral cortex:postcentral gyrus
Posterior limb ofinternal capsule
Ventral posterolateral(VPL) nucleus ofthalamus
Medial lemniscus
Gracile nucleus
Cuneate nucleus
Fasciculus gracilis
Fasciculus cuneatus
Dorsal (posterior) spinalroot ganglion
Proprioception,position Large
myelinatedfibers
Touch,pressure,vibration
Pain,temperature
Smallmyelinatedand unmyelin-ated fibers
Lateral cervical nucleus
Spinocervical tract
Lumbar partof spinal cord
Ventral (anterior)spinothalamic tract:touch, pressure
Lateralspinothalamic tract:pain, temperature
Cervical partof spinal cord
Reticular formation
Lower part ofmedulla oblongata
Spinothalamic tract
Mesencephalon(cerebral peduncles)
Sensory Pathways: I
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FIGURE 2.30 SOMESTHETIC SYSTEM OF THE HEAD•Nerve cells bodies for touch, pressure, pain, and temperature inthe head are in the trigeminal (semilunar) ganglion of the trigemi-nal (CN V) nerve (blue and red lines in figure). Neuronal cell bod-ies mediating proprioception reside in the mesencephalic nucleus
of CN V (purple fibers). Most relay neurons project to the con-tralateral VPM nucleus of the thalamus and thence to the postcen-tral gyrus of the cerebral cortex, where they are somatotopicallyrepresented.
Sensory Pathways: II
Facial (VII) n.
Vagus (X) n.
Dorsolateral fasciculus (of Lissauer)
Substantia gelatinosa (Iamina II)
Cervicalpart ofspinalcord
Spinaltrigeminalnucleus
Spinaltrigeminaltract
Medullaryreticularformation
Pons
Dorsal trigeminal lemniscus
Trigeminal mesencephalic nucleus
Trigeminal motor nucleus
Principal sensory trigeminal nucleus
Touch, pressure
Pain, temperature
Proprioception
Trigeminal (semilunar) ganglion
Ophthalmic n.
Maxillary n.
Sensory rootandMotor root of mandibular n.
Pontinereticularformation
Ventraltrigeminallemniscus
Midbrain(cerebralpeduncles)
Cerebral cortex:postcentral gyrus
Ventral posteromedial (VPM)nucleus of thalamus
Internal capsule
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FIGURE 2.31 DERMATOMES•Sensory information below the head is localized to specific areasof the body, which reflect the distribution of peripheral sensoryfibers that convey sensations to the spinal cord through the dorsalroots (sensory nerve cell bodies reside in the corresponding dorsalroot ganglion). The area of skin subserved by afferent fibers of one
dorsal root is called a dermatome. This figure shows the der-matome segments and lists key dermatome levels used by clini-cians. Variability and overlap occur, so all dermatome segmentsare only approximations.
Levels of principal dermatomes
C5C5, 6, 7C8, T1C6C6, 7, 8C8T4
ClaviclesLateral parts of upper limbsMedial sides of upper limbsThumbHandRing and little fingersLevel of nipples
T10T12L1, 2, 3, 4 L4, 5, S1L4S1, 2, L5S1S2, 3, 4
Level of umbilicusInguinal or groin regionsAnterior and inner surfaces of lower limbsFootMedial side of great toePosterior and outer surfaces of lower limbsLateral margin of foot and little toePerineum
C7C8
C2
C3
C4C5C6
T1T2T3T4T5T6T7T8T9T10T11T12
T1T2T3T4T5T6T7T8T9
T10
T11
T12
L1L2L3L4L5
S1
S1
S2
S2
S2S1
L4L4
L5L5
S1
L4
S1
S3
C8
C8
C5
C6 C6
C2
C3C4
C5
T1
C8 C7
C7
C7
C6
S4
S5
L5
L1
L1
L2S2, 3
L3
L4
L5
L2
L3
Schematic demarcation of dermatomes shown as distinct segments. There is actually considerable overlap between any two adjacent dermatomes
Sensory Pathways: III
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NEUROPHYSIOLOGY
FIGURE 2.32 VISUAL RECEPTORS•The rods and cones of the retina transduce light into electrical sig-nals. As illustrated for the rod, light is absorbed by rhodopsin, andthrough the second messenger cGMP (not shown), Na� channelsin 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 receptorresponses, in which the response to a stimulus results in a depolar-ization of the receptor cell membrane.
Visual System: Receptors
Photonsof light
Lumirhodopsin
Metarhodopsin
Retinene+
Opsin
Vitamin A
Rhodopsin
Metabolicenergy
Retinene+
Opsin
Vitamin A
Circulation
A. Eyeball
Suspensoryligament
IrisLens
Cornea
Ciliarybody
Retina
Choroid
Sclera
FoveaOptic nerve
Oraserrata
Anteriorchamber
Posteriorchamber
containingaqueous humor
Vitreous humor
Inner limitingmembrane
Ganglion cell
Amacrine cell
Bipolar cell
Horizontal cell
Rod
Cone
Pigment cellsof choroid
Müller cell(supporting glialcell)
Axons at surfaceof retina passingvia optic nerve,chiasm, and tractto lateralgeniculate body
B. Sectionthrough retina
Synapticendingfullypolarized
Synaptic bar
Nucleus
Centriole(basal body)
Na+
permeabilitydecreased
Synapticendingdepolarized
Currentflow
Na+
permeabilityincreased
C. Rod in dark D. Rod in light
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NEUROPHYSIOLOGY
FIGURE 2.33 RETINOGENICULOSTRIATE VISUAL PATHWAY•The retina has two types of photoreceptors: cones that mediatecolor vision and rods that mediate light perception but with lowacuity. The greatest acuity is found in the region of the macula ofthe retina, where only cones are found (upper left panel). Visualsignals are conveyed by the ganglion cells whose axons course inthe optic nerves. Visual signals from the nasal retina cross in the
optic chiasm while information from the temporal retina remains inthe ipsilateral optic tract. Fibers synapse in the lateral geniculatenucleus (visual field is topographically represented here andinverted), and signals are conveyed to the visual cortex on themedial surface of the occipital lobe.
Visual System: Visual Pathway
Overlappingvisual fields
Projection onleft retina
Projection onright retina
Centraldarkercirclerepresentsmacularzone
Lightestshadesrepresentmonocularfields
Eachquadranta differentcolor
Calcarinefissure
Projectionon leftoccipital lobe
Projectionon rightoccipital lobe
Projection on leftdorsal lateralgeniculate nucleus
Projection on rightdorsal lateralgeniculate nucleus
Lateralgeniculatebodies
Choroid Choroid
Periphery
Structure of retina (schematic):
ABCGHPR
GG
A
HH
R R C C
PP
A
B B
Amacrine cellsBipolar cellsConesGanglion cellsHorizontal cellsPigment cellsRods
Macula
Optic tracts
Optic chiasm
Optic(II) nerves
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NEUROPHYSIOLOGY
FIGURE 2.34 COCHLEAR RECEPTORS•The cochlea transduces sound into electrical signals. This isaccomplished by the hair cells, which depolarize in response tovibration of the basilar membrane. The basilar membrane moves in
response to pressure changes imparted on the oval window of thecochlea in response to vibrations of the tympanic membrane.
Auditory System: Cochlea
Utricle
Saccule
Semicircularcanals
Cochlear nerve
Oval window and stapesRound window
A. Membranouslabyrinth withinbony labyrinth(path of soundwaves)
B. Sectionthrough turnof cochlea
Spiral ganglion
Afferentnerve fibers
Efferentnerve fibers
Scala vestibuliCochlear duct(scala media)
Scala tympani
Scala vestibuli(perilymph); weakly positive +80 mV
Scala tympani(perilymph); 0 mV
Vestibular (Reissner’s)membrane
Cochlear duct (scala media;endolymph)
Tectorial membrane
Spiral ligament
Bone
Outer hair cells; �60 mV
Basilar membrane
Inner hair cell; �60 mV
As basilar membrane moves up, hairs are deflected outward, causingdepolarization of hair cells and increased firing of afferent nerve fibers
C. Spiral organof Corti Hair cells
Inner OuterTectorial membrane
Stereocilia
Basilar membrane
Supporting cells
Afferent nerve fibers
Efferent nerve fibers
Spiral laminaSpiral ganglion
Rodsandtunnelof Corti
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NEUROPHYSIOLOGY
FIGURE 2.35 AUDITORY PATHWAYS•The cochlea transduces sound into electrical signals. Axons conveythese signals to the dorsal and ventral cochlear nuclei, where it istonotopically organized. Following a series of integrated relaypathways, the ascending pathway projects to the thalamus (medial
geniculate bodies) and then the acoustic cortex in the transversegyrus of the temporal lobe, where information is tonotopically rep-resented (low, middle, and high tones).
Auditory System: Pathways
Brachium ofinferiorcolliculus
Inferiorcolliculus
Midbrain
Laterallemnisci
Medullaoblongata
Nuclei oflaterallemnisci
Acoustic area oftemporal lobe cortex
Medial geniculate body
Dorsal cochlear nucleus
Inferior cerebellar peduncle
Ventral cochlear nucleus
Cochlear division ofvestibulocochlear nerve
Spiral ganglion
Dorsalacoustic stria
Reticular formation
Trapezoid body
Intermediate acoustic stria
Correspondencebetween cochleaand acoustic areaof cortex:
Low tonesMiddle tonesHigh tones
Superior olivary complex
Hair cells
Inner Outer
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NEUROPHYSIOLOGY
FIGURE 2.36 VESTIBULAR RECEPTORS•The vestibular apparatus detects movement of the head in the formof linear and angular acceleration. This information is important forthe control of eye movements so that the retina can be providedwith a stable visual image. It is also important for the control ofposture. The utricle and saccule respond to linear acceleration,
such as the pull of gravity. The three semicircular canals arealigned so that the angular movement of the head can be sensed inall planes. The sensory hair cells are located in the maculae of theutricle and saccule and in the cristae within each ampullae.
Vestibular System: Receptors
Vestibular ganglion
Vestibularand cochleardivisions ofvestibulocochlear n.
Maculae
Saccule
Utricle
Cochlear duct(scala media)
B. Section of crista
Opposite wallof ampulla
Gelatinous cupula
Hair tufts
Hair cells
Nerve fibers
Basementmembrane
Superior semi-circular canal
Cristae withinampullae
Horizontal semi-circular canal
Posterior semi-circular canal
A. Membranous labyrinth
C. Section of macula
Otoconia
Gelatinous otolithicmembraneHair tuft
Hair cells
Supporting cells
Basement membrane
Nerve fibers
Hair cell (type II)
Supporting cell
Efferent nerveendings
Afferent nerveendings
Myelin sheath
D. Structure and innervationof hair cells
Hair cell (type I)
Supporting cells
Afferent nervecalyx
Efferent nerveending
Basementmembrane
Myelin sheath
Kinocilium
Stereocilia
Cuticle
Excitation
Inhibition
Basal body
Cuticle
Kinocilium
Stereocilia
Basal body
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NEUROPHYSIOLOGY Vestibular System: Vestibulospinal Tracts
Lowerlimb
ExcitatoryendingsInhibitoryendings
Ascending fibers in mediallongitudinal fasciculi
Motor neuron(controllingneck muscles)
Medial vestibulo-spinal fibers in mediallongitudinal fasciculi
Excitatoryendingsto backmuscles
Lowerpart ofcervicalspinal cord
To axialmuscles Inhibitory
endingLumbar part ofspinal cord
Medial
Lateral
Superior
Vestibular nuclei
Inferior
Tocerebellum
Vestibularganglionandnerve
Fibers from cristae(rotational stimuli)
Fibers from maculae(gravitational stimuli)
Lateralvestibulospinaltract
Excitatoryinterneuron
Inhibitoryinterneuron
To flexor muscles
To extensor muscles
Inhibitory ending??
? ?
To axial muscles
Excitatory ending
Lateral vestibulospinal tract
Inhibitory interneuron
Excitatory synapse
To flexor musclesTo extensor muscles
Somatotopicalpattern in lateralvestibular nucleus
Rostral
Caudal
TrunkUpperlimb
Ventral Dorsal
FIGURE 2.37 VESTIBULOSPINAL TRACTS•Sensory input from the vestibular apparatus is used to maintain sta-bility of the head and to maintain balance and posture. Axons con-vey vestibular information to the vestibular nuclei in the pons, andthen secondary axons distribute this information to five sites: spinal
cord (muscle control), cerebellum (vermis), reticular formation(vomiting center), extraocular muscles, and cortex (conscious per-ception). This figure shows only the spinal cord pathways.
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NEUROPHYSIOLOGYGustatory (Taste) System: Receptors
D. Detail of taste pore E. Detail of base of receptor cells
A. Tongue
Foliate papillae
Fungiformpapillae Vallate papillae
B. Sectionthrough vallatepapilla
Taste buds
Duct ofgustatory(Ebner’s)gland
C. Taste bud
Epithelium
Basement membrane
Nerve plexus
Nerve fibersemerging fromtaste buds
Microvilli
Taste cells
Taste pore
Microvilli
Epithelium
Desmosomes
Intercellular space Large nerve fiber
Small nerve fiber
Basement membrane
Collagen
Granules
Large nerve fiber Fibroblast
Schwann cell
FIGURE 2.38 TASTE RECEPTORS•Taste buds on the tongue respond to various chemical stimuli. Tastecells, like neurons, normally have a net negative charge internallyand are depolarized by stimuli, thus releasing transmitters that depo-
larize neurons connected to the taste cells. A single taste bud canrespond to more than one stimulus. The four traditional taste qualitiesthat are sensed are sweet, salty, sour, and bitter.
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NEUROPHYSIOLOGY Gustatory (Taste) System: Pathways
Lingual n.
Oticganglion
Chordatympani
Fungiform papillae
Foliate papillae
Valiate papillae
EpiglottisLarynx
Superior laryngeal n.
MesencephalicnucleusandMotor nucleus of trigeminal n.
Pons
Greater petrosal n.
Geniculate ganglion
Facial (VII) n.andNervus inermedius
Rostral part of nucleusof solitary tract
Glossopharyngeal (IX) n.
Lowerpart ofmedullaoblongata
Petrosal (inferior)ganglion ofglossopharyngeal n.
Nodose (inferior)ganglion of vagus n.
Vagus (X) n.
Ventral posteromedial (VPM)nucleus of thalamus
Sensory cortex (just belowface area)
Lateral hypothalamic area
Amygdala
Pontine taste area
Trigeminal (V) n.
Maxillary n.
Mandibular n.
Pterygo-palatineganglion
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 thepostcentral gyrus.
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NEUROPHYSIOLOGYOlfactory System: Receptors
Olfactorybulb
Lateral nasal wallSeptum
A. Distributionof olfactoryepithelium(blue area)
Cribriform plateof ethmoid bone
Cribriform plate
Schwann cell
Olfactory gland
Unmyelinatedolfactory axons
Basementmembrane
Sustentacularcells
Endoplasmicreticulum
Nucleus
Olfactory cells
Dendrites
Terminal bars(desmosomes)
Olfactory rod(vesicle)
Villi
Cilia
Mucus
B. Schema ofsection througholfactory mucosa
FIGURE 2.40 OLFACTORY RECEPTORS•The sensory cells that make up the olfactory epithelium respond toodorants by depolarizing. Like taste buds, an olfactory cell canrespond 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, pep-permint).
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NEUROPHYSIOLOGY Olfactory System: Pathway
FIGURE 2.41 OLFACTORY PATHWAY•Olfactory stimuli are detected by the nerve fibers of the olfactoryepithelium and conveyed to the olfactory bulb (detailed local cir-cuitry shown in upper left panel). Integrated signals pass along theolfactory tract and centrally diverge to pass to the anterior commis-
sure (some efferent projections course to the contralateral olfactorybulb, blue lines) or terminate in the ipsilateral olfactory trigone(olfactory tubercle). Axons then project to the primary olfactorycortex (piriform cortex), entorhinal cortex, and amygdala.
Fibers from contralateral olfactory bulb
Fibers to contralateral olfactory bulb
Anterior commissure
Medial olfactory stria
Anterior perforatedsubstance
Lateral olfactorystria
Lateral olfactorytract nucleus
Piriform lobe
Uncus
Amygdala(in phantom)
Entorhinal area
Efferent fibers
Afferent fibers
Granule cell (excited byand inhibiting to mitraland tufted cells)
Mitral cell
Recurrent process
Tufted cell
Periglom-erular cell
Glomerulus
Olfactorynerve fibers
Olfactory epithelium Olfactory tract
Olfactory nerves Anterior olfactory nucleus
Olfactory bulb Cribriform plate of ethmoid bone
Olfactory trigone andolfactory tubercle
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