Figure 331 shows a midsagittal section of the brain reveal-ing features of its major subdivisions.

Figure 332 demonstrates an oblique frontal section and horizontal sections of the brain.

The coverings of the brain are shown in Figure 333. The ow of cerebrospinal uid is illustrated in Figure 334.

Spinal nerves are shown in Figure 335 and their derma-tome distribution is illustrated in Figure 336.

162

33

Chapter 33 The structure and function of skin

Fig 331Divisions of the brain. A midsagittal section of the brain reveals features of its major divisions. A, anterior; I, inferior; P, posterior; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999.)

S

I

A P Cerebrum

CortexCorpus

callosum

DiencephalonThalamus

Pineal bodyHypothalamus

MidbrainPons

Medullaoblongata

Brainstem

Cerebellum

33 Section 2: Brain, peripheral nervous system, muscle

Chapter 33 Normal anatomy

Ch33-44-X4919_161-213.indd 162 10/10/08 11:08:06 AM

163

Chapter 33: Normal anatomy 33

S

I

R L

A

P

L R

A B

Septum pellucidum

Lateral ventricleFornix

Choroid plexus (of lateral ventricle)

Third ventricle

Optictract

Thalamus

Caudatenucleus(tail)

HippocampusCerebellum

Olive(of medulla)

Pyramid(of medulla)

Corpus callosumCaudatenucleus (head)

Internalcapsule

Thalamus

Insula

PutamenGlobuspallidus

Lentiformnucleus

PonsSubstantia nigra

Fourth ventricle

Lateral ventricle(anterior horn)

Caudatenucleus(head)

Corpus callosum

Lateral ventricle

Choroidplexus

Lateralventricle(posteriorhorn)

Visual area of cortex

Opticradiation

Lateralventricle(inferiorhorn)

Insula

GlobuspallidusPutamen

Lentiformnucleus

Internal capsule

Fig 332Human brain specimens. A, Oblique frontal section. B, Horizontal sections. The left section is slightly inferior to the right sections: A, anterior; I, inferior; L, left; P, posterior; R, right; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999)

Ch33-44-X4919_161-213.indd 163 10/10/08 11:08:08 AM

164

33 Section 2: Brain, peripheral nervous system, muscle

S

I

R L

S

I

A P

Superiorsagittal sinus

(of dura)Epiduralspace Periosteum

Dura materOne functionallayer

Arachnoid

Superarachnoidspace

Skin

Muscle

Periosteum

Subduralspace

Skull

Falxcerebri

Piamater

Falx cerebri

Inferior sagittalsinus of dura

Free margin oftentorium cerebelli

Attached margin oftentorium cerebelli

Tentorium cerebelli

Medulla oblongata

Spinal cord

Superior sagittalsinus of dura

Transverse sinusof dura

Margin of foramenmagnum

A

B

Fig 333Coverings of the brain. A, Frontal section of the superior portion of the head, as viewed from the front. Both the bony and membranous coverings of the brain can be seen. B, Transverse section of the skull, viewed from below. The dura mater has been retained in this specimen to show how it lines the inner roof of the cranium and the falx cerebri extending inward. A, anterior; I, inferior; L, left; P, posterior; R, right; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999.)

Ch33-44-X4919_161-213.indd 164 10/10/08 11:08:13 AM

165

Chapter 33: Normal anatomy 33

S

I

A P

Arachnoidvillus

Superiorsagittal sinus

Arachnoidvillus

Piamater

Falx cerebri(dura mater)

Arachnoid layerSubarachnoid

space

Cerebral cortex

Lateralforamen

Cisternamagna

Dura mater

Choroid plexusof lateral ventricle

Subarachnoidspace

Superiorsagittal

sinus

Interventricularforamen

Choroid plexusof third ventricle

Cerebral aqueductChoroid plexus

of fourth ventricle

Medianforamen

Central canalof spinal cord

Fig 334Flow of cerebrospinal uid. The uid produced by ltration of blood by the choroids plexus of each ventricle ows inferiorly through the lateral ventricles, interventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, and subarachnoid space and to the blood. A, anterior; I, inferior; P, posterior; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999.)

Ch33-44-X4919_161-213.indd 165 10/10/08 11:08:18 AM

166

33 Section 2: Brain, peripheral nervous system, muscle

S

I

L R

C1C2C3C4C5C6C7

S1S2S3S4S5

T1T2T3T4T5T6T7T8T9T10T11T12

L1L2L3L4L5

C1C2C3C4C5C6C7C8

T1T2T3T4T5T6T7T8T9T10T11T12

L1L2L3L4L5

Posterior mediansulcus of spinal cord

Dorsal roots ofC2, C3, and C4 nerves

Intervertebralforamen

Transverseprocessesof vertebrae(cut)

Dorsalrootganglion

Dura materCauda equina

Coccygealnerve

Sacrum

Coccyx

Filum terminale

Sacralnerves

Thoracicnerves

Cervicalnerves

Cervicalvertebrae

Thoracicvertebrae

Lumbarvertebrae Lumbar

nerves

Cerv

ical

plex

us

Lum

bar

plex

us

Sacr

al

plex

us

Brach

ial

plex

us

B

AFig 335Spinal nerves. Each of 31 pairs of spinal nerves exits the spinal cavity from the intervertebral foramina. A, Shown are the names of the vertebrae (left) and the names of the corresponding spinal nerves (right). Notice that after leaving the spinal cavity, many of the spinal nerves interconnect to form networks called plexuses. B, Dissection of the cervical region, showing a posterior view of cervical spinal nerves exiting the intervertebral fo-ramina on the right side. I, inferior; L, left; R, right; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999.)

Ch33-44-X4919_161-213.indd 166 10/10/08 11:08:20 AM

167

Chapter 33: Normal anatomy 33

S

I

L R

S

I

R L

S

I

P A

Trigeminalcranial nerve (V)

Trigeminalcranial nerve (V)

C3C3 C3

C2C2

C1C2C3C4C5C6C7C8

L1L2L3L4L5 L1

L2L3L4L5

T1T2T3T4T5T6T7T8T9T10T11T12

V1 V1

V2 V2

V3 V3C4

C4

C4C5

C5 C5

C5C5

C5 C5

C8

C7

C7

C8

C8

C8

C8C8

C6

C6

C6 C6

C6

T1 T1

T1

T1

T1

T2 T2

T2

T3 T3

T3

T4 T4

T4

T5 T5

T5

T6 T6

T6T7

T7

T7T8T8

T8T9

T9

T9T10

T10

T10T11

T11

T11T12

T12

T12S2

S2

S2

S2

S2

S2

S2

S3

S3

S3

S1

S1

S1S1

CX S4S5

L1

L1

L1

L1

L1L2

L2

L2

L2

L2

L2

L3

L3

L3 L3

L3

L3

L4

L4

L4

L4L4

L4L5

L5

L5

L5

L5L5

S2

S2

CX

B CA

Spinal cordsegments

Fig 336Dermatome distribution of spinal nerves. A, The front of the bodys surface. B, The back of the bodys surface. C, The side of the bodys surface. Inset, Segments of the spinal cord associated with each of the spinal nerves associated with the sensory dermatomes shown. A, anterior; I, inferior; P, posterior; S, superior.(From Thibodeau GA, Patton KP: Anatomy and Physiology, 4th ed. St. Louis, Mosby, 1999.)

Ch33-44-X4919_161-213.indd 167 10/10/08 11:08:24 AM