The Human Brain During the Third Trimester

GW26 Sagittal

CR 225 mm

Y147-63

Level 2: Section 481

Chor

oid plex

us

Chor

oid

p

lexus

Pontine gray

Optic chiasm

Olfactory peduncle

Transpontine corticospinal tract

Oculomotor nerve(III)

Superior cerebellar

peduncle

Primary fissure

Pyramid (corticospinal tract)

Pyramidal decussation

Medial lemniscus

Raphe nuclear complex (infiltrated by 9 )

Anterior

commissure

Anterior

commissure

FFornixornix

ThalamusThalamus

Cerebral peduncle

Medial longitudinal fasciculus

and tectospinal tract

Gracile fasciculus and nucleus

Central canal (spinal cord, surrounded by 10 )

F

or

n

ix

F

or

n

ix

Gyrus Gyrus rrectuectuss

Parietal

lobe

Parietal

lobe

Frontal

lobe

Frontal

lobe

Frontal

lobe

Frontal

lobe

Hypo-

thalamus

Hypo-

thalamus

Preoptic

area

Preoptic

area

GenuGenu

Sp

le

ni

um

Sp

le

ni

um

S

e

p

tu

m

S

e

p

tu

m

TTectuectumm

MidbraiMidbrainn

PPonsons

MedullaMedulla

Spinal cordSpinal cord

Occipital

lobe

Occipital

lobe

Cortical plate

White matter

Third

ventricle

Fourth

ventricle

Fourth

ventricl e

Interpeduncular

nucleus

Interpeduncular

nucleus

Cere bellum

(vermis)

Anterior

lobe

Anterior

lobe

Central

lobe

Central

lobe

Posterior

lobe

Po sterior

lobe

Inferior

lobe

Inferior

lobe

See high magnification views of the

cerebellar cortex and germinal trigone

in Plates 210-215.

TTe gmentumegmentum

Inferior

colliculus

Inferior

colliculus

Superior

colliculus

Superior

colliculus

Remnants of the germinal matrix, migratory streams, and transitional fields

11

22

33

33

44

5

1111

88

6

77

7 Mesencephalic glioepithelium/ependyma

4 Fo rnical glioepithelium

5 Strionuclear glioepithelium

6 Diencephalic (thalamic) glioepithelium/ependyma

12 External germinal layer (cerebellum)

1 Rostral migratory stream

8 Pontine and medullary glioepithelium/ependyma

9 Raphe migration
3 Callosal glioepithelium

2 Callosal sling

11 Germinal trigone (cerebellum)

10 Spinal glioepithelium/ependyma

C

or

pu

sc

all

osu

m

C

or

pu

sc

all

osu

m

Hippocampal

commissure

Cave of the

septum

Induseum

griseum

Cingulate gyrusCingulate gyrus

Layer I

12

13

12

13

13

13 Subpial granular layer (cortical)

See detail of brain core and

cerebellum in Plates 201A and B.

Damaged areas in section

Paracentral

lobule

Paracentral

lobu le

Pretectum

PLATE 191