The Human Brain During the Third Trimester

Fastigial

nucleus

Fa stigial

nucleus

3 Mesencephalic glioepithelium/ependyma

2 Hypothalamic glioepithelium/ependyma

1 Preoptic glioepithelium/ependyma

Remnants of the germinal matrix

9 Raphe migration

8 External germinal layer (cerebellum)

4 Pontine glioepithelium/ependyma

5 Cerebellar glioepithelium/ependyma

6 Medullary glioepithelium/ependyma

7 Germinal trigone (cerebellum)

11

22

33

33

33

8

8

55

7

6

99

44

Oculomotor

nuclear

complex (III)

Oculomotor

nuclear

complex (III)

Nodulus

X

Nodulus

X

Uvula

IX

Uvula

IX

Pyramis

VIII

Pyramis

VIII

Folium

VIIa

Fo lium

VIIa

Declive

VI

Declive

VI

Culmen

IV, V

Culmen

IV, V

Lingula

I, II

Lingula

I, II

Centralis

III

Centralis

III

Tuber

VIIb

Tuber

VIIb

PPontine grayontine gray

Oculomotor nerve (III)

Posterior commissure

Cerebral peduncle

Substantia nigra

Optic chiasm

Arcuate nucleus

Mammillary

body

Mammillary

body

Premammillary

area

Lamina terminalis

Third ve ntricle (preoptic recess)

Third ve ntricle (infundibu lar recess)

Third

Preoptic perive ntricular nucleus ventricl e

Pineal gland

Choroid

plexus

Choroid

plexus

Corpus

callosum

(splenium)

Corpus

callosum

(splenium)

Mammillothalamic tract

HYPO-

THALAMUS

HYPO-

THALAMUS

PREOPTIC

AREA

PREOPTIC

AREA

MIDBRAIMIDBRAINN

PONSPONS

PPrreetteeccttuumm

Inferior

colliculus

Inferior

colliculus

Ventral

tegmental

area

Ventra l

tegmental

ar ea

Reticular

formation

Reticular

fo rmation

Reticular

formation

Reticular

fo rmation

Reticular

formation

Reticular

formatio n

Trochlear

nucleus (IV)?

Tr ochlear

nucleus (IV)?

Cer

ebr

aqued al

uct

Reticular

tegmental

nucleus

Reticular

tegmental

nucleus

Dorsal

tegmental

nucleus

Dorsal

tegmental

nucleus

Medial lemniscus

(decussation)

Medial longitudinal fasciculus

and tectospinal tract

Pontocerebellar fibers

(thin transverse bundles

Transpontine corticofugal tract

(thick longitudinal bundles)

Middle cerebellar peduncle

Corticospinal

tract

Lateral corticospinal tract

(medial edge)

Medial motor nucleus

(spinal cord)

Gracile fasciculus

Inter-

peduncular

nucleus

Inter-

peduncular

nucleus

Fo urth

ventricl e

Gracile nucleus

M

e

d

ia

l

le

m

n

is

c

u

s

M

e

d

ia

l

le

m

n

is

c

u

s

M

ed

ia

l (^) l
me
n
is
uc
s
M
ed
ia
l (^) l
me
n
is
uc
s
TEGMENTUMTEGMENTUM
TECTUMTECTUM
Tr ochlear nerve root?
Brachium of the inferior colliculus
Superior medullary velum
AN
TE
RI
OR
LO
BE
AN
TE
RI
OR
LO
BE

INFERIOR

LOBE

INFERIOR

LOBE

POSTERIOR

LOBE

POSTERIOR

LOBE

V E R M I SV E R M I S

Preculminate fissure

A (separates centralis and culmen)

Primary fissure

(separates anterior and central lobes)

B

Secondary fissure

(separates central and posterior

lobes)

D

Prepyramidal fissure

(separates tuber and pyramis)

C

Posterolateral fissure

(separates posterior and inferior

lobes)

E

Cerebellar fissures

CC

AA

AA

BB

BB

CC

DD

DD

EE

EE

R

ap

he

nu

clea

r

co

m

p

le

x

R

ap

he

nu

clea

r

co

m

p

le

x

Raphe

nuclear

complex

Raphe

nuclear

complex

Superior

cerebellar

peduncle

Superior

cerebellar

peduncle

Medial

longitudinal

fasciculus

Medial

longitudinal

fasciculus

Raphe

nuclear

complex

Raphe

nuclear

complex

Dorsal motor nucleus (X)

Hypoglossal nucleus (XII)

Pyramidal

decussation

Pyramidal

decussation

PyramidPyramid

Substantia

nigra

Substantia

nigra

CE

N

T

R

A

L

L

O

B

E

CE

N

T

R

A

L

L

O

B

E

M

ed

ia

l

lo

n

gi

tu

d

in

a

lf

a

sc

ic

u

lu

s

M

ed

ia

l

lo

n

gi

tu

d

in

a

lf

a

sc

ic

u

lu

s

C

er

eb

ra

la

q

eu

ud

tc

Superior

colliculus

Superior

colliculus

Central

gray

Central

gray

Central

gray

Central

gray

D

or

sa

l

lo

ng

it

u

di

n

al

fa

sc

ic

u

ul

s

D

or

sa

l

lo

ng

it

u

di

n

al

fa

sc

ic

u

ul

s

Abducens

nucleus (VI)

Abducens

nucleus (VI)

Trapezoid

body?

Tr apezoid

body?

MEDULLAMEDULLA

SPISPINNAL CORDAL CORD

Damaged areas in section

C E R E B E L L U M

PLATE 102B