The Human Brain During the Third Trimester

1

2

Preculminate fissure

(separates centralis and culmen)

A

Primary fissure

B (separates anterior and central lobes)

Secondary fissure

(separates central and posterior

lobes)

D

Prepyramidal fissure

C (separates tuber and pyramis)

Posterolateral fissure

(separates posterior and inferior

lobes)

E

Cerebellar fissures

2 Fo rnical glioepithelium

1 Callosal sling

3 Strionuclear glioepithelium

8 External germinal layer (cerebellum)

4 Mesencephalic glioepithelium/ependyma

6 Medullary glioepithelium/ependyma

7 Germinal trigone (cerebellum)

5 Pontine glioepithelium/ependyma

Remnants of the germinal matrix

Mammillothalamic

tract

P

re

co

m

m

is

su

r

al

fo

rn

ix

C

en

tr

al

co

m

ple

x

Fo

rn

ix

(c

ol

um

n)

Periventricular

complex

Periventricular

complex

Ant

erom

edia

nucleus l

Ant

erom

edia

nucleus l

Dorsomedial

nucleus

Dorsomedial

nucleus

H

ab

en

u

lo

• 
  

in

te

rp

ed

u

nc

u

la

r

tr

ac

t

H

ab

en

u

lo

• 
  

in

te

rp

ed

u

nc

u

la

r

tr

ac

t

Centro-

median

n.

Centro-

median

n.

Central

lateral

nucleus

Central

lateral

nucleus

Anter

odorsal nucleu

s

Anter

odorsal nucleu

s

Anterior

complex

Anterior

complex

Dorsal compleDorsal complexx

C

en

tr

al

co

m

ple

x

In

te

rp

ed

un

cu

la

r

nu

cl

eu

s

In

te

rp

ed

un

cu

la

r

nu

cl

eu

s

FFornixornix

FFornixornix

Medial

preoptic

nucleus

Medial

preoptic

nucleus

Sexually

dimo rphic

nucleus

Sexually

dimorphic

nucleus

Bed nucleus

of the stria

terminalis

Bed nucleus

of the stria

terminalis

Gyrus Gyrus rrectuectuss

Corpus

callosum

(splenium)

Corpus

callosum

(splenium)

Corpus
callosum
(rostrum)

Corpus
callosum
(rostrum)

Fields of Fields of FForelorel

P

retectum

P

retectum

Central grayCentral gray

Superior colliculuSuperior colliculuss

Inferior

colliculus

Inferior

colliculus

Red nucleuRed nucleuss

Substantia nigrSubstantia nigraa

CeCerre bral peduncleebral peduncle

Superior

cerebellar

peduncle

Superior

cerebellar

peduncle

Reticular

formation

Reticular

fo rmation

Reticular

formation

Reticular

fo rmation

Reticular

formation

Reticular

fo rmation

Trochlear

nucleus (IV)?

Tr ochlear

nucleus (IV)?

Trochlear

nerve bundles?

Tr ochlear

nerve b undles?

Do

rsa

l

teg

me

nta

l

nuc

leu

s

Do

rsa

l

teg

me

nta

l

nuc

leu

s

Inferior

Oli

ve

principal

nucleus

Inferior

Olive

principal

nucleus

Reticular

tegmental

nucleus

Reticular

tegmental

nucleus

AArreeaa ppoossttrreemmaa??

Medial accessory olive

Pyramis

VIII

Pyramis

VIII

A

nte

ro

ve

nt

ra

l

nu

cle

us

A

nte

ro

ve

nt

ra

l

nu

cle

us

Ventro-

medial

nucleus

Ve ntro -

medial

nucleus

Dorso-

medial

nucleus

Dorso-

medial

nucleus

PREOPTIC

AREA

PREOPTIC

AREA

L

a

te

ra

l

se

p

ta

l

n

u

cl

eu

s

L

a

te

ra

l

se

p

ta

l

n

u

cl

eu

s

P

re

co

m

m

is

su

r

al

fo

rn

ix

Lateral

ventricle

Foramen of

Monro

Fo ramen of

Monro

Diagonal band of Broca

(vertical limb)

Substantia innominata/

olfactory tubercle

Nucleus accumbens

Larg e island of Calleja

Subcallosal arSubcallosal areaea

C

or

pus callosu

m

Cor (body)

pus callosu

m

Cor (body)

pus callosu

m

Corpus callosu(body)

m

(body)

Mam-

millary

body

Mam-

millary

body

Anterior

commissure

Choroid

plexus

Choroid

plexus

Induseum griseuInduseum griseumm

Cingulate gyrusCingulate gyrus

Fo

rn

ix

(c

ol

um

n)

S

tr

ia

m

ed

ul

la

ri

s

S

tr

ia

m

ed

ul

la

ri

s

Mammillothalamic

tract

HYPHYPOOTHALAMUSTHALAMUS

THALAMUSTHALAMUS

Raphe

nuclear

complex

Raphe

nuclear

complex

M

ed

ia

l

le

m

ni

sc

us

M

ed

ia

l

le

m

ni

sc

us

Medial

longitudinal

fasciculus

Medial

longitudinal

fasciculus

??

Deep

whitelayer

Deep

whitelayer

MIDBRAIMIDBRAINN

PONSPONS

TEGMENTUMTEGMENTUM

TECTUMTECTUM

Hippocampal

commissure

Brachium of

the inferior

colliculus

Cave of the

septum

Cave of th e

septum

Oculomotor nerve (III)

*Arcuate nucleus (medulla)

Pyramid (corticospinal tract)

Pyramidal decussation

Medial longitudinal fascuculus and tectospinal tract

Gracile fasciculus

Dorsal motor nucleus (X)

Hypoglossal nucleus (XII)

Gracilis nucleus

MEDULLAMEDULLA

Nodulus

X

Nodulus

X

Uvula

IX

Uvula

IX

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

Choroid

plexus

Choroid

plexus

Fo urth

ventricl e

Paraflocculus

(tonsil, extends from uvula

to hemisphere)

Paraflocculus

(tonsil, extends from uvula

to hemisphere )

P

ar

am

e

d

ia

n

lo

b

u

le

(e

xt

en

ds

f

ro

m

tu

be

r^

to

h

em

isp

he

re

)

P

ar

am

e

d

ia

n

lo

b

u

le

(e

xt

en

ds

f

ro

m

tu

b

er

t

o^

he

m

isp

he

re

)

Superior

cerebellar peduncle

A

N

T

E

R

IO

R

L

O

B

E

A

N

T

E

R

IO

R

L

O

B

E

CENTRAL

LOBE

CENTRAL

LOBE

INFERIOR

LOBE

INFERIOR

LOBE

POSTERIOR

LOBE

POSTERIOR

LOBE

V E R M I SV E R M I S

H

E

M

I

S

P

H

E

R

E

H

E

M

I

S

P

H

E

R

E

CC

AA

AA

BB

BB

CC

DD

DD

EE

EE

2

3

3

44

55

8

6

77

Habenulo-

interpeduncular

tract

Habenulo-

interpeduncular

tract

Dorsal longitudinal

fasciculus

Dorsal longitudinal

fasciculus

Medial longitudinal

fasciculus

Medial longitudinal

fasciculus

8

PPontine grayontine gray

Transpontine corticofugal tract

(thick longitudinal bundles)

Pontocerebellar fibers

(thin transverse bundles)

*Cells may be entering this nucleus

via the Raphe migration.

CEREBELLUM

PLATE 56B