The Human Brain During the Third Trimester

Cerebral

aqueduct

Tectospinal

tract

R

a

p

h

e

n

u

lc

e

a

r

c

o

m

p

le

x

Cere bral

aqueduct

Central

gray

Central

gray

Central

gray

Central

gray

Inferior

colliculus

Inferior

colliculus

Central

nucleus

Central

nucleus

Medial

longitudinal

fasciculus

Medial

longitudinal

fasciculus

Central

tegmental

tract

Central

tegmental

tract

Tectospinal

tract

Reticular

formation

Reticular

formation

Mesencephalic

nucleus V

Mesencephalic

nucleus V

Inferior

cerebellar

peduncle

Inferior

cerebellar

peduncle

Inferior

olive

Inferior

oliv e

A

n

te

ri

or

L

ob

e^

(H

I-

H

V

)

A

n

te

ri

or

L

ob

e^

(H

I-

H

V

)

Moto r

nucleus

V

Moto r

nucleus

V

Moto r

nucleus

VII

Moto r

nucleus

VII

Choroid

plexus

Choroid

plexus

Middle

cerebellar

peduncle

Middle

cerebellar

peduncle

Middle

cerebellar

peduncle

Middle

cerebellar

peduncle

Locus

coeruleus

Locus

coeruleus

Abducens

nucleus VI

Abducens

nucleus VI

P

ri

n

ci

p

al

s

e

n

so

ry

n

u

c

le

u

s^

(V

)

P

ri

n

ci

p

al

s

e

n

so

ry

n

u

c

le

u

s^

(V

)

Pontine

gray

Pontine

gray

P

a

r

a

b

r

a

ch

ia

l

n

u

cl

eu

s

P

a

r

a

b

r

a

ch

ia

l

n

u

cl

eu

s

Su

pe

ri

o

r

c

e

re

b

el

la

r

p

ed

u

n

cl

e

Su

pe

ri

o

r

c

e

re

b

el

la

r

p

ed

u

n

cl

L e

at

er

al

le

m

ni

sc

us

L

at

er

al

le

m

ni

sc

us

L

at

er

all

emniscu

s

L

at

er

all

emniscu

s

M

e

d

ia

l

le

m

n

is

c

u

s

M

e

d

ia

l

le

m

n

is

c

u

s

R

a

p

h

e

n

u

lc

e

a

r

c

o

m

p

le

x

Tr

ap

ezo

id

bod

y

Tr

ap

ezo

id

bod

y

Brachiumo

fin

fer

io

r

co

ll

ic

u

lu

s

Brachiumo

fin

fer

io

r

co

ll

ic

u

lu

s

Nerve VIII root

Nerve IV root and decussation?

Arcuate nucleus

(medullary)

Cochlear nucleus

(ventral)

Cochlear nucleus

(ventral)

Cochlear nucleus

(dorsal)

Cochlear nucleus

(dorsal)

Superior olive

(periolivary nuclei)

Superior olive

(periolivary nuclei)

Superior medullary velum

Frenulum

Molecular layer

Granular layer

Medullary layer

PONSPONS

MEDULLAMEDULLA

Corticospinal

(pyramidal) tract

Corticospinal

(pyramidal) tract

MIDBRAIMIDBRAINN

TTectuectumm

HemispheHemispherree

CEREBELLUMCEREBELLUM

Paramedian lobule?

(HVIIB)

Paramedian lobule?

(HVIIB)

S

im

p

le

x

(^) lo
bu
le

(H

V

I)

S

im

p

le

x

(^) lo
bu
le

(H

V

I)

External germinal layer

Germinal and transitional structuGerminal and transitional structurres ines in italicsitalics

Mesencephalic

glioepithelium/ependyma

Mesencephalic

glioepithelium/ependyma

IsthmuIsthmuss

Primary fissure

Inferior cerebellar peduncle

and spinocerebellar tracts

PLATE 42B