front matter 1

Ventral

corticospinal

tract

VVentral funiculusentral funiculus

Ventral

corticospinal

tract

VVentral grayentral gray

Intermediate grayIntermediate gray

Dorsal root bifur-

cation zone

Dorsal root bifur-

cation zone

Superficial fasciculus cuneatus

Deep fasciculus cuneatus

Superficial fasciculus gracilis

Deep fasciculus gracilis

Dorsal root

collateralization zone

Lissauer's tractLissauer's tract

Lateral

funiculus

Lateral

funiculus

EpendymaEpendyma

corticospinalLateral

tract

corticospinalLateral

tract

Tectospinal tract?

Medial longitudinal fasciculus?

VVestibulospinal tract?estibulospinal tract?

Dorsal grayDorsal gray

Ventral root and rootlets

(myelinated)

VVentral rootentral root

Dorsal rootDorsal root

Dorsal funiculus

Central canalCentral canal

S

p

i

n o c e r e b e l l a r t r a c t s

S

p

i

n o c e r e b e l l a r t r a c t s

Intrasp

in

al

tr

a

c

ts

?

Intrasp

in

al

tr

a

c

ts

?

Spi

no

ce

ph

al

ic

tr

ac

ts

?

Spi

no

ce

ph

al

ic

tr

ac

ts

?

No reactive glia

Myelination

in bifurcation zone

Dense reactive glia

in collateralization zone

Dorsal root

boundary cap

Dorsal root

boundary cap

Sparse reactive glia

Examples of reactive glia densities
and myelination

Myelinated proximal

axons of ventral horn

motoneurons

Myelinated proximal

axons of ventral horn

motoneurons

VVentral gray commissureentral gray commissure

VVentral white commissureentral white commissure

Ventral

median

fissure

Dorsal median septum

Dorsal intermediate septum

PLATE 49B

See the matched cell body stained section in Plates 50A and B