Lumbar
EnlargementCervical
EnlargementThoracic
areaSacral
areaCentral canal
(defines midline)Right Left
Medial motor columnsCentral and
lateral motor
columns
(cervical)Central and lateral
motor columns
(lumbar)❉❉
Posterior
edge of
white
matterPosterior
edge of
gray
matterA B
C
Anterior
edge of
white
matterAnterior
edge of
gray
matterAnterior edge
of gray matter
Figure 19. The entire spinal cord in specimen
Y380-62 (GW10.5, CR 56 mm) as viewed from the
front and top (A, B, C, this page) or the upper right
side (D, E, F, facing page). The front edge of the
reconstruction is section 361, the back edge is sec-
tion 1211. The total length after fi xation is 29.79 mm.
In this and the following reconstructions, the spinal
cord has been enlarged 3 times more crosswise than
lengthwise. Otherwise, the model is too long to see
the various motoneuron columns clearly. Solid out-
lines defi ne the outer edges of the white matter (trans-
parent envelope, A and D); dashed outlines defi ne the
outer edges of the gray matter (less transparent enve-
lope, A, B and D, E). The gray-white solid in
panels A-E is the central canal. The colored solids in
panels A-E are ventral horn motor columns. There are
nine pairs of motor columns on each side of the ven-
tral horn. The medial motor columns (cyan) extend
throughout the entire length, including sacral levels.
There are four lateral motor columns in the cervical
region, a long one (light brown) extending through-
out the entire region and three (red, orange, yellow)
that are limited to the cervical enlargement. The
lumbar enlargement is more prominent than at GW8.5,
and contains four central and lateral motor columns
(purple, pink, violet, pale violet). The asterisks in
C indicate the motor columns in the cervical enlarge-
ment that are not visible in the side view. The ventral
to dorsal stacking of the lateral motor columns is more
easily seen in the side views (especially panel F).FIGURE 19 GW10.5, CR 56 mm, Y380-62