front matter 1

3

4

5

Top View Side View

AB

CD

EF

White matter

outlined

Gray matter

outlined

Central canal

(defines midlline)

Central and lateral

motor columns

Medial motor

columns

11

22

3

4

5

Figure 20. The cervical region in specimen Y380-62 (GW10.5, CR 56 mm). The individual sections in this model are diagrammed in Figure 16 and
include sections 361-611. The reconstructed length is 8.79 mm after fi xation. Panels A, C, and E show the model from the top front, panels B, D, and
F from the upper right side. Panels A and B show both the white matter (outlined transparent envelope) and gray matter (inner transparent envelope)
around the central canal (gray-white solid) and motor columns (colored solids). Panels C and D show the gray matter (outlined transparent envelope)
around the central canal and motor columns. Panels E and F show the central canal and motor columns alone. Motor column 1 (cyan, axial muscle
motoneurons?) is located in the medial panel, ventral and dorsal tiers. Motor column 2 (light brown, proximal upper limb muscle motoneurons?) is
located in the central and lateral panels, ventral and dorsal tiers. Motor column 3 (red, arm and forearm muscle motoneurons?) is located in the cervical
enlargement in the lateral panel, dorsal tier. Motor column 4 (orange, wrist and hand muscle motoneurons?) is located in the cervical enlargement in
the lateral panel, retrodorsal tier. Motor column 5 (yellow, forearm muscle motoneurons?) in the posterior cervical enlargement (sections 551-611) is
located in the medial and central panels, ventral tier.

FIGURE 20 GW10.5, CR 56 mm, Y380-62