front matter 1

Top View Side View

AB

CD

EF

White matter

outlined

Gray matter

outlined

Central canal

(defines midlline)

Lateral

motor

columns

Medial motor

columns

11

22

33

44

55

Figure 13. The cervical region in specimen M2050 (GW8.5, CR 36 mm). The individual sections (730–1170) in this model are diagrammed in Figure
10. The reconstructed length in the specimen is 4.4 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 outer 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 only gray matter (outlined outer 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, shoulder girdle motoneurons?) is located
in the central panel, dorsal tier at high cervical levels. Motor column 3 (red, shoulder muscle motoneurons?) in the cervical enlargement is located in
the lateral and central panels, ventral tier. Motor column 4 (orange, arm and forearm muscle motoneurons?) in the cervical enlargement is located in
the lateral and central panels, dorsal tier. Motor column 5 (yellow, wrist and hand muscle motoneurons?) in the cervical enlargement is located in the
lateral panel, retrodorsal tier.

FIGURE 13 GW8.5, CR 36 mm, M2050