front matter 1

A

B

C

D E F G H I

White matter outlined

Gray matter outlined

Columns 1 and 4

Columns 1 and 5

Columns 1 and 6

Columns 1 and 7, 8, 9

Columns 1 and 2

Columns 1 and 3

Central canal

(defines midlline)

Central canal

Central and lateral

motor columns

Medial motor

columns

11

22

33

66

8877

99

44

55

Figure 28. A continuation of the previous fi gure in the same specimen, except that all panels show either the entire model or parts of it from the side
view. Motor column 1 (cyan, axial muscle motoneurons?) is located in the medial panel, ventral tier. Motor columns 2 and 3 (yellow, orange) at upper
cervical levels (sections 701-821) may innervate proximal upper limb muscles, and are located in the central and lateral panels, ventral and dorsal tiers.
Motor columns 4 to 6 (yellow brown, red, orange) are located in the cervical enlargement in the central and lateral panels, ventral, dorsal, and retrodorsal
tiers and may innervate arm and forearm muscles. Motor columns 7 to 9 (dark red orange, light red orange, yellow orange) are located in the cervical
enlargement in the lateral panel, retrodorsal tier and may innervate wrist and hand (digit) muscles.

GW14, CR 108 mm, Y68-65 FIGURE 28