front matter 1

Top View Side View

AB

CD

EF

Medial motor

columns

Medial motor column extending

into the sacral level

White matter

outlined

Gray matter

outlined

Central canal

(defines midlline)

Lateral

motor

columns

(^6611)

77

Figure 15. The lumbar and sacral regions in specimen M2050 (GW8.5, CR 36 mm). The individual sections in this model are diagrammed in Figure
11 and include sections 2008–2674. The reconstructed length in the specimen is 6.66 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 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 and central panels, ventral and dorsal tiers. Motor column 6 (purple,
proximal lower limb muscle motoneurons?) in the lumbar enlargement is located in the central and lateral panels, ventral tier. Motor column 7 (pink,
distal lower limb muscle motoneurons?) in the lumbar enlargement is located in the lateral panel, dorsal tier.

FIGURE 15 GW8.5, CR 36 mm, M2050