front matter 1

Top View Side View

AB

CD

EF

White matter

outlined

Gray matter

outlined

Central canal

(defines midlline)

Medial motor columns

11

Figure 21. The thoracic region in specimen Y380-62 (GW10.5, CR 56 mm). The individual sections in this model are diagrammed in Figure 17 and
include sections 671-881. The reconstructed length is 7.35 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 the medial motor columns (cyan). Panels C and D show the gray matter (outlined transparent envelope)
around the central canal and the medial motor columns. Panels E and F show the central canal and the medial motor columns alone. This region of the
spinal cord is distinguished from other regions by having only one motor column ( 1 ) that probably innervates axial muscles associated with the thoracic
vertebrae, rib cage, and dorsal abdominal wall.

GW10.5, CR 56 mm, Y380-62 FIGURE 21