Abstract
The chicken coccygeal cord consists of 5 segments, from the 37th to the 41st. The cord was gradually reduced in thickness toward the caudal end. The gray matter was found in segments 37 to 39, but its ventral and dorsal horns were distinguished only in segment 37. Only a few large motor neurons were found in segment 39. However, in segment 40 and in the rostral region of segment 41, there were located only small neurons. Degenerated never fiers were observed throughout the cord, probably degenerated spontaneously. In segment 41, which was avascular, the subependymal layer consisted largely of fibrous astrocytes heavily loaded with glycogen granules composing irregular clumps of various sizes, suggesting some relation between the avascularity and the heavy glycogen deposition. The caudal end of the central canal opened directly to the subarachnoid space, suggesting an active flow of the cerebrospinal fluid from the central canal to the subarachnoid space.
