Part of a section of the spinal cord stained with protargol, showing the central canal above, and the bottom of the antero-median fissure below. Between the two is the commissure of the spinal cord, and it is seen to contain many fibres undergoing decussation. These are fibres of the spino-thalamic tracts (conveying mainly impulses of pain and temperature) crossing over to ascend in the opposite side of the cord. On either side, a few large motor cells are seen in the most medial part of the anterior horn of grey matter. Note that the central canal of the cord is lined by a single layer of columnar cells − the ependymal epithelium. Supporting this epithelium is a thin sub-epithelial stratum of neuroglial tissue. The photograph is at a magnification of X 111.

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