Spinal cord

The spinal cord or medulla spinalis forms the elongated, nearly cylindrical, part of the central nervous system which occupies the upper two-thirds of the vertebral canal.

Its average length in the male is about 45 cm., in the female from 42 to 43 cm., while its weight amounts to about 30 gms.

It extends from the level of the upper border of the atlas to that of the lower border of the first, or upper border of the second, lumbar vertebra.

Above, it is continuous with the brain; below, it ends in a conical extremity, the conus medullaris, from the apex of which a delicate filament, the filum terminale, descends as far as the first segment of the coccyx.