The spinal cord is a cylindrical, grayish white structure that begins above at the foramen magnum, where it is continuous with the medulla oblongata of the brain.
It terminates below in the adult at the level of the lower border of the first lumbar vertebra.
In the young child, it is relatively longer and ends at the upper border of the third lumbar vertebra.
The spinal cord in the cervical region gives origin to the brachial plexus, and in the lower thoracic and lumbar regions, where it gives origin to the lumbosacral plexus.
Inferiorly, the spinal cord tapers off into the conus medullaris, from the apex of which a prolongation of the pia mater, the filum terminale, descends to be attached to the back of the coccyx.
BDC 4th ed., vol.3, page-309
Clinical Anatomy-Snell, 8th ed., page-867