Throughout the cervical and thoracic regions the central canal
is situated in the anterior third of the medulla spinalis; in
the lumbar enlargement it is near the middle, and in the conus
medullaris it approaches the posterior surface. It is filled
with cerebrospinal fluid, and lined by ciliated, columnar
epithelium, outside of which is an encircling band of gelatinous
substance, the substantia gelatinosa centralis (or central
gelatinous substance of spinal cord). This gelatinous substance
consists mainly of neuroglia, but contains a few nerve cells and
fibers; it is traversed by processes from the deep ends of the
columnar ciliated cells which line the central canal. This
article was originally based on an entry from a public domain
edition of Gray's Anatomy. As such, some of the information
contained herein may be outdated. Please edit the article if
this is the case, and feel free to remove this notice when it is
no longer relevant.