Throughout the cervical and thoracic regions the central canal

Central canal

For the engineering project, see Indiana Central Canal.The central canal is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord. The central canal is contiguous with the ventricular system of the brain...

 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

Cerebrospinal fluid

Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...

, 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

Central canal

For the engineering project, see Indiana Central Canal.The central canal is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord. The central canal is contiguous with the ventricular system of the brain...

.

It should not be confused with the Substantia gelatinosa of Rolando

Substantia gelatinosa of Rolando

The apex of the posterior horn of the gray matter of the spinal cord is capped by a V-shaped or crescentic mass of translucent, gelatinous neuroglia, termed the substantia gelatinosa of Rolando , which contains both neuroglia cells, and small nerve cells...

, which is located more dorsally.