The central canal is a narrow canal situated within the transverse grey commisure of the spinal cord.  The cord is present throughout the entire length of the spinal cord and extends into the lower part of the medulla oblongata, where it opens into the fourth ventricle.  In the conus medullaris the canal expands as a fusiform ventricle where it terminates in the upper third of the filum terminale; this ventricle becomes obliterated by the age of 40 years.

The central canal is lined by columnar epithelium (ependyma) and contains cerebrospinal fluid (CFS).