Relating to the membrane that covers the ventricles of the brain and the spinal cord canal: The ependymal lining of Clive's spinal cord canal was causing him pain because of an infection.

A circumscribed distention or stretching of some part of the central canal of the spinal cord or of the cerebral ventricles which are spaces in the brain that are located between sections of the brain and filled with cerebrospinal fluid: Dr. Anderson, the neurosurgeon, carefully examined the ependymal cyst in Jim's spinal cord.