central canal of spinal cord [Gk, kentron + L, canalis, channel] , the conduit that runs the entire length of the spinal cord and contains some of the 140 mL of cerebrospinal fluid (CSF) in the body of the average individual. The central canal of the spinal cord lies in the center of the cord between the ventral and the dorsal gray commissures and extends toward the cranium into the medulla oblongata, where it opens into the fourth ventricle of the brain. Lumbar puncture, often performed to obtain samples of CSF for diagnostic purposes, draws fluid from the subarachnoid space around the spinal cord and not from the central canal. See also lumbar puncture.
