For the engineering project, see Indiana Central Canal. The central canal, also known as ependymal canal, is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord. The central canal is continuous with the ventricular system of the brain. The fourth ventricle narrows at a region called the obex to become the central canal of the spinal cord. The central canal represents the adult remainder of the central cavity of the neural tube. It generally occludes (closes off) with age.