Spinal cord anatomy, illustration. This sagittal view is orientated with the rear of the spine at right. The labelled components are at left the body of a vertebra and an intervertebral disc, and a spinous process and interspinous ligament at right. Down centre is the spinal cord, with the posterior longitudinal ligament down left. The layers surrounding the spinal cord are (from outer to inner): the epidural space, the dura mater, the subarachnoid membrane, and the intrathecal space and cerebrospinal fluid.