Type: Term Definitions: 1. continuation of the dura mater inferior to the termination (caudal end) of the spinal cord (L2 vertebral level), surrounding the lumbar cistern, cauda equina, and filum terminale.
Dural sac: The membranous sac that encases the spinal cord within the bony structure of the vertebral column. Dural refers to the dura, the name of the membrane around the spinal cord (and brain, too).