Epidural space

In the spine, the epidural space (from Ancient Greek ἐπί, "on, upon" + dura mater also known as "epidural cavity", "extradural space" or "peridural space") is an anatomic space that is the outermost part of the spinal canal. It is the space within the canal (formed by the surrounding vertebrae) lying outside the dura mater (which encloses the arachnoid mater, subarachnoid space, the cerebrospinal fluid, and the spinal cord). In humans the epidural space contains lymphatics, spinal nerve roots, loose connective tissue, fatty tissue, small arteries, and a network of internal vertebral venous plexuses.