Spinal epidural space is largest at 3rd lumbar veebrae .Spinal epidural space is a closed anatomic space between the dura mater and the bony spinal canal. It extends from the foramen magnum to the sacrum. Unlike its intracranial counterpa, spinal epidural space is real. The presence of anchoring plicae and meningoveebral ligaments divide the space into anterior, lateral and posterior compaments. Ref - pubmed.com