AXIAL VIEW THROUGH A LUMBAR VERTEBRA The posterior epidural space (shown in orange) is triangle-shaped with its apex located in the dorsal midline. The ligamentum flavum forms the dorsal roof of the epidural space and blends with the capsules of the facet joints laterally. Connective tissue septa separate the anterior epidural space from the lateral and posterior epidural spaces. A midline connective tissue band extending from the annular ligament divides the anterior epidural space into lateral halves. The anterior epidural space is almost entirely filled with veins which communicate with the basivertebral vein.