[TA] plexus of unvalved veins embedded in the fat of the epidural space within the vertebral canal, with greatest venous density posterior to the vertebral bodies and intervertebral discs (anterior internal vertebral venous plexus [TA]) and anterior to the laminae and ligamentum flavum (posterior internal vertebral venous plexus [TA]); receives drainage from the vertebral bodies through the basivertebral veins, communicates superiorly with the dural venous sinuses, and through the intervertebral foramina by way of the intervertebral veins at all levels.vertebral venous system. SYN: plexus venosus vertebralis internus [TA], epidural venous plexus.