1. A network of valveless veins in the human body that connect the deep pelvic veins and thoracic veins(draining the inferior end of the urinary bladder, breast and prostate) to the internal vertebral venous plexuses. Because of their location and lack of valves, they are believed to provide a route for the spread of cancer metastases. (wikipedia.org)
2. Any of four interconnected venous networks surrounding the vertebral column; anterior external vertebral venous plexus, the small system around the vertebral bodies; posterior external vertebral venous plexus, the extensive system around the vertebral processes; anterior internal vertebral venous plexus, the system running the length of the vertebral canal anterior to the dura; posterior internal vertebral venous plexus, the system running the length of the vertebral canal posterior to the dura; the latter two constitute the epidural venous plexus. (biology-online.org)
Syn: Batson veins, plexus venosus vertebralis, batsons plexus, vertebral venous plexus.