Posterior Internal Vertebral Venous Plexus (Sacral; Left)

Origin

The posterior internal venous plexus is formed by a network of vessels located within the vertebral canal, anterior to the vertebral arches and lining the posterior aspect of the epidural space. They are in ruminant formation in the cervical region but more developed caudally.

Course

The posterior internal venous plexus is composed of valveless veins, which are free to anastomose with the posterior external vertebral venous plexus.

Additionally, around the foramen magnum, the venous plexus communicates with the occipital and sigmoid sinuses, the basilar plexus, and the condylar emissary veins. It communicates laterally with the intervertebral veins which drain the vertebral venous plexus into the vertebral vein in the neck, the posterior intercostal veins in the thorax, and the lumbar and lateral sacral veins caudally.

Tributaries

The posterior internal venous plexus receives blood from the posterior external vertebral venous plexus, carrying blood from outside the vertebral canal inside.

Structures Drained

The posterior internal vertebral venous plexus drains the vertebrae, epidural space, spinal cord, and local tissue.

List of Clinical Correlates

- Spinal epidural hematoma