They are arranged into four interconnected, vertically oriented vessels - two situated anteriorly, and two posteriorly:[3] The anterior and posterior internal plexuses communicate via a series of venous rings - one near each vertebra.

[3] Due to these interconnections, the anterior and posterior internal plexuses were formerly considered a single vascular unit - the retia venosa vertebrarum.

[4] The internal vertebral venous plexuses are composed of valveless veins.

[2] They form a denser vascular network than the external vertebral venous plexuses.

[2] Around the foramen magnum, they form a dense venous network with the vertebral veins, sigmoid sinuses, occipital sinuses, the basilar plexus, the condyloid emissary veins, and the rete canalis hypoglossi.