Venous plexus of hypoglossal canal

The venous plexus of hypoglossal canal is a small venous plexus surrounding the hypoglossal nerve (cranial nerve XII) as it passes through the hypoglossal canal. The plexus connects with the occipital sinus (intercranially), inferior petrosal sinus (intercranially), internal jugular vein (extracranially), condylar vein, and paravertebral venous plexus.

Anatomy
Anatomical studies have demonstrated that the venous plexus is the dominant structure of the hypoglossal canal. Research has shown that the size of the hypoglossal canal varies in relation to an individual's skull size, suggesting that the venous plexus functions as an essential emissary veinous structure.

Variation
Occasionally, it may be a single vein rather than a venous plexus.

Clinical significance
A case report described an instance of a dilated venous plexus of hypoglossal canal portruding into the cerebellomedullary cistern and thus mimicking a pathological mass upon MRI imaging.