Hypoglossal canal

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Structures of the cranial fossae.

The hypoglossal canal is a small opening in the occipital bone. There are two hypoglossal canals (left and right) located in the anterolateral margins of the foramen magnum, deep to the occipital condyles. The canals take a slightly oblique angle, facing in a superoanterior direction.

The hypoglossal canal is the cranial exit for the hypoglossal nerve (cranial nerve XII). This nerve provides somatic motor innervation to the intrinsic and extrinsic muscles of tongue (except palatoglossus). It also transmits the meningeal branch of the ascending pharyngeal artery, the venous plexus of the hypoglossal canal which has connections to emissary vein/s from the basilar plexus. It also allows the re-entry into the skull of the meningeal branches of the hypoglossal nerve (which in fact carry fibers from the sensory spinal ganglion of C2 spinal nerve rather than hypoglossal nerve fibers).