The Hypoglossal Nerve exits the skull from its own foramen. It lies superficial to both the internal and external carotid arteries. Inferior to the posterior belly of digastric the hypoglossal nerve lies on three arteries (lingual, occipital, and external carotid). The hypoglossal nerve passes between the mylohyoid and hyoglossus muscles (the mylohyoid cleft).
Injury to the hypoglossal
nerve results in unilateral paralysis of the tongue. The tongue deviates to the
affected side upon protrusion. Chronic unilateral paralysis results in atrophy
and wrinkling of the affected side.