Hypoglossal Nerve (CN XII), Gross Anatomy

Description

Seen from a superior aspect into the cranial cavity, the opened skull base exposes the posterior cranial fossa with the clivus and foramen magnum as the dominant midline landmarks. The hypoglossal nerve (cranial nerve XII) is traced in yellow as rootlets emerging from the anterolateral medulla, then coursing anteriorly and laterally to exit the skull via the hypoglossal canal, situated superior to the occipital condyle and lateral to the foramen magnum. Nearby cranial nerves at the jugular foramen and internal acoustic meatus provide orientation, while venous sinuses and other vascular channels appear in blue. A top down cranial cavity view helps you teach where CN XII sits in the packed neurovascular geography of the skull base and why its bony exit matters. Lesions at the hypoglossal canal, including occipital condyle fractures, skull base metastasis, or hypoglossal schwannoma, produce ipsilateral tongue weakness with deviation toward the side of injury on protrusion, a pattern that differs from supranuclear dysarthria syndromes. The proximity of CN XII to the vertebral and basilar arterial system and to lower cranial nerves also makes it a key landmark when correlating brainstem stroke syndromes and planning far lateral or transcondylar skull base approaches. Small space, big consequences. Use this illustration in gross anatomy, neuroanatomy, and head and neck modules to reinforce foramina identification, cranial nerve numbering, and the exit pathways from the posterior cranial fossa. It also suits operative anatomy figures for skull base surgery texts and radiology teaching files when correlating CT of the hypoglossal canal and MRI of lower cranial nerve palsies. Anatomical accuracy verified by SciePro's Medical Advisory Board.