anatomy of cranial nerve XII
Last reviewed 01/2018
The hypoglossal nerve arises in the hypoglossal nucleus of the medulla in the floor of the fourth ventricle at the level of the inferior olive. Rootlets emerge from the brainstem between the inferior olives and the pyramids to merge as a bundle which passes through the hypoglossal canal. It descends between the internal carotid artery and internal jugular vein. Just above the bifurcation of the common carotid artery, the hypoglossal fibres penetrate the floor of the mouth to innervate the extrinsic and intrinsic muscles of the tongue.