Left lateral subtemporal view of tentorium and associated neurovasculature. For orientation, the temporal lobe is reflected at the lower border of the image and the tentorium is seen along the superior border. Anterior is toward the right side of the image; posterior to the left. The oculomotor nerve emerges from the anterior aspect of the lower midbrain between the superior cerebellar and posterior cerebral arteries, branches of the basilar artery. The trochlear nerve emerges from the dorsal surface of the midbrain, the only cranial nerve that arises from the dorsum, and courses toward the cavernous sinus in relation to the superior cerebellar artery. The intracranial portion of the internal carotid artery is in view giving rise to the posterior communicating artery before terminating into anterior and middle cerebral arteries.  (Image courtesy of AL Rhoton, Jr.)