Magnified view of left lateral subtemporal area with tentorium and associated neurovasculature. For orientation, the temporal lobe is reflected at the lower border of the image and the tentorium is seen divided 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 to do so, and courses toward the cavernous sinus in relation to the superior cerebellar artery. The trigeminal nerve can be seen emerging beneath the cerebellum after emerging from the lateral mid-pons. (Image courtesy of AL Rhoton, Jr.)