Anteroinferior view of interpeduncular fossa and cistern. The distal end of the basilar artery is shown approaching the pontomesencephalic junction. Here it gives rise to superior cerebellar and terminal posterior cerebral arteries. The oculomotor nerves emerge from the anterior midbrain (from the lateral walls of the interpeduncular fossa) between these two arteries. In this view, the P1 and P2 segments of the posterior cerebral arteries are nicely visualized with the posterior communicating arteries the landmark between these two segments. The mammillary bodies, part of the hypothalamus of the diencephalon, are located posterior to the pituitary infundibulum. The latter connects the hypothalamus and posterior pituitary gland and lies between the optic chiasm and the mammillary bodies. (Image courtesy of AL Rhoton, Jr.)