Endoscopic view of right anteromedial aspect of petroclival area. Petrosal and clival bone have been removed to expose the internal carotid artery (at left border of image) and basilar artery overlying the pons. The abducens nerve is shown coursing from the lower ventral pons through a remnant of clival bone and dura into the cavernous sinus on the lateral surface of the internal carotid artery. The anterior inferior cerebellar artery arises from the proximal portion of the basilar artery and passes posteriorly toward the cerebellum. Pontine circumflex branches emerge from the basilar and follow the surface of the pons laterally. The superior cerebellar artery is shown near the rostral end of the pons. (Image courtesy of AL Rhoton, Jr.)