Branches of the superior cerebellar artery ramifying on the superior surface of the cerebellum. The crus cerebri, substantia nigra, interpeduncular fossa, cerebral aqueduct, and tectum of the midbrain are in view. The right oculomotor nerve emerges from the lateral surface of the interpeduncular fossa and enters the subarachnoid space above the origin of the superior cerebellar artery from the basilar artery. The trochlear nerve emerges from the tectal surface and wraps around the cerebral peduncle. Both nerves (III and IV) course toward the cavernous sinus. The tentorium cerebelli has been cut away to reveal multiple hemispheric branches of the superior cerebellar artery. The main trunk of this artery passes inferior to the trochlear nerve and tentorial edge at the anterolateral midbrain and divides into a rostral and caudal trunk. The rostral trunk courses posteriorly above the trochlear nerve. The superior cerebellar artery supplies the superior vermis and superior surface of the hemispheres. The lateral, intermediate, and medial hemispheric branches penetrate to supply deep areas and nuclei of the cerebellum. (Image courtesy of AL Rhoton, Jr.)