Posterosuperior view of left cerebellopontine angle. The cerebellum has been reflected away and bone removed at the internal acoustic meatus to visualize the facial (CN VII) and vestibulocochlear (CN VIII) nerves (acousticofacial bundle) entering the meatus. Anterior inferior cerebellar artery (AICA) arises from the basilar artery to supply the cerebellum. The labyrinthine artery most commonly branches from AICA and accompanies CN VIII to the inner ear. Glossopharyngeal (CN IX) and vagus (CN X) nerves emerge from the medulla to exit the skull via the jugular foramen. The superior petrosal vein is an important drainage vein of the anterior cerebellum and brainstem and is formed by the union of several veins including the pontine trigeminal vein and veins of the cerebellopontine fissure and middle cerebellar peduncle. It empties into the superior petrosal sinus.  (Image courtesy of AL Rhoton, Jr.)