Right posterolateral view of posterior fossa following mastoidectomy and selective petrosectomy. For orientation, the posterior surface of the petrous portion of the temporal bone (partially resected) is in the middle of the image. Here, nerves can be seen coursing toward the internal auditory meatus and jugular foramen. The anterior inferior cerebellar artery arises from the lower third of the basilar artery and supplies the inferior and ventral surfaces of the cerebellum and lateral pons. It commonly gives rise to a labyrinthine artery that enters the internal auditory canal and supplies the facial and vestibulocochlear nerves, the labyrinth, and cochlea. Bony removal has exposed the many segments of the facial nerve (meatal, labyrinthine, tympanic, and mastoid). The glossopharyngeal, vagus, and cranial roots of the spinal accessory nerves are shown coursing toward the jugular foramen. (Image courtesy of AL Rhoton, Jr.)