Left lateral view of posterior surface of petrous temporal bone. The cerebellum has been retracted to expose the area along the posterior surface of the petrous temporal bone. The facial and vestibulocochlear nerves leave the lateral pontomedullary junction to course toward the internal auditory meatus in company with a loop of the anterior inferior cerebellar artery. Posteroinferior to this opening is the jugular foramen to which course the glossopharyngeal, vagus, and spinal accessory nerves. Posterior to these nerves is a segment of the posterior inferior cerebellar artery, the largest branch of the vertebral artery. (Image courtesy of AL Rhoton, Jr.)