Endocranial views of the left internal auditory meatus and jugular foramen. The vestibulocochlear-facial nerve bundle can be seen coursing toward the internal auditory meatus on the posterior wall of the petrous temporal bone. Posterior to this is the endocranial opening to the jugular foramen, which is an irregular space formed by reciprocal depressions of petrous bone and occipital bone. Intrajugular compartments receive the glossopharyngeal, vagus, and spinal accessory nerves as well as the inferior petrosal and sigmoid sinuses. In this view, a bridging vein also traverses the foramen to enter a sinus. The jugular tubercle, an elevation of bone from the inferolateral margin of the clivus, projects posterosuperiorly over the hypoglossal canal that receives the hypoglossal nerve. The medulla and cerebellum have been retracted slightly to expose the posterior inferior cerebellar artery, the largest branch of the vertebral artery. (Image courtesy of AL Rhoton, Jr.)