Magnified view of right cerebellopontine angle. The right cerebellum is reflected to expose the flocculus and cranial nerves emerging from the brainstem. The trigeminal (CNV) nerve leaves the lateral pons and courses toward the apex of the petrous bone. The abducens (CNVI) nerve is visible after leaving the caudal portion of the pons to ascend along the clivus. The facial (CNVII) and vestibulocochlear (CNVIII) nerves leave the lateral pontomedullary junction and course to the internal auditory meatus. A loop of the anterior inferior cerebellar artery, a branch of the basilar artery, is nearby. Emerging from the anterolateral surface of the medulla and traveling to the jugular foramen are, in rostral-to-caudal sequence, the glossopharyngeal (CNIX) and vagus (CNX) nerves. The spinal accessory (CNXI) nerve can be seen near the right lower corner of the image. After ascending through the foramen magnum it also courses toward the jugular foramen only to exit the skull through that foramen. Rootlets of the hypoglossal (CNXII) nerve emerge more anteriorly from the medulla and course posterior to the vertebral artery toward the hypoglossal canal. The superior petrosal vein drains the anterior and lateral surfaces of the brainstem and some of the lateral part of the tentorial and suboccipital surfaces of the cerebellum before emptying into the superior petrosal sinus near the trigeminal nerve. (Image courtesy of M Nunez)