Suboccipital exposure of the left cerebellar hemisphere and cranial nerves V-XI. The cerebellum has been reflected to expose the flocculus and several cranial nerves traversing the cerebellopontine cistern. The trigeminal (CNV) leaves the lateral pons to cross the apex of the petrous bone into Meckel's cave. The abducens (CNVI) nerve lies deep in the image. It left the lower portion of the pons and penetrates dura on the clivus and courses to the cavernous sinus. 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 traverses these nerves. It gives rise to the labyrinthine artery, which accompanies the nerves into the meatus. Emerging from the anterolateral surface of the medulla and traveling to the jugular foramen are the (in rostral-to-caudal sequence) glossopharyngeal (CNIX), vagus (CNX), and cranial portion of the spinal accessory (CNXI) nerves. The spinal root of the accessory nerve arises from fibers emanating from the C1-C5 levels of the spinal cord and ascends through the foramen magnum to unite with the cranial portion within the jugular foramen. A portion of the superior cerebellar artery, a branch of the basilar artery, is shown coursing on the superior surface of the cerebellum. (Image courtesy of M Nunez)