Medial view of right cerebellopontine angle. The roof of the petrous portion of temporal bone has been removed to visualize the nervus intermedius, facial (CN VII), and vestibulocochlear (CN VIII) nerves entering the internal acoustic meatus. The latter are shown dividing further into the cochlear and superior and inferior vestibular branches. The anterior inferior cerebellar artery (AICA) arises from the basilar artery and often passes between CN VII and CN VIII. Nervus intermedius is part of CN VII that contains sensory and parasympathetic fibers. At the geniculate ganglion, parasympathetic fibers from the nervus intermedius diverge to form the greater superficial petrosal nerve that exits the petrous bone and travels in a groove deep to the trigeminal ganglion toward the foramen lacerum. Sensory neurons in the trigeminal (Gasserian) ganglion give rise to the trigeminal nerve (CN V) and central processes of the neurons enter the brainstem at the pons. (Image courtesy of AL Rhoton, Jr.)