the eighth cranial nerve: a sensory nerve containing tracts that innervate both the sense of hearing and the sense of balance. It has two divisions, the vestibular nerve, originating in the vestibule and the semicircular canals, and the auditory nerve (acoustic or cochlear nerve), originating in the cochlea. The vestibulocochlear nerve transmits impulses from the inner ear to the medulla oblongata and pons and has fibers that continue into the cerebrum and cerebellum. Also called cranial nerve VIII.