As the sound waves move through the perilymph they displace the basilar membrane, which causes deflection of the hair cells in the organ of Corti (eFig. 9.81A). These sensory receptors synapse with sensory neurons, which have cell bodies in spiral ganglion located within the modiolus of the cochlea (eFig. 9.80). Axons leaving the modiolus form the cochlear nerve near the base of the cochlea. The cochlear nerve then passes through the internal acoustic meatus and subarachnoid space to enter the pontomedullary junction at the cerebellopontine angle.