Cranial Nerve VIII – Statoacoustic, Vestibulocochlear, Auditory Nerve
Figure 25. Cranial Nerve VIII – Statoacoustic, Vestibulocochlear, Auditory Nerve
The eighth cranial nerve wins the most names contest but if you are trying to remember what the function of the nerve is remember only the first two names as you will see that the third one on the list is incomplete. The vestibulocochlear nerve passes like the facial nerve, through the internal acoustic meatus, but stays within the temporal bone. It originates at the cochlea, the semicircular canals, the maculae, the saccule and the utricle. The cochlear is the area where the cells that sense vibrations that are ultimately translated into auditory information so it carries fibers going towards the brain. The other four organs mentioned are involved with the special sense of equilibrium and their afferent fibers form the vestibular branch of the nerve hence the name vestibulocochlear as that is just the name of the two nerves that form it. The statoacoustic name comes from the two special senses that it carries, those of equilibrium (stato) and hearing (acoustic). While some authors use the acoustic nerve for cranial nerve VIII that name neglects an important function as anyone with vertigo will attest as it carries special sensory fibers for equilibrium as well as hearing.