The seventh cranial nerve (CN VII) which runs from the brainstem to the muscles of the face and tongue. It controls facial expressions, as well as receives some taste sensations from the tongue. It also controls the stapedius muscle in the middle ear, which is responsible for protecting the ears from loud noises.
Some conditions which affect the facial nerve include infection of the facial nerve, tumors, and Bell’s palsy. Because the facial nerve runs very close to the vestibulocochlear nerve (CN VIII), conditions affecting either of one of these nerves may affect the other. That is why acoustic neuromas and some cholesteatomas can affect facial nerve function, and Bell’s palsy, which affects the facial nerve, may also affect the ear.