The facial nerve (cranial nerve 7) supplies branchiomotor fibres to all second-pharyngeal-arch muscles (i.e., the muscles of facial expression). It also carries preganglionic parasympathetic fibres to the lacrimal, submandibular, sublingual and nasal mucous glands, conveys taste from the anterior two-thirds of the tongue via the chorda tympani, and contributes some general sensation to the skin of the external auditory meatus.
It leaves the brainstem as a large motor root and a smaller nervus intermedius (parasympathetic and sensory), enters the internal acoustic meatus with the vestibulocochlear nerve, traverses the facial canal in the petrous temporal bone, bends at the geniculate ganglion, descends on the posterior wall of the tympanic cavity, exits the skull through the stylomastoid foramen, and then enters the parotid gland where it divides into upper and lower divisions.
Intratemporal branches (before exiting the skull):
Greater petrosal nerve: parasympathetic fibres to the lacrimal gland via the pterygopalatine ganglion.
Nerve to stapedius: motor to stapedius to dampen ossicular and tympanic membrane vibration.
Chorda tympani: taste from anterior two-thirds of the tongue; parasympathetic fibres to submandibular and sublingual glands via the lingual nerve (which is a branch of the mandibular division of the trigeminal nerve).