1. A derivative of the nervus intermedius (root of the facial nerve) which leaves the main nerve in the facial canal to enter the middle ear cavity.
2. A nerve given off from the facial nerve in the facial canal which passes through the posterior canaliculus of the chorda tympani into the tympanic cavity, crosses over the tympanic membrane and handle of the malleus, and passes out through the anterior canaliculus of the chorda tympani in the petrotympanic fissure to join the lingual branch of the mandibular nerve in the infratemporal fossa.

It conveys taste sensation from the anterior two-thirds of the tongue and carries parasympathetic preganglionic fibers to the submandibular ganglion, for innervation of the submandibular and sublingual salivary glands.