Chorda tympani

The chorda tympani is a nerve that arises from the mastoid segment of the facial nerve, carrying afferent special sensation from the anterior two-thirds of the tongue via the lingual nerve, as well as efferent parasympathetic secretomotor innervation to the submandibular and sublingual glands.

Gross anatomy

After branching off from the facial nerve, the chorda tympani courses through the temporal bone before joining the lingual nerve :

• branch from mastoid segment of facial nerve: the branching site can be variable from either the proximal, mid- or distal mastoid segment of facial nerve; occasionally the chorda tympani can even branch off from the facial nerve after exiting the stylomastoid foramen
• posterior canaliculus: the chorda tympani then courses superiorly to the level of the manubrium/neck of malleus; the distance of ascent is variable, depending on the initial branching pattern from the mastoid segment of facial nerve
• tympanic segment is the segment of chorda tympani as it traverses the middle ear cavity between the malleus and incus in a posteroanterior direction; not visible with current imaging techniques
• anterior canaliculus: the chorda tympani re-emerges on the anterior wall of the middle ear cavity and enters the petrotympanic fissure, which is medial to the temporomandibular joint
• the chorda tympani exits the petrotympanic fissure and joins the lingual nerve approximately 2 cm below the skull base

Siehe auch:

• Cavum tympani