Chorda tympani
1 - vestibular nerve
2 - cochlear nerve
3 - facial nerve
4 - geniculate ganglion
5 - tympanic chord
6 - cochlea
7 - semicircular canals
8 - malleus
9 - tympanic membrane
10 - Eustachian tube
Large in the background the eardrum with the hammer grip attached (in the picture HANDLE OF MAL. ). The anvil has been removed for the sake of clarity. The chorda tympani (in the picture CHORDA TYMPANI NERVE ) crosses the hammer between the hammer handle and the hammer head (in the picture HEAD OF MALLEUS ) and runs open, like a string , in the air-filled tympanic cavity. On the right of the picture the junction of the chorda tympani from the facial nerve (in the picture FACIAL NERVE ). The fibers of the chorda tympani run from the branch together with the other fibers of the facial nerve upwards (cut in the picture) to the geniculate ganglion. On the left the further course through the fissura petrotympanica (in the picture GLASERIAN FISSURE ) into the innervation area of the lower jaw.
The chorda tympani (“timpani string”) is a branch of the seventh cranial nerve , the facial nerve . It has sensory and parasympathetic fibers.
The chorda tympani separates in the facial canal from the facial nerve and runs through the middle ear . It is sometimes visible as a delicate strand through the eardrum when examined with an otoscope , which is what led to its naming. It leaves the petrous pyramid through the petrotympanic fissure (Glaser's fissure ) or through the sphenopetrosal fissure , through which the anterior tympanic artery also runs. They then superimposed on the lingual nerve - a branch of the mandibular nerve of the trigeminal nerve - and uses this as a line structure. Afferent and efferent information is carried through these fibers :
- The parasympathetic fibers stimulate the secretion of the lower salivary glands ( mandibular and sublingual glands ) as well as the tongue glands . These fibers are switched to postganglionic fibers in the submandibular ganglion before they enter their target organs .
- The Chorda tympani derives sensory taste stimuli from the front two thirds of the tongue.
Damage to the chorda tympani on one side leads to the loss of the sense of taste on the same side of the front half of the tongue, and damage to both sides leads to the loss of taste on the front half of the tongue. A Ageusia is not the result, since the rear third of the tongue from the sensory glossopharyngeal is supplied.