Chorda tympani
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.