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Chorda Tympani

What is Chorda tympani?

Chorda tympani is one of the branches that belongs to the facial nerve, its origin being represented by the taste buds that are located in the anterior part of the tongue. After it leaves its origin, it travels along the middle ear and reaches the brain with information related to the taste sensation. At the level of the facial canal, it joins the facial nerve (also known as the 7th cranial nerve). This union takes place at the point where the facial nerve actually leaves the skull, meaning through the petrotympanic fissure.

There are three cranial nerves that are involved in the taste sensation, the chorda tympani being one of them. All of the three nerves function in perfect synchronization, with each of the nerves working to make sure that the signals of the other nerves are inhibited. The influence of the chorda tympani over the other taste nerves is quite strong; the nerve also influences that pain fibers that are found throughout the tongue. In the situation that the chorda tympani suffers from damage, the inhibitory signals are going to be altered – this means that the other nerves are not going to be so inhibited by the chorda tympani anymore.

It is possible that the chorda tympani nerve varies from one person to the other. There are patients in which the nerve starts at the proximal part of the facial nerve, sometimes quite at a close distance from the geniculate ganglion. Its length can also vary – it can be between 3 and 14 mm. The posterior canaliculus is absent in 10% of the individuals or it may be replaced by a grove.

When it comes to fetuses and small infants, the chorda tympani will separate from the facial nerve outside the skull. However, as the mastoid process begins to grow and develop, it will reach a more anterior position. The growth of the facial canal stimulates the divergence of the chorda tympani from the facial nerve when children reach the age of one year.


The internal acoustic meatus is the point that is used by the chorda tympani in order to leave the cranial cavity, along with the facial nerve. Once it exits the cranial cavity, the chorda tympani is going to run through the middle ear, along the tympanic membrane (from posterior to anterior). Upon its journey, the nerve travels between the incus and the malleus.

It continues through the petrotympanic fissure, reaching the infratemporal fossa. Soon, it will follow the same pathway as the larger lingual nerve, which is actually a branch of the mandibular nerve. Both the chorda tympani and the lingual nerve will travel all the way to the submandibular ganglion. Upon reaching the ganglion, the preganglionic fibers will connect with the postganglionic ones and go on to innervate the salivary glands in the area (submandibular and sublingual). The chorda tympani also has special sensory fibers (for taste) that travel to the anterior part of the tongue (along the lingual nerve).

The chorda tympani also contains fibers that come from two of the brain stem nuclei, meaning the superior salivatory nucleus and the nucleus of tractus solitaris. In the first nucleus, there are the cell bodies that belong to the secretomotor preganglionic parasympathetic neurons. As for the nucleus of tractus solitaris, it is its superior portion that contributes to the chorda tympani. The connections of the chorda tympani at the level of the facial canal include the sensory branch of the facial nerve and the nervus intermedius of Wrisberg.

What is the Function of Chorda Tympani?

The functions of the chorda tympani are given by the nerve fibers that it contains. On one hand, it has special sensory fibers, covering the taste sensation for the anterior part of the tongue. On the other hand, it is the nerve that provides the secretomotor innervation for the above-mentioned salivary glands; apart from these glands, however, the chorda tympani also influences the activity of the blood vessels in the area. For example, if stimulated, it can lead to the dilation of the respective blood vessels (this is because it supplies efferent vasodilator fibers to the tongue).

In the situation that the chorda tympani nerve suffers an injury, the person might experience either the loss or distortion of the taste sensation. If the damage to the nerve has been extensive, it is possible that a person might not be able to differentiate certain tastes from one another. On the other hand, if a part of the tongue is affected (meaning one of the chorda tympani nerve), it has been discovered that the taste intensity on the other part of the tongue is heightened (as a form of compensation).

Pictures of Chorda Tympani

chorda tympani
Chorda Tympani Picture 1 : Diagrammatic representation of Chorda Tympani and other parts including Tegman tympani, Malleus, Aditus to mastoid antrum, Incus, Mastoid process, Epitympanic recess, Tensor tympani, Tympanic membrane, Pharyngotympanic tube, Tympanic cavity, Facial nerve (CN VII), Internal jugular vein, Internal carotid artery, and Carotid sheath.

chorda tympani pictures
Chorda Tympani Picture 2 : Picture showing the Facial nerve and the Chorda Tympani nerve.

Chorda Tympani and Taste

Many studies have tried to identify the relationship between chorda tympani and taste. Diverse sweeteners have been used in studies that involved mice, rats and primates – based on this research, it was discovered that the sweet taste is detected by the sensory fibers of chorda tympani only in mice and primates (not in rates). Other studies have revealed that the sensory fibers are sensitive to substances such as sodium chloride. The response to quinine has been identified at low levels and, when it comes to hydrochloride, the findings are non-specific. A comparison has also been made between the sensory fibers of chorda tympani and the greater superficial petrosal nerve – it was discovered that the first has a lower response rate to substances such as sucrose.


A study has demonstrated that, upon the chorda tympani being resected at a young age, the taste buds that are innervated by it are not going to grow back at what should be the full strength. Another study performed on mice showed that the preference for sodium chloride increases upon both the chorda tympani being resected. It is also known that the innervation of the fungiform papillae on the tongue is handled by the chorda tympani. Interestingly enough, if the chorda tympani is resected, these papillae are going to undergo what can be described as a structural change (from fungiform to filiform).

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