The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the

mandibular division In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth Cranial nerves, cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which ...

of the trigeminal nerve (CN V) and from the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

(CN VII). The fibres from the trigeminal nerve are for touch, pain and temperature (general sensation), and the ones from the facial nerve are for taste (special sensation).

Structure

Origin

The lingual nerve arises from the posterior trunk of mandibular nerve (CN V) within the infratemporal fossa.

Course

The lingual nerve first courses deep to the lateral pterygoid muscle and superior to the tensor veli palatini muscle; while passing between these two muscle, it is joined by the

chorda tympani Chorda tympani is a branch of the facial nerve that carries gustatory (taste) sensory innervation from the front of the tongue and parasympathetic ( secretomotor) innervation to the submandibular and sublingual salivary glands. Chorda tymp ...

, and often by a communicating branch from the inferior alveolar nerve. The nerve then comes to pass inferoanteriorly upon the medial pterygoid muscle towards the medial aspect of the

ramus of mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

, eventually meeting the mandible at the junction of the ramus and body of mandible. Here, the lingual nerve is anterior and somewhat medial (deep) to the inferior alveolar nerve. It crosses obliquely to the side of the tongue beneath the constrictor pharyngis superior and styloglossus, and then between the hyoglossus and deep part of the submandibular gland; it finally runs from laterally to medially inferiorly crossing the duct of the submandibular gland, and along the tongue to its tip becoming the sublingual nerve, lying immediately beneath the

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

. The submandibular ganglion is suspended by two nerve filaments from the lingual nerve.

Distribution

General sensory

The lingual nerve supplies general somatic afferent (i.e. general sensory) innervation to the

of the anterior two-thirds of the tongue (i.e. body of tongue) (whereas the posterior one-third (i.e. root of tongue) is innervated via the glossopharyngeal nerve (CN IX)), the floor of the

oral cavity A mouth also referred to as the oral is the body orifice through which many animals ingest food and vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also the first part of the alime ...

, and the mandibular/inferior lingual gingiva.

Special sensory and parasymathetic autonomic

The lingual nerve also comes to convey fibres of the

(which are derived from the facial nerve (CN VII)), which provide special sensation (taste) to the anterior two-thirds of the tongue as well as

parasympathetic The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The autonomic nervous system is responsible for regulat ...

and sympathetic innervation.

Clinical significance

Lingual nerve injuries

The most common cause of lingual nerve injuries is third molar (

wisdom tooth The third molar, commonly called wisdom tooth, is the most posterior of the three molars in each quadrant of the human dentition. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs between late teens a ...

) surgery, less commonly the lingual nerve can be injured by local anaesthetic dental injections (particularly inferior dental block injections) and sublingual or submandibular surgery. Any injury to sensory nerves can result in pain, altered sensation and/or numbness, but usually a combination of all three symptoms arises. This can have a significant negative effect on the patient's quality of life affecting their daily function and psychological health. Patients should be routinely warned about lingual nerve injuries prior to wisdom tooth and floor of mouth surgery. The risk associated with wisdom tooth surgery is commonly accepted to be 2% temporary and 0.2% permanent. Warning patients of nerve injury prior to administration of deep dental injections has a risk of injury in approximately 1:14,000 with 25% of these remaining persistent. Preoperative warning about these injuries is routinely undertaken in the US and Germany. This reflects good practice recommended by the Royal College of Anaesthetists (prior warning of potential nerve injury in relation to spinal and epidural blocks 1 on 24–57,000 risk). Infiltration dentistry is a technique that may reduce the possibility of lingual nerve injuries by avoiding deep injections. Avoiding lingual access when undertaking wisdom tooth surgery will also avoid unnecessary lingual nerve injuryEur J Dent Educ. 1999 May;3(2):52-5.The effect of surgical technique on lingual nerve damage during lower 3rd molar removal by dental students.Robinson PP, Loescher AR, Smith KG.

Additional images

File:Gray178.png, Mandible of human embryo 24 mm. long. Outer aspect. File:Gray781.png, Mandibular division of the trifacial nerve. File:Gray782 updated.png, Mandibular division of trifacial nerve, seen from the middle line. File:Gray788.png, Plan of the facial and intermediate nerves and their communication with other nerves. File:Gray794.png, Hypoglossal nerve, cervical plexus, and their branches. File:Gray842.png, Sympathetic connections of the submaxillary and superior cervical ganglia. File:Slide1vv.JPG, Lingual nerve File:Slide11dddd.JPG, Lingual nerve File:Slide2cec.JPG, Mandibular nerve and bone. Deep dissection. Anterior view. File:Slide7cece.JPG, Infratemporal fossa. Lingual and inferior alveolar nerve. Deep dissection. Anterolateral view

References

External links

* * * () * () * {{Portal bar, Anatomy Mandibular nerve Gustatory system Innervation of the tongue