Lingual nerve

At a glance

English

Lingual nerve

Latin (TA2)

Nervus lingualis

System

Nerve

Region

Head

Side

Paired, left and right

About the lingual nerve

The lingual nerve is a branch of the posterior division of the mandibular nerve (V3). Its own fibres give general sensation, that is touch, pain and temperature, from the lining of the front two-thirds (the body) of the tongue, the floor of the mouth and the gum on the tongue side of the lower teeth. It also acts as a carrier for fibres of the facial nerve, which join it through the chorda tympani: taste fibres for the same part of the tongue and parasympathetic fibres for two salivary glands. The back third of the tongue belongs to the glossopharyngeal nerve.

It starts deep to lateral pterygoid, lying in front of and medial to the inferior alveolar nerve; it is sometimes linked to it by a small branch that may cross the maxillary artery. Here the chorda tympani joins it from behind at a sharp angle. The nerve then descends between the mandibular ramus and medial pterygoid, then curves forwards. Just behind the third molar it lies directly against the inner surface of the jaw, covered only by the gum, before it passes below the lower edge of the superior constrictor and above the mylohyoid line into the floor of the mouth.

In the floor of the mouth it runs forwards on the outer surface of hyoglossus, between that muscle and the submandibular gland's deep part. The submandibular ganglion hangs from it here by two short roots. The nerve then loops under the submandibular duct, passing from its outer side, below it, to its inner side, and climbs onto the tongue, running to the tip just beneath the mucosa and giving sublingual branches to the floor of the mouth and the sublingual gland.

Because of its exposed position behind the last molar, the nerve is at risk during removal of lower wisdom teeth, and less often from deep dental injections, especially the inferior alveolar block, and from operations on the sublingual or submandibular glands. Injury leaves numbness, tingling or pain of one side of the tongue, sometimes with loss of taste, and can be long lasting. Surgical approaches that avoid lifting tissue on the tongue side of the molar, and anaesthetic techniques that avoid deep injections, reduce the risk.

Course and supply

Arises from

The posterior division of the mandibular nerve (V3) deep to lateral pterygoid, where it is joined by the chorda tympani.

Ends in

Ends in branches to the mucosa of the front two-thirds of the tongue, reaching the tip, with sublingual branches to the floor of the mouth.

Supplies

General sensation from the body of the tongue, the floor of the mouth and the lingual gum of the lower teeth; through chorda tympani fibres, taste from the same region and secretomotor supply (via the submandibular ganglion) to the submandibular and sublingual glands.