Nervous System

Lingual Nerve

Nervus lingualis

Quick Facts

Origin: Posterior division of the mandibular nerve.

Course: Originates in the infratemporal fossa, deep to the lateral pterygoid muscle. Runs anteroinferiorly between the medial pterygoid muscle and the mandible, passing into the oral cavity between the hyoglossus and mylohyoid muscles. Continues anteriorly, passing medially under the submandibular duct to enter the anterolateral surface of the tongue.

Branches: Sublingual nerve, posterior branches to submandibular ganglion, communications with the hypoglossal nerve and chorda tympani.

Supply: Sensory: conveys general sense fibers from the mucosa of the anterior two-thirds of the tongue, floor of the mouth, and lingual gingiva. It conveys special taste sensation from the anterior two thirds of the tongue back to the chorda tympani; Parasympathetic: transmits parasympathetic innervation from the chorda tympani to the submandibular and sublingual glands.

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Related parts of the anatomy

Origin

The lingual nerve originates as one of the major branches of the posterior division of the mandibular nerve, deep to the lateral pterygoid muscle in the infratemporal fossa. The proximal lingual nerve is entirely sensory with cell bodies residing in the trigeminal ganglion.

Distal to the point at which the chorda tympani merges with the lingual nerve, it also conveys special taste sensation and parasympathetic fibers of the facial nerve. These originate in the geniculate ganglion and superior salivatory nuclei, respectively.

Course

From its origin in the infratemporal fossa, the lingual nerve runs inferiorly. Prior to descending past the inferior edge of the lateral pterygoid muscle, the chorda tympani runs obliquely from behind to merge with the lingual nerve.

The lingual nerve continues inferiorly, crossing to the medial pterygoid muscle to run down the ramus of the mandible, roughly 1 cm anterior to the mandibular foramen, before passing between the mylohyoid and hyoglossus muscles to enter the oral cavity.

It runs deep to the mucosa of the lateral oral cavity floor, passing underneath the submandibular duct, from lateral to medial, roughly in line with the first or second mandibular molar. After crossing medially, the lingual nerve fans out into several branches which run into the lateral mucosal surface of the tongue.

Branches

The lingual nerve has several branches, most of which are indistinct projections of fibers rather than easily identifiable nerves.

While still in the infratemporal fossa, deep to the lateral pterygoid muscle, the chorda tympani descends obliquely to merge with the lingual nerve.

Two or more short branches connect the lingual nerve to the submandibular ganglion, roughly where the lingual nerve passes lateral to the hyoglossus and styloglossus muscles.

The sublingual nerve refers to the postganglionic parasympathetic fibers that run from the submandibular ganglion to the sublingual gland. It is unclear whether they do so directly as a distinct nerve or indirectly as an indistinct set of postganglionic parasympathetic fibers that run from the submandibular ganglion back to the lingual nerve, and then into the sublingual gland.

The lingual nerve has many indistinct communications with the hypoglossal nerve at the level of terminal branches in the tongue.

Medial branches of the lingual nerve run medially into the ventrolateral surface of the tongue and convey general and taste sensation from the middle third of the tongue. The lateral branches of the lingual nerve run anteromedially into the ventrolateral surface of the tongue, before moving anteriorly to convey general and taste sensation from the tip of the tongue (Standring, 2016).

Supplied Structures

The lingual nerve is a mixed nerve that conveys sensory and parasympathetic fibers.

The sensory fibers are of two types. General sense fibers from the mucosa of the anterior two thirds of the tongue, the floor of the oral cavity, and the lingual mandibular gingiva are conveyed by the lingual nerve back to the trigeminal ganglion.

Special sense fibers conveying taste sensation from taste receptors in the anterior two thirds of the tongue are conveyed by the lingual nerve back to the chorda tympani and the facial nerve. Thus, while these taste fibers travel with the lingual nerve, they originate not as a part of the trigeminal nerve but rather the facial nerve.

Preganglionic parasympathetic fibers traveling with the chorda tympani merge onto the lingual nerve and travel with it to reach the submandibular ganglion. These synapse with postganglionic parasympathetic fibers that target the submandibular gland and the sublingual gland. Some postganglionic parasympathetic fibers then rejoin the lingual nerve briefly to be distributed to the sublingual gland and small glands in the oral mucosa (Zur et al, 2004).