Lingual nerve

Structure

Origin

The lingual nerve arises from the posterior trunk of mandibular nerve (CN V₃) 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, 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, 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.

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 mucous membrane 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, and the mandibular/inferior lingual gingiva.

Special sensory and parasymathetic autonomic

The lingual nerve also comes to convey fibres of the chorda tympani (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 and sympathetic innervation.