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, 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. ==Clinical significance==