lingual nerve
The lingual nerve is a sensory branch of the posterior division of the mandibular division of the trigeminal nerve supplying sensation (both gustatory (taste) and non-gustatory) to the anterior two-thirds of the tongue.
Gross anatomy
The lingual nerve divides off the posterior division and descends anterior to the inferior alveolar nerve to course between the lateral pterygoid and tensor veli palatini muscles and then medial pterygoid muscle and the mandible, contacting the internal surface of the mandible at the posterior margin of the mylohyoid line. Hence it is deep to the mylohyoid muscle and lies in the floor of the mouth under the mucous membrane adjacent to the third molar mandibular tooth.
Running anteriorly, it passes lateral to the styloglossus and hyoglossus muscles and has small sensory branches that supply the floor of the mouth and the mandibular lingual gingiva. Whilst on the hyoglossus and superior to the submandibular gland there are two small sensory roots suspend the submandibular ganglion from the nerve.
The nerve continues anteriorly passing from lateral to medial under the submandibular duct and then enters the lateral margin of the mid tongue to supply sensation to the anterior two-thirds of the tongue.
The lingual nerve receives secretomotor parasympathetic fibers (which derive from the submandibular ganglion) from the chorda tympani and sympathetic fibers from the facial artery which supply the submandibular glands, sublingual glands and minor salivary glands of the floor of the mouth and the mandibular lingual gingiva.
The lingual nerve also carries special visceral sensory fibers to the chorda tympani for taste from the anterior 2/3 of the tongue which synapse at the geniculate ganglion of the facial nerve.