Quick Facts
Origin: Posterior division of the mandibular nerve.
Course: Runs anteroinferiorly between the medial pterygoid muscle and the mandible, passing into the ramus of the mandible at the mandibular foramen. It continues forward in the substance of the mandible to the anterior most aspect where it emerges as the mental nerve.
Branches: Nerve to mylohyoid muscle, incisive and mental nerves, and nerves of the inferior dental plexus.
Supply: Sensory: conveys general sense fibers from the mucosa and skin of the lower lip, skin of the chin, mandibular teeth, and labial mandibular gingiva; Motor: transmits branchial motor fibers to the mylohyoid and the anterior digastric muscles.
Related parts of the anatomy
Origin
The inferior alveolar nerve originates as one of the major branches of the posterior division of the mandibular nerve. This occurs in the infratemporal fossa, deep to the lateral pterygoid muscle and just inferior to the otic ganglion.
The neurons of the sensory fibers are located in the trigeminal ganglion, while those of the motor neurons are in the motor nucleus of the trigeminal nerve in the pons.
Course
From its origin in the infratemporal fossa, the inferior alveolar nerve runs inferiorly. It crosses lateral to the medial pterygoid muscle to run down the ramus of the mandible and passes into the mandibular foramen. The inferior alveolar nerve continues down and forward through the substance of the mandible in the mandibular canal. It terminates in the anterior portion of the mandible (Zur et al, 2004).
Branches
The inferior alveolar nerve has several branches.
—The nerve to mylohyoid is given off early, prior to the inferior alveolar nerve’s entry into the mandible.
—The branches to the inferior dental plexus are given off as the inferior alveolar nerve runs through the mandible.
—The incisive nerve is one of the terminal branches of the inferior alveolar nerve. It runs within the anterior mandible, from roughly the mental foramen medially to the midline.
—The mental nerve is the second of the terminal branches of the inferior alveolar nerve. It runs anteriorly through the mental foramen, emerging on the anterior surface of the mandible.
Supplied Structures
The inferior alveolar nerve is a mixed nerve that conveys sensory and motor fibers.
The branches to the inferior dental plexus convey general sense information from the teeth and some buccal gingiva of the mandible posterior to the canines.
The incisive nerve conveys general sense information from the incisors and canines as well as the labial gingiva of the mandible.
The mental nerve conveys general sense information from the skin of the chin and the skin and mucosa of the lower lip.
The motor fibers of the inferior alveolar nerve transmit branchial motor efferent fibers to the mylohyoid and anterior digastric muscles.
References
Zur, K. B., Mu, L. & Sanders, I. (2004) Distribution pattern of the human lingual nerve. Clin Anat, 17(2), 88-92.
