Inferior alveolar nerve

Last revised by Daniel J Bell on 29 Jan 2024

The inferior alveolar nerve, also known as inferior dental nerve, is a mixed sensory and motor branch of the posterior division of the mandibular division of the trigeminal nerve, located in the pterygomandibular space of the oral cavity/masticator space.

The inferior alveolar nerve divides off the posterior division and descends posterior to the lingual nerve, deep to lateral pterygoid muscle and lateral to the pterygomandibular raphe, between the sphenomandibular ligament and the ramus of the mandible. It enters the mandibular foramen anterior to the inferior alveolar artery and vein. It then courses in the mandibular canal.

The inferior alveolar nerve has three major branches:

  • nerve to mylohyoid:

    • branches off just before entering the mandible

    • motor supply to the mylohyoid and anterior belly of digastric muscles

  • incisive nerve:

    • one of the two terminal branches

    • remains within the mandibular canal

    • supplies sensation to the pulp and periodontal membranes of the canine and both incisors

  • mental nerve:

    • one of the two terminal branches

    • leaves the mandibular canal through the mental foramen, accompanied by the mental artery

    • supplies sensation to skin and mucous membrane of the lower lip and labial gum from the midline to second premolar tooth

In the mandibular canal, the nerve also gives off small unnamed twigs that contribute to the inferior dental plexus (supplying the mandibular three molar and two premolar teeth).

Some authors document the mental nerve carrying parasympathetic fibers from the otic ganglion to the labial glands of the lower lip.

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