Inferior alveolar nerve
Overview
The inferior alveolar nerve (sometimes called the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch (V3) of the fifth cranial nerve, the trigeminal nerve (cranial nerve V).
Before traversing the mandibular foramen, it first gives off the nerve to the mylohyoid, a motor nerve supplying the mylohyoid and the anterior belly of the digastric. It then enters the mandible via the mandibular foramen.
While in the mandibular canal within the mandible, it supplies the mandibular (lower) teeth with sensory branches that form into the inferior dental plexus and give off small gingival and dental nerves to the teeth.
Anteriorly, the nerve gives off the mental nerve at about the level of the mandibular 2nd premolars, which exits the mandible via the mental foramen (supplying sensory branches to the chin and lower lip).
The inferior alveolar nerve continues to innervate the mandibular canines and incisors.
Anesthesia
The inferior alveolar nerve is a common target for anesthesia during dental procedures involving the mandibular teeth.
Administration of anesthesia near the mandibular foramen causes blockage of the inferior alveolar nerve and the nearby lingual nerve (supplying the tongue). This is why the numbing of the lower jaw during dental procedures causes the patient to lose sensation in:
- their teeth (inferior alveolar nerve block)
- their lower lip and chin (mental nerve block)
- and their tongue (lingual nerve block).
Additional images
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Mandible of human embryo 95 mm. long. Inner aspect. Nuclei of cartilage stippled.
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Mandibular division of trifacial nerve, seen from the middle line.
