Nerve
Inferior alveolar nerve
A mandibular pathway that divides into dental and mental branches
High-yield
The mental nerve is an exiting branch, not the entire continuation of the inferior alveolar nerve. The incisive branch continues within bone toward the anterior teeth.
Overview
The inferior alveolar nerve descends from the posterior division of V3 toward the mandibular foramen. Before entering bone, it gives off the nerve to mylohyoid. Within the mandibular canal, dental branches supply the lower teeth. An anterior continuation, the incisive branch, remains inside the mandible, while the mental branch exits to the lower lip and chin.
Learning this group? Read How to memorize the cranial nerves.
Reference facts
- Origin
- Posterior division of mandibular V3 in the infratemporal fossa
- Course
- Descends medial to the mandibular ramus, gives the mylohyoid branch and enters the mandibular foramen near the lingula. Dental branches arise in the canal; mental fibers leave through the mental foramen and incisive fibers continue anteriorly
- Motor
- Through the mylohyoid branch, supplies mylohyoid and the anterior belly of digastric
- Sensory
- Lower teeth; mental branches supply the lower lip and chin and adjacent anterior labial gingiva. Other gingival regions also depend on the buccal and lingual nerves
Clinical correlation
Injury during mandibular trauma or dental surgery can alter sensation in the lower teeth, lip or chin, depending on the branch affected. Tongue numbness suggests involvement of the neighboring lingual nerve rather than an isolated mental-nerve injury.
Frequently asked questions
Where does the inferior alveolar nerve arise?
Posterior division of mandibular V3 in the infratemporal fossa.
What muscles does the inferior alveolar nerve supply?
Through the mylohyoid branch, supplies mylohyoid and the anterior belly of digastric.
What is the sensory distribution of the inferior alveolar nerve?
Lower teeth; mental branches supply the lower lip and chin and adjacent anterior labial gingiva. Other gingival regions also depend on the buccal and lingual nerves.
What is the course of the inferior alveolar nerve?
Descends medial to the mandibular ramus, gives the mylohyoid branch and enters the mandibular foramen near the lingula. Dental branches arise in the canal; mental fibers leave through the mental foramen and incisive fibers continue anteriorly.