Structure and Location - The mental foramen is located on the anterior surface of the mandible. - It is below the commisure of the lips and the tendon of the depressor labii inferioris muscle. - The mandibular canal begins at the mandibular foramen on the posterior surface of the mandible and ends at the mental foramen. - The mental foramen transmits the terminal branches of the inferior alveolar nerve (the mental nerve), the mental artery, and the mental vein.

Variation - In toothless individuals, the mental foramen descends slightly. - Approximately 63% of people have the mental foramen in line with the longitudinal axis of the 2nd premolar. - The mental foramen generally lies at the level of the vestibular fornix and about a finger's breadth above the inferior border of the mandible. - About 17% of mandibles have an additional mental foramen or foramina on at least one side. - Approximately 4% of mandibles show multiple mental foramina on both sides, often with unequal sizes.

Clinical Significance - The mental nerve can be anesthetised as it leaves the mental foramen. - Anaesthesia of the mental nerve causes loss of sensation to the lower lip and chin on the same side.

Additional Images - Side view of the skull. - The skull from the front. - Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion. - Mandibular division of the trigeminal nerve. - The permanent teeth, viewed from the right.

Related Concepts - Mandibular foramen.