Mandible

The mandible, or lower jaw, is the largest and strongest bone of the human face. It forms the lower part of the skull and, together with the temporal bones, creates the temporomandibular joints (TMJs), which allow movement for chewing and speech. The mandible is U- or horseshoe-shaped and consists of a horizontal body and two perpendicular rami that rise on either side.

Key anatomical features include the body, which houses the sockets for the lower teeth along its superior border; the mental foramen on the external surface of the body near the premolars, through which the mental nerve and vessels pass; and the mandibular canal within the body that contains the inferior alveolar nerve and vessels. Each ramus ascends to form a coronoid process, for attachment of the temporalis muscle, and a condylar process, which includes the condyle that articulates with the mandibular fossa of the temporal bone at the TMJ. The two halves of the mandible join at the mandibular symphysis in the front, a joint line that typically ossifies with age.

Developmentally, the mandible forms by intramembranous ossification from two halves that fuse during early life; the symphysis may remain a fibrous joint before ossifying in many individuals.

Clinically, the mandible supports dental arches, serves as the insertion point for several masticatory muscles, and transmits nerves and vessels to the lower face. It is frequently involved in fractures from trauma, and the inferior alveolar nerve is a common target for dental anesthesia. Evolutionarily, the dentary bone comprises the mammalian lower jaw, with articulations between jaw and skull evolving into the TMJ.