The mandible is the lower jaw — a dense, U-shaped bone that forms the structural foundation of the lower face and is the only movable bone in the adult skull. It supports the lower dentition, provides attachment points for the muscles of mastication, and functions in concert with the maxilla to enable chewing, speaking, and swallowing.

Anatomy of the Mandible

The mandible is divided into two primary regions — the horizontal body, which carries the lower teeth, and the vertical ramus on each side, which angles upward to connect with the skull. Key anatomical landmarks include:

• Alveolar bone — the tooth-bearing ridge along the upper edge of the body, where each tooth is anchored through the periodontal ligament
• Condyle — the rounded projection at the top of each ramus that articulates with the temporal bone, forming the temporomandibular joint (TMJ)
• Coronoid process — a triangular bony projection serving as the insertion point for the temporalis muscle
• Mandibular canal — a bony channel running through the body that carries the inferior alveolar nerve and vessels
• Mental foramen — bilateral openings near the premolar region through which the mental nerve exits, a critical landmark for anesthetic injections and surgical planning

Clinical Significance

The mandible is central to virtually every dental specialty. Oral surgeons must precisely locate the mandibular canal before extracting lower molars or placing implants — inadvertent contact with the inferior alveolar nerve can cause paresthesia or permanent numbness. Orthodontists evaluate the mandible’s size, shape, and position relative to the maxilla when diagnosing skeletal discrepancies and planning treatment for malocclusions. Restorative clinicians must account for the occlusal forces transmitted through the mandible when designing crowns, bridges, and implant-supported prostheses.

Mandibular fractures, commonly caused by trauma, most frequently occur at the condyle, the angle where the body meets the ramus, and the symphysis at the midline. Pathologic conditions — including cysts, tumors, and medication-related osteonecrosis — can also compromise the bone’s integrity and require careful radiographic assessment.

Because jaw alignment, bite function, and the health of every lower tooth depend directly on the mandible’s structure and movement, a thorough clinical examination always includes evaluation of its anatomy, position, and range of motion.