Human mandible

Human Mandible

The human mandible is the largest and strongest bone in the human face. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear).

File:Human mandible diagram.png

Diagram of a human mandible

Anatomy

The human mandible is composed of two main parts. The horizontal part, the body, forms the chin and the vertical part, the ramus, connects the mandible to the skull. The mandible has two surfaces and two borders.

Body

The body of the mandible is curved, and the front part gives structure to the chin. It has two surfaces and two borders. From the outside, it is marked in the midline by a faint ridge, indicating the symphysis menti, or line of junction of the two pieces of which the bone is composed at an early period of life.

Ramus

The ramus of the human mandible has four sides, two surfaces, four borders, and two processes. On the inside at the center is an oblique ridge, the oblique line. The ramus communicates with the body, which is described as the angle of the mandible.

Function

The mandible plays a vital role in many common tasks, including chewing, speech, and facial expression.

Clinical significance

Diseases of the mandible include fracture of the mandible, osteomyelitis, and cancer of the jaw. Infections can also affect the mandible. Dental procedures and oral surgery can change the shape of the mandible.

Development

The human mandible starts as a horseshoe-shaped cartilaginous structure, which ossifies near the end of fetal development by a process known as intramembranous ossification.

See also

• Maxilla
• Bone
• Skull
• Teeth
• Jaw