Head Muscle Terms

Front 1

Temporomandibular Joint

Back 1

The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ. There are two TMJs, one on either side, working in unison.The TMJs are one of the only synovial joints in the human body with an articular disc, another being the sternoclavicular joint.

The lower joint compartment formed by the mandible and the articular disc is involved in rotational movement (opening and closing movements). The upper joint compartment formed by the articular disk and the temporal bone is involved in translational movements (sliding the lower jaw forward or side to side). The part of the mandible which mates to the under-surface of the disc is the condyle and the part of the temporal bone which mates to the upper surface of the disk is the glenoid (or mandibular) fossa.

Front 2

Articulations

Back 2

A joint is the location at which two or more bones make contact.[1] They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.
-Synovial Condyloid Joint

Front 3

Elevation
(Movement of Temporomandibular Joint)

Back 3

Close the mouth.

Front 4

Depression
(Movement of Temporomandibular Joint)

Back 4

Open the mouth.

Front 5

Protrusion
(Movement of Temporomandibular Joint)

Back 5

Sticking bottom jaw out.

Front 6

Retraction
(Movement of Temporomandibular Joint)

Back 6

Bring bottom jaw in.

Front 7

Rotation / Lateral
(Movement of Temporomandibular Joint)

Back 7

"Teeth grind."
Coranid and Condyloid

Front 8

Bruxism

Back 8

Nightly grinding of teeth.

Front 9

Masticate

Back 9

Chew.