Anatomy of the Temporomandibular Joint
The Temporomandibular Joint is the joint connecting the jaw (mandible) to the skull (temporal bone). The two bones are held together and function via a complex group of muscles, ligaments and other soft tissue. The temporomandibular joints are the only two joints that function together as a single unit unlike any other joint in the body in that they must coordinate with the coming together of the upper and lower teeth (accompanied by the surrounding periodontal ligamentous attachments, nerves and surrounding bones and gum tissue, during opening and closing cycles of chewing, swallowing, breathing, talking, wistling, kissing, sucking and resting modes.
The “TMJ” is a two joint system connected by the main body of the mandible and ramus on each side. The two condyles are the upper boney portion of the jaw bone (mandible) that is housed within the glenoid fossa within the boney skull just forward of the ear (auditory meatus). The condyles are able to swing and rotate within the fossa, but limited by the surround ligamentous attachments (temporomandibular ligaments) and surrounding muscles. The disc (articular disc) is a thin ligamentous tissue that acts like a cushion between the condylar head and upper glenoid fossa of the skull. Attached to the articular disc are fine muscles (lateral pterygoids) as well as surrounding ligaments that help in positioning the disc over the condyles as they move within the joint compartment during functioning and resting modes.
The temporal bone has a concavity call the glenoid fossa in which the head of the jawbone (the condyle) sits. A cartilage disc call the articular disc separates the two bones. The articular disc slides in conjunction with the mandible to provide smooth quiet movement and acts as a cushion against heavy forces generated by the strong jaw muscles. The right and left TMJ joints do not act as separate joints, but must move in coordination with one another.
The TMJ joints are considered the most complex joints in the human body because they must provide for rotational movements, sliding movements and an infinite range of combined movements and functions, unlike any other joint in the body.
The lower jaw (Mandible) has a RELATIONSHIP to the upper jaw (Maxilla). If this relationship is altered, the muscles of mastication (chewing muscles) go into spasm. This causes the muscles that have the same nerve intervention to also go into spasm. The resulting stresses may radiate throughout the head, neck, and even involve the back. The pain may be constant or intermittent, lasting minutes, hours, days, or even years. Many patients describe the pain as a migraine headache. Eventually a patient may demonstrate clicking, grating, snapping, or popping sounds in the joint.
Finding a dentist who understands the importance of this relationship is key to your health and recovery! The dental and medical community cannot guess this relationship when it becomes misaligned. Measurements before and after muscle relaxation is crucial to re-establishing physiologic and anatomical realignment.
