TMJ Structure: Articular Disc

Temporomandibular joint (jaw joint) is formed between temporal bone and a condyle.

Inside this joint, there is a structure called an Articular Disc which usually fits and sits on top of the condyle like a straw hat. There are one disc each on both left and right joint.

Functions for the articular disc are;

– provides protection for the articular cartilage by reducing friction and wearing

– distributes joint lubricants (synovial fluid) which contains nutrients evenly throughout the joint cartilage surface

Articular disc is made of;

– fibrous connective tissue

– no blood vessels and no nerves

– divides the joint into three zones, anterior, intermediate and posterior

– nerve and blood vessels to the surrounding structures such as retrodiscal laminae

As you can see in the two pictures,

in the first picture, the disc in the joint (blue coloured) is sitting correctly in the joint

in the second picture, the disc (blue coloured) is displaced forward and it is sitting outside the joint.

The clicking in your jaw is often the result of either this disc displacing from the joint or relocating back inside the joint with your mouth opening or closing.

If you are suffering from clicky jaw, then Physiotherapy for your TMJ will focus on finding out what structure is causing the disc to displace or replace.

Structures involved are often combination of

1. Joint capsule,

2. Joint ligaments,

3. Muscles of mastication such as masseter, temporalis, medial pterygoids and lateral pterygoids,

4. Muscles of your neck for posturing.

Your jaw Physiotherapy will focus on assessing and finding out which one of the 4 structures are the primary driver for your complaint and treat it in order of priority.

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