TMJ Disorders: Disc Displacement

Popping and clicking jaw joints, or temporomandibular joints (TMJs), are due to displacement of the cushioning disc within the joint. The name temporomandibular is derived from the two separate parts of the joint: the mandibular (lower jaw) connection and the temporal bone (skull base) connection. The TMJ disc is a cushioning buffer between the two opposing bony surfaces of the joint.

The TMJ disc can be viewed in two mouth positions to determine disc displacement: closed mouth and open mouth positions.

In the closed mouth position (Figure 1a), the ‘normal’ disc (yellow color in Figures 1 and 2) rests just superiorly and slightly anteriorly to the mandibular connection. When the mouth opens (Figure 1b), this disc should remain between the mandibular connection and the overlying temporal bone.


Figure 1a: Normal TMJ disc (yellow), closed mouth


Figure 1b: Normal TMJ disc (yellow), open mouth

A displaced disc will be in an abnormal, forward location in the closed mouth position (Figure 2a), and will remain trapped ahead of the mandibular connection in the open mouth position (Figure 2b) until it suddenly snaps back into the ‘normal’ position (Figure 1b). The clicking or popping noise that we hear during jaw movement occurs when this trapped disc suddenly snaps back into place. Occasionally, the disc does not snap back into the ‘normal’ position and remains trapped in the forward position (Figure 2b). This trapping of the disc (also known as ‘closed lock’) greatly reduces the ability to fully open your mouth.


Figure 2a: Displaced TMJ disc (yellow), closed mouth


Figure 2b: Displaced TMJ disc (yellow), open mouth

Treatment options vary depending on your particular TMJ disorder, how long it has been present, and which treatment options you have already tried.

Come in to see us at Oxford OMS Centre for a consultation appointment to discuss your TMJ condition and its management options. We looking forward to meeting you!