I see a lot of patients with varying grades of TMJ dysfunction – from vague aching following dental intervention or bite change, to disc disorders in the joint and associated complexes of muscle tightness and pain with wider musculoskeletal consequences.
The TMJ joint demonstrates a two-phase mechanical movement during opening, mainly consisting of hinging then sliding/hinging movements of the mandibular condyle in the glenoid fossa of the temporal bone. In cases of dysfunction, the articular disc often becomes displaced and degenerated, so that a common presentation is TMJ clicking and even locking.
This video presents moving dissections of the joint, demonstrating normal function, opening and closing, medial and lateral disc displacements and posterior disc ligament ruptures. If you excuse the *slightly* dated music at the beginning and end of the film, it is a very clear demonstration of the anatomy of TMJ disorder.
0:38 – The Anatomy of the Joint
2:46 – The Normal TMJ Joint
3:30 – The Biconcave Disc – showing small central perforation
5:08 – Anterior Disc Displacement – clicking on closing AND opening
6:15 – Anteromedial Disc Displacement – showing biplanar disc and medial/lateral movement of the disc
7:30 – Medial Disc Displacement
8:25 – Anterior Disc displacement – disc consistently anterior to the condyle
9:25 – Degenerative Joint – large perforation
YouTube – TMJ Anatomy – Standard YouTube License
Sagittal section of the articulation of the mandible – Wikimedia Commons License