Clinical Assessment of the Most Common (TMJ) Imaging Modalities Including Magnetic Resonance Imaging (MRI)

Abstract

An accurate diagnosis of the temporomandibular joint (TMJ) status requires a thorough knowledge of the normal and abnormal anatomy of the joint as well as the mechanics of its movement [Figs, la and b]. The TMJ is a synovial joint consisting of the mandibular condyle, glenoid fossa and articular eminence soft tissue disc,1,2 and posterior attachment (bilaminar zone)3' 4- The disc, also termed a meniscus, is a biconcave structure consisting mainly of dense fibrous tissue interposed between the condyle and the glenoid fossa. Posteriorly, the disc is attached by the bilaminar zone, a fibroelastic tissue, rich in nerves and vessels.3' 4 The medial and lateral attachments anchor the disc to the condylar poles. Anteriorly, the disc fuses with the fibrous joint capsule and anterio-medially it attaches to the superior belly of the lateral pterygoid muscle. The disc and its attachments divide the joint into upper and lower joint spaces. These joint spaces, with the exception of the disc surfaces are lined by synovial tissue. Surrounding the joint is a tough, fibrous capsule reinforced laterally by the lateral ligament.