This functionality is caused by the presence of the articular disc, which divides the joint cavity into two chambers. The upper chamber is the translational motion (head moves down the back slope of the articular tubercle). In the lower chamber at the same time there are rotational motions around a horizontal axis. Thus, the two divisions of the joint, isolated from one another disk, are united in the performance of functions. Distinctive functional characteristics of the TMJ: synchronous movement of two joints, interconnected azygos mandibular bone. This feature must be considered when the diagnosis of diseases of TMJ. For example, when the usual dislocation of one joint always disturbed the function of another. In forming the secondary deforming osteoarthritis in one joint, the joint patient incurs additional functional loads due to the healthy.
At the same time in a healthy joint, limited mobility develops at the expense of function of the diseased joint. Age peculiarities of the TMJ: A newborn head n / h rounded shape and is virtually identical Medio-lateral and anteroposterior dimensions. With age, it gradually vytyagivaetya in the transverse direction. Since the eruption of milk teeth and up to 2 years is an increase in the head, then its dimensions are stabilized. Stabilization lasts up to 6 years: the emergence of the first permanent tooth size head again increase. A newborn is not pronounced tilt head forward: with the age of the head leans forward in relation to cervical articular process. In infancy N / h in a distal position.