Temporomandibular joint ankylosis

Joint ankylosis is the fixation and loss of movement of a joint due to disease, injury, or surgery. Temporomandibular joint ankylosis can be clinically classified into intra-articular ankylosis and extra-articular ankylosis. It often presents as chronic, painless limitation of mouth opening. Extra-articular ankylosis involves lesions in the skin, mucous membranes, or deep tissues between the upper and lower jaws outside the joint, also known as intermaxillary contracture, or sometimes referred to as pseudoankylosis. This condition can be divided into fibrous intermaxillary contracture and bony intermaxillary contracture based on the nature of the lesion. Intra-articular ankylosis is caused by lesions occurring within one or both joints, ultimately leading to fibrous or bony adhesions within the joint. This is simply called joint ankylosis, or sometimes true ankylosis. According to pathological changes, it can be divided into fibrous ankylosis and bony ankylosis. Furthermore, when both intra-articular and extra-articular ankylosis are present simultaneously, it is called mixed ankylosis.