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X-ray diagnosis of temporomandibular joint disorders
Last reviewed: 04.07.2025
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The complexity of the anatomical structure and function of the temporomandibular joint, the connection of the latter with the state of the bite and masticatory muscles, the absence of a direct relationship between the clinical picture and radiographic changes cause significant difficulties in recognizing diseases of this joint. In 70-80% of cases, pathological processes in the joint are associated with pathology of its soft tissue components - the articular disc, intra-articular ligaments and capsule. Based on the results of studies using highly effective technologies (contrast arthrotomography, X-ray computed arthrotomography, magnetic resonance imaging, arthroscopy), a classification of temporomandibular joint diseases is proposed.
Deforming arthrosis. Dystrophic changes in the joint are among the most frequently observed lesions, arising as a result of disturbances in closure, articulation, tone of the masticatory muscles, hormonal and endogenous disorders, and trauma.
Deforming arthrosis begins with the development of dystrophy of articular cartilage, which leads to their thinning, cracks, and destruction. Along with defects and deformation of the articular disc, adhesion of the disc to the head and posterior slope of the articular tubercle is noted, which occurs as a result of the adhesive process. The detected areas of the bone slide over each other during movement. In the most loaded subchondral sections of the bones, osteosclerotic reorganization (subchondral sclerosis) of the endplates occurs. Due to the appearance of additional marginal bone growths at the attachment sites of ligaments and muscles, the area of the articular bones increases and, as a consequence, the pressure per unit surface decreases. Marginal bone growths first occur in the area of the glenoid cavity, and then in the articular head.
Deforming arthrosis is sometimes manifested by slightly greater mobility in the joint (anterior subluxation). The most characteristic symptoms of deforming arthrosis are narrowing of the X-ray joint space, sclerosis and increased intensity of the cortical endplates of the head and posterior slope of the articular tubercle. In this case, the function of the joint is impaired: the excursion of the head is limited, reducible dislocations and subluxations occur less frequently.
With deforming arthrosis, changes in the shape of the head and articular tubercle occur: flattening and erasure of the head in height, pointed or club-shaped deformation and the formation of exophytes, flattening of the tubercle or exophytic formations on it.
Similar clinical symptoms may be observed with changes in the position of the disc. In these cases, diagnosis is facilitated by the introduction of a contrast agent into the joint (arthrography) in combination with CT scans or MRI without contrast.
Arthritis. Inflammatory processes in the temporomandibular joints develop less frequently. Joint infection can occur with childhood infections, the spread of the inflammatory process to the bone elements of the joint, osteomyelitis of the lower jaw, mumps, otitis, and injuries.
The first sign of joint inflammation is a pronounced impairment of head mobility, after 15-20 days its osteoporosis and uneven narrowing of the X-ray joint space occur. The cortical endplates in certain areas lose clarity, marginal erosions of the head and along the posterior edge of the tubercle are revealed.
The death of the disc and articular cartilage in children and adolescents leads to the development of bone ankylosis. In these cases, the image of the X-ray joint space on the image is completely or partially absent, the structure of the bone tissue of the head passes to the bone tissue of the joint cavity. The function of the joint is absent.
Ankylosis in early childhood leads to growth disorders of the lower jaw on the affected side and deformation of the maxillofacial region. For distinctive recognition of bone ankylosis and deforming arthrosis, fibrous ankylosis, it is necessary to perform tomograms in direct and lateral projections.
Temporomandibular joint damage is detected in 50% of patients with rheumatism. In the initial stages, only impaired mobility of the head is observed radiologically; in case of exacerbation, osteoporosis of the joint elements, indistinct cortical plates, narrowing of the joint space, and limited mobility of the head are observed. Later, these changes serve as a background for the development of degenerative-dystrophic changes.
Arthritis of the temporomandibular joint, which develops in 60% of patients with Bechterew's disease, causes fibrous or bony ankylosis with loss of joint function.