Medical imaging is important for the diagnosis, treatment and prognosis of TMJ disorders. 1.Lateral oblique temporomandibular joint film This film is also called Schuyler’s film or trans-cranial lateral oblique temporomandibular joint film. This film can show the lateral oblique image of TMJ, and the projection of temporal bone rock is below the condyle, which can show the joint fossa, joint nodes, condyle and joint gap at the same time. 2.Corrected lateral oblique temporomandibular joint film is also called corrected Schuyler’s position or corrected trans-cranial lateral oblique temporomandibular joint. This technique adjusts the vertical and horizontal angles of the x-ray centerline according to the horizontal and vertical angles of the condylar process of each patient, thus accurately displaying the morphology of the joint space and joint structures. The lateral 1/3 of the joint space and the bony structures of the joint can be accurately displayed. 3. Transpharyngeal lateral view of the condyle The anterior and posterior oblique lateral images of the condyle can be clearly displayed. The normal condylar surface is rounded and smooth, with a thin, uniform, dense dense bone margin. This method can avoid the overlap between the condyle and the skull image. 4.Temporomandibular joint lateral body film can show the lateral body image of the joint through the middle of the articular fossa. The surface of the condyle is smooth, with a uniform, dense dense bone plate. The articular tuberosity is a rounded protrusion with a smooth curve. The supra-articular gap is slightly larger than the posterior gap, and the posterior gap is slightly larger than the anterior gap. 5. Lateral body radiographs of the corrected temporomandibular joint Adjust the patient’s head position according to the horizontal and vertical angles of the condylar process of each subject, which can accurately show the position of the condylar process in the articular fossa and the morphology of the bony structures of the joint. It can accurately show the different levels of the sagittal plane of the joint, and generally the sagittal plane of the center of the joint fossa is the most commonly used. 6.Surface tomography film can show bilateral maxilla, mandible, maxillary sinus, temporomandibular joint and whole mouth teeth on one film, which is often used to observe the lesions in the above parts. Curved body layer film of mandibular position is mainly used to observe mandibular lesions, and it is more satisfactory to show condylar process. 7.General temporomandibular arthrography is divided into two types: supra-articular arthrography and subarticular arthrography, and is divided into two types: simple iodine arthrography and double arthrography. Indications and contraindications: where there are bony changes in the joint or obvious abnormalities in the joint space on plain film or body layer photography; clinical examination reveals continuous frictional sounds in the joint and suspected joint disc perforation; clinical examination reveals symptoms of joint structural disorders such as joint popping, strangulation, and obvious restriction of condylar movement and further clarification of the type of changes; evaluation of the effect of joint splinting; observation of joint disc repositioning or Temporomandibular arthrography can be performed to further confirm the diagnosis of intra-articular free bodies or occupying lesions. Contraindications: Arthrography is not recommended for patients with a history of severe iodine allergic reaction and local skin infection of the joint, patients with bleeding disorders and those treated with anticoagulant drugs. 8.Digital subtraction temporomandibular arthrography is basically the same as ordinary arthrography, except that digital subtraction arthrography eliminates the interference of cranial images, which makes the arthrography images clearer and facilitates image analysis. CT scan of TMJ can clearly show the lesions of bony structures of the joint, but the CT image of the joint disc is not satisfactory and the development of magnetic resonance, and now CT is basically not used for the examination of temporomandibular joint disc lesions. 10.Temporomandibular joint magnetic resonance imaging can obtain very clear images of the sagittal plane of the temporomandibular joint, especially the images of the joint disc and the pterygoid muscle can be displayed directly and clearly, without any radiological damage to the human body or invasive operation; however, it cannot make dynamic observation of the functional movement of the joint, and cannot understand the changes in the relationship between the position of the joint disc and the condyle during the functional activity of the joint, and the detection of joint disc perforation is poor. The ability to detect disc perforation is poor, and cannot completely replace arthrography.