Head and Neck Imaging

Temporomandibular joint, pathology

Internal derangement
Pain and discomfort caused by internal derangement of the temporomandibular joint are frequent. An abnormal position of the disc relative to the mandibular condyle and the articular surface of the temporal bone is the most important cause of internal derangement of this joint. Often, the disc is dislocated anteriorly, with or without reduction when the mouth is opened. For a more detailed discussion, see internal derangement, temporomandibular joint .
Condylar malformation
see mandibular condyle, development defects .
Arthritis
Chronic arthritis of the temporomandibular joints is seen primarily in rheumatoid arthritis, temporomandibular joint (also, see rheumatoid arthritis ), ankylosing spondylitis and in psoriatic arthritis .
Synovial chondromatosis
see synovial chondromatosis , synovial chondromatosis
Ganglion cyst
Fibrocystic structure that develops as a result of herniation of the synovium into the surrounding tissues, ectopic placement of synovial tissue, or post-traumatic degeneration of connective tissue. Such a cyst may clinically mimic a parotid tumour or periparotid adenopathy (Fig. 1).
Tumours
Primary neoplasms include chondrosarcoma, head and neck (also, see chondrosarcoma ), fibrosarcoma and synovial sarcoma . The temporomandibular joint may be affected secondarily by neoplasms arising in the parotid gland, pathology , external auditory canal and by other local tumours (see external ear, pathology ).
Trauma
Temporal bone fractures may extend into the glenoid fossa. Condylar and subcondylar fractures mostly result from indirect trauma, commonly occurring in association with other fractures of the mandible. Also, see facial fractures , empty glenoid fossa sign .

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