Sideways and rotational displacement of the temporomandibular joint disk: diagnosis by arthrography and correlation to cryosectional morphology.

Arthrography and arthrotomography were performed on 29 fresh temporomandibular joint autopsy specimens to diagnose medial and lateral disk displacement. A horizontal contrast medium margin crossing over the condyle (edge sign) and the relative size of the anterior recess of the lower joint compartment in the lateral and medial parts of the joints were used as indicators of the mediolateral position of the disk. Arthrographic findings were compared with coronal cryosections in a blinded fashion. The edge sign underdiagnosed all the joints with lateral disk displacement and about 50% of the joints with medial disk displacement. The assessment of the relative size of the anterior recess of the lower joint compartment underdiagnosed 50% of the joints with medial disk displacement and overdiagnosed lateral disk displacement by 100%. It was concluded that arthrographic diagnosis of medial and lateral disk displacement may be difficult and includes substantial risks of both overdiagnosis and underdiagnosis. Other diagnostic methods should be considered when these types of disk displacement are suspected.