Arthrotic changes and deviation in form of the temporomandibular joint--an autopsy study.

An autopsy study was performed on 84 left human temporomandibular joints. Frequency and location of osteoarthrosis and deviation in form were registered in each joint component. Locations of disc perforations were registered with special emphasis on involvement of the bilaminar zone. The anatomical relationship between the deep masseter muscle and the TMJ capsule was investigated in part of the material. Deviation in form was most frequent in condyles (53%) compared with temporal components (40%) and discs (15%). The relative frequencies of the three joint components were opposite for osteoarthrosis; discs (32%), temporal components (26%) and condyles (21%). Higher frequency of arthrotic changes was found in edentulous specimens than in dentulous ones. Disc perforations were located within disc tissue except for one joint where it also included part of the bilaminar zone. No correlation between sex and arthrosis and/or deviation in form was found. Insertion of the posterior fibres of the deep masseter muscle into the anterior capsule was macroscopically observed in six of ten joints.