ABSTRACT-A group of 30 operative cases (32 sides) with TMJ disturbanc syndrome was included in the present study. The authors carried out a comparative study between radiographic, pathological and operative observations for these cases. Based on this study, we are confident that the nature of the organic destructive stage of the TMJ disturbance syndrome is essentially a secondary degenerative arthrosis, and that those cases showing transient PDS are probably functional and reversible; however. the indolent and deferred cases with internal derangement of TMJ actually belong to earlier manifestations of degenerative arthrosis.