The author analysed the interrelation between the morphologic changes of bone Structures and the position of condylar head from the routine radiographs of 134 cases of the temporomandibular joint arthrosis. The frequencies of coincidence between the site of bone defrmity and condylar head positional change were examined. Also, the positional changes of condylar head and the direction of condylar movement in relation to the kind of bone deformities were observed. The results obtained were as follows; 1. In 52.65 per cent of total cases, the site, of positional change of condylar head was coincided with the site of bone deformans. The frequencies of the coincidence between these in the five items among seven items examined were above 53 per cent. From the results, it seems that the positional changes of condylar head were related with the morphological change of bone structure. 2. Eburnation and erosion. revealed frequently positional changes in the opening and closing position of the mouth, although in the early stages of the TMJ arthrosis. 3. In the bone deformans, during opene position of the mough 44.81 per cent of total cases revealed backword movement and 37.74 per cent showed forward movement. In closed position of the mouth, downward movement was revealed in 35.23 per cent of total cases and upward movement 28.41 per ,cent of total cases. 4. In the cases showing eburnation, the frequencies of coincidence between the site of positional change and bone deformans were 58.57 per cent of the total cases. that means it was high in the early stages of the TMJ arthrosis.