Abstract
The secular trend in emargination of the Japanese patella was studied on a total of 220 specimens ranging from the prehistoric Jomon period to the present age. There was found a significant decrease both in the incidence and in the relative size of the supero-lateral notch of the patella with the progress of civilization. It was suggested that the emarginate patella was due to a deficiency of bone, in relation to the development of the quadriceps femoris muscle. Archaeological evidence indicated that the prehistoric Jomon people improved and broadened their subsistence economy from the Earliest to the Latest stage. The above hypothesis on the causation of emarginate patella gave a satisfactory explanation for the skeletal gracility in association with developed muscularity of the Earliest Jomon people who subsisted entirely on various forms of hunting, fishing, gathering and collecting under narrow circumstances.
