Abstract
The grade of development of the temporal line, to which the temporalis muscle relating to masticatory function is attached, was assessed on 335 Japanese crania of the Jomon period, the Kofun period, the Kamakura to Edo period and the present age. By means of comparing the frequencies of each developmental grade in the samples of different periods, the secular changes in the development of the temporal line were investigated. The results indicated that there was a decreasing tendency in development of the temporal line from the prehistoric Jomon to the present age regardless of sex. In particular, the frequency pattern of the grades in the Jomon crania was different from those in the other crania, with significantly higher incidences of high grades in the development of the line. This finding indicates that the muscles of mastication of the prehistoric Jomon people were more robust than those of peoples in the protohistoric and historic periods, and that powerful mastication was required in the life of the preagricultural Jomon people who subsisted on hunting and gathering.
