Estimation of Age at Death from Pubic Symphysis for the Prehistoric Human Skeletons in Japan

Abstract

Among excavated human skeletons of the prehistoric Jomon period in Japan collected at the Department of Anthropology of the University of Tokyo there are found 38 skeletons whose pubic symphyses of either one or both sides remain in fairly good condition. The author has examined the morphological features of these pubic symphyses mainly from the viewpoint of aging and tried to estimate the age at death of the skeletons. The skeletons used consist of 25 males and 13 females, the youngest of which is estimated not less than 18 years old. They were excavated from shell mounds of various times of the Jomon period in different regions of Japan, but as the number of the samples is too small to be divided into period or regional groups, there is no attempt at such grouping in this study.For the estimation of age at death the author refered to the studies on the changes in the pubic bone by Todd, Brooks, and McKern and Stewart, and the similar studies for the Japanese by Hanihara and Koyama, and also refered to the author's own survey based on age-known recent Japanese skeletons. The age estimation in the present study is not based exclusively on the pubic symphysis, but other parts of the skeleton were also carefully observed and taken into consideration for the age estimation as checking factors.The probable age range estimated is different from case to case, but for the statistical convenience the author took the pivotal age of the age range in respective cases and tabulated it into a table arranged by five-year age categories. The estimated age distribution is as follows: 1) males: 1 in 15-19 years, 3 in 20-24 years, 4 in 25-29 years, 9 in 30-34 years, 4 in 35-39 years, 2 in40-44 years and 2 in 50 years or more; 2) females: 4 in 20-24 years, 2 in 25-29 years, 3 in 30-34 years, 1 in 35-39 years and 3 in 40-44 years.The present paper does not deal with the problem of the relationships between aging stage of the pubic symphysis and that of other parts of the skeleton, but the author is engaged in pursuing this problem for the ancient skeletons in Japan for the purpose of obtaining age criterions in the age estimation of the majority of excavated skeletons lacking the pubic Symphysis.