The relationship of the pre‐auricular groove of the llium to pregnancy

Am. J. Phys. Anthropol.

Hirata

Yokota

et al. 2006

The purpose of this study is to obtain demographic data regarding the medieval population buried at the Yuigahama-minami site in Kamakura, Japan, and to detect a secular trend in the life expectancy of Japanese population over the last several thousand years. The Yuigahama-minami skeletal sample consists of 260 individuals, including 98 subadults (under 20 years old) and 162 adults. A Yuigahama-minami abridged life-table analysis yielded a life expectancy at birth (e0) of 24.0 years for both sexes, a life expectancy at age 15 years (e15) of 15.8 years for males, and an e15 of 18.0 years for females. The reliability of the estimated e0 was confirmed by analysis of the juvenility index. Demographic profiles comparing the Yuigahama-minami series with other skeletal series indicated that both the survivorship curve and life expectancy of the Yuigahama-minami sample are similar to those of the Mesolithic-Neolithic Jomon population, but are far lower than those of the early modern Edo population. These comparisons strongly suggest that life expectancy changed little over the thousands of years between the Mesolithic-Neolithic Jomon and medieval periods, but then improved remarkably during the few hundred years between the medieval period and early modern Edo period. The short-lived tendency of the Yuigahama-minami sample does not contradict the archaeological hypothesis of unsanitary living conditions in medieval Kamakura. This is the first investigation to address the demographic features of a medieval population in Japan, and will help refine our understanding of long-term trends in the demographic profiles of inhabitants of Japan.

Section: Sex Determinationmentioning

confidence: 99%

Paleodemography of a medieval population in Japan: Analysis of human skeletal remains from the Yuigahama-minami site

Am. J. Phys. Anthropol.

Hirata

Yokota

et al. 2006

“…The sex of adults was estimated by the morphology of the pelvis (Phenice, 1969;Houghton, 1974;Ferembach et al, 1980;Bruzek, 2002). The ages of subadult skeletons were estimated using a reference chart (Ubelaker, 1999).…”

Section: Bone Samplesmentioning

confidence: 99%

Infant feeding practice in medieval Japan: Stable carbon and nitrogen isotope analysis of human skeletons from Yuigahama‐minami

Tsutaya

Shimomi

American J Phys Anthropol

et al. 2014

A longer breastfeeding duration provides various positive effects in subadult health because of abundant immunological factors and nutrients in human breast milk, and decreases the natural fertility of a population through lactational amenorrhea. In this study, we measured stable carbon and nitrogen isotope ratios in the bone collagen of three adults and 45 subadults from the Yuigahama-minami site (from 12th to 14th century) in Kamakura, the early medieval capital of Japan. Marine foods, C3 -based terrestrial foods, and freshwater fish are the primarily protein sources for adults. The changes in the nitrogen isotope ratios of subadults suggest that the relative dietary protein contribution from breast milk started to decrease from 1.1 years of age and ended at 3.8 years. The age at the end of weaning in the Yuigahama-minami population was greater than that in the typical non-industrial populations, a premodern population in the Edo period Japan, and medieval populations in the UK. Skeletons of townspeople from medieval Kamakura indicate severe nutritional stress (e.g., enamel hypoplasia and cribra orbitalia), yet this longer duration of breastfeeding did not compensate adverse effects for nutritional deficiency. The longer breastfeeding period may have been a consequence of complementary food shortage and bad health of subadults. Kamakura experienced urbanization and population increase in the early medieval period. The younger age-at-death distribution and high nutritional stresses in the Yuigahama-minami population and later weaning, which is closely associated with longer inter-birth interval for mothers, suggests that Kamakura developed and increased its population by immigration during urbanization.

“…Dimorphic criteria of the pelvis include the greater sciatic notch, preauricular sulcus, ventral arc, subpubic concavity, and medial aspect of the ischiopubic ramus (Genovés, 1959;Phenice, 1969;Houghton, 1974;Workshop of European Anthropologists, 1980;Bruzek, 2002). Sexual dimorphism of long bones includes their robustness, which provides clues for sex determination (Workshop of European Anthropologists, 1980).…”

Section: Sex Determinationmentioning

confidence: 99%

Sex determination using mastoid process measurements: standards for Japanese human skeletons of the medieval and early modern periods

Shizushima²,

Sawada

et al. 2008

The purpose of this study was to develop new standards for determining the sex of fragmentary human skeletal remains. We measured height, width, and length of the mastoid process in medieval to early modern Japanese skeletons, from the Yuigahama-minami and Hitotsubashi sites, in order to provide a metric standard for the diagnosis of sex using the mastoid process. We calculated discriminant functions based on these measurements; the accuracy of sex classification was over 80% using a single variable, and reached 82-92% with two variables, mastoid height and width. This accuracy is equal to or better than that reported by some previous studies of sex determination using the cranium. However, when we examined intra-and interobserver errors in the mastoid process measurements, we found a high level of errors, and this highlights the difficulty involved in intraobserver repeatability and interobserver reproducibility. Our results imply that, in order to achieve reliable results of sex determination using the mastoid process, the measurement methods need to be carefully determined and executed.