Variation in Talar Joint Facets of the Early-Modern Human Calcaneus from Kumejima, Okinawa

Abstract

We examined 396 talar joint facets of the calcaneus and talus of early-modern human remains from Kumejima, Okinawa to classify into 4 types of articular facet (Continuous Type/Demarcated Type/Separate Type/No Anterior facet Type); using the standard by Tanaka et al. (2004a). Significant correlations between right and left facet types were recognized. The frequency of the demarcated type was significantly higher in males, while that of the continuous type was higher in females. The respective appearances of the continuous type and smooth type, demarcated type and angular type, no-anterior facet type and no-anterior facet type of the calcaneus and talus were correlated. The appearance of the calcanean separate facet type corresponded to those of the angular type and grooved type in the talus. Analysis of variance showed that there were significant differences in length between the anterior and middle talar articular facets of the calcaneus among the continuous, demarcated and separate types. The demarcated type had a significantly longer articular surface length (AB) than the continuous type. The separate facet type showed a significantly deeper depth (C) than the continuous type. The separate facet type had a significantly higher depth index (C/AB) than the consecutive models. The Kumejima Island and central Kyushu groups of the modern period showed a high frequency of calcanean separate facet type among Japanese Islanders, while prehistoric and historic East Japanese showed rather lower frequencies.