Department of Anthropology, University of Victoria
Saturday 3:30-3:45, Galleria North
Obstetric selection acts on the female pelvic canal to accommodate the human neonate and contributes to pelvic sexual dimorphism. Pelvic canal size is related to overall body size in some dimensions, though many obstetrically critical dimensions are not related to body size indicating that there is a complex relationship between selection for obstetric sufficiency and for overall body size in humans. The relationship between selective pressures may differ between populations of different body size and proportions. Pelvic canal dimensions have also been shown to vary among populations, perhaps to accommodate differences in body proportionality. The relationships among pelvic canal and body size and shape were examined using nine skeletal samples (total N = 277) from diverse geographical regions, representing a range of body size and proportionality characteristics. Pelvic, vertebral and long bone measurements were collected. Principle component analyses demonstrate pelvic and body size and shape differences among the samples; pelvic shape differences are clearer among the females. High latitude samples have larger and broader bodies, and pelvic canals of larger size and relatively broader medio-lateral dimensions compared to low latitude samples, which tend to display relatively expanded inlet antero-posterior and posterior canal dimensions. Despite this patterning in some characteristics, samples also differ in canal shape with no association to latitude or body size, suggesting relative independence of canal shape from body size and shape. These results contribute to an understanding of variation in pelvic shape among human populations in relation to obstetric pressures and geographic patterning in body shape.
This research was supported by funding from the Social Sciences and Humanities Research Council of Canada.