The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Reevaluating the relationship of the bicondylar angle to dimensions of the pelvis and femur

MARIA R. DARR and CHRISTOPHER A. DAVIS.

Department of Anthropology, University of Texas at Austin

March 26, 2015 1:30, Grand Ballroom E/F/G Add to calendar

The femoral bicondylar angle characteristic of humans and fossil hominins is an adaptation for bipedal gait, as it places the foot closer to the midline, below the body’s center of mass, during stance phase. Ontogenetic studies have shown that during early development the bicondylar angle consistently covaries with other variables related to bipedal gait and stance, such as pelvic breadth and femoral length. Although the large bicondylar angles of Australopithecus africanus and A. afarensis have been attributed to their broad pelves and short stature, the relationship among these variables has not been well tested in adults. In this study, pelvic breadth, femoral length, femoral neck length, and the cervico-diaphyseal angle were measured to determine which variables are correlated with the bicondylar angle in an adult human skeletal sample (n= 86). Results indicate that none of the measurements examined here are significantly correlated with bicondylar angle among adults. Femoral neck length is positively correlated with total femoral length across the sample. Pelvic breadth and femoral neck length are positively correlated in females. Males display a positive relationship between femoral length and biacetabular breadth, pelvic breadth and neck angle, and neck length and neck angle. However, these results do not support the assertion that a wider pelvis and short stature (or femora) predicts a larger bicondylar angle among adults. These results weaken previous interpretations of bicondylar angle in fossil hominins and have implications for interpreting lower limb skeletal adaptations and locomotor mechanics in the hominin skeletal record.