Variation in the human bicondylar angle

Abstract

The results highlight the degree of variation in the bicondylar angle that exists intraspecifically. Differing degrees of variation due to sex suggest that sexual dimorphism is not universal in the human bicondylar angle. Furthermore, the broad impact of age on this feature is discussed, including the potential for plasticity through adulthood. By recognizing and explicitly examining morphological features that vary in human populations, we can appreciate the origins of variation and its implications for locomotor function, human diversity and evolutionary relationships. Am J Phys Anthropol 160:334-340, 2016. © 2016 Wiley Periodicals, Inc.

Femoral angle development and locomotor progression in children from 18th and 19th century London

“…After the age of 2 years, BCA continues to increase but does so at a slower rate during the later phase of toddling and acquisition of mature gait. BCA values do not stabilize within the age range included in this study and are likely to continue to increase throughout later childhood and adolescence (Pujol et al, 2014, 2016; Tardieu & Damsin, 1997) and potentially change again during adulthood as a result of age‐related changes in physical activity (Waxenbaum & Stock, 2016). Nevertheless, the data suggest that values at the lowest end of the adult range (6°–8°) are attained by approximately 5 years, coinciding with the development of mature gait (locomotor stage 5).…”

“…With increased walking proficiency, children start to reach low adult values of approximately 6–8° between the ages of 4 and 8 years, with the angle stabilizing close to adult values during adolescence (Pujol, Rissech, Ventura, & Turbón, 2016; Tardieu & Damsin, 1997). Adult BCA values typically range between 8° and 11° (Tardieu & Damsin, 1997) but have been reported to vary considerably due to different levels of physical activity within and between human populations (Waxenbaum & Stock, 2016) and differences in femur length and interacetabular width between males and females (Pandya, Singel, Patel, & Gohil, 2008; Pujol et al, 2016).…”

Variation in the intertrochanteric line in a modern human population from southwestern China (19th–20th centuries)

“…The hominin femur exhibits several traits that are indicators of bipedalism (e.g. the bicondylar angle and a deep patellar groove), and have been used extensively in reconstructions of locomotor patterns (Heiple and Lovejoy, 1971;Aiello and Dean, 1990;Tardieu and Trinkaus, 1994;Waxenbaum and Stock, 2016). The intertrochanteric line has been proposed to be one such functional indicator of bipedalism (Lovejoy and Heiple, 1972;Aiello and Dean, 1990;Pickford et al, 2002).…”