Early ontogeny of the human femoral bicondylar angle


  • Christine Tardieu,

    Corresponding author
    1. UA 1137 du C. N. R. S., Laboratoire d'Anatomie Comparée, Muséum National d'Histoire Naturelle, 75005 Paris, France
    • Laboratoire d'Anatomie Comparée, Muséum National d'Histoire Naturelle, 55 rue Bufon, 75005 Paris, France
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  • Erik Trinkaus

    1. Department of Anthropology, University of New Mexico, Albuquerque, New Mexico 87131
    2. Laboratoire d'Anthropologie, UA 376 du C. N. R. S., Université de Bordeaux I, 33405 Talence, France
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The presence of a femoral bicondylar angle consistently and significantly greater than 0° has been a hallmark of hominid bipedality, but its pattern of development has not been documented. We have therefore compiled cross-sectional data on the development of the articular bicondylar angle for a clinical sample of modern humans and of the metaphyseal bicondylar angle for two Recent human skeletal samples, one predominantly European in origin and the other Amerindian. All three samples exhibit a pattern of a bicondylar angle of 0° at birth and then a steady average increase in the angle from late in the first year postnatal, through infancy, and into the juvenile years. The two skeletal samples reach low adult values by approximately 4 years postnatal, whereas the clinical sample with a lowered activity level appears to attain consistent adult values slightly later (approximately 6 years postnatal). In addition, two modern human individuals, one nonambulatory and the other minimally ambulatory, show no and little development, respectively, of a bicondylar angle. These data, in conjunction with clinical and experimental observations on the potential and form of angular changes during epiphyseal growth, establish a high degree of potential for plasticity in the development of the human bicondylar angle and the direct association of a bipedal locomotion and (especially) posture with the developmental emergence of a human femoral bicondylar angle. © 1994 Wiley-Liss, Inc.