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Ontogenetic changes in femoral cross‐sectional geometry during childhood locomotor development
Author(s) -
Swan Karen R.,
Ives Rachel,
Wilson Laura A. B.,
Humphrey Louise T.
Publication year - 2020
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.24080
Subject(s) - femur , ontogeny , cortical bone , diaphysis , anatomy , bone development , bone growth , cross section (physics) , bone structure , long bone , rigidity (electromagnetism) , orthodontics , materials science , biology , medicine , physics , composite material , paleontology , genetics , quantum mechanics , endocrinology
Abstract Objectives The femur is a major weight‐bearing bone that is variably loaded throughout growth as children transition through locomotory states prior to the attainment of a mature bipedal gait. Here, we document ontogenetic trends in femoral cross‐sectional geometry (CSG) and explore how changes in loading regime may impact the structural arrangement of cortical bone along the length of the developing diaphysis. Materials and methods Micro‐CT scans of 110 immature femora were generated from a documented archaeological sample ranging in age from birth to 8.5 years old. CSG properties indicative of relative bone strength and bending rigidity were analyzed from cross‐sections extracted at 35%, 50% and 65% of total intermetaphyseal length. Results Infants experience a marked redistribution of cortical bone between birth and 7 months facilitating a more advantageous mechanical structure for early load bearing behaviors as bone is displaced further from the section centroid. Early walkers are characterized by a mediolaterally reinforced cross‐section that becomes more circular as gait continues to develop. Discussion During ontogeny the femur undergoes distinct morphological phases, which correspond with changes in loading regime. This study illustrates the importance of loading conditions in shaping immature bone morphology. Nonmechanical factors such as changes in hormonal environmental can also impact on this dynamic.