Department of Earth Sciences, Natural History Museum, London, UK.
School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
Am J Phys Anthropol. 2020 Sep;173(1):80-95. doi: 10.1002/ajpa.24080. Epub 2020 Jul 12.
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.
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.
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.
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.
股骨是主要的承重骨，在儿童经历运动状态转变以获得成熟的双足步态之前，其会随着生长而发生不同的负荷。在此，我们记录了股骨横截面几何形状（CSG）的发育趋势，并探讨了负荷方式的变化如何影响皮质骨在发育骨干长度上的结构排列。
从一个记录在案的考古样本中生成了 110 个未成熟股骨的微 CT 扫描，这些样本的年龄从出生到 8.5 岁不等。从总干骺端 35%、50%和 65%处提取的横截面分析了指示相对骨强度和弯曲刚度的 CSG 特性。
婴儿在出生到 7 个月期间经历了皮质骨的明显再分配，这有利于在骨骼从截面质心进一步移位时，为早期承重行为提供更有利的机械结构。早期步行者的特点是横截面在中间和外侧得到加强，随着步态的继续发展，横截面变得更加圆形。
在发育过程中，股骨经历了明显的形态阶段，这与负荷方式的变化相对应。本研究说明了负荷条件在塑造未成熟骨形态方面的重要性。非机械因素，如激素环境的变化，也会对这种动态产生影响。
