Abstract：
Geometric morphometrics (GMM) have been applied to understand morphological variation in biological structures. However, research studying cortical bone through geometric histomorphometrics (GHMM) is scarce. This research aims to develop a landmark-based GHMM protocol to depict osteonal shape variation in the femoral diaphysis, exploring the role of age and biomechanics in bone microstructure. Proximal, midshaft, and distal anatomical segments from the femoral diaphysis of six individuals were assessed, with 864 secondary intact osteons from eight periosteal sampling areas being manually landmarked. Observer error was tested using Procrustes ANOVA. Average osteonal shape and anatomical segment-specific variation were explored using principal component analysis. Osteon shape differences between segments were examined using canonical variate analysis (CVA). Sex differences were assessed through Procrustes ANOVA and discriminant function analysis (DFA). The impact of osteonal size on osteonal shape was investigated. High repeatability and reproducibility in osteon shape landmarking were reported. The average osteon shape captured was an elliptical structure, with PC1 reflecting more circular osteons. Significant differences in osteon shape were observed between proximal and distal segments according to CVA. Osteon shape differed between males and females, with DFA showing 52% cross-validation accuracies. No effect of size on shape was reported. Osteonal shape variation observed in this study might be explained by the elderly nature of the sample as well as biomechanical and physiological mechanisms playing different roles along the femoral diaphysis. Although a larger sample is needed to corroborate these findings, this study contributes to the best of our knowledge on human microanatomy, proposing a novel GHMM approach.
摘要：
几何形态计量学（GMM）已用于理解生物结构的形态变化。然而,通过几何组织形态计量学(GHMM)研究皮质骨的研究很少。这项研究旨在开发一个具有里程碑意义的GHMM协议来描述股骨骨干中的骨骼形状变化，探讨年龄和生物力学在骨微结构中的作用。近端,中轴,和来自6个人的股骨干的远端解剖节段进行了评估，来自八个骨膜采样区域的864个次要完整骨被手动标记。使用ProcrustesANOVA测试了观察者错误。使用主成分分析探索平均骨形态和解剖节段特异性变异。使用规范变量分析（CVA）检查节段之间的骨形状差异。通过ProcrustesANOVA和判别函数分析（DFA）评估性别差异。研究了骨骼大小对骨骼形状的影响。据报道，骨骼形状标志具有很高的可重复性和可重复性。捕获的平均骨骼形状是椭圆形结构，PC1反射更多的圆形骨。根据CVA，在近端和远端段之间观察到骨骼形状的显着差异。男性和女性的骨骼形状不同，DFA显示52%的交叉验证准确性。没有报道尺寸对形状的影响。在这项研究中观察到的骨骼形状变化可能是由样本的老年人性质以及沿股骨干发挥不同作用的生物力学和生理机制来解释的。尽管需要更大的样本来证实这些发现，这项研究有助于我们对人体显微解剖学的知识，提出了一种新的GHMM方法。
