Doctoral Dissertation Improvement: Ontogeny of Bipedalism: Pedal Mechanics and Trabecular Bone Morphology

用两只脚走路（双足行走）是人类行为的标志，在整个发展过程中逐渐成熟。在蹒跚学步的幼儿和成人中，脚接触地面的方式，以及走路时脚骨的受力方式是不同的。随着幼儿的成长，他们的内骨（小梁）的形状和结构也会发生变化。本研究的目的是在比较的背景下记录人类足部骨负荷和内部骨结构的并发发育变化。此外，本研究使用了来自现存猿类和人类的比较数据来确定早期人类祖先（南方古猿阿法种）行走适应的性质和发展。本研究包括三个主要部分：1)对人类幼儿两足行走时足部负荷力的实验分析，2)对人类和非洲猿在行走过程中承受高力的足部骨小梁结构的微CT扫描分析，以及3)对幼年和成年阿法种古猿足部骨小梁的分析。通过在人类足骨中识别与两足行走有关的功能上的重要解剖学相关性，本研究将有助于解决关于南方古猿阿法种两足行走在多大程度上与现代人类相似的争论。此外，这项研究将比以前的研究更详细地研究南方古猿阿法种的两足行走，因为它将是第一个从该化石物种的足骨推断两足发育的研究。在体质人类学的范围之外，本研究对儿童骨科具有临床意义，包括对青少年正常和病理骨变化的研究。该项目还将扩大本科生的研究机会，为本科生（特别是代表性不足的群体的成员）提供通过协助数据收集获得实践研究经验的机会。

Walking on two feet (bipedal walking) is a hallmark of human behavior that matures gradually throughout development. The way in which the foot contacts the ground, and thus the way in which foot bones are loaded during walking, differ in toddlers and adults. As toddlers grow, the shape and structure of their internal (trabecular) bone also changes. The objective of this study is to document concurrent developmental changes in human foot bone loading and internal bone structure within a comparative context. Additionally, this study uses comparative data from living apes and humans to determine the nature and development of walking adaptations in early human ancestors (Australopithecus afarensis). This study consists of three main parts: 1) an experimental analysis of forces that load the foot during bipedal walking in human toddlers, 2) a micro CT scan analysis of trabecular structure in human and African ape foot bones that receive high forces during walking, and 3) a trabecular analysis of juvenile and adult A. afarensis foot bones. By identifying functionally significant anatomical correlates to bipedal walking within human foot bones, this study will help resolve debate regarding the extent to which bipedal walking in A. afarensis resembled that of modern humans. Moreover, this study will examine the bipedalism of A. afarensis in greater detail than previous studies because it will be the first to infer bipedal development from foot bones in this fossil species.Beyond the scope of physical anthropology, this study has clinical implications for pediatric orthopedics including the study of normal and pathological bone changes in juveniles. This project will also expand research opportunities available to undergraduates by affording undergraduate students (particularly members of under-represented groups) the opportunity to obtain hands-on research experience by aiding in data collection.