Doctoral Dissertation Improvement: Biomechanical and Behavioral Significance of the Neanderthal Femur

许多研究人员认为，与现代人相比，尼安德特人股骨的更强的健壮性和由此产生的强度是由于在觅食和狩猎时长期使用。这被称为流动性假说。本研究通过对大量活体灵长类动物的骨骼特征和范围行为进行检查，以确定使用是否等同于更强的健壮性，从而检验了这一假设。研究结果将为人类学、灵长类学、骨科、工程学和数量遗传学等领域提供信息。该研究还影响了对股骨机械环境的理解，这可能有助于髋关节假体的发展。此外，该研究提高了对遗传学和股骨形态之间相关性的理解，并促进了工程和社会科学之间的跨学科合作。尼安德特人的股骨在四个方面与现代人类不同，这表明尼安德特人的股骨在生物力学上更强壮，更弯曲，骨头更厚，轴是圆形而不是椭圆形，颈轴的角度更小。这些差异可以用流动性假说来解释。由于生存策略严重依赖于对动物资源的开发，尼安德特人在寻找食物的过程中可能比现代人走得更远，因此他们的下肢负荷更大。本研究采用三个阶段的方法来检验流动性假说。第一阶段建立了与35种现存灵长类动物的股骨骨骼特征的移动性相关的比较基础，并记录了测距行为，使用的方法将产生并传播数百个计算机化的3D表面模型。第二阶段分析了21个系共413只近交系实验室小鼠的关键骨骼特征是遗传的或环境产生的程度。最后一个阶段探索完整的尼安德特人和现代人股骨在每个物种的特定解剖背景下的强度，使用工程技术（有限元分析）来研究复杂结构对负载的反应，并包括现实肌肉和髋关节反作用力的影响。

Many researchers have suggested that the greater robusticity and resultant strength of Neandertal femora, compared with those of modern humans, is due to extended use while foraging and hunting. This is known as the mobility hypothesis. This study examines that hypothesis by examining skeletal features and ranging behaviors in a large sample of living primates to determine if use equates with greater robusticity. Results will inform the fields of anthropology, primatology, orthopedics, engineering, and quantitative genetics. The study also impacts understanding of the femur's mechanical environment, which could aid the development of hip prosthetics. Furthermore, this study improves understanding of the correlation between genetics and femoral morphology, and promotes interdisciplinarity between engineering and social sciences.The Neanderthal femur differs from that of recent modern humans in four ways that suggest it is more robust, or biomechanically stronger: it is more curved, has thicker bone, a round rather than elliptical shaft, and a smaller neck-shaft angle. These differences may be explained by the mobility hypothesis. Due to subsistence strategies relying heavily on the exploitation of animal resources, Neanderthals may have been traveling farther than modern humans in search of food, and would thus be loading their lower limbs to a greater extent. This study tests the mobility hypothesis using a three phase approach. The first phase establishes a comparative basis relating mobility to femoral skeletal features in 35 species of living primates with documented ranging behavior, using a method that will produce and disseminate hundreds of computerized 3D surface models. The second phase analyzes the degree to which key skeletal features are heritable or environmentally produced using 21 strains of inbred laboratory mice totaling 413 individuals. The final phase explores the strength of complete Neanderthal and modern human femora within each species' particular anatomical context, using an engineering technique (finite element analysis) designed to investigate how complex structures respond to loads, and include the impact of realistic muscle and hip joint reaction forces.