1957年,在辽宁省建平县发现了一根古人类肱骨化石,编号PA103。通过同一批龙骨中筛选的哺乳动物化石,吴汝康推断PA103应该为更新世晚期古人类,并对该化石进行了表面形态特征观察和描述。为了对PA103化石的内外结构进行更全面的了解,除了线性测量数据的对比,本文还通过计算机断层扫描技术,结合生物力学和形态示量图分析对建平古人类右侧肱骨化石PA103进行了分析。通过本研究发现,PA103骨干横断面的生物力学粗壮度和力学形状指数明显小于尼安德特人,而与同时期欧亚大陆古人类不利手侧最为接近,这说明建平人右侧肱骨可能不是惯用手,同时,建平人的行为活动应该与同时期同地区的古人类处于同一水平,而小于尼安德特人。整体来看,PA103骨干骨密质厚度和截面惯性矩与近现代人的分布模式较为接近,除局部数值增大外,其整体数值小于近现代人的平均水平,这可能与遗传或行为活动有关,由于缺少古人类化石对比数据,更详细的了解还需后期开展更多相关的研究。

In 1957, one humeral diaphysis of human (PA103) was discovered in Jianping couty, Liaoning province, northern China. According to the comparison of mammal fossils from the same layer, PA103 could be attributed to Late Pleistocene. This specimen has been described in detail. Given the scarcity of upper limb fossil of Late Pleistocene humans from East Asia, a more detailed comparative study is warranted. Here, we provide a comparative assessment of Jianping PA103 humeral inner morphology. Specifically, we analyze the diaphyseal structure of PA103 using micro-computed tomography coupled with methods of cross-sectional geometry and morphometric maps. Cross-sectional properties, continuous cortical bone thickness, and continuous bone strength of PA103 are compared to those of Neandetrals, Middle and Upper Paleolithic modern humans. The PA103 were found to be similar to those of Late Upper Paleolithic in cross-sectional shape of midshaft and biomechanical robusticity. The individual represented by PA103 is more similar to the non-dominant side of comtemporary samples, i.e. biomechanical robusticity and shape index at midshaft. Although the distribution pattern of cortical bone thickness and bone strength in modern human is similar, the cortical thickness of the humeral diaphysis do not seem to correlate strongly with bone strength. Thus, caution is warranted when equating the cortical thickness of a long bone diaphysis to its overall strength.