人类股骨断面面积与形状的不对称性——基于三维激光扫描的形态测量分析

人类股骨横断面面积、形状及其左右侧差异记载的人类演化、人群差异及生存活动的重要信息一直为古人类学研究所关注。多年来, 对股骨断面的研究通常采用破坏性地切割或者制作模型的方法。本文利用三维激光表面扫描技术, 无损、快捷、方便地获取了20对现代中国人左右侧股骨外轮廓的三维数据, 采用CAD软件及几何形态测量方法对两侧股骨断面轮廓的大小及形状进行了对比和分析。初步研究结果发现: 两侧股骨的横断面相对面积差异极其显著, 绝对面积差异不显著, 不对称方式表现为波动不对称性, 而不是偏向不对称性; 个体之间两侧股骨横断面外轮廓形状的波动不对称性极其显著, 偏向不对称性虽有差异但不显著; 平均形状和面积分析结果似乎表明股骨稍有偏左侧优势。虽然本文所采用的标本量有限, 所得出的结论需要更多标本的进一步验证, 但是, 本文的研究结果提示利用三维激光扫描技术获取股骨横断面外轮廓数据, 并采用形态测量方法分析确实能够揭示出一些以往研究方法不能发现的重要信息, 这种研究骨骼不对称性的新方法值得进一步的应用。

Bilateral Asymmetry in Human Femoral Cross-sectional Surface Areas and Shapes: Morphometric Analysis Using 3D Laser Scanning

Paleoanthropologists have been paying more attention to human femoral cross- sectional surface areas, shapes and bilateral asymmetry because of the application of this informations to human evolution, population differences, and survival movements. Traditional analyses of femoral cross-sections usually adopt methods of destructive cutting, or labor- intensive model making. In this study, using 3D laser scanning, we nondestructively and conveniently get the outer contour of 20 paired femoral 3-D data from a modern Chinese population. With the software of CAD and method of geometric morphometrics, we examine bilateral asymmetry between the left and right femoral cross-sectional area and shape. The results indicate that bilateral asymmetry in femoral size and shape exists. Cross-sectional areas of paired femora have no significant differences in absolute values, but have significant differences in relative ones. Paired femora show flutuating asymmetry, rather than directional asymmetry. Moreover, significant differences on paired femoral cross-sectional shapes show fluctuating asymmetry. Directional asymmetry exists on paired femoral cross-sectional shapes, but it is not statistically significant. Average cross-sectional shapes and areas seem to indicate that human femora have a slight left-lateral dominance. Although the samples in this study are limited, and the conclusion need more specimens for further verification, our results show that using 3D laser scanning techniques, we can get data of femoral cross-sectional outer contour, and the methods of morphometric analysis does reveal some important information that traditional methods can not determine. This paper establishes a new method to examine bone asymmetry, and can be used for additional studies in human evolution.