Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Physical Anthropology, Penn Museum, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Am J Phys Anthropol. 2021 Dec;176(4):652-671. doi: 10.1002/ajpa.24399. Epub 2021 Sep 15.
In humans, the pelvis is the most sexually dimorphic skeletal element and is often utilized in aging and sexing remains. The pelvis has become greatly relied upon in anthropological research (e.g., forensics, demographics, obstetrics, evolutionary history); however, pelvis morphology is highly variable, and very little is known about the nature, sources, patterning, and interpretation of this variation. This study aims to quantify pelvis shape variation, document sexual shape variation, and estimate the plasticity of morphology. This will ultimately give greater ability to interpret modern, archaeological, and evolutionary patterns to gain deeper insight into processes which shape human anatomy.
Using a sample of 129 Medieval Danish skeletons, shape variation is documented in the greater sciatic notch (GSN), iliac crest (IC), arcuate line (AL), and sub-pubic angle (SPA) using 3D geometric morphometrics. The landmarking method applied here has the advantage of being applicable to fragmentary remains, rather than requiring whole bones. This allows it to be easily applied to archaeological samples and for the interpretation of separate bone features. Differences in shape were statistically analyzed by principle component analysis, linear discriminate analysis, and morphological disparity. Relationships between maximum femur length, body mass, and shape centroid size were also test by allometric regression.
Results quantify the sexual dimorphism and shape variation present in these features. The GSN shape is the most variable, while the AL is the least. Similarly, the IC is the only feature which shows almost no dimorphism in shape, and instead best reflects lifestyle/activity patterns. Evidence of dimorphism in the IC is likely a result of cultural labor patterns rather than genetic and hormonal influence. Finally, the shapes of the GSN, AL, and SPA are more related to body mass than to femur length, such that individuals with increased mass exhibit more classically "male" shapes and those with less mass have more "female" shapes.
The results have important implications for the evolution of pelvic anatomy, and sexual dimorphism, but also highlight the plasticity inherent in pelvic morphology. Analyzing pelvis features separately in a clearly defined, relatively genetically homogenous population gives insight into the determinants of bone morphology, which are not readily observable by other means. The relationship between body mass and shape suggests dimorphism in body size and composition may affect bone shape.
在人类中，骨盆是最具性别二态性的骨骼元素，常用于鉴定遗骸的年龄和性别。骨盆在人类学研究中（例如法医学、人口统计学、产科、进化史）得到了广泛应用；然而，骨盆形态具有高度变异性，对于这种变异性的本质、来源、模式和解释知之甚少。本研究旨在量化骨盆形状变化，记录性别形状变化，并估计形态的可塑性。这将最终使我们能够更好地解释现代、考古和进化模式，深入了解塑造人类解剖结构的过程。
使用 129 具中世纪丹麦骨骼的样本，通过三维几何形态计量学记录坐骨大切迹（GSN）、髂嵴（IC）、弧形线（AL）和耻骨下角（SPA）的形状变化。应用的标志点方法具有适用于碎片遗骸的优势，而不需要完整的骨骼。这使其易于应用于考古样本，并用于解释单独的骨骼特征。通过主成分分析、线性判别分析和形态差异度对形状差异进行了统计学分析。还通过比较回归分析测试了最大股骨长度、体重和形状质心大小之间的关系。
结果量化了这些特征中存在的性别二态性和形状变化。GSN 形状变化最大，而 AL 最小。同样，IC 是唯一形状变化几乎没有二态性的特征，而是最好地反映了生活方式/活动模式。IC 中的二态性的证据可能是文化劳动模式的结果，而不是遗传和激素的影响。最后，GSN、AL 和 SPA 的形状与体重的关系比与股骨长度的关系更密切，因此，体重增加的个体表现出更典型的“男性”形状，而体重较轻的个体具有更多的“女性”形状。
结果对骨盆解剖结构和性别二态性的进化具有重要意义，但也突出了骨盆形态固有的可塑性。在一个明确界定、相对遗传同质的人群中分别分析骨盆特征，可以深入了解骨骼形态的决定因素，这些因素通过其他手段不易观察到。体重和形状之间的关系表明，身体大小和组成的二态性可能会影响骨骼形状。
