This study aims to carry out the first geometric morphometric analysis of the 3D size and shape of the full series of cervical vertebrae delving into variability related to sex and population background. For this reason, we analyzed the cervical vertebrae of both males and females belonging to Europeans, Africans, and Greenland Inuit. We 3D-scanned a total of 219 cervical vertebrae of males and females of three different modern human populations (European, African, and Inuit). A minimum of 72 landmarks and curve semilandmarks were positioned in each of the 3D vertebral models. Landmark configurations were analyzed following the standards of 3D Geometric Morphometrics to test for size and shape differences related to sex or population variation. Results show that male cervical vertebrae are consistently larger than in females while no regular shape differences are observed between males and females in any of the populations. Sex differences in cervical lordosis are thus not supported at the skeletal level of the 3D shape. On the other hand, there is no evidence for population-specific differences in size while shape does vary considerably, possibly also in relation to eco-geographic factors of overall trunk shape. Cervical vertebrae in cold-adapted Inuit were consistently shorter than in Europeans and Africans. The cervical spine may show a different pattern than the thoracic and lumbar spine, which might be related to stronger integration with the cranium, head mobility, and soft-tissue dependence. Our findings suggest that morpho-functional interpretations of the cervical spine based on vertebral skeletal morphology requires caution.

中文翻译：

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人类颈椎的几何形态测量学：性别和人口变化。

本研究旨在对全系列颈椎的 3D 尺寸和形状进行首次几何形态计量分析，深入研究与性别和人口背景相关的变异性。出于这个原因，我们分析了属于欧洲人、非洲人和格陵兰因纽特人的男性和女性的颈椎。我们对三个不同的现代人群（欧洲人、非洲人和因纽特人）的男性和女性总共 219 块颈椎进行了 3D 扫描。在每个 3D 椎体模型中至少放置了 72 个地标和曲线半地标。按照 3D 几何形态测量学的标准分析地标配置，以测试与性别或人口变化相关的大小和形状差异。结果表明，男性颈椎始终比女性大，而在任何人群中，男性和女性之间都没有观察到规律的形状差异。因此，在 3D 形状的骨骼水平上不支持颈椎前凸的性别差异。另一方面，没有证据表明人口特定的大小差异，而形状确实有很大差异，可能也与整体树干形状的生态地理因素有关。适应寒冷的因纽特人的颈椎一直比欧洲人和非洲人短。颈椎可能表现出与胸椎和腰椎不同的模式，这可能与更强的颅骨整合、头部活动度和软组织依赖性有关。