Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain.
Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain.
J Hum Evol. 2020 Apr;141:102738. doi: 10.1016/j.jhevol.2019.102738. Epub 2020 Mar 5.
The evolution of the body form in Homo and its potential morphological connection to the arrangement of different skeletal systems is of major interest in human evolution. Patella morphology as part of the knee is potentially influenced by body form. Here, we describe for the first time the patellae remains recovered at El Sidrón Neandertal site and analyze them in a comparative evolutionary framework. We aim to clarify whether morphometric features frequently observed in Neandertal and modern human patellae are retained from a primitive anatomical arrangement or whether they represent derived features (apomorphies). For this purpose, we combine analyses of discrete features, classic anthropological measurements, and 3D geometric morphometrics based on generalized Procrustes analysis, mean size and shape comparisons, and principal components analysis. We found a size increment of the patella in hominin evolution, with large species showing a larger patella. Modern humans and Neandertals exhibit overall larger patellae, with maximum values observed in the latter, likely as a consequence of their broader body shape. Also, some Neandertals display a thicker patella, which has been linked to larger quadriceps muscles. However, Neandertals retain a primitive morphology in their patellar articular surfaces, with similar-sized lateral and medial articular facets, leading to a more symmetrical internal face. This feature is inherited from a primitive Homo ancestor and suggests a different configuration of the knee in Neandertals. Conversely, Homo sapiens exhibits an autoapomorphic patellar anatomy with expanded lateral articular facets. We propose that these distinct configurations of the patella within Homo may be a consequence of different body forms rather than specific functional adaptations of the knee. Thus, the slender body form of modern humans may entail a medial reorientation of the tibial tuberosity (patellar ligament), allowing lateral surface expansion. These anatomical evolutionary variations may involve subtle secondary differences in bipedalism within Homo.
人体形态的演变及其与不同骨骼系统排列的潜在形态联系是人类进化研究的重点。髌骨形态作为膝关节的一部分，可能受到身体形态的影响。在这里，我们首次描述了在埃尔·西德龙尼安德特遗址发现的髌骨，并在比较进化框架下对其进行了分析。我们旨在澄清在尼安德特人和现代人类髌骨中经常观察到的形态特征是保留了原始的解剖结构，还是代表了衍生特征（独特的性状）。为此，我们结合了离散特征分析、经典人类学测量以及基于广义 Procrustes 分析、平均大小和形状比较以及主成分分析的 3D 几何形态测量。我们发现，在人类进化过程中，髌骨的大小有所增加，大型物种的髌骨较大。现代人类和尼安德特人总体上显示出更大的髌骨，后者的髌骨最大，这可能是由于他们更宽阔的体型所致。此外，一些尼安德特人显示出更厚的髌骨，这与更大的四头肌有关。然而，尼安德特人在其髌骨关节表面保留了原始的形态，其外侧和内侧关节面具有相似的大小，导致内部表面更加对称。这一特征源自原始的 Homo 祖先，表明尼安德特人的膝关节具有不同的结构。相反，智人具有扩展的外侧关节面的独特髌骨解剖结构。我们提出， Homo 内部髌骨的这些不同形态结构可能是不同身体形态的结果，而不是膝关节的特定功能适应的结果。因此，现代人的苗条体型可能导致胫骨粗隆（髌韧带）的内侧重新定向，从而允许外侧表面的扩展。这些解剖学上的进化变化可能涉及 Homo 内部微妙的双足行走的次要差异。
