Lewton Kristi L, Scott Jeremiah E
Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California.
Department of Biological Sciences, University of Southern California, Los Angeles, California.
Anat Rec (Hoboken). 2017 May;300(5):845-858. doi: 10.1002/ar.23543.
Human ischia contrast with those of great apes in being craniocaudally short and dorsally projecting. This configuration is thought to facilitate greater hip extension in humans during bipedal locomotion. This link has been used to infer kinematics in early hominins, but the consequences of variation in ischial configuration for gait remain uncertain. Kinematic data for a limited sample of extant nonhuman primates demonstrate that there is variation in hip extension in these taxa during bipedal behaviors-specifically, Hylobates and Ateles are capable of greater extension than Pan and Macaca. In this study, we tested the hypothesis that ischial length and orientation are functionally linked with hip extension during bipedalism among these taxa. As expected, humans have the shortest ischia, followed by gibbons, spider monkeys, chimpanzees, and macaques. Our predictions for ischial orientation are not supported, however: macaques, gibbons, and spider monkeys do not vary in this trait, and they have ischia that are less dorsally angled than that of the chimpanzee. The results for ischium length provide limited support for the idea that the early hominin Ardipithecus ramidus, with its long, caudally oriented ischium was not capable of humanlike extended-hip bipedalism, and that the ischial shortening observed in post-Ardipithecus hominins reflects a shift toward a more humanlike gait. In contrast, while our results do not necessarily refute a link between ischial orientation and hip extension in hominins, they do not provide comparative support, making changes in ischial orientation in this part of the fossil record more difficult to interpret. Anat Rec, 300:845-858, 2017. © 2017 Wiley Periodicals, Inc.
人类的坐骨与大猩猩的坐骨相比，在颅尾方向上较短且背侧突出。这种形态被认为有助于人类在双足行走时实现更大程度的髋关节伸展。这一联系已被用于推断早期人类的运动学，但坐骨形态变化对步态的影响仍不确定。对有限数量的现存非人类灵长类动物样本的运动学数据表明，这些分类群在双足行为期间髋关节伸展存在差异——具体而言，长臂猿和蛛猴比黑猩猩和猕猴能够实现更大程度的伸展。在本研究中，我们测试了这样一个假设：在这些分类群的双足行走过程中，坐骨长度和方向与髋关节伸展在功能上存在联系。正如预期的那样，人类的坐骨最短，其次是长臂猿、蜘蛛猴、黑猩猩和猕猴。然而，我们对坐骨方向的预测并未得到支持：猕猴、长臂猿和蜘蛛猴在这一特征上没有差异，而且它们的坐骨背侧角度比黑猩猩的要小。坐骨长度的结果为以下观点提供了有限的支持，即早期人类始祖地猿，因其坐骨长且尾向，无法进行类似人类的髋关节伸展双足行走，并且在始祖地猿之后的人类中观察到的坐骨缩短反映了向更类似人类步态的转变。相比之下，虽然我们的结果不一定反驳人类坐骨方向与髋关节伸展之间的联系，但它们并未提供比较性的支持，使得化石记录中这一部分坐骨方向的变化更难解释。《解剖学记录》，300:845 - 858，2017年。© 2017威利期刊公司。
