Dissertation Research: Thoracic Shape and Arm Mobility in Primates

人类学家认为，人类和类人猿(即类人猿)胸部从前到后的扁平增加了肩膀上手臂的运动范围，这样它们就可以向各个方向伸展。这被认为是从一根树枝摆动到另一根树枝的交接过程中必不可少的，就像大多数现存的类人猿(大概也是我们类人猿的祖先)一样。然而，这种摆动手臂的类人族解剖学假说最近受到了其他假说的挑战，这些假说认为，类人族胸部的特殊形状是为了缓慢攀登(这也需要向各个方向伸展)或在垂直的树干上攀登而进化的。不幸的是，人类胸部扁平的功能，就像许多其他肩部解剖特征的功能一样，不能被澄清，因为完全缺乏关于灵长类肩部活动的数据。这项研究将对镇静动物和骨骼和韧带准备情况下的3个维度的手臂活动范围进行视频测量，以比较不同形状胸部动物的手臂活动范围。这项研究还将使用X光测量具有不同运动行为的灵长类物种的胸部形状，以检验运动行为与胸部形状的关系。这项拟议的研究结果将为评估人类和灵长类肩部的功能和进化解剖学研究中的众多假说提供急需的流动性数据。

Anthropologists have argued that the front-to-back flattening of the chest of humans and apes (i.e. hominoids) increases the range of arm movement at the shoulder so that they can reach out in all directions. This is supposedly essential for swinging from branch to branch hand-over hand, like most living apes (and presumably, our ape-like ancestors). However, this arm-swinging hypothesis of hominoid anatomy has recently been challenged by other hypotheses, which argue that the special shape of the hominoid chest evolved for slow climbing (which also requires reaching out in all directions) or for climbing on vertical tree trunks. Unfortunately, the function of the flattened chest in hominoids, like the functions of many other shoulder anatomical features, cannot be clarified because of a complete lack of data on shoulder mobility in primates. This study will videographically measure the range of arm movement in 3 dimensions, on sedated animals and on preparations of bones and ligaments, in order to compare the range of arm movement in animals with chests of different shapes. This study will also measure chest shape using x-rays of primate species with different locomotor behaviors, in order to examine the relationship between locomotor behavior and chest shape. The results of the proposed research will provide much-needed mobility data for evaluating numerous hypotheses in the study of the functional and evolutionary anatomy of human and primate shoulders.