Wunderlich R E, Jungers W L
Department of Biology, James Madison University, Harrisonburg, VA 22807, USA.
Am J Phys Anthropol. 2009 Jul;139(3):394-403. doi: 10.1002/ajpa.20994.
Considerable attention has been given to hand morphology and function associated with knuckle-walking in the African apes because of the implications they have for the evolution of bipedalism in early hominins. Knuckle-walking is associated with a unique suite of musculoskeletal features of the wrist and hand, and numerous studies have hypothesized that these anatomical features are associated with the dynamics of load distribution across the digits during knuckle-walking. We collected dynamic digital pressures on two chimpanzees during terrestrial and simulated arboreal locomotion. Comparisons were made across substrates, limb positions, hand positions, and age categories. Peak digital pressures were similar on the pole and on the ground but were distributed differently across the digits on each substrate. In young animals, pressure was equally high on digits 2-4 on the ground but higher on digits 3 and 4 on the pole. Older animals experience higher pressures on digits 2 and 3 on the ground. Hand posture (palm-in vs. palm-back) influenced the distribution and timing of peak pressures. Age-related increases in body mass also result in higher overall pressures and increased variation across the digital row. In chimpanzees, digit 5 typically bears relatively little load regardless of hand position or substrate. These are the first quantitative data on digital pressures during knuckle-walking in hominoids, and they afford the opportunity to develop hypotheses about variation among hominoids and biomechanical models of wrist and forearm loading.
由于非洲猿类的指关节行走与早期人类两足行走的进化相关，因此人们对其手部形态和功能给予了相当多的关注。指关节行走与手腕和手部独特的肌肉骨骼特征相关，许多研究推测这些解剖特征与指关节行走过程中各手指间的负荷分配动态有关。我们在两只黑猩猩进行陆地和模拟树栖运动时收集了动态指压数据。对不同的基质、肢体位置、手部位置和年龄类别进行了比较。在杆子上和地面上的峰值指压相似，但在每种基质上各手指的压力分布不同。在幼年动物中，地面上第2 - 4指的压力同样高，但在杆子上第3和4指的压力更高。老年动物在地面上第2和3指承受的压力更高。手部姿势（掌心向内与掌心向后）影响峰值压力的分布和时间。与年龄相关的体重增加也会导致整体压力更高，并且各手指间的压力差异增大。在黑猩猩中，无论手部位置或基质如何，第5指通常承受的负荷相对较小。这些是关于类人猿指关节行走时指压的首批定量数据，它们为提出关于类人猿之间差异的假设以及手腕和前臂负荷的生物力学模型提供了机会。
