Department of Anthropology, Central Connecticut State University, New Britain, Connecticut.
Anat Rec (Hoboken). 2020 Sep;303(9):2330-2343. doi: 10.1002/ar.24377. Epub 2020 Feb 5.
The unique abductor capability of the human lesser gluteal muscles among extant hominoids has been suggested to be associated, in part, with biomechanical neck length of the femur. Beyond the hominin lineage, the relationship between biomechanical neck length and locomotor performance remains unclear due, in part, to the limited number of primate taxa directly compared and the need to examine species characterized by a wider range of locomotor diversity. Measurements were taken on the proximal femora of 28 extant taxa, with each species being assigned to a locomotor and phylogenetic category. Pairwise comparisons and phylogenetic generalized least-squares analysis were performed to examine the impact of phylogeny and locomotor adaptation on relative biomechanical neck length. Arboreal quadrupeds that perform varying proportions of climbing/clambering versus leaping were characterized by different biomechanical neck lengths, whereas semi-terrestrial anthropoids that perform either knuckle-walking or palmigrade/digitigrade quadrupedalism were found to have similar relative neck lengths. Samples categorized as either orthograde clamberers or bipeds were distinct from all other anthropoid samples and characterized by the relatively shortest and longest biomechanical neck lengths, respectively. Results of additional analyses that included prosimian primates suggest that relatively long biomechanical necks characterize species adapted to hind limb-dominated forms of locomotion (e.g., vertical clinging and leaping and bipedalism). Thus, biomechanical neck length is useful for signaling reliance on bipedalism (as performed by humans) or leaping, including subtle variation in leaping performance among arboreal quadrupeds. Furthermore, this trait is informative regarding reliance on irregular gait clambering as performed by orangutans.
人类臀小肌独特的外展能力被认为部分与股骨的生物力学颈长有关。在人科之外，生物力学颈长与运动表现之间的关系尚不清楚，部分原因是直接比较的灵长类动物类群数量有限，需要研究具有更广泛运动多样性的物种。对 28 种现存分类群的股骨近端进行了测量，每个物种都被归入运动和系统发育类别。进行了成对比较和系统发育广义最小二乘法分析，以检验系统发育和运动适应对相对生物力学颈长的影响。表现出不同比例攀爬/攀登与跳跃的树栖四足动物具有不同的生物力学颈长，而进行指节行走或掌跖行/趾行四足行走的半陆生类人猿则具有相似的相对颈长。被归类为直爬或两足动物的样本与所有其他类人猿样本明显不同，其生物力学颈长分别相对最短和最长。包括原猴类的额外分析的结果表明，相对较长的生物力学颈长特征是适应后肢主导形式运动的物种（例如，垂直抓握和跳跃以及两足行走）。因此，生物力学颈长可用于表示对两足行走（如人类）或跳跃的依赖，包括树栖四足动物中跳跃表现的细微变化。此外，该特征对于依赖猩猩进行的不规则步态攀爬很有用。
