Kambic Robert E, Roberts Thomas J, Gatesy Stephen M
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.
J Anat. 2017 Dec;231(6):906-920. doi: 10.1111/joa.12680. Epub 2017 Aug 18.
Measuring range of motion (ROM) is a valuable technique that can link bone morphology to joint function in both extant and extinct taxa. ROM results are commonly presented as tables or graphs of maxima and minima for each rotational degree of freedom. We investigate the interactions among three degrees of freedom using X-ray reconstruction of moving morphology (XROMM) to measure ROM of the main hind limb joints of Helmeted Guineafowl (Numida meleagris). By plotting each rotation on an axis, we generate three-dimensional ROM volumes or envelopes composed of hundreds of extreme joint positions for the hip, knee, and intertarsal joints. We find that the shapes of ROM volumes can be quite complex, and that the contribution of long-axis rotation is often substantial. Plotting in vivo poses from individual birds executing different behaviors shows varying use of potential rotational combinations within their ROM envelopes. XROMM can provide unprecedented high-resolution data on the spatial relationship of skeletal elements and thereby illuminate/elucidate the complex ways in which soft and hard tissues interact to produce functional joints. In joints with three rotational degrees of freedom, two-dimensional representations of ROM (flexion/extension and abduction/adduction) are incomplete.
测量运动范围（ROM）是一项很有价值的技术，它能够将现存和已灭绝类群的骨骼形态与关节功能联系起来。ROM的结果通常以每个旋转自由度的最大值和最小值的表格或图表形式呈现。我们利用运动形态的X射线重建技术（XROMM）来测量头盔珠鸡（Numida meleagris）主要后肢关节的ROM，从而研究三个自由度之间的相互作用。通过将每次旋转绘制在一个轴上，我们生成了三维ROM体积或包络，这些体积或包络由髋、膝和跗间关节的数百个极端关节位置组成。我们发现ROM体积的形状可能相当复杂，并且长轴旋转的贡献通常很大。绘制执行不同行为的个体鸟类的体内姿势，可以显示出它们在ROM包络内对潜在旋转组合的不同使用情况。XROMM能够提供关于骨骼元素空间关系的前所未有的高分辨率数据，从而阐明软组织和硬组织相互作用产生功能性关节的复杂方式。在具有三个旋转自由度的关节中，ROM的二维表示（屈伸和外展/内收）是不完整的。
