A three-dimensional model of the rat hindlimb: Musculoskeletal geometry and muscle moment arms
A three-dimensional model of the rat hindlimb: Musculoskeletal geometry and muscle moment arms
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DOI：
10.1016/j.jbiomech.2007.10.004
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Edgerton, V. Reggie
中科院分区：
文献类型：
--
作者：
Johnson, Will L.;Jindrich, Devin L.;Edgerton, V. Reggie
作为建立大鼠后肢动态模型的第一步，我们使用立体摄影测量法测量了肌肉附着和关节中心相对于骨骼地标的坐标。利用这些测量，我们分析了大多数后肢肌肉的肌力矩臂作为关节角度的函数，并检验了仅姿势变化就足以改变所选Lea肌肉的功能的假设。我们将肌肉附着部位描述为二级曲线。拟合抛物线的长度和垂直方向上的残差给出了肌肉附着大小的估计，这与在解剖过程中所观察到的一致。我们将每个关节建模为一个依赖于关节角度的运动点，相对终点误差小于7%，表明该方法是准确的。大多数肌肉都有力矩臂，在关节角度的生理范围内范围很大，但它们的力矩臂在运动范围内达到峰值，变化很小。运动过程中力矩臂的微小变化潜在地简化了这一阶段的神经控制要求。在四足运动域内，随着角度的变化，许多肌肉的力矩臂都是零的，这表明它们本质上是稳定的。然而，在两足动物运动域中，这些肌肉的力矩臂不会超过零，因此不再本质上稳定。我们发现，肌肉功能在很大程度上取决于力矩臂随关节角度的变化，特别是从四足动物姿势到两足动物姿势的转变，这可能会改变固有的稳定排列或改变控制负担。(C)2007爱思唯尔有限公司。保留所有权利。
As a first step towards developing a dynamic model of the rat hindlimb, we measured muscle attachment and joint center coordinates relative to bony landmarks using stereophotogrammetry. Using these measurements, we analyzed muscle moment arms as functions of joint angle for most hindlimb muscles, and tested the hypothesis that postural change alone is sufficient to alter the function of selected muscles of the lea. We described muscle attachment sites as second-order curves. The length of the fit parabola and residual errors in the orthogonal directions give an estimate of muscle attachment sizes, which are consistent with observations made during dissection. We modeled each joint as a moving point dependent on joint angle; relative endpoint errors less than 7% indicate this method as accurate. Most muscles have moment arms with a large range across the physiological domain of joint angles, but their moment arms peak and vary little within the locomotion domain. The small variation in moment arms during locomotion potentially simplifies the neural control requirements during this phase. The moment arms of a number of muscles cross zero as angle varies within the quadrupedal locomotion domain, indicating they are intrinsically stabilizing. However, in the bipedal locomotion domain, the moment arms of these muscles do not cross zero and thus are no longer intrinsically stabilizing. We found that muscle function is largely determined by the change in moment arm with joint angle, particularly the transition from quadrupedal to bipedal posture, which may alter an intrinsically stabilizing arrangement or change the control burden. (c) 2007 Elsevier Ltd. All rights reserved.