Reich J, Daunicht W J
Neurologisches Therapiecentrum, Düsseldorf, Germany.
J Biomech. 2000 Sep;33(9):1159-68. doi: 10.1016/s0021-9290(00)00039-7.
In this article the forearm, with its complex, continuous motion of masses during pronation/supination, was approximated by a rigid body model consisting of a radial segment rotating around an ulnar segment. The method used to obtain the model parameters is based on three-dimensional voxel data that include velocity information. We propose a criterion that allows the voxels to be attributed to either of the two segments. It is based on the notion that the rotational kinetic energy determined from the voxel data equals the kinetic energy of the rigid body model. To obtain a three-dimensional smoothing we further propose a parameterization of the shape of both segments. These shapes can then be used to determine the dynamic integrals of the segments, i.e. mass, center of mass, and inertia. Using this approach we determined all model parameters for a human forearm from three series of MRI scans in a supinated, a pronated, and an intermediate position. In the appendix, a procedure is described that allows the dynamic quantities to be scaled homogeneously without recalculation of the integrals. Thus, this article provides all essential parameters required for three-dimensional dynamic simulations of general movements of the forearm.
在本文中，前臂在旋前/旋后过程中具有复杂的、连续的质量运动，通过一个由绕尺骨段旋转的桡骨段组成的刚体模型来近似。用于获取模型参数的方法基于包含速度信息的三维体素数据。我们提出了一个准则，该准则允许将体素归属于两个段中的任何一个。它基于这样一种观念，即从体素数据确定的转动动能等于刚体模型的动能。为了获得三维平滑，我们进一步提出了两个段形状的参数化。然后可以使用这些形状来确定段的动态积分，即质量、质心和惯性。使用这种方法，我们通过在旋后、旋前和中间位置的三组MRI扫描确定了人类前臂的所有模型参数。在附录中，描述了一种无需重新计算积分就能均匀缩放动态量的方法。因此，本文提供了前臂一般运动三维动态模拟所需的所有基本参数。
