Biomechanical study of the shoulder complex

肩部复合体由肩胛骨、锁骨和肱骨组成。肩部的运动是通过这些要素的协同作用来实现的。为了分析肩部复合体的形成机制，我们进行了以下实验：1)利用磁传感系统(3空间)测量肩胛骨和肱骨的运动和肌电。我们测量了肩胛骨和肱骨在矢状面、肩胛面和额面上的三维运动，测量了肩胛骨和肱骨的欧拉角(肩胸角)和肩胛骨相对于躯干上的参考坐标的偏移量。我们计算了肩胛骨和肱骨之间的相对Euler角(Gleno肱骨角)。在抬高过程中，肩关节和肩峰胸角的比率并不像迄今报道的那样是恒定的。相反，这一比例变化很大。外展运动方式不同于其他抬升运动方式。从生物力学的角度来看，外展被证明是一个困难的动作。与此相对应，异常肩关节的外展范围相当小。2)俯仰实验利用肱骨相对于躯干的三维角度，可以区分四个俯仰时相。熟练俯仰和非熟练俯仰的运动模式有明显不同，尤其是在肱骨旋转和肌电方面。3)身体肩部实验从身体标本的最大周长实验中发现，运动范围与肱骨旋转之间存在线性关系。这意味着限制肱骨的旋转会导致活动范围的减小。

The shoulder complex is composed of the scapula, clavicle and humerus. shoulder motion is attained by cooperation of these elements. In order to analyse the shoulder complex mechanism, we carried out following experiments.1)Measurement of motion of the scapula and humerus and EMGUsing a magnetic sensor system(3 SPACE). we measured three dimensional motion of the scapula and humerus in elevation in the sagittal, scapular and frontal plane.We measured Euler angles of the scapula(scapulothoracic angle)and humerus and excursion of the scapula with respect to the reference coordinte attached to the trunk. And we calculated relative Euler angles between the scapula and humerus(gleno humeral angle).The ratio of glenohumeral to scapulothoracic angle during elevation was not constant as reported so far. Instead this ratio varied considerably. Motion pattern of abduction was different from that of other elevation. The abduction proved to be difficult motion from a viewpoint of biomechanics. In accordance with this, ranges of abduction of abnormal shoulders were considerably small.2)Experiment of pitchingUsing 3-D angles of the humerus with respect to the trunk, it was possible to discriminate four phases of pitching. Motion pattern of skilled pitching was markedly different from that of unskilled pitching, especially in the rotation of the humerus and electromyographies.3)Experiment with the shoulders of cadaversFrom experiments of maximum circumduction of cadaver specimens, it was found that there exists linear relationship between the range of motion and the rotation of the humerus. This means restriction of rotation of the humerus causes decrease of the range of motion.