English A W
J Morphol. 1978 May;156(2):279-92. doi: 10.1002/jmor.1051560209.
The movements of the shoulder girdle of eight adult cats during overground stepping were studied, using standard slow motion cinematographic techniques. The patterns of activity of shoulder muscles were examined, using simultaneous intramuscular electromyography. Walking, trotting and galloping steps were analyzed from digitized single motion picture frame images. Angular movements of the shoulder girdle consist of biphasic flexion and extension of the shoulder joint and a monophasic flexion-extension alternation of the scapula on the thorax during each step cycle. In addition, the center of the scapula moves craniad during the swing phase and caudad during the stance phase with respect to a fixed reference point on the animal. Similar vertical movements of the center of the scapula also occur in each step cycle. Results of EMG studies of the 17 muscles capable of acting on the shoulder girdle indicate that three overall patterns of activity are found: (1) a pattern typical of extensor muscles, active during all the extension epochs; (2) a pattern typical of flexor muscles, active during the flexion epoch; and (3) a biphasic pattern of activity, active twice in each step. There data are used, along with a re-examination of previous models of the mechanics of the shoulder girdle of carnivores to examine the function and mechanics of shoulder motion. It is concluded that the rotary and translatory movements of the shoulder girdle during stepping combine to enhance step length.
利用标准慢动作电影摄影技术，对八只成年猫在地面行走时肩胛带的运动进行了研究。使用同步肌内肌电图检查了肩部肌肉的活动模式。从数字化的单帧电影图像中分析了行走、小跑和飞奔的步伐。在每个步周期中，肩胛带的角运动包括肩关节的双相屈曲和伸展以及肩胛骨在胸廓上的单相屈伸交替。此外，相对于动物身上的一个固定参考点，肩胛骨的中心在摆动期向头侧移动，在站立期向尾侧移动。在每个步周期中，肩胛骨中心也会出现类似的垂直运动。对17块能够作用于肩胛带的肌肉进行肌电图研究的结果表明，发现了三种总体活动模式：(1) 伸肌典型模式，在所有伸展期活跃；(2) 屈肌典型模式，在屈曲期活跃；(3) 双相活动模式，在每个步中活跃两次。这些数据与对食肉动物肩胛带力学先前模型的重新审视一起，用于研究肩部运动的功能和力学。得出的结论是，行走时肩胛带的旋转和平移运动相结合，可增加步长。
