견갑대 동작 보조 정도에 따른 견관절 부하 분석: 시뮬레이션 기반 연구

Abstract

Shoulder is the joint with the most complex mechanism in a human body. Clavicle and scapula, which connect thorax and humerus (i.e. upper arm), is called shoulder girdle. Scapulo-humeral rhythm (SHR), coordinated motions between the shoulder girdle and the humerus is essential for natural arm motions. Various robots have been developed to assist SHR during shoulder exercises. Among six degree of freedom (DOF) motion of the shoulder girdle, those robots support only two DOFs, elevation/depression and protraction/retraction of clavicle responsible for large portion of scapular motion. In this study, we evaluated kinematics and joint reaction forces of shoulder during shoulder abduction with shoulder girdle motion of varying DOFs. OpenSim, an open-source biomechanics simulation software was used to simulate the abduction motions. When all three rotations of clavicle including axial rotation as well as elevation and retraction were allowed, kinematics was similar compared to the case when full SHR was allowed. On the other hand, only with elevation and depression of clavicle, contribution of shoulder girdle to abduction was significantly reduced. In terms of reaction forces at glenohumeral joint, allowing axial rotation of clavicle slows down increase of the reaction forces.