Experimental investigation on the centros of abduction/adduction of the metacarpophalangeal joints of human hand

Estimation of kinematics anatomical parameter is a basic work of research into the biomechanical system for a better understanding of human motion especially the redundant control strategy underlying. This paper presents an experimental method to investigate the centro of abduction/adduction of finger using two recording pins fixed on the moving finger to record the paths of the two points on the finger. The overall centro and the path of instantaneous centro are determined by an optimum technique. The results showed that 1) the centros' position changes dramatically from subject to subject, 2) the averaged centro position is apparently different from the centro of flexion/extension and 3) it locates between O-4, the center of rotation of proximal interphalangeal (PIP) joint, and O-5, the center of the concave surface of MCP joint, and near the O-5, side.