Abstract:

Objective　To explore the digital motion course of thumb opposition, through acquiring the six degrees of freedom using motion capture and analysis system, evaluate a digital hand motion examination method and provide digital basis for the virtual reality of hand function.　Methods　One had specimen from a normal adult without morphological and functional abnormalities, was marked on the back of palm and the dorsal surface of the finger bone by fluorescent balls. Thumb opposition was defined and performed six degrees of freedom using motion capture motion capture and analysis system.　Results　The data of six degrees of freedom of the thumb opposition were collected.  At the free states, thumb contacted with the rest of 4 fingers. The biggest changes of line displacement and angular displacement occurred mainly in Y-axis and Z-axis, respectively, followed by the different displacement changes of the another two axis accordingly. The changes of displacement reduced at the fixed state.　Conclusions　Motion capture motion capture and analysis system are sensitive tool to detect the six degrees of freedom of thumb opposition. The digital rules of thumb opposition will be able to achieve with six degrees of freedom, and provide the basis for virtual simulation of hand functions.

Key words: Thumb opposition, Metacarpophalangeal joint, Degree of freedom