WRIST RHYTHM DURING WRIST JOINT MOTION EVALUATED BY DYNAMIC RADIOGRAPHY.

We hypothesized that wrist joint motion involves a "wrist rhythm" similar to the scapulohumeral rhythm. Therefore, we used a flat-panel detector to evaluate the ratio of radiolunate and capitolunate joint motions during wrist joint motion by dynamic radiography. The subjects were 20 healthy men. Dynamic imaging of the wrist joint was performed during active exercise for a total of ten seconds. In this study, we defined the radiocarpal (RL angle) and midcarpal joint angle (CL angle) as the wrist joint angle in the obtained images and measured the variation of these angles. The average curve was plotted and regression lines calculated from the average curve. The ratio was calculated from the slopes of the regression lines of the RL CL angles. These findings indicated that the ratio of the RL and CL angle motions was approximately 1:4 during palmar flexion and approximately 2:1 during dorsiflexion. [ABSTRACT FROM AUTHOR]