Linkage motion simulation and force analysis. (A) Finger and (C) thumb motion simulation with the initial flexion position linkage configurations bolded and the thumb linkage's slider shaft is shown as a dotted line (green). Finger and thumb images are superimposed at the flexed and extended positions. (B) For the fingers, mechanical advantage is output torque at the drive shaft joint that is aligned with the MCP divided by the input force located at the contact point between the linkage and the DIP joints. (D) For the thumb, mechanical advantage is the torque at the CMC joint divided by the force at the thumbtip. The x-axis of these plots is the angle of the driver link relative to the fully flexed initial position.