Figure 3.

Repositioning is expressed in terms of an anatomical coordinate system for the radius. The Z-axis (blue) is based on the longitudinal axis of the radius, the X-axis (red) points toward the radial styloid, the Y-axis (green) is perpendicular to the X- and Z-axes. The black arrows indicate the rotations around the axes and are referred to as φX, φY and φZ (in degrees). Translations along the axes are referred to as ΔX, ΔY and ΔZ (in millimetres). We define global wrist motion as the motion of the capitate relative to the coordinate system, resulting in flexion (X+), extension (X-), radial deviation (Y+), ulnar deviation (Y-), supination (Z+) and pronation (Z-).