Abduction

Movement away from the midline.  For fingers, it is movement away from the midline of the middle digit.  For the thumb, it is movement perpendicular to, and away from, the plane of the palm.  For the hand, at the wrist, it is radial deviation of the hand, which is away from the midline of the body in the anatomical position.  For the arm, at the shoulder joint, abduction moves the elbow in the frontal plane away from the midline of the body.

FlexionExtensionAdductionAbduction