Wrists and hands are complex regions with a multitude of bones, joints, and various musculatures. While you navigate through these review modules, keep in mind that wrists and hands, although technically separate regions of the upper extremity, function very much as a single unit with the actions of one impacting the other. One simple example of this is the action of gripping. The gripping motion requires that the fingers flex while the wrist naturally extends. Finger flexion without wrist extension, although possible, does not happen without deliberate planning.