Bone · Hand

3rd metacarpal

The middle metacarpal, recognisable by the styloid process — a small pointed projection from the back of its base on the thumb side, felt as a hard bump at the back of the wrist when the hand is bent forward. Its base is carried squarely on the capitate, and the tendon of extensor carpi radialis brevis attaches beside the styloid. The long axis of the hand runs through this ray, which is why spreading and closing the fingers is described as movement away from or toward the middle finger rather than toward the thumb.