Man's hand. Coloured X-ray of the healthy hand of a man, showing the arrangement of its bones. An outline of the flesh of the hand is seen. Bones of the hand consist of eight small carpals in the wrist (lower centre), which articulate with the two long forearm bones (at bottom). Five metacarpal bones (at centre) make up the palm of the hand. Each finger has three phalanges, except the thumb which has two such bones. This skeleton enables the human hand to be used with great flexibility, helped especially by the joint between the wrist and the opposable thumb. This well-adapted hand allowed our ancestors to use tools, facilitating human evolution.