Healthy hand. Coloured X-ray of the healthy hand of a 60 year old man, showing the skeleton of bones. The fleshy outline of the hand is seen. The arrangement of bones consists of eight small carpals in the wrist (at bottom right) which articulate with the two long forearm bones. Five metacarpal bones (at lower right) 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 and develop tools, facilitating human evolution.