Adult and child hands. Coloured X-rays of healthy human hands at 3 years (left) and at 20 years. Bones are green with flesh red. The child's hand has areas of cartilage in the joints between the finger bones (phalanges), where bone formation (ossification) and growth will occur. Only a few of the eight wrist bones (carpals) have formed. The palm is formed by the five metacarpal bones. In the adult hand, all the bones are present and the joints have closed.