Closure of bones is clinically known as epiphyseal closure and can be observed by X-ray examination of the corresponding area. For children and adolescents who are growing, there are bone growth centers at both ends of the long bones, and a layer of cartilage exists between the bone growth centers and the normal bone, which shows the unique structure on the X-ray film, and the images of epiphysis, epiphysis line and bone mass will appear. When the epiphysis and epiphysis have completed ossification and the bone has completed the long development process, the epiphysis is completely closed and disappears from the X-ray film.