The epiphysis is the cartilage between the epiphysis and the metaphysis. Whether the epiphysis is closed or not can be judged by X-ray, the criteria for determining whether the epiphysis is closed or not in knee X-ray are as follows. If the front and side X-ray of the knee joint shows a low-density line-like shadow in the epiphysis, that is to say, there is a wide translucent band on the X-ray, it usually indicates that the epiphysis has not been completely closed and the body can still continue to grow, which is mostly seen in adolescence. If the lateral X-ray of the knee joint shows that the low-density linear shadow has been replaced by a high-density dense shadow, that is to say, the X-ray has formed a closed “seam”, it usually indicates that the epiphysis has already closed, and the body can no longer continue to grow at this time, which is usually seen in adults. Before the epiphyses close, adolescents should strengthen physical exercise, eat a balanced diet and have a regular rest and relaxation program to achieve normal height.