Bone age is mainly measured by wrist and knee X-rays, and complete closure of the epiphysis indicates maturity. Therefore, there is no such thing as whether the epiphysis is closed or not. Bone age refers to the age of the bones, which is mainly assessed by X-ray examination of the bones and by the characteristics of changes in the bones at various ages, such as taking pictures of the metacarpal bones, carpal bones, and the development of the ossification center of the lower end of the radius and ulna, which can indicate the age of the bones. Epiphysis is an important tissue structure for children’s development and is mainly used to assess height development. X-ray epiphyseal ossification of the knee is generally the mainstay, which in turn assesses the child’s development. The results of bone age measurement are generally consistent with physiological age, and the combination of bone age and actual age can be used to diagnose early or late maturation of the human body. Epiphyseal closure is a sign of cessation of bone development.