Young parents often ask the question: “Our children are the same age as the neighbor’s children, but they don’t grow as tall or as strong as others, what’s wrong?” “I heard the doctor say that once the “bones grow”, there is no hope of growing taller. We should pay attention to the height of our children as early as possible. But what should we do as parents?” Some parents, in order to make their children grow taller, give them some growth-promoting drugs, which temporarily speed up their children’s growth, but affect their final height due to the early “braking” time, and when they come to the hospital, they find that there is nothing they can do. Do you also have this kind of confusion, then how to correctly understand the child’s growth and development status? Human growth and development can be expressed in two “ages”, namely, the age of life (calendar age) and biological age (bone age). Bone age is short for skeletal age and is determined with the help of a specific image of the bone in an X-ray camera. In order to find out the age of a person’s bones, an orthopantomograph of the left hand and wrist is usually taken, and the doctor determines the age of the bones by looking at the development of the finger bones, metacarpals, wrist bones and the secondary ossification center of the distal ulnar radius of the left hand. Therefore, bone age represents to a large extent the true developmental level of a child, so it is more accurate to use bone age to determine the maturity of the human body than the actual age. The difference between biological age (bone age) and life age is within ±1 year and is considered normal development. If the difference between biological age (bone age) and life age is more than 1 year, it is called early development (referred to as precocious). The difference of biological age (bone age) minus life age <-1 year is called backward development (abbreviated as: late maturity). The significance of taking bone age: ①, through the bone age can understand the child's bone growth, the degree of epiphyseal closure and late growth potential. The growth potential of the child can be determined based on the bone age shown on the wrist bone x-ray and the actual age of the child. If the bone age is earlier than the actual age, the child's growth potential is low; on the contrary, the child's growth potential is high. If the epiphysis is closed, not only does the growth stop, but there is no medicine to cure it. ②. Disease clues can be detected by bone age and have auxiliary diagnostic value. Most of the endocrine diseases produce metabolic disorders, which in turn affect bone development. Therefore, genetic diseases, metabolic diseases and endocrine diseases can be detected through bone age. For example, in growth hormone deficiency and hypothyroidism, the skeletal age is backward; in precocious puberty, the skeletal age is advanced. In addition, parents are advised to measure their children's height every 3 months, and if the growth rate is too slow, they need to seek prompt medical attention. The best age for treating dwarfism is 3-12 years old. The older the starting age, the smaller the contribution to adult height and the higher the treatment cost. The earlier the detection and the earlier the treatment, the more the adult height of the affected child can be maximized.