First of all, what is bone age? Bone age is short for skeletal age, which refers to the age of the bones. It is a developmental age obtained by comparing the actual development of a child’s bones with the standard developmental level. Bone age largely represents a child’s true level of development, so it is more accurate to determine the maturity of the body than the actual age. Doctors can generally determine the age of the bone from an orthopantomograph of the left hand (orthopantomograph of the left wrist, metacarpal and phalanges). The bone age of a normal person is consistent with or very similar to the physiological age. In disease states, however, it can vary widely. For example, if there is a complete lack of growth hormone, the bone age is less than the age, the physiological age is 12 years old, but the bone age may be only 8 or 9 years old, and the height is as high as that of 8 or 9 years old children; if there is precocious puberty, the bone age is greater than the age, the physiological age may be 8 or 9 years old, but the bone age may be 12 or 13 years old. For children with idiopathic dwarfism, the bone age and age are similar. Therefore, for height monitoring, bone age is very important. If you find that your child is shorter than children of the same age or has a slower growth rate in the last year, you should see your pediatrician for a bone age film to determine your child’s skeletal maturity, and then, based on the results of the bone age film, you can determine if further testing is needed.