What is bone age? Human growth and development can be expressed in terms of two “ages”, namely, life age (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 X-ray of the wrist of the left hand is usually taken, through which the doctor observes the degree of development of the metacarpal phalanges, the carpal bones and the ossification centers of the lower radius and ulna of the left hand to determine the age of the bones. What is the significance of measuring bone age In general, the bone age of a child is consistent with its actual age. However, in disease states, bone age often does not coincide with actual age. The changes in human bone development are basically similar, with each bone developing in a continuous and stage-specific process. Bones at different stages have different morphological characteristics; therefore, bone age assessment can more accurately reflect the growth and development level and maturity of an individual. It can not only determine the biological age of a child, but also provide an early understanding of the growth potential of a child and the trend of sexual maturity: the adult height of a child can also be predicted by bone age, and the determination of bone age is also very helpful for the diagnosis of some pediatric endocrine diseases.