Depending on the age, different parts of the body are examined by X-ray, and the age of the bones is estimated by observing the emergence of ossification centers and the closure of epiphyses in the X-ray. In short, to check the age of the bones is an X-ray examination. For adolescents under the age of 16, an X-ray examination of the left wrist and left hand is taken, which is generally regarded as about 50 dollars. The left wrist and left hand can be visualized on a single film and the cost is$50. If the child is older than 16, the epiphyses of the left wrist and hand, as well as the biochemical center, are essentially closed. Checking bone age for the large joints of the hips and knees is also around$50 for one area, and if 2 joints are to be photographed, the cost is around$100.