Bone age determination with the help of the carpal bones

The carpal bones are the 8 small bones that can be felt at the ball of the hand. In the male infant, all these bones are still made of cartilage at birth, which then ossify during development. A female infant is already born with 2 ossified carpal bones.

The complete ossification of these cartilages follows a very specific pattern and sequence, which is similar in every human being. Since cartilage is not visible in the X-ray image, more and more carpal bones appear in the X-ray image in the course of development until at the age of 14 years (girls) or 16 years (boys) the carpal bones are all visible. Thus, conclusions can be drawn about the state of skeletal development based on the growth joints and the number of visible bones.

Several doctors and scientists have developed standardized procedures on the basis of the typical ossification, which are used today to determine the skeletal age and to determine the final size, whereby only the 2 best known procedures are described here. According to the principle of Greulich and Pyle, the X-ray image is compared with images in an atlas with comparative images. The two have collected x-rays sorted by age and sex in an atlas and described the signs of maturity that can be seen on them.

Using the images that are most similar to the description and the child’s x-ray, the skeletal age and state of growth can be determined and statements about the final body size can be made. It is also possible to make statements as to whether growth spurts are still to be expected or whether the growth is already almost complete. The method according to Tanner and Whitehouse is somewhat more differentiated and is more frequently used in Germany.

Here several pictures are used and points are awarded. In addition to the carpal bones, the ulna and radius (the two bones of the forearm), as well as selected metacarpals (palpable long bones above the ball of the hand) and phalanges are included. The age of the bones can then be read from a table using the point value.