From this source link HERE

How does your endocrinologist determine whether you have stopped growing? Let’s find out.

There seems to be two main ways to determine skeletal maturity and bone age, using either the Greulich Pyle Method or the Tanner and Whitehouse Method. You get an X-ray or a radiograph done on your left hand. The reason it is your left hand has raised some questions and so far I have not found a reasonable answer for it. It seems the Greulich Pyle method is only used in the Netherlands from the source and it is far faster but not as reproducible and accurate as the Tanner and Whitehouse method.

For the Greulich Pyle Method…

There is a description for each of the development stages seen in the growth of the hand radiograph. The description is a guideline on how the physician should examine and diagnose the state of development of the bone.

Quoted from the source link…

The first step in an analysis is to compare the given radiograph with the image in the atlas that corresponds closest with the chronological age of the patient. Next one should compare it with adjacent images representing both younger and older children. When comparing the radiograph against an image in the atlas there are certain features a physician should use as maturity indicators. These features vary with the age of the child. In younger children the presence or absence of certain carpal or epiphyseal ossification centers are often pointers for the physician about the skeletal age of a child. In older children the shape of the epiphyses and the amount of fusion with the metaphysis is a good indicator of skeletal age. Once the atlas image that most resembles the radiograph is found the physician should conduct a more detailed examination of the individual bones and epiphyses. When the physician is sure that the matching radiograph has been found, she can find the skeletal age printed at the top of the page.

Me: When I read how this Method for determining bone age was done I couldn’t but felt slightly let down on how it is performed. I sort of expected the procedure to be more complex with some calculations. It seems to show that endocrinologists today might not even have a real way of calculating growth plate maturity, but sort of guess at it with an eyeball estimate which is not very accurate. 

For the Tanner and Whitehouse Method…

The tanner whitehouse method seems to be based on the bone standard maturity of certain areas in the hand instead of age. The method uses 20 regions of interest. Each region of interest is broken up into 3 parts, the epiphysis, diaphysis, and metaphysis, and the sections can be determined in the phalanx promixity.

Quoted from the source link…

The development of each ROI is divided into discrete stages and each stage is given a letter (A,B,C,D, . . ., I). A numerical score is associated with each stage of each bone. By adding the scores of all ROIs, an overall maturity score is obtained. This score is correlated with the bone age differently for males and females. The method has a modular structure which makes it suitable for automation. For the tanner whitehouse method, three score systems have been developed.

• TW2 20 Bones: characterized by twenty bones including the bones of the first, third and fifth finger and the
• carpal bones.
• RUS: considers the same bones of the TW2 method except the carpal bones;
• CARPAL: considers only the carpal bones.

For the finer details on the method, please refer to the source link above. I hope I gave you an idea on how pediatricians and endocrinologists try to evaluate whether you can still grow or not.