A person's physical growth develops with age, and the age of twelve is the best time for bones to grow, with the average number of wrist bones calcifying increasing by one every year during this period.
The best way to determine bone age is to use X-rays to take pictures of the child's wrist bones, measure the appearance, number, and morphological changes of the bone marrow centers, and standardize them.
Besides X-rays, there are two other kinds of people who can determine bone age.
One is a forensic doctor who examines dead bodies.
The other is Liu Suifeng, who looks at living people.
The core of plastic surgery is bone relocation, and thorough research on the bones of the human body is essential. His eyesight is almost as good as an X-ray; he can spot something wrong at a glance, and with a touch, he can confirm if something is wrong.
Not only does this require talent, but it also takes years of accumulation and practice to reach this level of expertise.
