In adulthood, although the epiphyseal cartilage at the epiphysis of the long bones has ossified and the long bones have lost the ability to continue to grow, the epiphyseal membrane of the long bones is still present. At this time, through the continuous proliferation of the epiphyseal membrane, the bone cortex of the long bones will thicken, and then the bones will become thicker. There are several situations in which the bones become thicker in adulthood: 1. Through continuous physical exercise or labor, the bones become thicker. This situation is often due to the continuous stimulation of external forces, resulting in the continuous proliferation of the epiphyseal membrane, which in turn produces the thickening of the bones. The purpose of bone thickening is to adapt to this ever-increasing external force load; 2. This condition may be caused by osteophytes, such as if the patient has been cold around the bone for a long time, or has a trauma such as a fracture or contusion, it will gradually produce abnormal calcium salt deposits in this area, which will then lead to bone thickening; 3. This condition may also be caused by an occupational disease of the bone, such as in 3. This condition may also be caused by an occupational disease of the bone, such as a tumor inside or around the bone, which may cause the bone to become thicker.