The peripheral shadow of bone scab indicates that the bone scab grows and calcifies, and the fracture gradually heals or develops heterotopic ossification. 1. Fracture healing: Fracture healing is divided into four stages: hematoma mechanization stage, fibrous bone scab stage, bony bone scab stage and bone formation alteration stage. In 2~8 weeks after the fracture, when the fibrous bone scab gradually calcifies and the bony bone scab is formed, the bone scab shadow can be seen on the X-ray film, which indicates that the fracture gradually heals. 2. Heterotopic ossification: that is, the formation of bone tissue in soft tissues that do not have the nature of ossification, which may be related to the strenuous limb activities in the early stage of injury or trauma to the central nervous system. Patients present with symptoms such as joint pain, swelling, limited movement, etc., and can be seen around the appearance of bone crust shadow. Patients who have bone scabs need to go to the hospital for a comprehensive diagnosis based on their own medical history and symptoms in order to identify the specific cause, such as abnormal ossification and other diseases that require timely and appropriate treatment.