Why is it that a fracture is not detected in the photos at the time of the injury, but is only detected on an x-ray two weeks later? Usually, when a fracture is suspected after an injury and not detected on an x-ray at the time, the doctor will recommend that the patient review the x-ray two weeks later and the fracture will be clearly visible at that time. Many people will ask why the fracture cannot be found in time when the X-ray is taken at the time of trauma. In fact, this is due to some special types of fractures and the natural physiological process of healing after fracture. According to the shape and degree after fracture, the fracture can be divided into incomplete fracture and complete fracture. Among them, when the fracture is incomplete or complete without displacement, because the shape of the bone is not changed and some subtle fracture lines are beyond the range of X-ray image, it is possible that the fracture is not visible on the X-ray film. However, due to the reaction of the fracture, at the beginning stage due to the disruption of the local blood supply at the fracture end, necrosis and resorption of several millimeters of bone at the fracture end occurs due to ischemia and injury. This process of decomposition and resorption usually takes about two weeks, so that when the film is taken again after two weeks, a clear widened fracture line will be found. Therefore, when a fracture is not found on the radiograph at the time of the trauma, but a fracture is highly suspected, it is important to take another radiograph in two weeks. Also follow the doctor’s advice during this time to protect and fix the fracture well so that it does not displace.