It is difficult to determine which bone has a fracture based solely on a description of the patient's presentation and the radiograph. An X-ray of the injured area would be needed to diagnose the fracture and determine which bone is involved. In this case, a fall on the elbow could result in a fracture of the humerus (upper arm bone), the clavicle (collarbone), scapula (shoulder blade), or ribs. The most likely fracture in this scenario, especially in children, is the clavicle as it is commonly fractured due to a fall on the outstretched arm or direct trauma.