Rib fractures often occur in ribs 4 to 10, while ribs 1 to 3 are protected by the clavicle at the front. Because the clavicle is more prominent and forward, if there is trauma, it is likely to bear the force first, making clavicle fractures more probable, whereas ribs 1 to 3 are less likely to fracture. If it is the back, the shoulder blade can provide protection, hence, the shoulder blade is likely to fracture first, making fractures of ribs 1 to 3 very unlikely. Furthermore, ribs 11 to 12 are floating ribs with greater mobility, thus the chance of fracture is very low, which is quite rare. After a fracture, radiographic examination is required for a clear diagnosis, and it is also necessary to rule out injuries to organs, such as pneumothorax or rupture of the liver or spleen, which requires an ultrasound for differentiation.