Patients with fractures are a good candidate for pulmonary embolism, which is related to three factors. On the one hand, the limbs of fracture patients are often immobile, which leads to blood stagnation and easy formation of thrombus. On the other hand, fractures are often accompanied by vascular damage and bleeding, and the damage to the vascular endothelium makes the inner wall of blood vessels unsmooth, which makes it easy to form thrombi. In addition, fracture increases the chance of fat from bone marrow entering the blood, which tends to form fat clots. Both the above mentioned blood clots and fat emboli have the opportunity to block the pulmonary artery and its branches, leading to pulmonary embolism.