DISCUSSION: PE treatment and diagnosis are frequently delayed because of the complex and nonspecific clinical manifestations. Only 30% of patients are diagnosed to PE who accepted to normal test. Young patients have little basic disease, making it more difficult to diagnose PE, so prevention of PE should be paid more attention. The main risk factors for PE are external injuries, bone fractures, and thrombosis in the veins of the lower extremities. Research indicates that 70% to 90% of thrombi in patients with acute PE originate in the peritoneal cavity, pelvic cavity, and deep veins . Thus, we could reduce the incidence of PE if we remove the risk factors. For young patients, external injuries and bone fractures have been evaluated, but vocational factors have been largely overlooked, such as long-haul truck drivers, electric welders, office workers, pipeline fabricators, therfore those in similar professions should exercise their lower extremities often and take regular physical examination.