Thirty-three percent of severely injured patients suffer from thoracic trauma [1]. Diagnosis of pleural and pulmonary lesions at the bedside in the emergency department is difficult. Clinical examination (CE) and chest X-ray (X-ray) have limited sensibility and specificity. Contrast-enhanced computed tomography (CT scan) is the gold standard. CT scan has limitations: it takes time to be performed, implies transport of severely injured patients, and has ionising effects. Thoracic ultrasonography (US) can be quickly performed at the bedside in the emergency room. It has good diagnosis accuracy in ARDS patients [2]. The purpose of this study is to evaluate the diagnosis accuracy of US in severely injured patients in the emergency room.