Traumatic diaphragmatic rupture is a life-threatening injury that may occur in patients with blunt trauma. At present, supine chest radiographs is the initial, most commonly performed imaging test to evaluate a traumatic injury of the thorax. However, computed tomography (CT) is the imaging tool of choice, as it is the 'gold standard' for the detection of diaphragmatic injury after trauma. In particular, recent literature indicates that multidetector CT with multiplanar reformations has significantly improved in accuracy. Radiologists working in the emergency room should keep in mind the possibility of diaphragmatic injuries and should routinely integrate the axial images CT with multiplanar reformations in order to detect any potential, subtle or doubtful sign of incomplete diaphragmatic injury.