The "shock lung syndrome," whenever associated with trauma, is probably in part the consequence of fat emboli, though aspiration, disseminated intravascular coagulation, microatelectasis, pulmonary edema, and hemorrhage due to other lung insults may be important in the etiology of many cases. When lung injury is due to fat emboli, there is an interval between the time of trauma and the onset of clinical symptoms and chest radiographic findings. The radiographic picture is that of a diffuse alveolar and interstitial lung density. In severe cases marked respiratory embarrassment requires the use of both oxygen therapy and mechanical respirators for survival.