Geraud Galvaing1,2, Laura Filaire1, Marie M. Tardy1, Jean-Baptiste Chadeyras1, Adel Naamee1, Marc Filaire1,2 Institutions : 1. Service de chirurgie thoracique et endocrinienne, CRLCC Jean-Perrin, Clermont-Ferrand 2. Laboratoire d’anatomie, faculté de médecine, université d’Auvergne, Clermont-Ferrand Objectives : Cardiac herniations are rare and life-threatening conditions occurring after thoracic procedures especially pneumonectomies. They can also occur after blunt chest trauma but also as a consequence of pericardial agenesia. Methods : Based on 4 case-reports dealing with cardiac herniation, we studied on cadaver the physiopathology of pericardial rupture as well as cardiac herniations, explaining their severity. Results : After a brief recall of pericardial embryology and cardiac fixity means inside the pericardium, we found that cardiac herniation non only stretched the pulmonary veins on the opposite side of the cardiac herniation but also generated a twist of the all caval axis especially in case of right-sided cardiac hernia. This situation engender an acute cardiac insufficiency that could be lethal, therefore it should be considered an absolute surgical emergency. Conclusion : Although rare, cardiac herniation should be in every thoracic surgeon’s mind. Any suspicion of such a diagnosis should justified surgical exploration and repair as cardiac herniation are life-threatening and imaging technique are of poor support in its diagnosis.