Thoracic stomach is the most severe form of hiatus hernia. It is distinguished by a dislocation of (parts of) the stomach from the abdominal into thoracic cavity. The hernial orifice is the esophageal hiatus of the diaphragm. Parts of the stomach dislocate into the mediastinal cavity next to the esophagus through the hiatus. The transition zone between esophagus and stomach is in its usual position. With persistent dislocation, an incarceration causes blood congestion and passage disorders.