Intrathoracic stomach: when does it obstruct?

Large esophageal and paraesophageal gastric herniations may occasionally produce gastric obstruction and strangulation. Seven cases of gastric intrathoracic herniation of varying degree, including 2 with obstruction, are presented with diagrams of the anatomy in each case. The cases with obstruction are discussed in relation to existing theories of the mechanism of obstruction: (a) tightness of the hernial ring; (b) acute volvulis of the herniated stomach; and (c) subdiaphragmatic redescent of the fundus with fundic distension and crowding of the hernial orifice. It is concluded that the last mechanism is the most common, but that a combination of mechanisms produces the obstruction in some cases.