Hiatus hernia refers to protrusion of the proximal part of the stomach through a defect in the diaphragm, into the thorax. There are two types of hiatus hernias called rolling and sliding. In the former the gastro-oesophageal junction remains in the abdomen, whilst in the latter it slides into the chest. Hiatus hernia predisposes to gastro-oesophageal reflux disease (GORD) and heartburn.