Hiatus hernia. Coloured barium X-ray of the stomach (brown) of a 9-month-old child suffering from a hiatus hernia (centre and upper right) and gastric volvulus. A hiatus hernia occurs when part of the stomach protrudes into the chest cavity through the hole through which the oesophagus (gullet) normally passes. The protrusion will need surgical correction. Gastric volvulus is a twisting of the stomach often associated with a hiatus hernia. It causes abdominal pain and vomiting, and can lead to strangulation, where the blood supply to the twisted part is cut off. This can lead to tissue death and gangrene. It therefore requires emergency surgery.