Hiatus hernia. Barium X-ray of the stomach of a 9- month-old child suffering from a hiatus hernia and gastric volvulus. A hiatus hernia occurs when part of the stomach (white, lower frame) 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 severe 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. Gastric volvulus therefore requires emergency surgery.