A hiatus hernia occurs when the stomach pushes upward through the small opening of the diaphragm called the hiatus. Many people who have this type of hernia might not know about it unless a physician discovers it when examining them for another condition.

Small hiatus hernias don’t cause problems. But a large hiatus hernia can allow food and acid to get into the esophagus, leading to heartburn. Doctors may recommend medications to treat the condition, but a large enough hernia may require surgery.