What is a hiatial hernia?

According to the Mayo Clinic, a hiatial hernia is a hernia that occurs from part of the stomach pushing in an upward direction and through the diaphragm. A diaphragm typically has a small opening called a hiatus through which the esophagus passes to connect to the stomach.

According to the Mayo Clinic, the stomach can push through the hiatus, resulting in a hiatial hernia. A small hiatial hernia typically does not cause problems, and a person may be unaware that a hiatial hernia is present unless it is discovered by a doctor while exploring a different condition. A large hiatial hernia, however, may cause food and acid to get backed up in the esophagus, resulting in heartburn.