A hiatal hernia is a movement of part of the stomach up into the chest cavity. The stomach presses up through a small hole in the diaphragm muscle. The diaphragm is the muscular wall that separates the abdominal cavity from the chest cavity.

Different types of hiatal hernias include:

  • Sliding hiatal hernia—part of the stomach slides into and out of the chest cavity. This is the most common type.
  • Fixed hiatal hernia—upper part of the stomach remains in the chest cavity.
  • Complicated hiatal hernia—Several other types of stomach herniation may be seen. These are uncommon but more serious and may require surgery.

Hiatal Hernia
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The exact cause of hiatal hernias is not clear. Some people are born with a hiatal hernia but most will develop it later in life.

The diaphragm has an opening that the esophagus can pass through. A weakening or injury to this opening can allow a hiatal hernia to develop. Increased pressure in the abdomen can also push the stomach up into the chest cavity.