Hiatal hernia is a condition in which the upper part of the stomach moves into the chest through a hole in the diaphragm. The diaphragm is the muscle that divides the chest cavity from the abdomen.
The esophagus is the tube that carries food from the mouth to the stomach. It enters the abdominal cavity through a hole in the diaphragm called the esophageal hiatus. When a person has hiatal hernia, the esophageal hiatus is usually weakened or larger than usual. At times, the upper part of the stomach can pass up through this larger-than-usual hole and into the diaphragm.
A hiatal hernia may be caused by: