Hiatal hernia occurs when the upper part of the stomach protrudes into the chest through the diaphragmatic hiatus. Hiatal hernia results in retention of acid and other contents above this opening, frequently resulting in reflux.

Coughing, vomiting, straining, or sudden physical exertion increases pressure in the abdomen resulting in hiatal hernia. Obesity and pregnancy also contribute to this condition.

Hiatal hernias are considered a normal condition of middle age.