This type of hernia results from weakness in the muscle fibers of the diaphragm where the esophagus(food tube) passes from the chest into the abdomen. This can cause the stomach to bulge abnormally into the chest. The hernias are extremely common, and frequently are asymptomatic. They can lead to excessive heartburn and acid reflux. These hernias can be safely observed if symptoms are well controlled with antacid medication, but should be repaired if symptoms become unmanageable despite medication.