8. What is a hiatal hernia?

The hiatus is the hole in the diaphragm that the esophagus passes through from the mouth to enter the stomach.  The valve is in the lower 2 inches of the esophagus, which should be below the diaphragm.

A hiatal hernia is a dilatation of this opening to allow the lower esophageal sphincter, the valve between the esophagus and the stomach, to herniate up above the diaphragm.  The negative pressure from breathing markedly interferes with the function of the lower esophageal sphincter.