Hiatal hernia

There is an opening in the diaphragm (breathing muscle between the chest and the abdomen) through which the esophagus passes from the chest cavity into the abdominal cavity where it connects to the stomach. Normally, the stomach is entirely within the abdominal cavity, below the diaphragm. In some people the top part of the stomach may pass backwards through this opening in the diaphragm and into the chest cavity. This portion of the stomach which has moved into the chest cavity is called a hiatal hernia.

A hiatal hernia may be important as a cause of GERD (backwashing of stomach acid and bile into the esophagus) but its role is uncertain. It is believed that a hiatal hernia weakens the lower esophageal sphincter (the valve at the bottom of the esophagus that keeps stomach contents out of the esophagus). This is because in patients who have a hiatal hernia, the lower esophageal sphincter (LES) has moved away from the diaphragm that provides part of its surrounding muscular function and support. Also, acid may become trapped in the hiatal hernia and continue to wash back into the esophagus.

The chance of having a hiatal hernia increases with age, as does GERD. Most people with GERD have a hiatal hernia, but, most people who have a hiatal hernia do not have symptoms of GERD. People who have Barrett's esophagus tend to have larger hiatal hernias than people with less severe GERD or people who don't have GERD at all.