What you need to know:
Esophagus: The tube through which food reaches the stomach
Lower Esophageal Sphincter (LES): A muscular ring-like valve that opens to let food into the stomach and closes to keep stomach contents from backing up into the esophagus.
Diaphragm: A muscular partition between the abdominal cavity and the chest cavity. The opening through which the esophagus passes is called the esophageal hiatus.
Pylorus: A muscular, valve-like opening that regulates the flow of stomach contents into the duodenum
Duodenum: The duodenum is the first section of the small intestine and is is largely responsible for the breakdown of food in the small intestine, using enzymes. The duodenum also regulates the rate of emptying of the stomach via hormonal pathways.
Hiatal Hernia: A protrusion of part of the stomach above the diaphragm.
When the hiatus allows the LES and part of the stoomach to protrude upward into the chest cavity, the result is a hiatal hernia. This condition is found in up to 50% of the population over the age of 50. If no symptoms are associated with it, treatment is usually not required. Frequently, however, patients with hiatal hernia also suffer from the symptom of heartburn. Heartburn is the result of stomach acid reflux into the esophagus. This occurs because of a failure of the LES to close properly. When this happens, stomach contents (which usually contain acid) are pushed back up into the esophagus, causing irritation and the burning sensation commonly called “heartburn.” Regurgitation of food and bile may also occur. Heartburn can also occur without hiatal hernia.