The connection between GERD and hiatal hernia is that GERD can occur as a result of hiatal hernia. GERD and hiatal hernia are two different medical conditions. GERD, or gastroesophageal reflux disease, is a condition in which a person’s stomach contents move upwards from the stomach and back into to the esophagus. Hiatal hernia is a condition in which the upper part of the stomach moves upwards through an opening in the diaphragm. To recognize the relationship between GERD and hiatal hernia, it is probably best to first understand the anatomy of the area in question.
When a person swallows, food goes down the esophagus and into the stomach. Though the esophagus is connected to the stomach, both organs are in different parts of the body; the esophagus is in the chest while the stomach is in the abdomen. The diaphragm is the muscle that essentially separates the chest from the abdomen. It has a small hole in which the esophagus passes through to connect to the stomach. With hiatal hernia, the upper part of the stomach ends up in the chest area.
Where the esophagus and stomach meet is the lower esophageal sphincter (LES), which opens to allow food to enter the stomach and closes so that food cannot travel back into the esophagus. The LES rests beneath the diaphragm and is closed most of the time. Below the LES is tissue that acts like a valve. When there is pressure in the stomach, this valve closes off the esophagus, which is another way of preventing food from entering the esophagus. The esophagus connects to the stomach at a sharp angle; this angle is what enables the correct amount of pressure for the valve to work.
What happens with GERD and hiatal hernia is that the latter causes the LES and the valve to improperly function, allowing food to move upwards into the esophagus. This is because with hiatal hernia, when the upper part of the stomach moves above the diaphragm and into the chest area, pressure decreases. The LES normally depends on this pressure, which comes from the diaphragm, to properly function. In other words, since the LES is no longer in its correct position, it ceases to receive enough pressure to act as it should. In addition, the valve also loses the pressure it needs to properly function as well, because the sharp angle it depends on is lost.