Some doctors believe a hiatal hernia may weaken the lower esophageal sphincter (LES) and increase the risk for gastroesophageal reflux. Hiatal hernia occurs when the upper part of the stomach moves up into the chest through a small opening in the diaphragm (diaphragmatic hiatus). The diaphragm is the muscle separating the abdomen from the chest. Recent studies show that the opening in the diaphragm helps support the lower end of the esophagus. Many people with a hiatal hernia will not have problems with heartburn or reflux. But having a hiatal hernia may allow stomach contents to reflux more easily into the esophagus.
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