A hernia occurs when an organ slips through the muscle wall that holds the organ in place. A hiatal hernia occurs when the upper part of the stomach pushes through an opening in the diaphragm, and up into the chest. This opening is called the esophageal hiatus or diaphragmatic hiatus. Some people suffer from Gastroesophageal reflux disease (GERD) because they have a hiatal hernia.
Studies have shown that the opening in the diaphragm, where the esophagus connects with the stomach, acts as an additional sphincter around the lower part of the esophagus. Normally the hiatus and the lower esophageal sphincter (LES)--the muscle connecting the esophagus with the stomach--line up with each other to keep stomach contents from backing up into the esophagus. It is believed that a hiatal hernia can weaken the (LES) and cause reflux. The hiatal hernia results in the retention of acid and other stomach contents above the opening (hiatus) and can result in this being easily refluxed into the esophagus.
