Topic Overview
 The abdomen and chest are separated by a sheetlike muscle called the
		diaphragm. The
		esophagus passes through an opening (the hiatus) in
		the diaphragm to connect to the stomach. A hiatal hernia occurs when part of
		the stomach bulges out of the abdomen, through the hiatus, and into the chest.
		When this happens, the
		lower esophageal sphincter (LES) may move above the
		diaphragm. 
Normally, pressure from the diaphragm muscle helps keep the LES valve
		closed. When a hiatal hernia occurs, the valve is pushed above the diaphragm so
		the diaphragm muscle can no longer help keep the valve closed. If the valve
		cannot prevent
		stomach acid and juices from backing up into the
		esophagus, symptoms of
		heartburn may occur.
A hiatal hernia is often associated with
		gastroesophageal reflux disease (GERD). The most
		noticeable symptom of GERD is heartburn.
A person may have a hiatal hernia or GERD or both. A person with a
		hiatal hernia may not always have GERD. And many people with GERD do not have a
		hiatal hernia. 
Credits
ByHealthwise Staff
Primary Medical ReviewerAdam Husney, MD - Family Medicine
Specialist Medical ReviewerArvydas D. Vanagunas, MD - Gastroenterology