Hiatus hernia: what is it?
A hernia is when part of the body bulges or protrudes into another part of the body that would not normally contain it. In the case of a hiatus hernia, a part of the stomach, normally in the abdomen, slides or protrudes into the chest cavity. The chest and abdomen are normally separated by the diaphragm, a thin sheet of muscle that aids in breathing.
Normal anatomy
To understand how this happens we have to understand a bit about the normal anatomy of the upper body. The diaphragm is a sheet of muscle separating the abdomen and the chest cavity. The oesophagus (the tube that food passes down from the mouth to the stomach) goes down through the chest, passing through a small opening (called a hiatus) in the diaphragm and entering the abdominal cavity as the stomach.
Hiatus hernia
When a hiatus hernia occurs (literally a bulge of part of the body through an opening), a portion of the stomach is able to slide upwards through the opening in the diaphragm, beside the oesophagus, into the chest.
There are 2 main types of hiatus hernia.
- Sliding hiatus hernia: this is the most common type of hiatus hernia, accounting for about 90 per cent of cases. It occurs when the junction between the oesophagus and the stomach and the upper part of the stomach protrude up through the oesophageal opening in the diaphragm into the chest cavity. The herniated portion of the stomach can slide back and forth, into and out of the chest.
- Rolling hiatus hernia: this is sometimes called a para-oesophageal hiatus hernia by doctors. In this case, part of the stomach bulges into the chest out of the weakest part of the diaphragm, which is the oesophageal opening. The junction of the oesophagus and stomach stays down within the abdomen, and the top part of the stomach (the fundus) bulges up into the chest cavity. This type of hernia normally remains in one place, sitting next to the oesophagus, and does not move in or out when you swallow.
Hiatus hernias often cause or contribute to pain in the abdominal area, heartburn, pains in the chest area and swallowing difficulties. However, these can also be the symptoms of a number of other conditions such as peptic ulcer and even heart disease. Always remember that your doctor needs to investigate any chest pain or swallowing difficulties you experience.
Who gets hiatus hernia?
Hiatus hernias are relatively common, occurring in about 10 per cent of the population. Often they are very small and people who have them don’t know it, as they don’t feel any symptoms or discomfort. Most hiatus hernias are seen in adults, and about 30 per cent of people over the age of 50 will have a hiatus hernia, although they may not know about it. Women are affected more often than men. Hiatus hernias are often seen in people who are overweight and in pregnant women.
What causes a hiatus hernia?
Hiatus hernias can occur when there is weakening of the muscle tissue around the gap where the oesophagus passes through the diaphragm or where this gap is otherwise stretched. A number of factors appear to contribute to hiatus hernias developing including:
- hereditary factors;
- obesity;
- pregnancy;
- sudden, hard physical exertion, such as lifting;
- a birth defect; and
- trauma or surgery to the abdominal area.
Last Reviewed: 26 June 2009
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