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. The upper stomach bulges through this opening to create a hiatal hernia. There are three main types of hiatal hernia: sliding, paraesophageal, and mixed.

Sliding hiatal hernia

In a sliding hiatal hernia, part of the stomach moves through the diaphragm so that it is positioned outside of the abdomen and in the chest. The lower esophageal sphincter (LES) moves up above its normal location in the opening of the diaphragm.

Most people with a sliding hiatal hernia have no symptoms, and it often is diagnosed when a person is being evaluated for other health concerns. But when the LES moves above the diaphragm, it may not close as well as it did before, and stomach acid and juices may back up into the esophagus (acid reflux). This results in an uncomfortable feeling of burning, warmth, heat, or pain behind the breastbone. This may occur after eating, soon after lying down, or when bending forward; and it may come and go. You may also have a sour taste in your mouth. This group of symptoms is commonly known as heartburn or reflux.

See a picture of a sliding hiatal hernia.

Paraesophageal hernia

In a paraesophageal hernia, the stomach bulges up through the opening in the diaphragm (hiatus) alongside the esophagus (upside-down stomach). The lower esophageal sphincter (LES) remains in its normal location inside the opening of the diaphragm. This type of hernia most commonly occurs when there is a large opening in the diaphragm next to the esophagus.

In rare cases of this type of hernia, other abdominal organs (such as the intestine, spleen, and colon) may also bulge into the chest.

Mixed hernia

In a mixed hiatal hernia, the lower esophageal sphincter (LES) is above the diaphragm as in a sliding hiatal hernia, and the stomach is alongside the esophagus as in a paraesophageal hiatal hernia.

See a picture of a paraesophageal and mixed hiatal hernia.

Paraesophageal and mixed hiatal hernias often have no symptoms or only minimal symptoms. Symptoms may include vague, nonspecific abdominal complaints such as indigestion, trouble swallowing, feeling full after eating only a small amount of food, or a feeling that you have a lump in your throat. If not treated, the hernia can grow. This can result in twisting (volvulus) of the stomach, which requires emergency surgical treatment. Because of the risk involved in emergency treatment, it generally is recommended that all people with these types of hernias have surgery regardless of their symptoms.¹