Hernia, hiatus: Protrusion of the stomach up into the opening normally occupied by the esophagus in the diaphragm, the great dome of muscle that separates the thoracic (chest) cavity from the abdomen.
Normally, the esophagus passes down through the chest, crosses the diaphragm, enters the abdomen through a hole in the diaphragm called the esophageal hiatus and joins the stomach just below the diaphragm. When there is a hiatal hernia, the opening of the esophageal hiatus is larger than normal and a part of the stomach slips up or passes (herniates) through the hiatus and into the chest.
This type of hernia can be congenital (present at birth), More often it may be acquired over the years, for example, through strenuous physical activity. Symptoms usually start with a tingling or burning sensation, although patients may be able to see a bulge where the hernia is located. If extreme pain is present, emergency surgery may be needed. Treatment is via conventional or laparoscopic (minimally invasive) surgery.
"Hiatus" in Latin means "an opening, gaping mouth, or chasm" which came from the verb "hiare" meaning "to gape or yawn." Therefore, a "hiatus" is a gaping opening in something, such as the opening of a cave in a cliff or a major interruption (hole) in a conversation. In this case, hiatus (or hiatal) refers to the opening in the diaphragm.