What medical condition occurs when part of the stomach pushes through the diaphragm?

A hiatus hernia is a medical condition in which a portion of the stomach bulges through the diaphragm into the chest cavity. This occurs because the diaphragm, which normally helps keep stomach contents from rising up into the esophagus, becomes weakened or damaged, allowing part of the stomach to protrude. This condition can lead to symptoms such as heartburn, regurgitation, and difficulty swallowing.

In contrast, gastroesophageal reflux disease (GERD) primarily involves the backward flow of stomach acid into the esophagus but is not specifically defined by the anatomical displacement of the stomach. A peptic ulcer refers to a sore on the lining of the stomach or the first part of the small intestine and is caused by factors such as H. pylori infection or the long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). Achalasia is a disorder that affects the esophagus, making it difficult for food to enter the stomach due to the failure of the lower esophageal sphincter to relax properly.

Thus, the characteristics and mechanics of a hiatus hernia distinctly identify it as the condition where the stomach pushes through the diaphragm.