What is a hiatal hernia?

A hiatal hernia is accurately described as a condition where a part of the stomach bulges through the diaphragm, the muscle that separates the chest cavity from the abdominal cavity. This occurs at the opening in the diaphragm through which the esophagus passes. When the stomach herniates, or protrudes, through this opening, it can lead to a range of symptoms, including heartburn and acid reflux.

The other options describe different conditions that do not fit the definition of a hiatal hernia. Inflammation of the diaphragm is not specifically related to the herniation of the stomach, while a rupture in the abdominal wall would refer to a different physical ailment, such as an abdominal hernia, which is distinct from a hiatal hernia. Additionally, esophageal cancer is a serious disease but is not a form of hernia; rather, it is characterized by malignant growths within the esophagus. Therefore, the definition provided in the correct option highlights the essential characteristics of a hiatal hernia.