The esophageal hiatus is the opening in the diaphragm through which the esophagus passes and then enters the stomach. It can be viewed by pushing aside the lungs and heart within the thoracic cavity and tracing the esophagus to the diaphragm. The inferior vena cava also can be found in this region, often running parallel to the esophagus and pierces the diaphragm at the caval opening.