Definition: STOMACH herniation located at or near the diaphragmatic opening for the ESOPHAGUS, esophageal hiatus. When the ESOPHAGOGASTRIC JUNCTION is above the DIAPHRAGM, it is called a SLIDING HIATAL HERNIA. When the ESOPHAGOGASTRIC JUNCTION is below the DIAPHRAGM, it is called a PARAESOPHAGEAL HIATAL HERNIA.