Patients with esophageal hiatal hernia often have an array of distressing complaints and physical signs that are difficult to interpret. Physiologic and anatomic studies of the gastroesophageal area in the region of the esophageal hiatus of the diaphragm indicate the existence of a three-in-line sphincter group, consisting of the inferior esophageal constrictor, diaphragmatic pinchcock and cardioesophageal junction. These mechanisms, acting in unison, prevent regurgitation in normal persons.It also can be deduced from clinical, radiologic and experimental data that anatomic disturbances at the esophageal hiatus account for physiologic alterations. A reasonable explanation for the symptoms and signs of esophageal hiatal hernia can be made on the basis of the functional competence of the three-in-line sphincter mechanisms.