Sliding hiatal hernia: Hiatal hernias are categorized as being either sliding or para-esophageal. Sliding hiatal hernias are those in which the junction of the esophagus and stomach, referred to as the gastro- esophageal junction, and part of the stomach protrude into the chest. The junction may reside permanently in the chest, but often it juts into the chest only during a swallow. This occurs because with each swallow the muscle of the esophagus contracts causing the esophagus to shorten and to pull up the stomach. When the swallow is finished, the herniated part of the stomach falls back into the abdomen.
Para-esophageal hernias are hernias in which the gastro- esophageal junction stays where it belongs (attached at the level of the diaphragm), but part of the stomach passes or bulges into the chest beside the esophagus. The para- esophageal hernias themselves remain in the chest at all times and are not affected by swallows.
A para-esophageal hiatal hernia that is large, particularly if it compresses the adjacent esophagus, may impede the passage of food into the stomach and cause food to stick in the esophagus after it is swallowed. Ulcers also may form in the herniated stomach due to the trauma caused by food that is stuck or acid from the stomach. Fortunately, large para-esophageal hernias are uncommon.