There are two categories of hiatal hernias, sliding and para-esophageal.
Sliding hiatal hernias are those in which the gastro-esophageal junction and part of the stomach slides into the chest. This junction can stay permanently in the chest, or just slide into the chest during swallowing. The later results because with each swallow, the esophagus contracts, causing the esophagus to shorten and pull on the stomach. After the swallow, the junction falls back into the abdomen. Approximately 90% of all hiatal hernias are the sliding type.
With para-esophageal hernias, the gastro-esophageal junction remains where it belongs, but part of the stomach is squeezed up into the chest beside the esophagus. These hernias remain in the chest at all times. With this type of hernia, complications can occur, such as incarceration and strangulation. Incarceration means the hernia is stuck and being squeezed. Strangulation results from teh lack of blood supply, leading to death ofthe tissues involved, when incarceration persists too long. Surgical intervention is required.