Diaphragmatic hernia--a diagnostic challenge.

The commonest situation is when the cardia slides through the oesophageal hiatus into the mediastinum (the sliding hernia); less commonly, the gastro-oesophageal junction remains in its correct position with the gastric fundus rolling alongside it through the hernia into the thoracic cavity (the rolling or paraoesophageal hernia) while in some cases the two conditions co-exist. A number of rare congenital hernias may occur; through the foramen ofMorgagni, situated anteriorly between the xiphoid and costal origins of the diaphragm, through the foramen of Bochdalek, representing the embryological pleuroperitoneal canal, lying posteriorly in the diaphragm, and occasionally through a congenital deficiency of the whole central tendon of the diaphragm. Rarely, trauma may rupture the diaphragm and this may lead to a traumatic diaphragmatic hernia. Hiatus hernia is extremely common in the Western world with a prevalence some 50 to 100 times greater than exists in Africa and Asia. Although equally distributed between the two sexes, symptomatic hiatus hernia is at least twice as frequent in the female. All ages may be affected, but the incidence rises with each decade until, in the elderly, it is present radiologically in some 60% of the population. Reviews oflarge series ofcases show that the sliding hernia occurs in the order of 75% of cases, the paraoesophageal hernia in 20% and the mixed variety in 5% (Hollender & Meyer, 1984). Clinical syndromes and their aetiology