Expansion
Bochdalek is Back and to the Left; Morgagni is anterior and to the right
Expansion
- Bochdalek - Back: posterolateral, from failure of the pleuroperitoneal membrane to close. About 90 per cent of cases, and about 85 per cent are left-sided because the liver plugs the defect on the right
- Morgagni - anterior, retrosternal, through the sternocostal triangle. Uncommon, usually right-sided, and often found incidentally in later life
The left-sided predominance of Bochdalek hernias matters clinically: abdominal viscera enter the chest during the canalicular stage of lung development and cause pulmonary hypoplasia, which is what determines survival rather than the hernia itself.