Congenital diaphragmatic hernias occur in 1 of every 2000-3000 live births and account for up to 8% of all major congenital abnormalities.

There are 3 main types of congenital diaphragmatic hernia:

1. posterolateral: Bochdalek hernia
2. anterior: Morgagni hernia
3. hiatus hernia

Left-sided Bochdalek hernias are most common, accounting for approximately 85% of cases. Left-sided hernias, lacking the 'protective' effect of the liver may have herniation of both the small and large bowel and intraabdominal solid organs into the thoracic cavity.

When right-sided, only the liver and a portion of the large bowel tend to herniate. Bilateral hernias are uncommon and are usually fatal due to pulmonary hypoplasia.