Bochdalek's foramen is a hiatus formed when their is incomplete fusion of the pleuroperitoneal membranes to close the pleuroperitoneal canal. It results in incomplete fusion of the lumbar and costal elements of the diaphragm during development. It has the same boundaries as the lumbocostal triangle but there is no connective tissue membrane spanning the foramen.
It is possible that impingement of the liver on the right causes a potential Bochdalek foramen to mature into a normal lumbocostal triangle. This may explain why Bochdalek hernia are more common on the left.
Bochdalek, Professor of Anatomy in Prague in the 19th century, originally described a completely different aperture to that which bears his name.
Last reviewed 01/2018