Last reviewed 01/2018

The diaphragm is derived from four embryological sources which fuse in the neck and then descend:

  • septum transversum; eventually forms the central diaphragmatic tendon
  • pleuroperitoneal membranes
  • the dorsal mesenteric mesoderm:
    • eventually forms the median section of the diaphragm
    • includes the crura and the mesentery around the oesophagus and vena cava
  • the dorsal body wall mesoderm:
    • relative enlargement of the lungs cleaves the inside surface of the body wall
    • the innermost layer of this division forms the peripheral margins of the eventual diaphragm
    • mesenchyme from the septum transversum migrates into this area to form skeletal muscle:
      • myoblasts are derived from C3-5
      • in descent, they bring their nerve supply

Failure of tissue fusion of any of the four masses can lead to potential spaces that are traversed to produce congenital diaphragmatic hernia e.g.:

  • Bochdalek's foramen leading to Bochdalek's hernia
  • Morgagni's foramen leading to Morgagni's hernia