Embryology

• Septum transversum (central tendon)
• Pleuro-peritoneal mesodermal membranes
• Dorsal oesophageal mesentry
• Cervical myotomes (muscular input into septum transversum before descent)

Congenital hernias:

• Foramen of Bochdalek (failed pleuro-peritoneal membrane) - occurs on posterior left hand side
• Forman of Morgagni (anterior)
• - Oesophageal hiatus
• - Dome

Gross Anatomy

Blood supply

• Lower 5 intercostal arteries
• Subcostal arteries
• Inferior phrenic arteries
• Internal thoracic artery gives (1) pericardiophrenic artery (2) musculophrenic artery 

Nerve supply

• Phrenic
• Intercostals

Apertures

1. T8:
   • IVC
   • Right phrenic
2. T10:
   • Oesophagus
   • Vagus nerves
3. T12:
   • Aorta
   • Azygous vein
   • Thoracic duct