Expansion
Left phrenic nerve, superior epigastric vessels, splanchnic nerves, hemiazygos vein and lymphatics
Expansion
Beyond the three named apertures:
- Left phrenic nerve - pierces the muscular dome to the left of the pericardium
- Superior epigastric vessels - through the sternocostal triangle (foramen of Morgagni)
- Greater, lesser and least splanchnic nerves - pierce the crura
- Hemiazygos vein - pierces the left crus
- Sympathetic trunks - behind the medial arcuate ligament
- Subcostal vessels and nerve - behind the lateral arcuate ligament
- Lymphatics - from the liver, through several sites
The sternocostal triangle is a genuine weak point in the muscle, and it is the route of a Morgagni hernia as well as of the superior epigastric vessels.