Aortic hiatus (median arcuate ligament)
Hiatus aorticus
MuscularDeep musclesThorax
- What it is
- Arched opening behind the diaphragm at T12, bounded in front by the median arcuate ligament that joins the two crura across the vertebral column; it transmits the aorta, the thoracic duct and often the azygos vein.
- Function
- Lets the aorta pass behind the muscle rather than through it, so breathing does not squeeze it.
- Size
- About 2.5–3 cm across.
- Clinical note
- A low-lying median arcuate ligament can compress the coeliac trunk, causing pain after meals (median arcuate ligament syndrome).