Overview
It is convex cranially. Its periphery is muscular and its centre is a tendon (centrum tendineum). It has three openings: the aortic hiatus, the oesophageal hiatus and the caval foramen.
Origin
- Lumbar part: right and left crura, on the bodies of the cranial lumbar vertebrae (L3–L4).
- Costal part: medial surfaces of the eighth to thirteenth ribs, along the costal arch.
- Sternal part: xiphoid cartilage.
Insertion
Central tendon.
Action
Contraction flattens the dome, enlarges the thorax and produces inspiration.
Innervation
Phrenic nerve (n. phrenicus), formed by ventral branches of cervical nerves C5 to C7.
Clinical relevance
- Traumatic diaphragmatic hernia, usually after road accidents, displaces abdominal organs into the thorax.
- Peritoneopericardial diaphragmatic hernia is congenital.
- Hiatal hernia is described mostly in brachycephalic breeds and the Shar-Pei.