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 esophageal hiatus and the caval foramen.
Origin
- Lumbar part: right and left crura, on the bodies of the cranial lumbar vertebrae.
- Costal part: medial surfaces of the last ribs and their cartilages, along the costal arch.
- Sternal part: xiphoid process.
Insertion
Central tendon.
Action
Contraction flattens the dome, enlarges the thorax and produces inspiration.
Innervation
Phrenic nerve (n. phrenicus), formed by ventral branches of the caudal cervical nerves.
Clinical relevance
- Traumatic diaphragmatic hernia occurs in the cat after road accidents and falls from height. Liver, small intestine and stomach move into the thorax, and signs may appear weeks after the trauma.
- Peritoneopericardial diaphragmatic hernia is congenital and is the most common pericardial anomaly in the cat. It is often an incidental finding and is described more often in Persian, Himalayan and long-haired cats.