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.
In cattle the line of attachment is very oblique: on the ventral midline it attaches far cranially, near the xiphoid process, and from there it climbs caudodorsally along the costal arch to the last rib. As a result the dome reaches far cranially and much of the abdomen lies under cover of the ribs. The reticulum lies directly against the abdominal surface of the ventral diaphragm, with the heart and pericardium on the other side; the liver lies against its right part.
Origin
- Lumbar part: right and left crura, on the bodies of the cranial lumbar vertebrae.
- Costal part: medial surfaces of the caudal 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
- In traumatic reticuloperitonitis an ingested metallic foreign body (wire, nail) perforates the reticular wall. Because the diaphragm is so close, it can pass through it and reach the pericardium, causing traumatic pericarditis. Oral magnets, which stay in the reticulum, are used to prevent it.
- Diaphragmatic hernia in cattle is associated with traumatic reticuloperitonitis: the reticulum passes through a defect in the diaphragm into the thorax and can cause recurrent bloat and indigestion.