Overview
Cattle have thirteen pairs of ribs (costae), one for each thoracic vertebra. Each rib has a dorsal bony part and a ventral costal cartilage. The first eight pairs are sternal (true) ribs: their cartilage articulates directly with the sternum. The last five are asternal (false) ribs: they do not reach the sternum and their cartilages form the costal arch (arcus costalis). Compared with those of the dog and cat, bovine ribs are broad and flat, and the intercostal spaces are relatively narrow.
Key features
- Head (caput costae): articulates with the costal foveae of two consecutive vertebrae.
- Neck and tubercle: the tubercle articulates with the transverse process of the vertebra of the same number.
- Body: long, curved and broad; the intercostal vein, artery and nerve run along its caudal border.
- Angle: point of greatest curvature, where the rib changes direction.
- Costochondral junction: between the bony part and the cartilage.
- Thorax and abdomen: because the diaphragm attaches far cranially, the last ribs cover abdominal organs: the reticulum and rumen on the left, the liver and omasum on the right.
Clinical relevance
- Rib fractures in calves: common after dystocia with forced traction, especially in large calves; they can cause respiratory distress and injure the lung or heart.
- Left displaced abomasum: the characteristic "ping" is heard by simultaneous auscultation and percussion over the last left ribs.
- Rib resection: gives access to the thoracic cavity, for example for pericardiotomy in traumatic pericarditis.