Topography
- Cranial vena cava (vena cava cranialis): formed at the thoracic inlet by the union of the brachiocephalic veins, it runs through the cranial mediastinum ventral and to the right of the trachea and opens into the right atrium. It receives the right azygos vein.
- Caudal vena cava (vena cava caudalis): formed in the caudal lumbar region by the common iliac veins, it runs right of the aorta and receives the renal veins. It then passes through the dorsal border of the liver, where it receives the hepatic veins, crosses the caval foramen of the diaphragm and opens into the right atrium.
Clinical relevance
- Radiography: on a lateral view the caudal vena cava is seen between the heart and the diaphragm; its width helps assess volume status and right-sided heart failure.
- Gastric dilatation-volvulus: the distended stomach compresses the caudal vena cava and the portal vein, reducing venous return and contributing to shock.
- Portosystemic shunts: anomalous vessels that divert portal blood into the caudal vena cava or the azygos vein, bypassing the liver.
3D model
Where both venae cavae open into the right atrium is segmented from the heart CT. The rest of their course is modelled: the cranial vena cava up to the thoracic inlet, and the caudal vena cava through the liver and along the right of the aorta, with which it was fused in the abdominal CT. The azygos vein is not included.