Topography
- Aorta: leaves the left ventricle, forms the aortic arch (giving the brachiocephalic trunk and the left subclavian artery) and descends ventral to the vertebral bodies, slightly left of the median plane. It crosses the diaphragm through the aortic hiatus between the crura and in the abdomen gives the coeliac, cranial mesenteric, renal, gonadal and caudal mesenteric arteries. At the last lumbar vertebrae it gives off the two external iliac arteries and ends by dividing into the internal iliac arteries and the median sacral artery: the so-called aortic trifurcation.
- Caudal vena cava (vena cava caudalis): formed by the common iliac veins in the caudal lumbar region, it runs right of the aorta, receives the renal veins, passes through the dorsal border of the liver and the caval foramen of the diaphragm, and opens into the right atrium.
Clinical relevance
- Feline aortic thromboembolism: a thrombus formed in an enlarged left atrium (mostly from hypertrophic cardiomyopathy) lodges most often at the aortic trifurcation (a "saddle thrombus"). It causes acute, painful paralysis of the pelvic limbs, which are cold with no femoral pulse and with firm gastrocnemius muscles.
- Femoral pulse: palpated on the medial thigh; its absence or asymmetry is a key sign of thromboembolism.
- Systemic hypertension: common in older cats with chronic kidney disease or hyperthyroidism; it damages the retina, heart, kidney and brain. Blood pressure is measured indirectly with Doppler or oscillometry.
- Portosystemic shunts: in the cat they are usually single and extrahepatic, often arising from the left gastric vein, and carry portal blood into the caudal vena cava, bypassing the liver. Ptyalism and, in cats without blue eyes, copper-coloured irises are typical.
3D model
The abdominal part (aorta, caudal vena cava, renal and iliac vessels) comes from the blood volume of the same feline CT that provides the abdominal organs, fitted to the atlas skeleton; the thoracic aorta with the brachiocephalic trunk and left subclavian artery, and the thoracic caudal vena cava, are modelled (modelled fidelity).