Inferior vena cava (abdominal part)

At a glance

English

Inferior vena cava (abdominal part)

Latin (TA2)

Vena cava inferior (pars abdominis)

System

Vein

Region

Trunk

Side

Single, on the midline

About the inferior vena cava (abdominal part)

Below the diaphragm, the inferior vena cava forms the main venous trunk of the abdomen, carrying blood from the lower limbs, pelvis, abdominal walls and paired abdominal organs towards the heart. It begins in front of the body of the fifth lumbar vertebra, a little right of the midline, where the right and left common iliac veins join behind the right common iliac artery. From there it climbs behind the peritoneum along the right of the vertebral bodies, with the abdominal aorta on its left, until it reaches the diaphragm. It has no valves along this stretch. The name comes from the Latin for 'hollow vein'.

On its way up it lies on the right psoas major, the right crus of the diaphragm and the right sympathetic trunk, and its back is crossed by the right renal and lumbar arteries. In front of it lie, from below upwards, the root of the mesentery, the third part of the duodenum, the head of the pancreas with the bile duct, the portal vein in the free edge of the lesser omentum and the epiploic foramen. Its upper part runs in a deep groove on the bare area of the liver, sometimes bridged by liver tissue, and passes through the caval opening in the central tendon of the diaphragm at about the eighth thoracic vertebra.

Because the vessel is on the right, its tributaries are not symmetrical. It receives the lumbar veins, both renal veins, the right suprarenal and right gonadal veins, the inferior phrenic veins and, just below the diaphragm, the hepatic veins. On the left the suprarenal and gonadal veins end in the left renal vein instead. The cava also communicates with the azygos system and the vertebral venous plexuses, which can carry blood around a blockage.

Its pressure is low, so it is more often squeezed than torn. An aortic aneurysm, tumours of the kidney or bowel, and large abdominal masses can compress it. Thrombosis within it is uncommon but serious; it may extend from leg veins, follow liver transplantation or femoral catheters, or form around an IVC filter. Its size and position vary rarely: it may be doubled below the renal veins or lie on the left. Injury to it bleeds heavily and is difficult to repair.

Course and drainage

Begins at

Formed in front of L5, slightly right of the midline, by the union of the right and left common iliac veins.

Drains into

Ascends on the right of the lumbar vertebral bodies and behind the liver to pass through the caval opening of the diaphragm at about T8, continuing as the thoracic part.

Drains

Drains the lower limbs, pelvis, posterior abdominal wall, kidneys, suprarenal glands and liver, receiving the lumbar, renal, right suprarenal, right gonadal, inferior phrenic and hepatic veins.