inferior vena cava
Inferior vena cava and its tributaries.
The inferior vena cava is ne of two great veins, known as vena cavae, in the general or systemic circulatory system of the body, the other being the superior vena cava. The inferior vena cava is the widest vein in the body and one of the longest; it conveys most of the blood from the body below the diaphragm to the right atrium of the heart.
The inferior vena cava lies immediately to the right of the aorta. It starts in the lower abdomen, in front of the fifth lumbar vertebra, and is formed by the union of the two common iliac veins (which receive blood from the legs and pelvic organs), the junction lying behind the right common iliac artery. The inferior vena cava also receives blood from the hepatic vein, which drains the liver, and the renal veins, which drain the kidneys. It travels some 25 cm upwards in front of the spine, behind the liver, piercing the central tendon of the diaphragm, and entering the right atrium of the heart.
Bearing in mind that the venous blood from the abdominal portion of the gastrointestinal tract drains to the liver by means of the tributaries of the portal vein, and that the left suprarenal and testicular or ovarian veins drain first into the left renal vein, then it is apparent that the tributaries of the inferior vena cava correspond quite closely to the branches of the abdominal portion of the aorta.