Inferior vena cava

The inferior vena cava originates at the confluence of the common iliac veins at the level of the fifth lumbar vertebra (L5). It ascends in the retroperitoneal space, to the right of the vertebral column, and passes through the diaphragm at the level of the eighth thoracic vertebra (T8) to enter the right atrium.

The major tributaries of the inferior vena cava include:

• Hepatic veins (last tributaries before the inferior vena cava enters the right atrium).

• Inferior phrenic veins

• Lumbar veins

• Right suprarenal vein

• Right renal vein and left renal vein

• Right ovarian vein/Right testicular vein

• Common iliac vein

The inferior vena cava (IVC) is anatomically divided into four segments: intrahepatic, suprarenal, renal, and infrarenal. Each segment arises from different embryonic structures, contributing to the complexity of its development and potential for congenital anomalies. [1]

1. Intrahepatic segment (Intrahepatic part of inferior vena cava): This segment runs through the liver and is closely associated with the hepatic veins.

2. Suprarenal segment (Suprarenal part of inferior vena cava): Located above the renal veins, this segment is in proximity to the adrenal glands.

3. Renal segment (Interrenal part of inferior vena cava): This segment includes the portion of the IVC that receives the renal veins.

4. Infrarenal segment (Infrarenal part of inferior vena cava): This segment extends from below the renal veins to the point where the IVC bifurcates into the common iliac veins.

Some sources describe a thoracic segment (thoracic part of inferior cava), as a fifth segment, that is the small portion located between the hepatic veins and the right atrium.