F) Veins Of The Abdomen

Inferior Vena Cava

The inferior vena cava is the major vessel for the return of blood to the heart from the abdomen and pelvis. Many abdominal viscera drain via the portal system to the liver; but hepatic veins still empty into the inferior vena cava just prior to its entry into the right atrium. The IVC is typically considered in four parts:

  • The long abdominal section which runs from L5 to L1
  • The intrahepatic part that lies within the substance of the liver
  • The short suprahepatic segment between the liver and the diaphragm
  • The short thoracic part that empties into the right atrium

The relations of the inferior vena cava are:

  • Anteriorly (from inferior to superior), the right common iliac artery, the peritoneal cavity (including small intestine, large intestine), the third part of the duodenum, the head of the pancreas, the first part of the duodenum, the peritoneal cavity again, and then the liver.
  • Posteriorly, with the lumbar vertebrae and twelfth thoracic vertebra. The right renal artery crosses posteriorly at the level of L2, and the right suprarenal artery crosses posteriorly just above this.
  • Right lateral, with the right ureter, right kidney, the second part of the duodenum and the right lobe of the liver.
  • Left lateral, with the aorta and left ureter.

Tributaries are numerous:

  • The IVC is formed by the union of the two common iliac veins at the level of L5.
  • Numerous lumbar veins enter its posterolateral aspect
  • The right gonadal vein typically drains into the IVC directly
  • The paired renal veins enter at about L1; the left is significantly longer and passes anterior to the abdominal aorta to reach the left kidney. The left gonadal vein typically empties into the left renal vein, as does the left suprarenal vein.
  • The right suprarenal vein usually empties directly into the IVC
  • The large left, middle and right hepatic veins empty into the IVC during its intrahepatic course, just prior to its passage through the caval foramen in the diaphragm.

The thoracic course of the IVC is very short.

Portal Vein

The portal venous system drains blood from the spleen, pancreas and gastrointestinal tract to the liver, separate to the systemic venous return. It is not covered in this section.