Inferior Vena Cava.
The inferior vena cava is a larger vein than the superior vena cava and carries deoxygenated blood from the lower part of the body below the diaphragm (lower limbs, abdominal viscera and pelvis) and empties it into the right atrium of the heart. It is also called the posterior vena cava.
Course of Inferior Vena Cava.
The inferior vena cava is formed by coming together of the two common iliac veins at the level of the 5th lumbar vertebra in the abdomen. It is situated retroperitoneally and runs in the posterior of the abdominal cavity alongside the vertebral column to its right. It passes the dorsal surface of the liver where it forms a groove. It then passes through the opening of the diaphragm (caval opening) at the level of the 8th thoracic vertebra. It enters the right atrium at the back side of the heart.
The thoracic pressure falls during inspiration and this helps to draw the blood in the inferior vena cava upwards towards the heart. Increase in size of the caval opening also helps to increase the flow of blood.
Dimensions of Inferior Vena Cava.
The average diameter of the IVC at its middle part
Inferior Vena Cava Valve.
Its opening in the right atrium is situated just below the opening of the superior vena cava and is guarded by Eustachian valve or the valve of the inferior vena cava. Typically the Eustachian valve is a semilunar shaped fold of endocardium which arises from the anterior fold of the IVC opening.
Picture of inferior vena cava and its tributaries.
Tributaries of Inferior Vena Cava.
On its way the inferior vena cava collects a number of tributaries which drain the muscles of the sides of the abdomen and pelvis (loins), abdominal walls, the pelvis, kidneys and the liver. Refer to the image above.
- The left and right common iliac veins which bring blood from the respective lower extremity.
- Hepatic veins which drain the liver
- Inferior phrenic veins which drain the diaphragm
- Suprarenal veins which receive blood from the adrenal glands.
- Renal veins which drain the kidneys.
- Gonadal vein which carry blood from the gonads — testes in males and ovaries in women.
- Lumbar veins which drain the posterior abdominal wall and the lumbar vertebral venous plexuses veins.
What is Inferior Vena Cava Filter.
The inferior vena cava filter is a medical device which acts as a vascular filter and which is implanted by vascular surgeons into the infrarenal inferior vena cava to prevent occurrence of fatal pulmonary embolism in cases of venous thromboembolic disease.
Indications:
These filters are particularly used when anticoagulants have failed or anticoagulants are contraindicated, or prophylactically in patients with high risk of pulmonary embolism.
Procedure.
IVC filters are placed intravascularly using a catheter which is inserted through the femoral vein in the groin.
IVC filters are mostly permanent and nowadays filters are also retrievable. They are retrieved if necessary within three weeks of implantation as later they may be overgrown by cells of the inferior vena cava wall.
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