Inferior vena cava

The Inferior vena cava will also be inferior vena cava called. It flows into the right atrium of the heart together with the superior vena cava, the superior vena cava. The inferior vena cava transports oxygen-poor blood from the periphery of the body back to the heart.

The vein is formed by the union with the so-called Vv. Iliacae communes and has its origin between the fourth and fifth lumbar vertebrae. The pressure in the vein cava fluctuates. This venous pressure is used for diagnostic purposes to assess the cardiovascular function. A so-called vena cava compression syndrome can occur during pregnancy, especially in the third trimester. This can be a life-threatening situation for both the mother and the unborn child. Tumors or swellings can also be the cause of this syndrome.

What is the inferior vena cava?

The inferior vena cava is also called the inferior vena cava. It is the strongest vein in the human body. Veins are blood vessels that carry blood from the organs to the heart. The lower and upper vena cava carry the blood from the body's organs into the right atrium. From there the blood flows into the right ventricle of the heart.

After a contraction, the deoxygenated blood is released into the pulmonary arteries. From there it is transported to the lungs, which re-oxygenate the blood. After the guest exchange, the now more oxygen-rich blood is pumped from the pulmonary veins into the left atrium of the heart. From there it goes into the left ventricle. When blood pressure rises in the left ventricle, the aortic valve opens. Oxygen-rich blood now flows into the body organs via the main artery.

Anatomy & structure

The inferior vena cava arises between the fourth and fifth lumbar vertebrae from the union of the so-called Vv. Iliacae communes. To the right of the aorta, also known as the main artery, the inferior vena cava extends on the posterior abdominal wall at the diaphragm.

The inferior vena cava runs through the vena cava hole of the diaphragm and flows over the thorax together with the superior vena cava into the right atrium of the heart. This is divided into two chambers. The inferior vena cava and superior vena cava both open into the posterior portion of the atrium. The inferior vena cava lies in the lowest corner of the atrium. It is separated at the front by a sickle-shaped valve called the valvula venae cavae inferioris. The veins from the paired abdominal organs flow directly into the inferior vena cava. The deoxygenated blood from the stomach, pancreas and spleen first take a detour via the portal vein into the liver.

This blood is then transported to the inferior vena cava via the hepatic veins. In addition to these veins, the lumbar and diaphragmatic veins as well as ovarian and testicular veins also flow into the inferior vena cava. The pressure in the vein is variable depending on the amount of blood in the system and the performance of the heart. It is also dependent on the pumping force of the heart muscle and the suction effect of breathing. The latter occurs because the pressure in the chest drops to negative values ​​when you inhale.

It follows that the blood is drawn in from the periphery of the body. At the same time, the lowering of the diaphragm causes the pressure in the abdomen to increase when you inhale. This narrows the blood vessels in the abdomen and increases blood flow back to the heart. So that the blood can only pass in one direction, there are heart valves that act like valves. Venous valves in the legs also prevent the blood from sinking back into the periphery. However, the inferior vena cava itself is not equipped with venous valves.

Function & tasks

The inferior vena cava is responsible for transporting oxygen-poor blood from the pelvic organs, the legs, the paired organs and the liver back to the heart. The lower and also the upper vena cava transport the blood from the body's organs into the right atrium. From there the blood flows into the right ventricle of the heart.

After a contraction, the deoxygenated blood is released into the pulmonary arteries. From there it is transported to the lungs, which re-oxygenate the blood. After the guest exchange, the now more oxygen-rich blood is pumped from the pulmonary veins into the left atrium of the heart. From there it goes into the left ventricle. When the blood pressure in the left ventricle rises, the aortic valve opens. Oxygen-rich blood now flows into the body organs via the main artery.

In addition to transporting the blood from the periphery of the body, the inferior vena cava is also responsible for filling the right heart. The pressure in the vein is between 0 to 15 mmHg and fluctuates depending on the breathing. This is also known as a venous pulse. The venous pulse is particularly important for diagnostics in medicine. It can be used to assess the function of the cardiovascular system.

Diseases

During pregnancy, the increasing weight of the unborn baby can cause the uterus to expand significantly. This can cause the inferior vena cava to be compressed. This condition is called vena cava compression syndrome. The syndrome results in a disruption of the venous blood flow.

This leads to a reduction in cardiac output, a lowering of the arterial blood pressure and a reduced cerebral blood flow. The pregnant women affected suffer from dizziness, paleness, sweating and shortness of breath. This condition is comparable to symptoms of shock. This represents a life-threatening situation for the fetus, as it can no longer be optimally supplied with oxygen. The pregnant woman may faint. In order to relieve the inferior vena cava, the pregnant woman should be brought to the left side as soon as possible so that the condition can normalize. Women especially suffer from this syndrome in the third trimester.

However, the problem can also be triggered by tumors or swelling.