The inferior vena cava is also called the inferior vena cava. It opens into the right atrium of the heart along with the superior vena cava, the superior vena cava. The inferior vena cava transports deoxygenated blood from the periphery of the body back to the heart. The vein is formed by joining with the so-called vv. iliacae communes and originates between the fourth and fifth lumbar vertebrae. There is a fluctuating pressure in the vena cava. This venous pressure is used for diagnostic purposes to assess cardiovascular function. During pregnancy, a so-called vena cava compression syndrome can occur, 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 organs to the heart. The inferior and superior vena cava carry blood from the body organs to the right atrium. From there, the blood flows to the right ventricle of the heart. After 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 gas exchange, the now more oxygen-rich blood is pumped by the pulmonary veins into the left atrium of the heart. From there, it enters the left ventricle. When the blood pressure in the left ventricle rises, the aortic valve is opened. Oxygen-rich blood now flows through the aorta into the body’s organs.
Anatomy and structure
Between the fourth and fifth lumbar vertebrae, the inferior vena cava arises from a union of the so-called vv. iliacae communes. To the right of the aorta, also called the aorta, the inferior vena cava extends along the posterior abdominal wall at the diaphragm. The inferior vena cava passes through the vena cava of the diaphragm and, together with the superior vena cava, opens across the chest into the right atrium of the heart. This is divided into two chambers. The inferior vena cava and the superior vena cava both open into the posterior section of the atrium. The inferior vena cava is located in the lowest angle of the atrium. It is separated anteriorly by a crescent-shaped valve called the valvula venae cavae inferioris. The veins from the paired abdominal orifices open directly into the inferior vena cava. The deoxygenated blood from the stomach, pancreas and spleen first take a circuitous route via the portal vein to the liver. This blood is then transported via the hepatic veins into the inferior vena cava. In addition to these veins, the lumbar and diaphragmatic veins as well as ovarian and testicular veins also drain into the inferior vena cava. Depending on the blood filling in the system and the power of the heart, the pressure in the vein is variable. Furthermore, it depends on the pumping power of the heart muscle and the suction effect of breathing. The latter occurs because the pressure in the chest decreases to negative values during inhalation. As a result, blood is drawn in from the periphery of the body. At the same time, the lowering of the diaphragm during inhalation causes an increase in pressure in the abdominal cavity. As a result, the abdominal vessels are constricted and the return flow of blood to the heart increases. To ensure that the blood can only pass in one direction, there are heart valves that act like valves. Venous valves in the legs additionally prevent the blood from slumping back into the periphery. However, the inferior vena cava itself is not equipped with venous valves.
Function and tasks
The inferior vena cava is responsible for carrying deoxygenated blood from the pelvic organs, legs, paired organs, and liver back to the heart. The inferior vena cava and also the superior vena cava carry blood from the body organs to the right atrium. From there, the blood flows into the right ventricle of the heart. After 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 gas exchange, the now more oxygenated blood is pumped by the pulmonary veins into the left atrium of the heart. From there, it enters the left ventricle. When the blood pressure in the left ventricle rises, the aortic valve is opened. Oxygen-rich blood now flows via the aorta into the body’s organs.In addition to transporting blood from the periphery of the body, the inferior vena cava is partly responsible for filling the right heart. The pressure in the vein ranges from 0 to 15 mmHg and exhibits respiration-dependent fluctuations. This circumstance is also called venous pulse. The vein pulse is particularly important for medical diagnostics. Through it, the function of the cardiovascular system can be assessed.
Diseases
During pregnancy, the increasing weight of the unborn baby can cause the uterus to expand greatly. This can result in the inferior vena cava being compressed. This condition is called vena cava compression syndrome. The syndrome results in a disruption of venous blood flow. This results in a decrease in cardiac output, a decrease in arterial blood pressure, and decreased cerebral blood flow. Affected pregnant women suffer from dizziness, pallor, sweating and shortness of breath. This condition is comparable to shock symptoms. For the fetus, this represents a life-threatening situation, as it can no longer be optimally supplied with oxygen. The pregnant woman may suffer a fainting spell. To relieve the inferior vena cava, the pregnant woman should be placed in a left lateral line as soon as possible to allow the condition to normalize. Women suffer from this syndrome mainly in the third trimester. However, the problem can also be caused by tumors or swelling.
