| Inferior vena cava 67 | |
|---|---|
 Anterior (frontal) view of the opened heart. White arrows indicate valid blood flow. | |
 Superior vena cava, inferior vena cava, azygos vein and their tributaries | |
| Details | |
| Source | Common iliac vein lumbar veins testicular vein renal vein suprarenal vein hepatic vein |
| Drains to | Right atrium |
| Artery | Abdominal aorta |
| Identifiers | |
| Latin | vena cava inferior |
| Acronym | IVC |
| MeSH | D014682 |
| TA98 | A12.3.09.001 |
| TA2 | 4991 |
| FMA | 10951 |
| Anatomical terminology | |
Theinferior vena cava is a large vein that carries the deoxygenatedblood from the lower and middle body into theright atrium of theheart. It is formed by the joining of the right and the leftcommon iliac veins, usually at the level of the fifthlumbar vertebra.[1][2]
The inferior vena cava is the lower ("inferior") of the twovenae cavae, the two largeveins that carry deoxygenatedblood from the body to the right atrium of the heart: the inferior vena cava carries blood from the lower half of the body whilst thesuperior vena cava carries blood from the upper half of the body. Together, the venae cavae (in addition to thecoronary sinus, which carries blood from the muscle of the heart itself) form the venous counterparts of theaorta.
It is a largeretroperitoneal vein that liesposterior to theabdominal cavity and runs along the right side of thevertebral column.[1] It enters the right auricle at the lower right, back side of the heart. The name derives fromLatin:vena, "vein", cavus, "hollow".
The IVC is formed by the joining of the left and rightcommon iliac veins and brings collected blood into theright atrium of the heart.[1] It alsojoins with theazygos vein (which runs on the right side of the vertebral column) and venousplexuses next to thespinal cord.
The inferior vena cava begins as the left and right common iliac veins behind theabdomen unite, at about the level ofL5.[1][2] It passes through thethoracic diaphragm at thecaval opening at the level ofT8.[1][3] It passes to the right of thedescending aorta.[3]
The specific levels of the tributaries are as follows:
| Level | Vein |
|---|---|
| T8 | hepatic veins,inferior phrenic vein |
| L1 | rightsuprarenal vein,renal veins |
| L2 | rightgonadal vein |
| L1–L5 | lumbar veins |
| L5 | common iliac veins |
Because the inferior vena cava is located to the right of the midline, drainage of the tributaries is not always symmetrical. On the right, thegonadal veins andsuprarenal veins drain into the inferior vena cava directly.[1] On the left, they drain into therenal vein which in turn drains into the inferior vena cava.[1] By contrast, all thelumbar veins andhepatic veins usually drain directly into the inferior vena cava.[1]
In theembryo, the inferior vena cava and right auricle are separated by thevalve of the inferior vena cava, also known as theEustachian valve. In the adult, this valve typically has totally regressed or remains as a small fold ofendocardium.[4]
The anatomy of the IVC can exhibit abnormalities in approximately 8.7% of the global population.[5] These variations may arise during its development, specifically between the 4th and 8th weeks of gestation, due to the intricate process of vessel formation. The IVC is composed of four segments formed from the anastomoses of various vessels: hepatic, suprarenal, renal, and infrarenal. The hepatic segment originates from the vitelline vein, while the suprarenal segment includes a portion of the right subcardinal vein that does not regress. The renal segment is created through the anastomoses of the right suprasubcardinal and postsubcardinal veins, and the infrarenal segment derives from the right supracardinal vein. The subcardinal and supracardinal veins gradually replace the postcardinal veins, which persist as the common iliac veins within the pelvis.
The formation of the IVC is a complex process that can result in anomalies. These anomalies are more frequently observed in individuals with other cardiovascular defects.[5] The most common variants are the duplicated IVC and left IVC. In a duplicated IVC, both supracardinal veins persist, a rare variant affecting 0.2–3% of the population. Most of these anatomical variations are asymptomatic, but their identification is crucial for the accurate planning of complex surgeries to avoid complications. Ultrasound (US) systems are typically used to identify these variations; however, other techniques such as computed tomography (CT), which involves ionizing radiation, or magnetic resonance imaging (MRI), which is more costly, are often preferred due to the user-dependent nature of US analysis.[5]
In between 0.2% to 0.3% of people,[6] the inferior vena cava may be duplicated beneath the level of the renal veins.[7]
The inferior vena cava is avein. It carries deoxygenated blood from the lower half of the body to theright atrium of theheart.[7]
The corresponding vein that carries deoxygenated blood from the upper half of the body is thesuperior vena cava.
Various image-processing methods have been applied to US scans of the IVC.[5] The number of algorithms is slightly larger for the analysis of transverse than longitudinal view. This may stem from the fact that it is easier to segment a closed cross-section than an open long-axis portion of the IVC, as the latter requires careful tracking of the region of interest.[5] In recent years, deep learning approaches are gaining more importance, so that further developments are expected in the future in such a direction.[5]
Health problems attributed to the IVC are most often associated with it being compressed (ruptures are rare because it has a lowintraluminalpressure). Typical sources of external pressure are an enlargedaorta (abdominal aortic aneurysm), thegraviduterus (aortocaval compression syndrome) and abdominal malignancies, such ascolorectal cancer,renal cell carcinoma andovarian cancer. Since the inferior vena cava is primarily a right-sided structure, unconscious pregnant women should be turned on to their left side (therecovery position), to relieve pressure on it and facilitate venous return[citation needed]. In rare cases, straining associated withdefecation can lead to restricted blood flow through the IVC and result insyncope (fainting).[8]
Blockage of the inferior vena cava is rare and is treated urgently as a life-threatening condition. It is associated withdeep vein thrombosis,IVC filters,liver transplantation andsurgical procedures such as the insertion of acatheter in thefemoral vein in thegroin.[9]
Trauma to the vena cava is usually fatal as unstoppableexcessive blood loss occurs.
This article incorporates text from this source, which is available under theCC BY 4.0 license.
