Inferior vena cava

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Inferior vena cava
Right ventricle Left ventricle Aortic valve Mitral valve Left atrium Right atrium Aorta Pulmonary valve Tricuspid valve Inferior vena cava Superior vena cava Pulmonary artery Pulmonary veinDiagram of the human heart (cropped).svg
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Superior vena cava, inferior vena cava, azygos vein and their tributaries.
Details
Latin vena cava inferior
Source
common iliac vein
lumbar veins
testicular vein
renal vein
suprarenal vein
hepatic vein
Drains to
heart
abdominal aorta
Identifiers
Gray's p.677
MeSH A07.231.908.949.648
TA A12.3.09.001
FMA FMA:10951
Anatomical terminology

The inferior vena cava (or IVC), also known as the posterior vena cava,[1] is the large vein that carries deoxygenated blood from the lower half of the body into the right atrium of the heart.

It is posterior to the abdominal cavity and runs alongside of the vertebral column on its right side (i.e. it is a retroperitoneal structure). It enters the right atrium at the lower right, back side of the heart.

Structure[edit]

The IVC is formed by the joining of the left and right common iliac veins and brings blood into the right atrium of the heart. It also anastomoses with the azygos vein system (which runs on the right side of the vertebral column) and venous plexuses next to the spinal cord.

The caval opening is at T8. The specific levels of the tributaries are as follows:

Vein Level
hepatic veins T8
inferior phrenic vein T8
right suprarenal vein L1
renal veins L1
right gonadal vein L2
lumbar veins L1-L5
common iliac veins L5

Because the IVC is not centrally located, there are some asymmetries in drainage patterns. The gonadal veins and suprarenal veins drain into the IVC on the right side, but into the renal vein on the left side, which in turn drains into the IVC. By contrast, all the lumbar veins and hepatic veins usually drain directly into the IVC.

Note that the vein that carries de-oxygenated blood from the upper half of the body is the superior vena cava.

Development[edit]

In the embryo, the IVC and right atrium are separated by the Eustachian valve, also known in Latin as the valvula venae cavae inferioris (valve of the inferior vena cava). In the adult, this structure typically has totally regressed or remains as a small endocardial fold.[2]

Function[edit]

Transport blood rich in carbon dioxide from the lower half of the body to the right atrium.

Clinical signifiance[edit]

Health problems attributed to the IVC are most often associated with it being compressed (ruptures are rare because it has a low intraluminal pressure). Typical sources of external pressure are an enlarged aorta (abdominal aortic aneurysm), the gravid uterus (aortocaval compression syndrome) and abdominal maligancies, such as colorectal cancer, renal cell carcinoma and ovarian cancer. Since the inferior vena cava is primarily a right-sided structure, unconscious pregnant women should be turned on to their left side (the recovery position), to relieve pressure on it and facilitate venous return. In rare cases, straining associated with defecation can lead to restricted blood flow through the IVC and result in syncope (fainting).[3]

Occlusion of the IVC is rare, but considered life-threatening and is an emergency. It is associated with deep vein thrombosis, IVC filters, liver transplantation and instrumentation (e.g. catheter in the femoral vein).[4]

Trauma to the vena cava is a potentially life-threatening situation as exsanguination may occur rapidly.

History[edit]

Additional images[edit]

See also[edit]

References[edit]

  1. ^ Organisms and Populations 3rd Ed.
  2. ^ Turhan Yavuz; Nazli, C; Kinay, O; Kutsal, A (2002). "Giant Eustachian Valve: with Echocardiographic Appearance of Divided Right Atrium". Texas Heart Institute Journal 29 (4): 336–8. PMC 140300. PMID 12484622. 
  3. ^ Brophy, CM; Evans, L; Sumpio, BE (1993). "Defecation syncope secondary to functional inferior vena caval obstruction during a Valsalva maneuver". Annals of vascular surgery 7 (4): 374–7. doi:10.1007/BF02002893. PMID 8268080. 
  4. ^ Geehan DM, Inferior Vena Caval Thrombosis, emedicine.com, URL: http://www.emedicine.com/med/topic2718.htm, Accessed: August 3, 2005.

External links[edit]