The inferior vena cava is a large vein that carries the deoxygenated

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

from the lower and middle body into the right atrium of the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

. It is formed by the joining of the right and the left

common iliac vein In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the fifth lumbar vertebra, forming the inferior vena ...

s, usually at the level of the fifth

lumbar vertebra The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse p ...

. The inferior vena cava is the lower (" inferior") of the two

venae cavae In anatomy, the venae cavae (; singular: vena cava ; ) are two large veins (great vessels) that return deoxygenated blood from the body into the heart. In humans they are the superior vena cava and the inferior vena cava, and both empty into the ...

, the two large

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

s that carry deoxygenated

from the body to the right atrium of the heart: the inferior vena cava carries blood from the lower half of the body whilst the superior vena cava carries blood from the upper half of the body. Together, the venae cavae (in addition to the coronary sinus, which carries blood from the muscle of the heart itself) form the venous counterparts of the aorta. It is a large retroperitoneal vein that lies posterior to the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the th ...

and runs along the right side of the

vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordata, ...

. It enters the right auricle at the lower right, back side of the heart. The name derives from la, vena, "vein", cavus, "hollow".

Structure

The IVC is formed by the joining of the left and right

s and brings collected blood into the right atrium of the heart. It also

joins Join may refer to: * Join (law), to include additional counts or additional defendants on an indictment *In mathematics: ** Join (mathematics), a least upper bound of sets orders in lattice theory ** Join (topology), an operation combining two topo ...

with the azygos vein (which runs on the right side of the vertebral column) and venous

plexus In neuroanatomy, a plexus (from the Latin term for "braid") is a branching network of vessels or nerves. The vessels may be blood vessels (veins, capillaries) or lymphatic vessels. The nerves are typically axons outside the central nervous syste ...

es next to the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

. The inferior vena cava begins as the left and right common iliac veins behind the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

unite, at about the level of L5. It passes through the

thoracic diaphragm The thoracic diaphragm, or simply the diaphragm ( grc, διάφραγμα, diáphragma, partition), is a sheet of internal Skeletal striated muscle, skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavit ...

at the

caval opening The thoracic diaphragm, or simply the diaphragm ( grc, διάφραγμα, diáphragma, partition), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the mo ...

at the level of T8 - T9. It passes to the right of the descending aorta.

Tributaries

The specific levels of the tributaries are as follows: Because the inferior vena cava is located to the right of the midline, drainage of the tributaries is not always symmetrical. On the right, the

gonadal vein In medicine, gonadal vein refers to the blood vessel that carries blood away from the gonad (testis, ovary) toward the heart. These are different arteries in women (ovarian vein) and men (testicular vein), but share the same embryological origin. ...

s and

suprarenal vein The suprarenal veins are two in number: * the ''right'' ends in the inferior vena cava. * the ''left'' ends in the left renal or left inferior phrenic vein. They receive blood from the adrenal glands and will sometimes form anastomoses An anast ...

s drain into the inferior vena cava directly. On the left, they drain into the renal vein which in turn drains into the inferior vena cava. By contrast, all the

lumbar veins The lumbar veins are four pairs of veins running along the inside of the posterior abdominal wall, and drain venous blood from parts of the abdominal wall. Each lumbar vein accompanies a single lumbar artery. The lower two pairs of lumbar veins ...

and hepatic veins usually drain directly into the inferior vena cava.

Development

In the

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

, the inferior vena cava and right auricle are separated by the

valve of the inferior vena cava The valve of the inferior vena cava (eustachian valve) is a venous valve that lies at the junction of the inferior vena cava and right atrium. Development In prenatal development, the eustachian valve helps direct the flow of oxygen-rich bloo ...

, also known as the ''Eustachian valve''. In the adult, this valve typically has totally regressed or remains as a small fold of

endocardium The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the va ...

Variation

Rarely, the inferior vena cava may vary in its size and position. In transposition of the great arteries the inferior vena cava may lie on the left. In between 0.2% to 0.3% of people, the inferior vena cava may be duplicated beneath the level of the renal veins.

Function

The inferior vena cava is a

. It carries deoxygenated blood from the lower half of the body to the right atrium of the

. The corresponding vein that carries deoxygenated blood from the upper half of the body is the superior vena cava.

Clinical significance

Health problems attributed to the IVC are most often associated with it being compressed (ruptures are rare because it has a low

intraluminal In biology, a lumen (plural lumina) is the inside space of a tubular structure, such as an artery or intestine. It comes . It can refer to: *The interior of a vessel, such as the central space in an artery, vein or capillary through which blood f ...

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

). Typical sources of external pressure are an enlarged aorta ( abdominal aortic aneurysm), the

gravid In biology and human medicine, gravidity and parity are the number of times a woman is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional te ...

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The uter ...

(

aortocaval compression syndrome Aortocaval compression syndrome is compression of the abdominal aorta and inferior vena cava by the gravid uterus when a pregnant woman lies on her back, i.e. in the supine position. It is a frequent cause of low maternal blood pressure (hypotens ...

) and abdominal malignancies, such as

colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...

renal cell carcinoma Renal cell carcinoma (RCC) is a kidney cancer that originates in the lining of the proximal convoluted tubule, a part of the very small tubes in the kidney that transport primary urine. RCC is the most common type of kidney cancer in adults, resp ...

and

ovarian cancer Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different c ...

. 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 In first aid, the recovery position (also called semi-prone) is one of a series of variations on a lateral recumbent or three-quarters prone position of the body, often used for unconscious but breathing casualties. An unconscious person, a perso ...

), to relieve pressure on it and facilitate venous return. In rare cases, straining associated with

defecation Defecation (or defaecation) follows digestion, and is a necessary process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces from the digestive tract via the anus. The act has a variety of names ranging f ...

can lead to restricted blood flow through the IVC and result in syncope (fainting). Blockage of the inferior vena cava is rare and is treated urgently as a life-threatening condition. It is associated with deep vein thrombosis,

IVC filter An inferior vena cava filter is a medical device made of metal that is implanted by vascular surgeons or interventional radiologists into the inferior vena cava to prevent a life-threatening pulmonary embolism (PE) or venous thromboembolism (VTE) ...

liver transplantation Liver transplantation or hepatic transplantation is the replacement of a diseased liver with the healthy liver from another person (allograft). Liver transplantation is a treatment option for end-stage liver disease and acute liver failure, al ...

and surgical procedures such as the insertion of a catheter in the femoral vein in the groin.Geehan DM, Inferior Vena Caval Thrombosis, emedicine.com, URL: http://www.emedicine.com/med/topic2718.htm, Accessed: August 3, 2005. Major Veins

Trauma to the vena cava is usually fatal as unstoppable excessive blood loss occurs.

Additional images

File:Inferiorvenacava.png, Inferior vena cava File:Slide10bek.JPG, Inferior vena cava front view File:Inferior vena cava filter.jpg, Image of an inferior vena cava filter File:3D Medical Animation Inferior Vena Filter.jpg, Image showing an inferior vena cava filter in its position

References

External links

* - "Posterior Abdominal Wall: Tributaries to the Inferior Vena Cava" * {{Authority control Veins of the torso