View source for Inferior vena cava

{{Use American English|date = January 2019}}
{{Short description|One of two veinous trunks bringing deoxygenated blood back to the heart}}
{{Use mdy dates|date = January 2019}}
{{Infobox Vein
|  Name        = Inferior vena cava 67
|  Latin       = vena cava inferior
|  Image       = {{Heart diagram 250px}}
|  Caption     =  Anterior (frontal) view of the opened heart. White arrows indicate valid  blood flow.
|  Image2      = Gray577.png
|  Caption2    = Superior vena cava, inferior vena cava, azygos vein and their tributaries
|  DrainsFrom  =
|  Source      = [[Common iliac vein]]<br/>[[lumbar veins]]<br/>[[testicular vein]]<br/>[[renal vein]]<br/>[[suprarenal vein]]<br/>[[hepatic vein]]
|  DrainsTo    = [[Right atrium]]
|  Artery      = [[Abdominal aorta]]
|  Acronym     = IVC
}}

The '''inferior vena cava''' is a large vein that carries the deoxygenated [[blood]] from the lower and middle body into the [[right atrium]] of the [[heart]]. It is formed by the joining of the right and the left [[common iliac vein]]s, usually at the level of the fifth [[Lumbar vertebrae|lumbar vertebra]].<ref name=":0">{{Citation|last1=Mozes|first1=GEZA|title=CHAPTER 2 - Venous Embryology and Anatomy|date=2007-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780123695154500053|work=The Vein Book|pages=15–25|editor-last=Bergan|editor-first=John J.|place=Burlington|publisher=Academic Press|language=en|doi=10.1016/b978-012369515-4/50005-3|isbn=978-0-12-369515-4|access-date=2020-11-22|last2=Gloviczki|first2=PETER|url-access=subscription}}</ref><ref name=":1">{{Citation|last1=Dardis|first1=Ronan M.|title=Chapter 154 - Disc Replacement Technologies in the Cervical and Lumbar Spine|date=2012-01-01|url=http://www.sciencedirect.com/science/article/pii/B9781416068396101546|work=Schmidek and Sweet Operative Neurosurgical Techniques (Sixth Edition)|pages=1777–1788|editor-last=Quiñones-Hinojosa|editor-first=Alfredo|place=Philadelphia|publisher=W.B. Saunders|language=en|doi=10.1016/b978-1-4160-6839-6.10154-6|isbn=978-1-4160-6839-6|access-date=2020-11-22|last2=Saxena|first2=Amar|last3=Shad|first3=Amjad|last4=Chitnavis|first4=Bhupal|last5=Gullan|first5=Richard|url-access=subscription}}</ref>

The inferior vena cava is the lower ("[[anatomical terms of location#Superior and inferior|inferior]]") of the two [[venae cavae]], the two large [[vein]]s that carry deoxygenated [[blood]] 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 (anatomy)|posterior]] to the [[abdominal cavity]] and runs along the right side of the [[vertebral column]].<ref name=":0" /> It enters the right auricle at the lower right, back side of the heart. The name derives from {{langx|la|vena, "vein", cavus, "hollow"}}.

==Structure==
The IVC is formed by the joining of the left and right [[common iliac vein]]s and brings collected blood into the [[right atrium]] of the heart.<ref name=":0" /> It also [[Anastomosis|joins]] with the [[azygos vein]] (which runs on the right side of the vertebral column) and venous [[plexus]]es next to the [[spinal cord]]. 

The inferior vena cava begins as the left and right common iliac veins behind the [[abdomen]] unite, at about the level of [[lumbar vertebra|L5]].<ref name=":0" /><ref name=":1" /> It passes through the [[thoracic diaphragm]] at the [[caval opening]] at the level of [[thoracic vertebra|T8]].<ref name=":0" /><ref name=":2">{{Citation|last1=Blumgart|first1=Leslie H.|title=Chapter 2 - Surgical and radiologic anatomy of the liver, biliary tract, and pancreas|date=2017-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323340625000029|work=Blumgart's Surgery of the Liver, Biliary Tract and Pancreas, 2-Volume Set (Sixth Edition)|pages=32–59.e1|editor-last=Jarnagin|editor-first=William R.|place=Philadelphia|publisher=Elsevier|language=en|doi=10.1016/b978-0-323-34062-5.00002-9|isbn=978-0-323-34062-5|access-date=2020-11-22|last2=Schwartz|first2=Lawrence H.|last3=DeMatteo|first3=Ronald P.|url-access=subscription}}</ref> It passes to the right of the [[descending aorta]].<ref name=":2" />

===Tributaries===
The specific levels of the tributaries are as follows:

{| class="wikitable"
! Level !! Vein
 |-
 | T8 || [[hepatic veins]], [[inferior phrenic vein]] 
 |-
 |L1 || right [[suprarenal vein]], [[renal veins]]
 |-
 | L2 ||  right [[gonadal 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, the [[gonadal vein]]s and [[suprarenal vein]]s drain into the inferior vena cava directly.<ref name=":0" /> On the left, they drain into the [[renal vein]] which in turn drains into the inferior vena cava.<ref name=":0" /> By contrast, all the [[lumbar veins]] and [[hepatic veins]] usually drain directly into the inferior vena cava.<ref name=":0" />

===Development===
In the [[embryo]], the inferior vena cava and right auricle are separated by the [[valve of the inferior vena cava]], also known as the ''Eustachian valve''. In the adult, this valve typically has totally regressed or remains as a small fold of [[endocardium]].<ref>{{cite journal | author1 = Turhan Yavuz | last2 = Nazli | first2 = C | last3 = Kinay | first3 = O | last4 = Kutsal | first4 = A | title = Giant Eustachian Valve: with Echocardiographic Appearance of Divided Right Atrium | journal = Texas Heart Institute Journal | volume = 29 | issue = 4 | pages = 336–8 | year = 2002 | pmid = 12484622 | pmc = 140300 }}</ref>

===Anatomy variations===
The anatomy of the IVC can exhibit abnormalities in approximately 8.7% of the global population.<ref name=":3">{{Cite journal |last1=Policastro |first1=Piero |last2=Mesin |first2=Luca |date=September 2023 |title=Processing Ultrasound Scans of the Inferior Vena Cava: Techniques and Applications |journal=Bioengineering |language=en |volume=10 |issue=9 |pages=1076 |doi=10.3390/bioengineering10091076 |doi-access=free |issn=2306-5354 |pmc=10525913 |pmid=37760178}}{{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref> 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.<ref name=":3" /> 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.<ref name=":3" />

In between 0.2% to 0.3% of people,<ref>{{Citation|last1=Stavropoulos|first1=S. William|title=Chapter 30 - Inferior Vena Cava Filters|date=2011-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323067942000304|work=Radiology Secrets Plus (Third Edition)|pages=223–227|editor-last=Pretorius|editor-first=E. Scott|place=Philadelphia|publisher=Mosby|language=en|doi=10.1016/b978-0-323-06794-2.00030-4|isbn=978-0-323-06794-2|access-date=2020-11-22|last2=Solomon|first2=Jeffrey A.|editor2-last=Solomon|editor2-first=Jeffrey A.|url-access=subscription}}</ref> the inferior vena cava may be duplicated beneath the level of the renal veins.<ref name="GRAYS40TH" />

==Function==
The inferior vena cava is a [[vein]]. It carries deoxygenated blood from the lower half of the body to the [[right atrium]] of the [[heart]].<ref name=GRAYS40TH>{{cite book |editor=Susan Standring |editor2=Neil R. Borley |title=Gray's anatomy : the anatomical basis of clinical practice |date=2008|publisher=Churchill Livingstone |location=London |isbn=978-0-8089-2371-8 |edition=40th |ref={{harvid|Gray's Anatomy|2008}}|display-editors=etal}}</ref>

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

== Diameter evaluation of IVC ==
Various image-processing methods have been applied to US scans of the IVC.<ref name=":3" /> 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.<ref name=":3" /> In recent years, deep learning approaches are gaining more importance, so that further developments are expected in the future in such a direction.<ref name=":3" />

==Clinical significance==
Health problems attributed to the IVC are most often associated with it being compressed (ruptures are rare because it has a low [[lumen (anatomy)|intraluminal]] [[pressure]]). Typical sources of external pressure are an enlarged [[aorta]] ([[abdominal aortic aneurysm]]), the [[pregnant|gravid]] [[uterus]] ([[aortocaval compression syndrome]]) and abdominal malignancies, 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{{citation needed|date=June 2018}}.  In rare cases, straining associated with [[defecation]] can lead to restricted blood flow through the IVC and result in [[fainting|syncope]] (fainting).<ref>{{cite journal | last1 = Brophy | first1 = CM | last2 = Evans | first2 = L | last3 = Sumpio | first3 = BE | title = Defecation syncope secondary to functional inferior vena caval obstruction during a Valsalva maneuver | journal = Annals of Vascular Surgery | volume = 7 | issue = 4 | pages = 374–7 | year = 1993 | pmid = 8268080 | doi = 10.1007/BF02002893 | s2cid = 42135883 | doi-access = free }}</ref>

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]]s, [[liver transplantation]] and [[surgical procedures]] such as the insertion of a [[catheter]] in the [[femoral vein]] in the [[groin]].<ref>Geehan DM, Inferior Vena Caval Thrombosis, emedicine.com, URL: http://www.emedicine.com/med/topic2718.htm, Accessed: August 3, 2005.</ref>
[[File:Major Veins.png|thumb|Branches of Inferior Vena Cava]]
Trauma to the vena cava is usually fatal as unstoppable [[exsanguination|excessive blood loss]] occurs.

==Additional images==
<gallery>
 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
</gallery>

==See also==
* [[Atriocaval shunt]]
* [[Inferior vena cava syndrome]]
* [[Recovery position]]

==References==
{{Reflist}}

==External links==
* {{SUNYAnatomyLabs|40|13|01|01}} - "Posterior Abdominal Wall: Tributaries to the Inferior Vena Cava"
* {{ViennaCrossSection|pembody/body12a}}

{{Veins}}
{{Authority control}}

[[Category:Veins of the torso]]