A portocaval anastomosis or porto-systemic anastomosis is a specific type of

anastomosis An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be norm ...

that occurs between the veins of the

portal circulation In the circulatory system of animals, a portal venous system occurs when a capillary bed pools into another capillary bed through veins, without first going through the heart. Both capillary beds and the blood vessels that connect them are con ...

and those of the

systemic circulation The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, t ...

. When there is a blockage of the portal system, portocaval anastomosis enables the blood to still reach the systemic venous circulation. The inferior end of the

esophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to t ...

and the superior part of the

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...

are potential sites of a harmful portocaval anastomosis. In

portal hypertension Portal hypertension is abnormally increased portal venous pressure – blood pressure in the portal vein and its branches, that drain from most of the intestine to the liver. Portal hypertension is defined as a hepatic venous pressure gradient ...

, as in the case of

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue rep ...

of the liver, the anastomoses become congested and form venous dilatations. Such dilatation can lead to

esophageal varices Esophageal varices are extremely dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis. People with esophageal varices have a strong tendency to develop s ...

and anorectal varices. Caput medusae can also result.'' Gray's Anatomy for Students'' Gray H, Drake R, Vogl W, Mitchell A, Tibbitts R, Richardson P. Philadelphia: Elsevier/Churchill Livingstone; 2010. p. 226 __TOC__

Presentation

Clinical presentations of

include: A dilated inferior mesenteric vein may or may not be related to portal hypertension. Other areas of anastomosis include the

bare area of the liver The bare area of the liver (nonperitoneal area) is a large triangular area on the diaphragmatic surface of the liver. It is the only part of the liver with no peritoneal covering, although it is still covered by Glisson’s capsule. It is attach ...

as it connects to the

diaphragm Diaphragm may refer to: Anatomy * Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen * Pelvic diaphragm or pelvic floor, a pelvic structure * Urogenital diaphragm or triangular ligament, a pelvic structure Other * Diap ...

, the posterior portion of the

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

as it touches the posterior abdominal wall, the posterior surface of the

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an ...

, and the inferior part of the esophagus.

References

Vascular diseases Diseases of veins, lymphatic vessels and lymph nodes {{circulatory-disease-stub