A portacaval anastomosis (also known as portal systemic anastomosis or portal caval system) is a specific type of anastomosis

Anastomosis

An anastomosis is the reconnection of two streams that previously branched out, such as blood vessels or leaf veins. The term is used in medicine, biology, mycology and geology....

 that occurs between the veins of portal circulation and those of systemic circulation

Systemic circulation

Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart. This physiologic theory of circulation was first described by William Harvey...

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The lower end of esophagus is one of the important sites for the portosystemic anastomosis . In portal hypertension as in the case of cirrhosis of liver the anastomosis opens and forms venous dilatation called esophageal varices. Their rupture causes severe and dangerous haematesis (hematemesis

Hematemesis

Hematemesis or haematemesis is the vomiting of blood. The source is generally the upper gastrointestinal tract. Patients can easily confuse it with hemoptysis , although the latter is more common.-Signs:...

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Specific types include:

Region

Name of clinical condition

Portal circulation

Systemic circulation >- | Esophageal Esophageal Esophageal can refer to:* The esophagus* Esophageal arteries* Esophageal glands...

Esophageal varices Esophageal varices In medicine , esophageal varices are extremely dilated sub-mucosal veins in the lower esophagus...

Esophageal branch of left gastric vein

>- | Rectal

Hemorrhoids

Superior rectal vein Superior rectal vein The inferior mesenteric vein begins in the rectum as the superior rectal vein , which has its origin in the hemorrhoidal plexus, and through this plexus communicates with the middle and inferior hemorrhoidal veins....

Middle rectal veins Middle rectal veins The middle rectal veins take origin in the hemorrhoidal plexus and receive tributaries from the bladder, prostate, and seminal vesicle....  and inferior rectal veins Inferior rectal veins The lower part of the external hemorrhoidal plexus is drained by the inferior rectal veins into the internal pudendal vein.... >- | Paraumbilical Navel The navel is a scar on the abdomen caused when the umbilical cord is removed from a newborn baby...

Caput medusae Caput medusae Caput medusae is the appearance of distended and engorged paraumbilical veins, which are seen radiating from the umbilicus across the abdomen to join systemic veins...

Paraumbilical veins Paraumbilical veins In the course of the round ligament of liver and of the median umbilical ligament, small veins are found which establish an anastomosis between the veins of the anterior abdominal wall and the hepatic portal, hypogastric, and iliac veins....

Superficial epigastric vein Superficial epigastric vein The superficial epigastric vein is a vein which travels with the superficial epigastric artery. It joins the accessory saphenous vein near the fossa ovalis.-External links: - "Anterior Abdominal Wall: Blood Vessels in the Superficial Fascia"... >- | Retroperitoneal

(no clinical name)

Right colic vein Right colic vein The right colic vein drains the ascending colon, and is a tributary of the superior mesenteric vein. It travels with its corresponding artery, the right colic artery.... , middle colic vein Middle colic vein The middle colic vein drains the transverse colon. It is a tributary of the superior mesenteric vein, and follows the path of its corresponding artery, the middle colic artery.... , left colic vein Left colic vein The left colic vein drains the descending colon. It is a tributary of the inferior mesenteric vein, and follows the path of its corresponding artery, the left colic artery....

Renal vein Renal vein The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava.It is usually singular to each kidney, except in the condition "multiple renal veins".It also divides into 2 divisions upon entering the kidney:... , suprarenal vein, paravertebral vein, and gonadal vein Gonadal vein In medicine, gonadal vein refers to the blood vessel that carrying blood away from the gonad toward the heart.* Females : ovarian vein* Males : testicular vein... >- | Intrahepatic Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

Patent ductus venosus Ductus venosus In the fetus, the ductus venosus shunts approximately half of the blood flow of the umbilical vein directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver. In conjunction with the other fetal shunts, the foramen ovale and ductus arteriosus, it...

Left branch of portal vein

Inferior vena cava Inferior vena cava The inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....

It can be one of the conditions caused by portal hypertension

Portal hypertension

In medicine, portal hypertension is hypertension in the portal vein and its tributaries.It is often defined as a portal pressure gradient of 10 mmHg or greater.-Causes:Causes can be divided into prehepatic, intrahepatic, and posthepatic...

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A useful mnemonic is that portal hypertension causes problems in the butt, the gut, and caput.
A dilated inferior mesenteric vein may or may not be related to portal hypertension.