Middle rectal veins

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Middle rectal veins
Gray587.png
Scheme of the anastomosis of the veins of the rectum
Details
Drains from Rectum
Drains to Internal iliac vein
Artery Middle rectal artery
Identifiers
Latin venae rectales mediae
TA98 A12.3.10.018
TA2 5030
FMA 70912
Anatomical terminology

The middle rectal veins (or middle hemorrhoidal vein) take origin in the hemorrhoidal plexus and receive tributaries from the bladder, prostate, and seminal vesicle.

They run lateralward on the pelvic surface of the levator ani to end in the internal iliac vein. Veins superior to the middle rectal vein in the colon and rectum drain via the portal system to the liver. Veins inferior, and including, the middle rectal vein drain into systemic circulation and are returned to the heart, bypassing the liver. [1]

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<span class="mw-page-title-main">Hemorrhoid</span> Vascular structures in the anal canal

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<span class="mw-page-title-main">Inferior mesenteric artery</span>

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<span class="mw-page-title-main">Inferior mesenteric vein</span> Vein which drains blood from the large intestine

In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV).

<span class="mw-page-title-main">Hepatic veins</span> One of two sets of veins connected to the liver

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<span class="mw-page-title-main">Middle rectal artery</span>

The middle rectal artery is an artery in the pelvis that supplies blood to the rectum.

<span class="mw-page-title-main">Inferior rectal artery</span>

The inferior rectal artery is an artery that supplies blood to the lower third of the anal canal below the pectinate line.

<span class="mw-page-title-main">Hepatic portal system</span> System of veins comprising the hepatic portal vein and its tributaries

In human anatomy, the hepatic portal system or portal venous system is the system of veins comprising the portal vein and its tributaries. The other portal venous systems in the body are the renal portal system, and the hypophyseal portal system.

<span class="mw-page-title-main">Rectal venous plexus</span>

The rectal venous plexus is the venous plexus surrounding the rectum. It consists of an internal and an external rectal plexus. It is drained by the superior, middle, and inferior rectal veins. It forms a portosystemic (portocaval) anastomosis. This allows rectally administered medications to bypass first pass metabolism.

<span class="mw-page-title-main">Superior rectal artery</span>

The superior rectal artery is an artery that descends into the pelvis to supply blood to the rectum.

<span class="mw-page-title-main">Inferior anal nerves</span>

The inferior rectal nerves usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior rectal artery and veins, toward the anal canal and the lower end of the rectum, and is distributed to the sphincter ani externus and to the integument (skin) around the anus.

<span class="mw-page-title-main">Superior rectal vein</span>

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<span class="mw-page-title-main">Inferior rectal veins</span>

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Transanal hemorrhoidal dearterialization (THD) is a minimally invasive surgical procedure for the treatment of internal hemorrhoids.

Anorectal varices are the dilation of collateral submucosal vessels due to backflow in the veins of the rectum. Typically this occurs due to portal hypertension which shunts venous blood from the portal system through the portosystemic anastomosis present at this site into the systemic venous system. This can also occur in the esophagus, causing esophageal varices, and at the level of the umbilicus, causing caput medusae. Between 44% and 78% of patients with portal hypertension get anorectal varices.

<span class="mw-page-title-main">Liver segment</span> An anatomical unit of the liver

A liver segment is one of eight segments of the liver as described in the widely used Couinaud classification in the anatomy of the liver. This system divides the lobes of the liver into eight segments based on a transverse plane through the bifurcation of the main portal vein, arranged in a clockwise manner starting from the caudate lobe.

References

PD-icon.svgThis article incorporates text in the public domain from page 676 of the 20th edition of Gray's Anatomy (1918)

  1. van Hoogdalem, Edward; de Boer, Albertus G.; Breimer, Douwe D. (July 1991). "Pharmacokinetics of rectal drug administration, Part I. General considerations and clinical applications of centrally acting drugs". Clinical Pharmacokinetics. 21 (1): 14. doi:10.2165/00003088-199121010-00002. ISSN   0312-5963 . Retrieved 18 March 2024. The superior rectal vein, perfusing the upper part of the rectum, drains into the portal vein and subsequently into the liver On the other hand, the middle and inferior rectal veins drain the lower part of the rectum and venous blood is returned to the inferior vena cava.