The mesentery is a twin fold that peritoneal organization that suspends the tiny intestine and big intestine native the posterior abdominal muscle wall.

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It was formerly thought to it is in a collection of discrete frameworks – every with different insertions into the posterior wall. However, current research has discovered the mesentery to it is in one contiguous structure, which has actually led to proposals because that its reclassification together an organ.

In this article, we shall look in ~ the anatomy the the mesentery – that is anatomical structure, vasculature, innervation, lymphatics and also clinical relevance.

Note: Research concerning the mesentery is relatively recent, and also some enlarge textbooks may still explain the various parts the the mesentery as separate structures – this is now thought to it is in incorrect.


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Fig 1 – streamlined illustration of the mesentery. That acts to attach the tiny intestine and huge intestine come the posterior ab wall.


Function

The mesentery has actually several functions in the abdomen:

Suspends the little and huge intestine indigenous the posterior ab wall; anchoring lock in place, whilst still enabling some movement.Provides a conduit because that blood vessels, nerves and also lymphatic vessels.Postulated to play a pathological role in inflammation diseases such together Crohn’s disease.

Structure

The mesentery is developed by a double layered fold the peritoneum.

Although the mesentery is currently thought to be a contiguous structure, subsections that the mesentery have the right to be named according to the viscera it is linked with. Thus, names such together mesocolon, mesorectum, mesosigmoid all relate to different parts that the mesentery.

The ‘root’ the the mesentery is the suggest where the mesentery attaches come the posterior ab wall, and also is because of this a ‘bare area’. Due to the selection of abdominal muscle organs the mesentery envelopes, the root is long, narrow and also has an oblique orientation, native the left next of the L2 vertebra come the right sacroiliac junction roughly.

In the cradle tract, over there are 6 flexures of note: duodenojejunal, ileocaecal, hepatic, splenic, and those in between the descending and sigmoid colon and the sigmoid and also rectum. These flexures are often used to mark the difference between different portions the the mesentery:

Mesentery of the tiny intestine – associate the loops of jejunum and ileum come the posterior abdominal wall and is a mobile structure. (1)Right mesocolon – flattened against the posterior abdominal wall surface (2)Transverse mesocolon – a mobile structure and also lies in between the colic flexures (3)Left mesocolon – flattened against the posterior abdominal wall surface (4)Mesosigmoid – has a medial section which is flattened versus the posterior abdominal wall, whereas the an ar of mesentery linked with the sigmoid colon itself is mobile. (5)Mesorectum – assists in anchoring the rectum v the pelvis.(6)
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Fig 2 – little intestine and also and big intestine emphasize to show linked mesentery.


The locations of the mesentery that are flattened versus the posterior abdominal wall surface (the right and also left mesocolon and the medial mesosigmoid) are attached come the abdominal wall surface via secondary layer of connective tissue known as Toldt’s fascia. The fascia has several lymphatic channels.


Clinical Relevance: minister Volvulus

A volvulus occurs as soon as a loop of intestine twists roughly itself and also its mesentery, leading to obstruction that the bowel. That is feasible that the bowel will twist tightly sufficient to prevent the blood supply to the intestine, and result in bowel infarction.

The many commonly impacted area the bowel is the sigmoid colon. The risk of intestinal volvulus is enhanced in kids with minister malrotation, a congenital defect in which the embryological intestinal rotation is incomplete, leading to improper anchoring that the intestines to the posterior abdominal muscle wall.

Medical imaging (abdominal x-ray, CT abdo-pelvis) is generally used to confirm a diagnosis, and also serious instances require surgical intervention.


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Fig 3 – abdominal muscle x-ray demonstrating a sigmoid volvulus


Vasculature

The mesentery action a conduit for neurovascular structures.

The superior and inferior mesenteric arteries (SMA and IMA) arise from the ab aorta and also travel in the mesentery to it is provided the ab viscera. This vessels likewise give rise to branches the supply the mesentery itself.

Superior mesenteric artery – provides the guts of the midgut – indigenous the significant duodenal papilla come the proximal two thirds the the transverse colon.Inferior mesenteric artery – gives the offal of the hindgut – the distal one 3rd of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum.

The venous drainage of the mesentery is via the remarkable mesenteric vein (SMV) and inferior mesenteric vein (IMV), i m sorry both run alongside their linked arteries.


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Fig 4 – The superior mesenteric artery and also its branches. Note: the inferior pancreatoduodenal artery arises more proximally, and also is no visible ~ above this illustration.


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Fig 5 – major branches that the worse mesenteric artery demonstrated in green


Innervation

The superior mesenteric plexus (a continuation of the celiac plexus) accompanies the exceptional mesenteric artery into the mesentery.

The premium mesenteric plexus climate divides right into many second plexuses i m sorry contain parasympathetic and sympathetic innervation come the mesentery connected with a details organ, the guts themselves and their related blood vessels.


Lymphatics

The mesentery contains both lymph nodes and lymphatic vessels. There space several teams of lymph nodes found within the mesentery:

Inferior mesenteric lymph nodes – receives lymph from the hindgut organs, and also drains into the premium mesenteric lymph nodes.

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Superior mesenteric lymph nodes – obtain lymph from the midgut offal (and from the inferior mesenteric nodes), and drains right into the pre-aortic lymph nodes.