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UPDATED: The term [mesentery] is of Greek origin. The prefix [mes(o)-] arises from the Greek [μέσο] meaning "middle", the root term [-enter-] means "small intestine" or "intestine", and the suffix [-y] means "process" or "structure". Thus, the mesentery is "a structure in the middle".
The term [mesentery] can be used as a generic word to denote a double-layered peritoneal membrane that stretches between an abdominal viscus and the abdominal wall. A more precise use of the term is that of mesentery proper, which extends between the posterior abdominal wall and the jejunum and ileum. The superior mesenteric artery and veins are found at the root of the mesentery proper, along with a large accumulation of lymphatic nodes, and sysmpathetic and parasympathetic nerves.
Between the two layers of the mesentery proper, there are jejunal and ileal arteries and veins, a complex system of arterial and venous arches, as well as lymphatic vessels, autonomic nerves, and varying degrees of fat. Because of the presence of the mesentery proper, the jejunum and ileum are mobile or intraperitoneal, that is, they can slither, turn and twist with the movements of peristalsis. This movement is helped by the presence of a small amount of peritoneal fluid.
The fact that the mesentery is intraperitoneal is important in surgery. If the organ can already move around because of its mesentery, then it does not need to be "mobilized", it is already mobile!! If the organ (jejunum or ileum) have adhesions that limit their mobility within the abdominal cavity, the surgeon may have to perform and adhesiolysis to restore their mobility.
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The first image shows an anatomical dissection where the greater omentum has been pulled anteriorly, exposing the small intestine and its mesentery, as well as the transverse mesocolon. Click on the image for a larger depiction. The second image (courtesy of Dr. Michiaki Akashi) is artwork depicting the surgical technique of transillumination, where the surgeon will shine a light through the mesentery to visualize the blood supply to the intestine prior to ligation and transection. The mesentery-like structure being transilluminated is the transverse mesocolon
WARNING: The first image is a photograph of a human dissection and can be considered descriptive.
NOTE: My personal thanks to Michiaki Akashi, M.D.for allowing us to use his artwork in this article. Dr. Akashi works as a surgeon and pathologist in the Saga Prefectural Hospital Koseikan in Saga, Japan.Dr. Miranda
First image property of: CAA.Inc. Photographer:David M. Klein
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