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Superior & Inferior Mesenteric Arteries
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Superior & Inferior Mesenteric Arteries

Mesenteric arteries
Both the superior and inferior arteries arise from the abdominal aorta and travel through the mesentery to deliver blood to organs of the digestive tract.
Mesenteric arterial networks are highly variable; for example, it is not uncommon for the right or middle colic arteries to be absent.
Superior mesenteric artery
Supplies the pancreas, segments of the small intestine, and the proximal segments of the large intestine
  • Branches:
    • Inferior pancreaticoduodenal a.
    • Middle colic a.
    • Right colic a.
    • Ileocolic a.
    • The intestinal arteries (which supply the jejunum and ileum).
Inferior mesenteric artery
Supplies the distal segments of the large intestine.
  • Branches:
    • Left colic a.
    • Multiple sigmoid aa.
    • Superior rectal a.
Marginal artery
Forms from anastomoses of the superior and inferior mesenteric arteries. it runs along the inferior border of the large intestine and links the ileocolic, right colic, middle colic, and left colic arteries.
Clinical correlations:
The marginal artery provides an alternative blood pathway for the distal portion of the large intestine if the inferior mesenteric artery is infarcted.
However, if the superior mesenteric artery is infarcted, necrosis of the small and large intestine results.
"Watershed regions" where the colon receives dual blood supply:
    • Both the SMA and the IMA supply blood to the splenic flexure.
    • Both the final sigmoidal artery branch and the superior rectal artery supply the rectosigmoid junction.
    • These regions are vulnerable in colonic ischemia.
Nutcracker Syndrome occurs when the left renal vein is compressed by the superior mesenteric artery and the aorta; patients experience flank pain, elevated renal vein pressure, and hematuria.
Superior mesenteric artery syndrome occurs when the Superior mesenteric artery and aorta compress & obstruct the transverse portion of the duodenum; patients experience postprandial pain. It is most likely to occur in patients with weight loss, but not always.

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