See also: Superior Mesenteric Artery Syndrome

In human anatomy, the superior mesenteric artery (SMA) arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies the intestine from the lower part of the duodenum to the left colic flexure and the pancreas.

Location and path

It arises anterior to vertebra L1 in an adult. It is usually 1cm lower than the celiac trunk. It initially travels in an anterior/inferior direction, passing behind/under the neck of the pancreas and the splenic vein. Located under this portion of the superior mesenteric artery, between it and the aorta, are the following:

• left renal vein - travels between the left kidney and the inferior vena cava (can be compressed by the SMA at this location, leading to Nutcracker Syndrome.
• the third part of the duodenum, a segment of the small intestines (can be compressed by the SMA at this location, leading to Superior Mesenteric Artery Syndrome).
• uncinate process of the pancreas - this is a small part of the pancreas that hooks around the SMA.

The SMA typically runs to the left of the similarly named vein, the superior mesenteric vein. After passing the neck of the pancreas it starts giving off its branches.

Branches

|- 
| inferior pancreaticoduodenal artery 

|- 
| middle colic artery 

|- 
| right colic artery 

|- 
| intestinal arteries 

|- 
| ileocolic artery

The middle, right, and ileocecal branches anastomose with each other to form a marginal artery along the inner border of the colon. This artery is completed by branches of the left colic which is a branch of the inferior mesenteric artery.

Pathology

• Compared to other vessels of similar size, the SMA is largely spared the effects of atherosclerosis. This is likely due to protective haemodynamic conditions
• Occlusion of the SMA almost invariably leads to intestinal ischemia and often has devastating consequences; up to 80% of SMA occlusions lead to death.^[1]
• The SMA can compress the left renal vein, leading to the nutcracker syndrome and/or the third (horizontal) part of the duodenum, leading to Wilkie's Syndrome (Superior Mesenteric Artery Syndrome).

Additional images

<gallery> Image:Gray533.png|The celiac artery and its branches; the stomach has been raised and the peritoneum removed. Image:Gray985.png|Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks. Image:Gray1121.png|Posterior abdominal wall, after removal of the peritoneum, showing kidneys, suprarenal capsules, and great vessels. Image:Gray1122.png|The anterior surfaces of the kidneys, showing the areas of contact of neighboring viscera. Image:Gray1227.png|Front of abdomen, showing surface markings for arteries and inguinal canal. </gallery>

References

1. ↑ Redaelli CA, Schilling MK, Buchler MW. Intraoperative laser Doppler flowmetry: a predictor of ischemic injury in acute mesenteric infarction. Dig Surg. 1998;15(1):55-9. PMID 9845564. Full Text.

External links

• - "Branches of the inferior mesenteric artery."
• - "Posterior Abdominal Wall: Branches of the Abdominal Aorta"
• - "Posterior Abdominal Wall, Dissection, Anterior View"

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