Superior mesenteric artery

Artery: Superior mesenteric artery
Frontal view of the superior mesenteric artery and its branches. The large vessel (blue) beside the SMA is the superior mesenteric vein. A considerable number of different branching patterns exist.
3D-rendered computed tomography of abdominal aortic branches, showing exit of superior mesenteric artery between the kidneys.
Latin	arteria mesenterica superior
Gray's	subject #154 606
Supplies	intestine
Source	abdominal aorta
Branches	inferior pancreaticoduodenal middle colic right colic intestinal branches (jejunal, ileal) ileocolic
Vein	superior mesenteric vein
Precursor	vitelline arteries
MeSH	Mesenteric+Artery,+Superior

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 through two-thirds of the transverse colon, as well as 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 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

Branch	Supplies
inferior pancreaticoduodenal artery	head of the pancreas and to the ascending and inferior parts of the duodenum
middle colic artery	to the transverse colon
right colic artery	to ascending colon
intestinal arteries	branches to ileum, branches to jejunum
ileocolic artery	(terminal branch of the SMA) supplies last part of ileum, cecum, and appendix

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.

Pathophysiology

• Compared to other vessels of similar size, the SMA is largely spared from the effects of atherosclerosis. This may be due to protective haemodynamic conditions.^{[citation needed]}
• Occlusion of the SMA almost invariably leads to intestinal ischemia and often has devastating consequences, with up to 80% of SMA occlusions leading to death.^[1]
• The SMA can compress the left renal vein, leading to nutcracker syndrome; and/or the third (horizontal) part of the duodenum, leading to superior mesenteric artery syndrome.

Additional images

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  The pancreas and duodenum from behind. (Superior mesenteric artery labeled at upper right.)

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  The celiac artery and its branches; the stomach has been raised and the peritoneum removed.

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  Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks.

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  Posterior abdominal wall, after removal of the peritoneum, showing kidneys, suprarenal capsules, and great vessels.

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  The anterior surfaces of the kidneys, showing the areas of contact of neighboring viscera.

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  Front of abdomen, showing surface markings for arteries and inguinal canal.

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  Arteries and veins around the pancreas and spleen.

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  Colonic blood supply Hussam

References

1. ^ Redaelli CA, Schilling MK, Büchler MW (1998). "Intraoperative laser Doppler flowmetry: a predictor of ischemic injury in acute mesenteric infarction". Digestive surgery 15 (1): 55–9. doi:10.1159/000018587. ISSN 0253-4886. PMID 9845564. 

External links

• SUNY Figs 39:02-01 - "Branches of the inferior mesenteric artery."
• SUNY Labs 40:11-0102 - "Posterior Abdominal Wall: Branches of the Abdominal Aorta"
• SUNY Anatomy Image 8008
• SUNY Anatomy Image 8404
• SUNY Anatomy Image 8815
• SUNY Anatomy Image 8841
• Atlas of anatomy at UMich abdo_wall70 - "Posterior Abdominal Wall, Dissection, Anterior View"
• sup&infmesentericart at The Anatomy Lesson by Wesley Norman (Georgetown University)