superior mesenteric artery
Summary
The superior mesenteric artery (SMA) is a major unpaired branch of the abdominal aorta that supplies blood to the midgut derivatives, including the small intestine (except proximal duodenum) and proximal large intestine up to the splenic flexure. SMA syndrome occurs when the third part of the duodenum is compressed between the SMA and aorta.
Detail
The superior mesenteric artery arises from the anterior aspect of the abdominal aorta at the L1 vertebral level, approximately 1-2 cm below the celiac trunk. It supplies the embryological midgut structures through several branches: jejunal and ileal arteries (via arcades and vasa recta), ileocolic artery (terminal ileum, cecum, appendix), right colic artery (ascending colon), and middle colic artery (transverse colon up to splenic flexure). The SMA forms important anastomoses with the celiac trunk via the pancreaticoduodenal arteries and with the inferior mesenteric artery via the marginal artery of Drummond. Clinically significant conditions include SMA syndrome (duodenal compression causing obstruction), mesenteric ischemia (acute or chronic), and SMA embolism/thrombosis leading to bowel necrosis. The artery's anatomical relationship is crucial during surgical procedures, as it passes over the third part of the duodenum and behind the neck of the pancreas.
Sources
- Gray's Anatomy
- Netter's Atlas of Human Anatomy
- First Aid for the USMLE Step 1
- Moore's Clinically Oriented Anatomy
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