human anatomy Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross ...

, the superior mesenteric artery (SMA) is an

artery An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the

duodenum The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest p ...

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

pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...

Structure

Origin

In the adult, the SMA arises anterior to inferior border of vertebra L1 ( transpyloric plane). It is usually 1 cm lower than the celiac trunk.

Course and relations

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 In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

and the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...

(can be compressed between the SMA and the abdominal aorta at this location, leading to

nutcracker syndrome The nutcracker syndrome (NCS) results most commonly from the compression of the left renal vein (LRV) between the abdominal aorta (AA) and superior mesenteric artery (SMA), although other variants exist. The name derives from the fact that, in ...

). * the third part of the

, 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 its associated vein, the

superior mesenteric vein In human anatomy, the superior mesenteric vein (SMV) is a blood vessel that drains blood from the small intestine (jejunum and ileum). Behind the neck of the pancreas, the superior mesenteric vein combines with the splenic vein to form the portal ...

. After passing the neck of the pancreas it starts giving off its branches.

Branches

The number of arterial arcades in the ileum is more than the number of arcades in the jejunum. 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.

Clinical significance

* Compared to other vessels of similar size, the SMA is largely spared from the effects of

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

. This may be due to protective haemodynamic conditions. * Acute 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. * The SMA can compress the left renal vein, leading to

; and/or the third (horizontal) part of the

, leading to superior mesenteric artery syndrome.

Additional images

File:Volume rendered CT scan of abdominal and pelvic blood vessels (smaller).gif, Animated Volume rendered

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

of abdominal and pelvic blood vessels. File:Intestinal arteries.JPG, Superior mesenteric artery File:Slide10gre.JPG, Dissection showing the anatomical relationship between the superior mesenteric artery and surrounding structures

References

External links

* - "Branches of the inferior mesenteric artery." * - "Posterior Abdominal Wall: Branches of the Abdominal Aorta" * * * * * - "Posterior Abdominal Wall, Dissection, Anterior View" * {{Authority control Arteries of the abdomen