human anatomy The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body. It comprises a hea ...

, the superior mesenteric artery (SMA) is an

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

which arises from the anterior surface of the

abdominal aorta In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax). Structure The abdominal aorta begins at the level of the diaphr ...

, just inferior to the origin of the

celiac trunk The celiac () artery (also spelled ''coeliac''), also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12) in ...

, and supplies blood to the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans an ...

from the lower part of the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...

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

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an ...

Structure

It arises anterior to lower border of vertebra L1 in an adult. It is usually 1 cm 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 The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

. 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 The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...

and the inferior vena cava (can be compressed between the SMA and the

at this location, leading to nutcracker syndrome). * 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 the similarly named 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 hepa ...

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

SMA 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 In human anatomy, the inferior mesenteric artery, often abbreviated as IMA, is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the a ...

Clinical relevance

* 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 in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...

. 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 nutcracker syndrome; 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 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