Superior mesenteric artery
Encyclopedia
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
.
. Located under this portion of the superior mesenteric artery, between it and the aorta, are the following:
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.
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
.
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...
, the superior mesenteric artery (SMA) arises from the anterior surface of the abdominal aorta
Abdominal aorta
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 .-Path:...
, just inferior to the origin of the celiac trunk
Celiac artery
The celiac artery, also known as the celiac trunk, is the first major branch of the abdominal aorta. Branching from the aorta anterior to the upper border of L1 vertebra in humans, it is one of three anterior/ midline branches of the abdominal aorta The celiac (or coeliac) artery, also known as...
, and supplies the intestine
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
from the lower part of the duodenum
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 may be used instead of duodenum...
through two-thirds of the transverse colon
Transverse colon
The transverse colon, the longest and most movable part of the colon, passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath...
, as well as the pancreas
Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
.
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 veinSplenic vein
In anatomy, the splenic vein is the blood vessel that drains blood from the spleen.It joins with the superior mesenteric vein, to form the hepatic portal vein and follows a course superior to the pancreas, alongside of the similarly named artery, the splenic artery.It collects branches from the...
. Located under this portion of the superior mesenteric artery, between it and the aorta, are the following:
- left renal veinRenal veinThe renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava.It is usually singular to each kidney, except in the condition "multiple renal veins".It also divides into 2 divisions upon entering the kidney:...
- travels between the left kidneyKidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
and the inferior vena cavaInferior vena cavaThe inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....
(can be compressed by the SMA at this location, leading to Nutcracker SyndromeNutcracker syndromeIn medicine, the nutcracker syndrome — is a clinically manifest variant of nutcracker phenomenon, renal vein entrapment syndrome, or mesoaortic compression of the left renal vein. It results most commonly from the compression of the left renal vein between the abdominal aorta and superior...
). - the third part of the duodenumDuodenumThe 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 may be used instead of duodenum...
, a segment of the small intestines (can be compressed by the SMA at this location, leading to Superior Mesenteric Artery SyndromeSuperior mesenteric artery syndromeSuperior mesenteric artery syndrome is a very rare, life-threatening gastro-vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta and the overlying superior mesenteric artery...
). - uncinate process of pancreasUncinate process of pancreasIn the head of the pancreas, the angle of junction of the lower and left lateral borders forms a prolongation, termed the uncinate process.During the embryonic development of the distal foregut, the duodenum c-shape is formed while rotating the ventral pancreatic bud into the dorsal bud. The dorsal...
- 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
Superior mesenteric vein
In anatomy, the superior mesenteric vein is a blood vessel that drains blood from the small intestine . At its termination behind the neck of the pancreas, the SMV combines with the splenic vein to form the hepatic portal vein...
. After passing the neck of the pancreas it starts giving off its branches.
Branches
| Branch | Supplies >- | inferior pancreaticoduodenal artery Inferior pancreaticoduodenal artery The inferior pancreaticoduodenal artery is a branch of the superior mesenteric artery or from its first intestinal branch, opposite the upper border of the inferior part of the duodenum.... |
pancreas Pancreas The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist... and to the ascending and inferior parts of the duodenum 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 may be used instead of duodenum... >- | middle colic artery Middle colic artery The middle colic artery is a branch of the superior mesenteric artery that mostly supplies the transverse colon. It arises just below the pancreas, and, passing downward and forward between the layers of the transverse mesocolon, divides into two branches: right and left.* The right branch... |
>- | >- | ileum Ileum The ileum is the final 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 posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum... , branches to jejunum Jejunum The jejunum is the middle 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 middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum... >- | ileocolic artery Ileocolic artery The ileocolic artery is the lowest branch arising from the concavity of the superior mesenteric artery.It passes downward and to the right behind the peritoneum toward the right iliac fossa, where it divides into a superior and an inferior branch; the inferior anastomoses with the end of the... |
(terminal branch of the SMA) supplies last part of ileum, cecum Cecum The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic... , and appendix Vermiform appendix The appendix is a blind-ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouchlike structure of the colon... |
The middle, right, and ileocecal branches anastomose with each other to form a marginal artery
Marginal artery of the colon
In human anatomy, the marginal artery of the colon, also known as the marginal artery of Drummond and artery of Drummond , is a blood vessel that anastomoses the inferior mesenteric artery with the superior mesenteric 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
Inferior mesenteric artery
In human anatomy, the inferior mesenteric artery, often abbreviated as IMA, supplies the large intestine from the left colic flexure to the upper part of the rectum, which includes the descending colon, the sigmoid colon, and part of the rectum...
.
Pathophysiology
- Compared to other vessels of similar size, the SMA is largely spared from the effects of atherosclerosisAtherosclerosisAtherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
. This may be due to protective haemodynamic conditions. - Occlusion of the SMA almost invariably leads to intestinal ischemiaIschemic colitisIschemic colitis is a medical condition in which inflammation and injury of the large intestine result from inadequate blood supply. Although uncommon in the general population, ischemic colitis occurs with greater frequency in the elderly, and is the most common form of bowel ischemia...
and often has devastating consequences, with up to 80% of SMA occlusions leading to death. - The SMA can compress the left renal veinRenal veinThe renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava.It is usually singular to each kidney, except in the condition "multiple renal veins".It also divides into 2 divisions upon entering the kidney:...
, leading to nutcracker syndromeNutcracker syndromeIn medicine, the nutcracker syndrome — is a clinically manifest variant of nutcracker phenomenon, renal vein entrapment syndrome, or mesoaortic compression of the left renal vein. It results most commonly from the compression of the left renal vein between the abdominal aorta and superior...
; and/or the third (horizontal) part of the duodenumDuodenumThe 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 may be used instead of duodenum...
, leading to superior mesenteric artery syndromeSuperior mesenteric artery syndromeSuperior mesenteric artery syndrome is a very rare, life-threatening gastro-vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta and the overlying superior mesenteric artery...
.