superior mesenteric artery
The superior mesenteric artery (SMA) is one of the three non-paired major visceral arteries in the abdominal cavity arising from the abdominal aorta and supplying the midgut.
Courses anteroinferiorly, behind the neck of the pancreas and splenic vein, crossing anterior to the left renal vein. It emerges anterior to the uncinate process of the pancreas and crosses anterior to the third part of the duodenum. It then enters the upper portion of the small bowel mesentery and runs along the root of the mesentery downwards to the right. Branches to the jejunum and ileum are given off to the left, and branches to the proximal and mid colon are given off to the right.
The superior mesenteric artery terminates at the ileum where it anastomoses with the ileal branch of the ileocolic artery. Some anatomists believe the ileocolic artery is the terminal portion of the SMA and that what many consider the terminal SMA is the last of the ileal branches.
Marginal artery of Drummond
The terminal branches of the superior mesenteric artery (ileocolic, right colic, middle colic) and inferior mesenteric artery (left colic, sigmoid) which supply the colon are linked together by a continuous arterial circle or arcade along the mesenteric border, known as the marginal artery of Drummond. This arcade is considered a normal structure, although may be absent in some people. It may supply collateral flow between the superior and inferior mesenteric artery circulations . From this marginal artery, straight vessels (also known as vasa recta) pass to the colon.
The superior mesenteric vein (SMV) should be positioned to the right of the SMA, especially the first 3 cm distal to its origin. Reversal of SMA/SMV relationship is classically associated with intestinal malrotation, although distally (>6 cm from origin) this may be a normal finding .
The superior mesenteric artery is the artery to the midgut. It supplies the gut from the ampulla of Vater of the 2 part of the duodenum to the distal third of the transverse colon, and includes structures in between such as :
- ascending colon
- hepatic flexure
- proximal 2/3rd of the transverse colon
The inferior pancreaticoduodenal artery also supplies the head of the pancreas.
- replaced right hepatic artery (10-17%)
- replaced left hepatic artery (2-4%)
- replaced common hepatic artery (1-3%)
- accessory right hepatic artery
- celiacomesenteric trunk (uncommon)
- replaced splenic artery
- replaced left gastric artery
- replaced dorsal pancreatic artery
- arc of Buhler
- arc of Riolan