Superior mesenteric artery Flashcards
what is the the superior mesenteric artery (SMA)?
a major artery of the abdomen
where does the SMA arise from?
abdominal aorta
what does the SMA supply?
supplies arterial blood to the organs of the midgut – which spans from the major duodenal papilla (of the duodenum) to the proximal 2/3 of the transverse colon
what is the superior mesenteric artery numbered in terms of branches and where from?
The superior mesenteric artery is the second of the three major anterior branches of the abdominal aorta
what are the 2 other branches of the abdominal aorta?
inferior mesenteric artery and coeliac trunk
where does the SMA arise from in terms of the abdominal aorta?
It arises anteriorly from the abdominal aorta at the level of the L1 vertebrae, immediately inferior to the origin of the coeliac trunk
what happens after the SMA has arose from the abdominal aorta?
the superior mesenteric artery descends down the posterior aspect of the abdomen
what is anterior to the SMA?
pyloric part of the stomach, splenic vein and neck of the pancreas
what is posterior to the SMA?
left renal vein, uncinate process of the pancreas and inferior part of the duodenum
what is the only part of the pancreas that hooks around the back of the SMA?
The uncinate process
what do the branches of the SMA supply?
the small intestines, cecum, ascending and part of the transverse colon
what are the branches of the SMA?
inferior pancreaticoduodenal artery
jejunal and ileal arteries
middle & right colic artery
ileocolic artery
what is the inferior pancreaticoduodenal artery?
The inferior pancreaticoduodenal artery is the first branch of the SMA
what does the inferior pancreaticoduodenal artery form?
anterior and posterior vessels
what do the anterior and posterior vessels of the inferior pancreaticoduodenal artery anastomose with?
branches of the superior pancreaticoduodenal artery
where is the superior pancreaticoduodenal artery derived from?
coeliac trunk
what does the network of the inferior pancreaticoduodenal artery and its anatomoses with superior pancreaticoduodenal artery supply?
supplies the inferior region of the head of the pancreas, the uncinate process, and the duodenum.
what does the superior mesenteric artery give rise to? what do they supply?
The superior mesenteric artery gives rise to numerous arteries that supply the jejunum and ileum
where do the arteries of the superior mesenteric artery pass between?
The arteries pass between the layers of the mesentery
what forms after the arteries of the superior mesenteric artery has passed between the layers of the mesentery?
anastomotic arcades
what arises from the anastomotic arcades and what do they supply?
smaller, straight arteries (known as the “vasa recta”) arise to supply the organs
what is the jejunal blood supply characterised by?
characterised by a smaller number of arterial arcades, but longer vasa recta
what is the ileal blood supply marked by in contrast?
the ileal blood supply is marked by more arterial arcades with shorter vasa recta
where do the right and middle colic arteries arise from?
the right side of the superior mesenteric artery
what does the middle colic artery supply?
transverse colon
what does the right colic artery supply?
ascending colon
what is the ileocolic artery in terms of branches of the superior mesenteric artery?
The ileocolic artery is the final major branch of the superior mesenteric artery. It passes inferiorly and to the right, giving rise to branches to the ascending colon, appendix, cecum, and ileum. In cases of appendectomy, the appendicular artery is ligated
where does the ileocolic artery pass? (direction)
It passes inferiorly and to the right
what does the ileocolic artery give rise to branches to?
giving rise to branches to the ascending colon, appendix, cecum, and ileum
what are causes of superior mesenteric artery occlusion?
thrombosis, embolism, abdominal aortic aneurysm and aortic dissection
what type of emergency is occlusion of the SMA?
acute
why is occlusion of the SMA acute?
occlusion of the SMA restricts blood flow to the midgut, resulting in intestinal ischaemia
what is occlusion of the SMA more common in?
elderly
how does occlusion of the SMA present with?
abdominal pain
what is the most useful investigation?
CT scan of the abdomen
what is treatment for the occlusion of the SMA?
surgery
