Gut blood supply
28 named structures.
Draft — not yet clinically reviewed. The structure of this map is checked automatically, but its wording has not been fact-checked against a textbook. Do not rely on it for an exam answer yet.
Hover or tab a structure to trace what it connects to. Some structures reveal further branches.
Clinical detail
- Abdominal aortaT12 L1 L3Atherosclerotic stenosis or occlusion of at least two of the three trunks (single-vessel disease is common and silent)1 question
- Coeliac trunkForegut T5–T9Median arcuate ligament of the diaphragm crosses and compresses the coeliac origin1 question
- Superior mesenteric arteryMidgut T10–T11Cardiac embolus (AF, recent MI, valve disease) lodges a few centimetres beyond the origin, distal to the middle colic take-off1 question
- Inferior mesenteric arteryHindgut T12–L2IMA ligated at open AAA repair, covered by an endograft, or occluded by atheroma1 question
- Left gastric arteryChronic gastric ulcer on the lesser curvature erodes the artery1 question
- Splenic arterySplenic artery aneurysm — commonest visceral aneurysm; multiparous women, portal hypertension, fibromuscular dysplasia1 question
- Common hepatic arteryPosterior duodenal bulb ulcer erodes the gastroduodenal artery running behind D11 question
- Inferior pancreaticoduodenal arteryCoeliac trunk stenosis or median arcuate ligament compression1 question
- Jejunal and ileal arteriesAdhesive band or volvulus twists the mesentery around its pedicle1 question
- Ileocolic arteryDistended, inflamed appendix compresses and thromboses its end artery1 question
- Right colic arteryRetroperitoneal course crosses the right ureter and gonadal vessels1 question
- Middle colic arterySMA embolus lodges just beyond the middle colic origin1 question
- Left colic arteryAscending branch fails to meet the middle colic — marginal artery deficient or absent at the flexure in up to ~18%1 question
- Sigmoid arteriesVasa recta stretched thin over the dome of a colonic diverticulum1 question
- Superior rectal arteryStraining, pregnancy or portal hypertension engorge the anal cushions fed by the terminal branches1 question
- Marginal artery of DrummondHypotension, cardiac failure, dialysis, vasopressors or cocaine reduce flow through the arcade's narrowest segments1 question
- Stomach and abdominal oesophagusForegut T5–T9Any single gastric artery ligated2 questions
- Liver, gallbladder and bile ductsForegut T5–T9Acute cholecystitis: visceral afferents (T5–T9) first, then parietal peritoneal inflammation1 question
- SpleenLUQ / L shoulderEmboli (AF, endocarditis), sickle cell disease or myeloproliferative disorders occlude segmental end-arteries
- Duodenum and pancreasForegut Midgut T5–T9Acute pancreatitis (gallstones, alcohol)1 question
- Jejunum and ileumMidgut T10–T11Acute SMA occlusion — embolus from AF, recent MI or valve disease1 question
- Caecum and appendixMidgut T10Luminal obstruction (faecolith, lymphoid hyperplasia) → distension → appendicular artery thrombosis1 question
- Ascending colonMidgut T10–T11Carcinoma of the caecum or ascending colon (wide lumen, liquid contents)1 question
- Transverse colonMidgut HindgutTumour on one side or the other of the SMA/IMA boundary1 question
- Splenic flexure (watershed)Midgut HindgutSystemic hypotension, cardiac failure, dialysis, vasopressors, cocaine or aortic surgery in an elderly arteriopath1 question
- Descending colonHindgut T12–L2Left-sided colon cancer (narrow lumen, formed stool)1 question
- Sigmoid colonHindgut T12–L2IMA ligated at open AAA repair or covered by an endograft with a poor marginal artery1 question
- Rectum and upper anal canalHindgutEngorgement of the anal cushions above the pectinate line1 question
Common questions
At which vertebral levels do the three unpaired gut arteries leave the aorta?
Coeliac trunk at T12 (just below the median arcuate ligament), superior mesenteric artery at L1 (behind the neck of the pancreas) and inferior mesenteric artery at L3 (about 3–4 cm above the L4 bifurcation).
Where is pain from each gut segment felt and why?
Visceral afferents run back with the sympathetic supply of the same embryonic segment. Foregut pain (coeliac territory) enters at T5–T9 via the greater splanchnic nerve and is felt in the epigastrium; midgut pain (SMA) enters at T10–T11 via the lesser splanchnic nerve and is felt around the umbilicus; hindgut pain (IMA) enters at T12–L2 via the least and lumbar splanchnic nerves and is felt in the suprapubic region. Pain localises to the organ only when the parietal peritoneum becomes involved, which is why appendicitis migrates from the umbilicus to the right iliac fossa.
Why is the splenic flexure the commonest site of ischaemic colitis?
It is the junction between the last SMA branch (left branch of the middle colic) and the first IMA branch (ascending left colic). The marginal artery of Drummond is at its thinnest here — Griffiths' point — and is deficient or absent in up to about 18% of people, so any fall in perfusion pressure (shock, cardiac failure, dialysis, aortic surgery) starves this segment first. The rectosigmoid junction (Sudeck's point) is the second watershed.
How does an SMA embolus differ from SMA thrombosis on the ground?
An embolus (usually from atrial fibrillation) lodges a few centimetres beyond the origin, just distal to the middle colic take-off, so the proximal jejunum and transverse colon are spared. Atherosclerotic thrombosis occurs at the origin itself and takes the whole midgut, including the proximal jejunum, caecum and ascending colon, and is usually preceded by weeks of postprandial pain and weight loss.
Why does the rectum survive when the IMA is occluded?
The superior rectal artery (IMA) anastomoses in the submucosa with the middle rectal artery from the internal iliac and the inferior rectal artery from the internal pudendal. This systemic supply keeps the rectum perfused, which is why ischaemic colitis stops at the rectosigmoid and rectal sparing on endoscopy helps distinguish it from ulcerative colitis.
Which ulcer bleeds from which artery?
A posterior duodenal bulb ulcer erodes the gastroduodenal artery (branch of the common hepatic) and gives the most dangerous peptic ulcer haemorrhage. A lesser-curvature gastric ulcer erodes the left gastric artery. Both are foregut and both present with epigastric pain and haematemesis or melaena.