Superior rectal artery
Sub-branch · Continues IMA Above pectinate line
Direct continuation of the IMA after the last sigmoid branch, crossing the left common iliac vessels into the sigmoid mesocolon and descending to divide behind the rectum. Supplies the rectum and anal canal above the pectinate line and anastomoses with the middle rectal (internal iliac) and inferior rectal (internal pudendal) arteries.
Traced from the start
- Abdominal aorta
- Inferior mesenteric artery
- Superior rectal artery
Detail
- Supplies
- Rectum and anal canal above the pectinate line
- Anastomoses
- Middle rectal and inferior rectal arteries
- Companion vein
- Superior rectal vein drains to the IMV and portal system; middle and inferior rectal veins drain to the systemic circulation
When it goes wrong
Weak marginal anastomosis at the rectosigmoid (Sudeck's point, between the last sigmoid artery and the superior rectal)
Second watershed zone for ischaemic colitis; the rectum itself is spared because of its dual internal iliac supply
High ligation of the IMA in anterior resection
Rectal stump and colon rely on middle rectal and marginal flow; poor collaterals lead to an ischaemic anastomotic leak
Portal hypertension distending the superior rectal vein
Anorectal varices at the portosystemic anastomosis, distinct from haemorrhoids
Practise this structure
1 question in the bank tagged Hindgut.