Superior rectal artery
Branch
Direct continuation of the IMA, crossing the left common iliac vessels into the sigmoid mesocolon and dividing into two branches that descend either side of the rectum to the anal columns. Anastomoses in the submucosa 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 down to the pectinate line
- Anastomoses
- Middle rectal (internal iliac), inferior rectal (internal pudendal)
- Terminal branches
- Feed the anal cushions at 3, 7 and 11 o'clock
- Companion vein
- Superior rectal vein → IMV → portal system; middle and inferior rectal veins are systemic
When it goes wrong
Straining, pregnancy or portal hypertension engorge the anal cushions fed by the terminal branches
Internal haemorrhoids at 3, 7 and 11 o'clock in the lithotomy position; painless bright-red bleeding; treated by banding or haemorrhoidal artery ligation/embolisation
IMA occluded or ligated
Rectum is rescued by internal iliac collaterals, so ischaemic colitis stops at the rectosigmoid and the rectum is spared
Practise this structure
1 question in the bank tagged Hindgut.