Sigmoid arteries
Branch
Two to four branches descending obliquely in the sigmoid mesocolon, forming arcades that join the left colic above but connect only weakly, if at all, with the superior rectal below.
Traced from the start
- Abdominal aorta
- Inferior mesenteric artery
- Sigmoid arteries
Detail
- Supplies
- Sigmoid colon and lowest descending colon
- Number
- 2–4
- Weak link
- Last sigmoid artery ↔ superior rectal (Sudeck's point at the rectosigmoid)
When it goes wrong
Vasa recta stretched thin over the dome of a colonic diverticulum
Painless, brisk, bright-red rectal bleeding that usually stops spontaneously — commonest cause of major lower GI bleeding in the elderly
Long sigmoid mesocolon twists on its vascular pedicle (elderly, constipated, institutionalised)
Sigmoid volvulus: closed-loop obstruction with 'coffee-bean' distension; venous then arterial occlusion → gangrene unless decompressed
Practise this structure
1 question in the bank tagged Large Bowel.