Sigmoid arteries
Arteriae sigmoideae
A small group of branches of the inferior mesenteric artery that run in the sigmoid mesocolon to supply the lower descending and sigmoid colon.
At a glance
- English
- Sigmoid arteries
- Latin (TA2)
- Arteriae sigmoideae
- System
- Artery
- Region
- Trunk
- Side
- Single, on the midline
About the sigmoid arteries
The sigmoid arteries arise from the inferior mesenteric artery, the artery of the hindgut, below its left colic branch. There are usually two or three, sometimes up to four, and they may leave the parent separately or from a short common trunk. They come off as the inferior mesenteric artery descends on the left side of the posterior abdominal wall, before it crosses the pelvic brim as the superior rectal artery.
They run obliquely downwards and to the left, at first behind the peritoneum of the posterior abdominal wall and then within the sigmoid mesocolon. On the way they cross in front of psoas major, the left ureter and the left gonadal vessels. In the root of the mesocolon they lie near the intersigmoid recess, a small pocket of peritoneum that is a useful guide to the ureter behind it.
Near the bowel each artery divides into branches that join their neighbours, forming a chain of arcades. The highest sigmoid artery joins the descending branch of the left colic artery above, and the lowest joins the superior rectal artery below. These arcades are part of the marginal artery of the colon, and from them short straight vessels pass into the wall of the lower descending colon and the sigmoid colon. The link between the lowest sigmoid artery and the superior rectal artery is often weak, a point sometimes called Sudeck's point.
The sigmoid arteries are divided in a sigmoid colectomy, for example for cancer, for diverticular disease or after a twist of the sigmoid loop (volvulus), and in operations that remove the rectum. Because the sigmoid colon is mobile on its mesentery, the vessels can be stretched or kinked when it twists, cutting off its supply. Surgeons find and protect the left ureter, which lies just behind these vessels, before dividing them.
Course and supply
- Arises from
- Arise from the inferior mesenteric artery below the left colic artery, separately or by a common trunk.
- Ends in
- End in arcades in the sigmoid mesocolon that join the left colic artery above and the superior rectal artery below.
- Supplies
- Supply the lower descending colon and the sigmoid colon.
Anthromica
See the sigmoid arteries where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
