Overview
Branch of the abdominal aorta supplying structures derived from embryological hindgut, i.e. the distal third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum.
- The foregut extends from the mouth to the major duodenal papilla (where the ampulla of Vater empties into the duodenum).
- The midgut extends from this point to the proximal two thirds of the way along the transverse colon.
- The hindgut runs from the distal third of the transverse colon to the dentate line of the anal canal
Origin
Anterior branch of the abdominal aorta at L3, just inferior to the gonadal arteries (testicular arteries) and the inferior border of the duodenum
Course
- Descends anterior to the abdominal aorta, passing toward the left retroperitoneally
- Crosses left common iliac vessels to enter sigmoid mesocolon
Termination
Terminates as superior rectal artery in the pelvis to supply the upper rectum
Branches
- Left colic artery – travels retroperitoneally, anterior to the psoas major muscle, left ureter and left internal spermatic vessels before dividing in two:
- Ascending branch – passes anterior to left kidney, passing superior to enter transverse mesocolon and anastomoses with the middle colic artery. It supplies the distal third of transverse colon and upper part of descending colon
- Descending branch – passes inferiorly, supplying lower part of descending colon, anastomoses with first sigmoid artery
- Sigmoid arteries (2-4 branches) – descend to the left within sigmoid mesocolon, supplies lower parts of descending colon and sigmoid colon. The sigmoid arteries anastomose superiorly with left colic artery, and inferiorly with superior rectal artery
- Superior rectal artery – terminal branch, descends into pelvic cavity in sigmoid mesocolon, crosses left common iliac arterial and vein, medial to the ureter near the apex of sigmoid mesocolon. It divides at level S3 into left and right superior rectal arteries which descend on either side of rectum to supply it. It anastomoses with middle rectal (branch of the anterior division of internal iliac artery) and inferior rectal arteries (branch of internal pudendal artery, another branch of the anterior division of internal iliac artery)
- Marginal artery of Drummond– The terminal branches of the superior mesenteric artery (middle colic, right colic and ileocolic arteries) and inferior mesenteric artery (left colic and sigmoid arteries) anastomose to form a continous arterial circle (arcade) that runs along the mesenteric border. It may supply collateral flow between the superior and inferior mesenteric artery circulations. From this marginal artery, straight vessels (also known as vasa recta) pass to the colon.
Anatomical Variants
- Double inferior mesenteric artery
- Absent inferior mesenteric artery
- Common trunks of left colic and rectosigmoid
- Absent left colic
- Arc of Riolan (mesenteric meandering artery of Moskowitz or central anastomotic mesenteric artery) – inconstant arterioarterial anastomosis between the superior and inferior mesenteric arteries.