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In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The regions supplied by the IMA are the descending colon, the sigmoid colon, and part of the rectum. [1]
The left colic artery is a branch of the inferior mesenteric artery distributed to the descending colon, and left part of the transverse colon.It ends by dividing into an ascending branch and a descending branch; [1] the terminal branches of the two branches go on to form anastomoses with the middle colic artery, and a sigmoid artery (respectively).
The sigmoid arteries are 2–5 branches of the inferior mesenteric artery that are distributed to the distal descending colon and the sigmoid colon. [1] Anatomy
From this first set of arches branches arise, which unite with similar branches from above and below and thus a second series of arches is formed; from the lower branches of the artery, a third, a fourth, or even a fifth series of arches may be formed, diminishing in size the nearer they approach the intestine.
The term mesenteric artery is also used to describe smaller branches of these vessels which, particularly in smaller animals, provide a significant source of vascular resistance. These branches have a dense innervation by sympathetic nerves, allowing the brain to control their diameter and hence the resistance to blood flow to the gut.
The Arc of Riolan (Riolan's arcade, Arch of Riolan, Haller's anastomosis), also known as the meandering mesenteric artery, is another vascular arcade present in the colonic mesentery that connect the proximal middle colic artery with a branch of the left colic artery. This artery is found low in the mesentery, near the root.
The organ of Zuckerkandl is a chromaffin body derived from the neural crest located at the bifurcation of the aorta or at the origin of the inferior mesenteric artery. It can be the source of a paraganglioma. [1]
The left colic flexure or splenic flexure (as it is close to the spleen) is the sharp bend between the transverse colon and the descending colon.The splenic flexure receives dual blood supply from the terminal branches of the superior mesenteric artery and the inferior mesenteric artery.