The inferior mesenteric artery gives off a left colic artery, sigmoidal branches, and the superior rectal artery as its terminal branch. The rectum also receives blood from the middle rectal arteries off the internal iliacs, and a minor supply from the inferior rectal (hemorrhoidal) branches of the internal pudendal arteries. The left colic has a variable connection to the middle colic along the marginal artery (of Drummond; see lower GI bleed).
To do a safe resection of this lesion, it was felt that the inferior mesenteric artery should be taken close to its origin. An enlarged lymph node was visualized at this location and was included with the specimen.
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