Basically, the resections of the colon should include either the lymphatic drainage area of the superior mesenteric vessels or that of the inferior mesenteric vessels. While this would approach the ideal, experience has shown that approximately four types of resections are commonly performed: right colectomy, left colectomy, anterior resection of the rectosigmoid, and abdominoperineal resection. For years lesions of the cecum, ascending colon, and hepatic flexure have been resected by a right colectomy with ligation of the ileocolic, right colic, and all or part of the middle colic vessels (A). Lesions in the cecal area may be associated with involved lymph glands along the ileocolic vessels. As a result, a segment of the terminal ileum is commonly resected along with the right colon. Lesions in the region of the splenic flexure are in the one area where left colectomy by a sleeve resection may be performed. Extensive resections can be carried out with good assurance of an adequate blood supply, since the marginal vessels are divided nearer their points of origin. In addition to the marginal vessels, the left colic artery near its point of origin and the inferior mesenteric vein are ligated even before manipulation of the tumor is carried out to minimize the venous spread of cancer cells. End-to-end anastomosis without tension can be accomplished by freeing the right colon of its peritoneal attachments and derotating the cecum back to its embryologic position on the left side. The blood supply is sustained through the middle colic vessels and the sigmoidal vessels. Although the veins tend to parallel the arteries, this is not the case with the inferior mesenteric vein. This vein courses to the left before it dips beneath the body of the pancreas to join the splenic vein (B).