“…However, the inherent elasticity of the colon, variability in colonic anatomy, and the absence of fixed internal landmarks (at least until the ileocaecal valve can be reached and reliably identified) makes it difficult to localize the endoscope tipp accurately during insertion, even for experienced endoscopists [4 -7]. Incorrect localization of the endoscope tip is most frequently reported between the sigmoid colon and the splenic flexure [5,7], or between the transverse and right colon [4,6].Precise localization of lesions is imperative prior to surgery [5, 8 -10], particularly for nonpalpable cancers or sessile polyps. For these reasons, barium enema is sometimes used as an adjunctive technique for preoperative localization of lesions and for visualization of the proximal colon in cases in which colonoscopy is incomplete [5,6,8,11].…”