Table 2

‚ÄÉMontreal classification of extent of ulcerative colitis (UC)

ExtentAnatomy
E1Ulcerative proctitisInvolvement limited to the rectum (that is, proximal extent of inflammation is distal to the rectosigmoid junction)
E2Left sided UC (distal UC)Involvement limited to a proportion of the colorectum distal to the splenic flexure
E3Extensive UC (pancolitis)Involvement extends proximal to the splenic flexure