title: Correct visualization of the anal ring.
authors.forename: S C
authors.initials: SC
authors.lastname: Thornton
authors.forename: S A
authors.initials: SA
authors.lastname: Hirshorn
authors.forename: M
authors.initials: M
authors.lastname: Bradway
authors.forename: D
authors.initials: D
authors.lastname: Levien
mesh_terms: D001003:Anal Canal / Q000473:pathology*; D001005:Anus Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity