[TA] the three or four crescentic folds placed horizontally in the rectal mucous membrane; the superior rectal fold is situated near the beginning of the rectum on the left side; the middle rectal fold (Houston or Kohlrausch fold) is most prominent and consistent and projects from the right side about 8 cm above the anus (approximately the level of the floor of the rectouterine or rectovesical pouch); the inferior rectal fold is on the left side about 5 cm above the anus. SYN: plicae transversae recti [TA], Houston folds, Kohlrausch folds, plicae recti, rectal folds, rectal valves.
