Although the term rectum means straight, these transverse folds overlap each other during the empty state of the intestine to such an extent that, as Houston remarked, they require considerable maneuvering to conduct an instrument along the canal, as often occurs in sigmoidoscopy and colonoscopy.

Transverse folds were first described by Irish anatomist John Houston, curator of the Royal College of Surgeons in Ireland Museum, in 1830.

They appear to be peculiar to human physiology: Baur (1863) looked for Houston's valves in a number of mammals, including wolf, bear, rhinoceros, and several Old World primates, but found no evidence.

They are formed very early during human development, and may be visible in embryos of as little as 55 mm in length (10 weeks of gestational age.

)[1] This article incorporates text in the public domain from page 1183 of the 20th edition of Gray's Anatomy (1918)