6 FRANKLIN PARADISE JOHNSON 



Plicae transversales recti 



Although the plicae transversales recti (valves of Houston), 

 which are found in the ampulla recti, have attracted a great deal 

 of attention from many anatomists, only a brief reference to the 

 literature regarding them need be made in this paper. Most 

 anatomists agree that Houston, after whom the plicae were named, 

 was the first to describe them adequately. The name Kohlrausch, 

 however, is often used in connection with the lower of these folds. 



Baur ('60) made a careful study of the plicae and found that 

 three are usually present. He also found indications of them in 

 embryos of three, three to four, and four to five months, and at 

 birth. 



Vance (78) describes these folds in a number of adult subjects 

 and emphasizes particularly the spiral arrangement of some of 

 them. He asks: ''Is it not reasonable to suppose that both 

 spiral folds and independent valves exist in the human rectum as 

 rudiments, and that, when present in that organ, they must be 

 looked upon as illustrations of the law of reversion?" In just 

 what manner they are to be regarded as illustrations of this law, 

 Vance does not state. 



Otis ('87) finds the rectal plicae constantly present and states 

 that there are either two or three of them, two of which are con- 

 stant in position, and one of which is variable. 



Pennington ('00) attaches particular importance to the folds 

 from a clinical point of view, stating that they are often the cause 

 of constipation. In describing their histological structure he 

 states that some are composed of the mucosa and the submucosa 

 alone, some have the circular muscle coat involved, while still 

 others have a part or the whole of the longitudinal muscle coat. 



Rectal columns, sinuses and valves 



The longitudinal folds at the lower extremity of the rectum 

 known as the column ae recti (columns of Morgagni) vary not only 

 in size and number, but also in position. This conclusion is 

 based not only upon the specimens I have myself examined, but 

 upon the widelj^ varying descriptions found in literature. Thus 



