Fig. 4.
1, The dotted lines indicate the normal direction of the anus and rectum; 2, 4, the cavities or pouch formed by dilatation or ballooning from the storage of impacted feces; 3, a probe bent at right angles, and introduced through a speculum, to ascertain the depth of the pouch, which is frequently found to be two and a half inches.
In not a few cases where dilatation of the rectum exists, the upper half or more of the anal canal is also dilated, leaving an anal canal only an eighth of an inch in length in some cases; in other cases, perhaps half an inch to an inch.
Similar dilatation of the sigmoid flexure occurs as the result of the severe contraction of the upper half of the rectum, and especially at the bend shown by Fig. [6] and Fig. [12]. This bend forms quite a sphincter for the normal receptacle—the sigmoid flexure. Here also prolapse, distention, and dislocation of the sigmoid flexure may occur, somewhat similar to the anal prolapse from disease and abuse.
Piles and itching of the anus are symptoms of proctitis, or inflammation of the anus and rectum. Why should we find such dissimilar symptoms proceeding from the same cause? The reason is plain when we consider the results following chronic inflammation of the mucous membrane of the anus and rectum and the deeper tissues. Those who suffer from catarrh of this membrane are familiar with the discharge of mucus that appears from time to time during the progress of the inflammation. But, as the inflammation penetrates the mucous membrane and the underlying tissues of the anus and rectum, the escape of the inflammatory product is prevented; and this imprisoned fluid must either be absorbed by the system or retained in reservoirs or in channels wherever the least resistance is offered to its invasion.
The mucous membrane of the anus and rectum is loosely attached to the subjacent parts by areolar tissue (Fig. [1], 3–3), which is sufficiently lax to allow an expansion of two inches; and in a puckered or contracted state the membrane is thrown into folds, or into shallow or deep wrinkles. The loose areolar attachment and folds of various depths afford space for lodgment of the inflammatory discharge, which channels its way down along the folds through the areolar tissue under the mucous membrane to that of the integument, and so on for a distance of a foot or more from the anus in some cases.