Complete absence of the anus and the lower end of the rectal pouch may be so marked that scarcely a dimple indicates the point where the anus should be found. In these cases the external sphincter may or may not be present, while the rectal pouch may present loosely in the pelvis, or be defective, or attached to some portion of the abdominal wall, the intervening space being filled with indifferent tissue. The fact that there appears to be a slight anal depression is to be taken for nothing more than an indication of what should be found, and signifies nothing regarding the deeper condition.
A somewhat mitigated expression of this last defect is seen when the anus is normal, with a more or less complete sphincter, but where a distinct partition separates this pouch from the rectum above. This, again, may vary considerably in thickness. If, then, fluctuation be detected the condition may prove less unfavorable for the little patient, since at this point communication may be easily established. Too often, however, this diaphragm is dense and tough. When successfully perforated, like the hymen, it may allow a slow dribbling of material, and will require constant attention and dilatation. [Figs. 590] and [591] portray these conditions in some of their expressions.
Fig. 590
Rectum ending in a blind pouch. (Kelsey.)
Fig. 591
Rectum ending in pouch; anus normal. (Kelsey.)
The anus itself is by no means a fixed anatomical opening, and its position may vary considerably. It may be found anywhere along the middle line of the perineum or even in the sacral region.
Another variety of complication is, with the conditions represented as above, a practically imperforate anus or rectum which nevertheless opens into one of the other pelvic cavities—the vagina, the bladder, or the urethra. In female infants an opening into the vagina may be of a size sufficient to serve its purpose, even throughout life. This condition has occurred in ignorant women who became wives and mothers, and were never conscious of anything abnormal. When the rectum communicates with the urinary passages meconium will escape with the urine. When the opening is in the urethra it is not so serious, and patients live to adult life, whereas when the bladder is thus involved the ureters will become infected and the patient eventually dies of a terminal infection of the kidney.