The rectum may be deficient from the superior third of the sacrum, and in this position is quite inaccessible for operation.
A compensatory coalition of the bowel with the bladder or urethra is sometimes present, and in these cases the feces are voided by the urinary passages.

Huxham mentions the fusion of the rectum and colon with the bladder, and similar instances are reported by Dumas and Baillie.

Zacutus Lusitanus describes an infant with an imperforate membrane over its anus who voided feces through the urethra for three months.

After puncture of the membrane, the discharge came through the natural passage and the child lived; Morgagni mentions a somewhat similar case in a little girl living in Bologna, and other modern instances have been reported.

The rectum may terminate in the vagina.
Masters has seen a child who lived nine days in whom the sigmoid flexure of the colon terminated in the fundus of the bladder.