Congenital Anterior Displacement of Anus
Anterior displacement of the anus is a common malformation which is a forme fruste of imperforate anus. Most patients seen were girls and the age of presentation was most often prior to 5 years. Patients had a uniform history of constipation, often dating from birth, which had been treated medically without success. The referring diagnosis was often Hirschprung's disease. Some patients had encopresis. Physical examination often revealed an obvious anterior displacement, but in other patients it was more subtle, especially in males.
In girls, the posterior fourchette of the vagina could be used as a reference point. Reisner and his colleagues defined a simple measurement to permit accurate diagnosis. A strip of narrow adhesive tape is laid from the perineum to the coccyx, and the site of the posterior fourchette (or scrotal-perineal junction), the middle of the anus, and the inferior border of the coccyx are marked.
