Congenital malformations of the anus and rectum are rather uncommon and are said to occur about once in every five thousand newly born babies. According to Allen,1 David2 and Gant,3 these deformities occur about once in every ten thousand births. A survey of the records at St. Mary's Hospital, which was opened in 1924, showed no anomalies of the anus and rectum until 1931, and from 1931 to the present time (1944) a total of 15 cases have been collected. During this period of twenty years, a total of 118,809 admissions were recorded, with 0.0013 per cent of the total admissions caused by the anomalies. Ladd and Gross,4 working at Children's Hospital in Boston, collected a total of 214 cases over a period of thirty-one years. Crowell and Dulin5 collected 28 cases over a period of twelve years at the University of Iowa Hospitals.
DMYTRYK ET. CONGENITAL MALFORMATIONS OF THE ANUS AND RECTUMA CLINICAL STUDY. Arch Surg. 1945;50(5):253-257. doi:10.1001/archsurg.1945.01230030262006