Imperforate anus can be defined as the defect of the development of the lowest portion of intestinal and urogenital tracts. Imperforate anus is a result of cloacal membrane imperforation. Anus and rectum develop from dorsal portion of the hindgut by forming urorectal septum which separates rectum and anal canal from bladder and urethra. It is believed to complete by the 7th week of gestation. The anus develops from anal tubercles and proctodeum, the external invagination which communicates with proximal parts after disintegration of anal membrane at 8th weeks’ gestation. The cause and genetic background for abnormal development is not fully elucidated, and no definite risk factors are known. As a result, rectum opens in abnormal locations in the perineum or female genitals. Stenosis, occlusive membranes, or agenesis of rectum and anal canal ensue with or without fistulas in perineal skin, urethra, prostate, bladder, vulva, or vagina.
References and Further Reading
- Fenoglio-Preiser, C., et al. (1999). Gastrointestinal pathology plus: An atlas and text. Philadelphia: Lippincott Williams & Wilkins.Google Scholar
- Rosen, N. G., & Cuffari, C. (2012). Pediatric imperforate anus. In Medscape reference drugs, diseases & procedures. www.emedicine.medscape.com/article/929904-clinical.