Definition:

Cloacal exstrophy is an extremely rare congenital complex deformity that is associated with anterior abdominal wall defects, reflex and exposure of the cloaca (uninterrupted ureter and bowel), aproctia, a widely separated pubic bone, and defects or dysplasia of external genital organs. Cloacal exstrophy is thought to be related to abnormal development of the cloacal membrane, a transitory structure composed of endoderm and ectoderm that overlies the embryonic cloaca. The result is primarily an abdominal wall defect with failed closure of the lower urinary tract. Cloacal exstrophy has also been referred to as the OEIS complex (omphalocele, exstrophy, imperforate anus and spinal defect), and other malformations of the urogenital, gastrointestinal, skeletal and neurospinal axis frequently coexist.