ABSTRACT
Incomplete closure of the lateral body folds may also be partially responsible for omphalocele; more typically, failure of the bowel to return to the abdomen after the normal herniation into the cord between the 8th and 12th weeks of gestation is held to be responsible (Figs. 1-3) (15). Gastroschisis is thought to arise from the occlusion of the right omphalomesenteric artery early in embryonic life, leading to infarction of the right anterior abdominal wall (15). Exstrophy of the bladder and cloaca is thought to result from persistence of the cloacal membrane, inhibiting normal development of the lower anterior abdominal wall, symphysis pubis, and perineum (Fig. 4). If the urorectal septum fails to develop completely as well, the bladder and hindgut continue to communicate with each other in a common chamber (the cloaca), and the anus remains imperforate (Fig. 5). Cloacal and bladder exstrophy or eversions result when the cloacal membrane finally breaks down (16).
