Exomphalos. Analysis of a 10-year series of 32 cases.

An 'exomphalos' is a herniation of abdominal viscera into the umbilical cord; the sac consists of two layers of tissue: the inner, the peritoneum, and the outer, the amnion, which are fused together to form a thin and avascular membrane. From published reports and from examination of the defect in various patients, the condition is divisible into two types which resemble one another only superficially. The first type consists of the herniation of a loop of bowel (often the mid-gut loop) through a normally placed but abnormally large umbilical ring into the base of the cord. This has been called the 'foetal type' by Dott (1932) and 'hernia into the umbilical cord' by Margulies (1945). The second type is much larger and has been named the 'embryonic type' by Dott and 'omphalocele or amniocele' by Margulies. Here the defect in the abdominal wall far exceeds the umbilical ring in size and extends upwards towards, or actually to, the ziphisternum, the sac nearly always containing the liver as well as the bowel. The two types are not simple gradations of the same condition but originate at different developmental stages of the embryo.