In early development a connecting stalk between the caudal end of the embryo and the chorion is established. This stalk contains at the embryonic end a small allanto-enteric diverticulum. Furthermore, it contains the umbilical (allantoic) vessels: one umbilical vein and two umbilical arteries and the urachus. It must be mentioned that a small exocoelomic recess is also included in the proximal (embryonic) part of the umbilical stalk. This recessus is also termed umbilical coelom and it is in continuation with the intra-embryonic coelom of the embryo. During the 6th to 10th week of development this umbilical coelom forms a sac, which receives the physiological umbilical hernia of the midgut. After the retraction of the physiological umbilical hernia, the umbilical coelom is usually obliterated and does not further exist. At birth these structures are dispensable, leading to an obliteration of the umbilical cord structures. The following granulation and scarring process typically leads to a fibrotic, collagenous plate characterized by criss-crossing fibre fusion with the neighbouring umbilical ring. According to this complicated development, the definitive umbilicus is a locus minoris resistentiae with a lifelong risk for herniation.