Umbilical Hernia vs. Partial amnion navel
Left picture: In this picture a middle-sized umbilical hernia is visible which is prominent constantly without crying. Right picture: This variation of the shape of the navel is a sequel of a so-called amniotic navel following which the transition to the normal abdominal skin is outside of the navel. Therefore instead of a normal skin with a wall of the navel there is thin skin.
Left picture: Instead of a regular navel this young infant shows a semi-spherical prominence with a smooth wall which differ from the surroundig normal skin. Right picture: 2 months old infant. The structure of the external layer of the navel does not correspond in the upper periphery and the adjacent surroundings to a normal skin and a navel ring.