Parts of the adult navel include the "umbilical cord remnant" or "umbilical tip", which is the scar left by the detachment of the umbilical cord. This is located in the centre of the navel, sometimes described as the button. Attached round the umbilical cord remnant, is the "umbilical collar", formed by the dense fibrous umbilical ring. Surrounding this is the periumbilical skin. Directly behind the navel is a thick fibrous cord formed from the umbilical cord, called the urachus, which originates from the bladder.