navel navel the navel (clinically known as the umbilicus, commonly known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. all placental mammals have a navel, although it is generally more conspicuous in humans. navelthe navel is a protruding, flat or hollowed scar left after the umbilical cord detaches.detailsprecursorumbilical cordductus venosusarteryumbilical arteryveinumbilical veinidentifierslatinumbilicusmeshd014472ta98a01.2.04.005ta2261fma61584anatomical terminology structure