An outie belly button, or navel (medically known as the umbilicus), is a normal variation of the scar remaining after the umbilical cord detaches following birth. This scar is the final physical marker of the connection that provided oxygen and nutrients during fetal development. While most people have an “innie,” or an indented navel, the protruding “outie” is a less common but completely natural occurrence.
How the Navel Forms
The human navel is essentially a scar, formed after the umbilical cord stump dries and falls off, typically within one to three weeks after birth. Whether the navel becomes an innie or an outie is determined by the specific way the skin and underlying scar tissue heal. The healing process is individualized, similar to how any other scar forms.
For an outie, the resulting scar tissue and skin protrude slightly outward instead of adhering inward to the abdominal wall. This creates the characteristic knot-like appearance. The final shape is largely a matter of chance, dictated by the amount of residual skin and the pattern of scar formation.
Body fat and abdominal musculature also influence the navel’s final look. These factors affect how the surrounding skin pulls on the umbilicus, altering its depth and shape. The differences in the healing of the umbilical ring, the original opening for the cord, account for the wide variety of navel shapes.
The Role of Umbilical Hernias
While many outies result from normal scar variation, a significant and persistent protrusion is frequently caused by an umbilical hernia. This occurs when a small gap remains in the fascia (the tissue layer making up the abdominal wall) near the navel. This opening allows a small amount of fatty tissue or, occasionally, a loop of intestine to push through, causing a visible bulge.
Umbilical hernias are common, affecting an estimated 10 to 20 percent of infants. This condition arises because the opening in the abdominal muscles that accommodated the umbilical cord during gestation did not fully close after birth. The bulge becomes more noticeable when the infant cries, coughs, or strains, as increased abdominal pressure pushes the tissue outward.
In the majority of cases, these hernias are harmless and painless in infancy. The abdominal muscles typically strengthen and grow together, causing the gap to close spontaneously. About 90 percent of umbilical hernias resolve naturally by the time a child reaches four or five years of age. Medical intervention is considered only if the hernia is very large, causes pain, or fails to close by age five.
Addressing Common Navel Myths
A persistent misconception is that the appearance of the navel is determined by the person who cuts or ties the umbilical cord at birth. This is untrue, as the final shape is a biological result of the body’s natural healing process. The way the cord is severed has no bearing on whether the scar tissue forms an innie or an outie.
The final look of the navel results from genetics and random chance in how the skin heals around the umbilical stump. Similarly, the myth that taping a coin or other object over an outie can force it to become an innie is not supported by medical evidence and is ineffective. The formation of an outie is a normal variation of human anatomy, and both innies and outies are considered healthy forms of the umbilicus.