The navel, commonly known as the belly button, is a depression or protrusion on the abdomen. It marks the location where the umbilical cord was once attached to the fetus. This anatomical feature is a scar, present in all placental mammals, including humans.
Anatomy and Origin
The navel’s formation begins with the umbilical cord, a flexible, tube-like structure connecting the developing fetus to the placenta. This cord transfers oxygen and nutrients from the mother and removes waste products from the fetus. It is approximately 50 centimeters long and contains two umbilical arteries, one umbilical vein, and Wharton’s jelly.
After birth, the umbilical cord is no longer needed as the baby breathes and feeds independently. Healthcare providers clamp and cut the cord, leaving a short stump. This stump dries and falls off within one to three weeks, leaving the distinctive scar known as the navel.
Variations and Common Features
The appearance of the navel varies significantly among individuals, primarily determined by how the scar tissue forms during the healing process. The two main types are “innies,” which are concave and appear as an inward depression, and “outies,” which are convex and protrude outward. Both forms are considered normal variations and are not influenced by how the umbilical cord was cut or cared for. While innies are more common, accounting for approximately 90% of the population, outies occur in about 10% of people.
Another common phenomenon associated with the navel is belly button lint. This fuzzy collection is composed mainly of stray clothing fibers, along with dead skin cells and body hair. Friction from clothing and body hair can direct these fibers towards the navel, where they accumulate. In adults, the navel serves no active biological function, existing solely as a remnant of the prenatal connection.
Clinical Relevance and Care
Maintaining proper navel hygiene is important because its shape can create a warm, moist environment where dirt, sweat, and dead skin cells can accumulate. This accumulation can lead to an unpleasant odor or provide a breeding ground for bacteria and fungi. Regular cleaning with mild soap and water during bathing, followed by thorough drying, can help prevent these issues.
While generally a low-maintenance area, the navel can occasionally develop minor health concerns. Infections, such as bacterial or fungal types, can occur if the area is not kept clean, presenting with symptoms like redness, discharge, odor, or pain. Another potential issue is an umbilical hernia, which happens when a part of the intestine or abdominal tissue protrudes through a weak spot in the abdominal muscles near the navel. Umbilical hernias are common in infants and often resolve on their own, though they can also affect adults. Most navel-related problems are minor and manageable with appropriate care.