A belly button, also known as a navel, is a common feature found on the abdomen of nearly every human. It serves as a permanent reminder of our earliest connection to our mothers, marking the spot where the umbilical cord once attached. Despite its universal presence, the appearance of each navel is unique, sparking curiosity about its varied shapes and depths.
The Anatomy and Formation of Your Navel
The belly button originates from the umbilical cord, a temporary yet essential structure connecting a developing fetus to the placenta. This cord acts as a lifeline, transporting oxygen and nutrient-rich blood from the mother to the fetus, while also carrying away waste products. It typically contains two umbilical arteries and one umbilical vein, all encased within a protective gelatinous substance known as Wharton’s jelly.
After birth, the umbilical cord is no longer needed for nutrient exchange or waste removal, so it is clamped and cut. This process is painless for the newborn as the cord lacks nerve endings. The remaining portion, called the umbilical stump, naturally dries, shrivels, and darkens over the course of one to three weeks.
The detachment of the umbilical stump leaves behind a small wound on the baby’s abdomen. As this wound heals, it forms a fibrous remnant, which is the belly button. This scar is a fusion of various peritoneal and fibrous structures that were once part of the umbilical connection. The way this scar tissue forms and the surrounding abdominal wall closes determines the final shape and appearance of the navel.
What Influences Belly Button Depth and Appearance?
The depth and overall appearance of a belly button are influenced by a combination of factors, ranging from genetics to body composition and life events. While the way the umbilical cord is cut at birth does not directly determine the final shape, the subsequent healing process plays a significant role. The belly button is essentially a scar, and like any scar, its final form can vary greatly between individuals.
One of the most noticeable factors influencing belly button depth is the amount and distribution of subcutaneous fat, the fat layer located just beneath the skin. Individuals with more subcutaneous fat around the abdominal area tend to have deeper belly buttons, as the surrounding tissue creates a more pronounced indentation. Conversely, less abdominal fat can result in a shallower navel. The structure of the abdominal muscles can also affect how the skin pulls around the belly button, further influencing its depth and shape.
Genetic predisposition also plays a part in determining the general shape and appearance of the navel, including whether someone has an “innie” or an “outie.” An “innie” belly button, the more common type, forms when the umbilical stump heals inward, creating a depression. An “outie” belly button, present in about 10% of people, occurs when a small portion of the umbilical scar tissue protrudes outward. This can be due to extra scar tissue or, in some cases, a minor umbilical hernia.
Weight fluctuations can significantly alter the appearance of a belly button. Both weight gain and loss can cause the surrounding skin and fat tissues to expand or contract, thereby changing the navel’s depth and shape. Pregnancy also commonly affects the belly button. As the uterus expands during the second and third trimesters, the increased pressure on the abdominal wall can cause an “innie” to flatten or even temporarily protrude, becoming an “outie.” While many belly buttons revert to their original shape after childbirth, some women may experience permanent changes due to shifts in skin elasticity or muscle tone.