Most of us probably don’t give our belly button a second thought.
However, this small fold of skin could harbor infections, cysts and even hernias, experts suggest.
Dr. Dan Baumgardt, a neuroscientist and physiologist at the University of Bristol in the United Kingdom, wrote for The conversation that the navel, known medically as the umbilicus, “is deeper than a few millimeters.”
The navel is a remnant of the umbilical cord that connects the fetus to its mother during pregnancy. There are many variations, but the two main groups are the “outsiders” and the “innies.”
About 10 percent of people worldwide have an outie, meaning their belly button sticks out, while the rest have an innie.
Most people have an ‘innie’ belly button, which means the flap of skin folds inward rather than sticking out.
While the belly button has no function after birth, subtle changes in its appearance could be an indicator that something is wrong with our health.
One of them, Dr. Baumgardt notes, is an umbilical hernia, which occurs when part of the intestine protrudes through the navel. This causes swelling or a lump coming out of the belly button.
They are usually harmless and mainly affect babies, although they are also the second most common hernia in adults. Being overweight or having multiple pregnancies can increase the risk of adults developing an umbilical hernia.
Most of the time, no treatment is needed, although the hernia may need to be surgically removed if it causes pain or blocks the intestine.
Dr. Baumgardt also pointed out a rare complication called Sister Mary Joseph nodule, named after a nun who discovered that many late-stage cancer patients had swelling or a nodule near the navel.
This may be a sign that the patient’s cancer has spread or is more advanced.
“It is not as common today, as more cancers are now diagnosed before they spread widely,” writes Dr. Baumgardt.
Another unusual condition of caput medusae, or head of Medusa.
Also called the palm tree sign, it is a network of swollen, painless veins around the navel. From a distance, it also looks like a black or blue bruise.
This is caused by portal hypertension, which is high pressure in the portal vein. The portal vein carried blood to the liver from the intestines, gallbladder, pancreas, and spleen. The liver then processes nutrients from the blood and sends them to the heart.
Medusa head (left) and Sister Mary Joseph nodule (right) are two rare conditions that form in or around the navel.
Medusa head itself is not a disease, although it is often a sign of liver scarring, also called cirrhosis.
The scarring hinders the flow of blood through the veins of the liver, causing it to pool in the portal vein and flow into nearby veins near the navel.
This enlarges those blood vessels until they form a Medusa-like pattern.
The belly button can also harbor infections, especially if you have an innie.
This fold can trap moisture and debris, and warm environments like this are prime environments for bacteria growth.
Signs of a belly button infection include redness, pain, swelling, bad odor, and drainage of pus or other fluids.