Your belly button is not just a scar. On the inside, it’s physically connected to several structures that run deep into your abdomen and pelvis, all of them remnants of the umbilical cord that kept you alive before birth. These connections link your navel to your liver, your bladder, and the blood vessels near your pelvis. None of them carry blood or waste anymore, but they persist as ligaments and cords that help anchor your internal organs in place.
What the Umbilical Cord Actually Did
Before birth, the umbilical cord was your lifeline. It contained three blood vessels: one large vein and two smaller arteries, all surrounded by a protective gelatin-like substance called Wharton’s jelly. The vein carried oxygen-rich blood and nutrients from the placenta to you. The two arteries carried your deoxygenated blood and waste products (carbon dioxide, urea) back to the placenta for filtering. Without this connection, a fetus has no way to receive oxygen or remove waste.
A separate tube called the urachus also ran through the cord during early development. It connected the fetal bladder to the umbilical cord and allowed urine to drain out through the placenta during the first trimester. The urachus typically closes before the end of that trimester as the bladder migrates downward into the pelvis.
Once you were born and the cord was cut, all of these structures lost their purpose. But they didn’t disappear. They shrank, hardened into fibrous tissue, and became the internal connections your belly button still has today.
The Connection to Your Liver
The single umbilical vein, which once delivered oxygenated blood from the placenta, degenerates after birth into a fibrous cord called the round ligament of the liver. This ligament runs from the inside of your belly button upward to the underside of your liver, sitting within a fold of tissue called the falciform ligament. It attaches between two specific segments of the liver, marking the spot where the old vein used to feed into the liver’s blood supply.
The falciform ligament itself acts as a structural anchor, connecting your liver to the front wall of your abdomen and the underside of your diaphragm. So when you press on your belly button, the deepest physical connection runs straight up to your liver, roughly 8 to 10 inches away depending on your body size.
The Connection to Your Bladder
Running downward from your belly button toward your pelvis is another fibrous cord called the median umbilical ligament. This is what remains of the urachus, that fetal tube that once drained urine. It stretches from the inner surface of your navel down to the dome of your bladder, traveling along the midline of your lower abdominal wall.
In most people, this structure is completely sealed off and does nothing. But in rare cases, the urachus doesn’t fully close. When this happens, it can create a small open channel between the belly button and the bladder (a patent urachus) or leave behind a cyst or sinus along the tract. These anomalies are usually caught in childhood, but they occasionally go undetected into adulthood. The telltale sign is persistent or recurring discharge from the belly button, sometimes accompanied by lower abdominal pain or fever. Ultrasound is typically the first imaging test used to check for this, and it appears as a tubular structure running from the navel downward.
The Connections to Your Pelvic Arteries
On either side of the bladder ligament, two more cords run from your belly button down into your pelvis. These are the medial umbilical ligaments, the remnants of the two fetal umbilical arteries. Each one is roughly 15 to 25 centimeters long and traces a path from the navel downward along the inner abdominal wall, past the sides of the bladder, and back to the internal iliac arteries in your pelvis.
Like the other remnants, these ligaments no longer carry blood. They serve as minor structural landmarks inside the abdomen, creating slight ridges along the inner wall that surgeons use for orientation during procedures.
Why the Belly Button Is So Thin
One thing that makes the belly button unique is how little tissue separates it from the inside of your abdominal cavity. In most of your torso, layers of muscle, fat, and connective tissue create a thick barrier between your skin and your organs. At the navel, these layers fuse together, and the subcutaneous fat is minimal. The belly button is the thinnest point on the entire abdominal wall, the shortest distance from skin to the peritoneal cavity where your organs sit.
This is why surgeons use the belly button as the primary entry point for laparoscopic procedures. A small incision there reaches the abdominal cavity quickly, with fewer tissue layers to cut through and no major structures in the way. If you’ve ever had laparoscopic surgery, the main camera port almost certainly went through your navel.
When Something Goes Wrong
Because the belly button is a closed-off junction of several embryonic structures, problems occasionally surface there. The most common issue in adults is simple infection, often triggered by trapped debris. Lint, dead skin, and hair can accumulate in a deep navel, and in combination with moisture and poor airflow, this can cause inflammation or abscess. Obesity and a particularly deep belly button increase the risk.
Less commonly, one of the fetal connections fails to close properly. A patent urachus or urachal sinus can cause clear or cloudy fluid to leak from the belly button, and it’s frequently misdiagnosed as a skin infection or dermatitis before imaging reveals the underlying tract. Similarly, remnants of another fetal structure called the vitelline duct (which once connected the gut to the yolk sac) can persist and cause discharge, though this is even rarer.
Persistent belly button discharge, especially if it’s watery or accompanied by lower abdominal pain, suggests something deeper than a surface infection. The discharge pattern matters: fluid that looks like urine points toward a urachal problem, while intestinal-looking discharge could indicate a vitelline duct remnant.