Your belly button was connected to your bladder before you were born, through a small tube called the urachus. In most people, that tube sealed itself shut during fetal development or shortly after birth, leaving behind nothing more than a thin fibrous cord buried in your abdominal wall. So the short answer is: it used to be, but it almost certainly isn’t anymore. The longer answer involves a surprisingly common set of exceptions where that old connection never fully closed, and what can go wrong when it doesn’t.
The Urachus and Why It Existed
During early development in the womb, a fetus needs a way to handle waste before the kidneys and bladder are fully operational. The urachus served that role: it was a tube running from the top of the developing bladder up to the umbilicus (the future belly button), connecting to a structure called the allantois that helped with waste elimination.1PubMed Central. Uncommon Encounter in Urachus: A Rare Case of Xanthogranulomatous Urachitis With Review of Literature Think of it as a temporary plumbing line between the bladder and the umbilical cord.
Somewhere around the fourth to fifth month of pregnancy, the fetal bladder descends into the pelvis, and the urachus stretches and narrows as it does. Eventually, the inner channel closes off entirely, leaving a solid fibrous cord rather than an open tube.2PubMed Central. Patent Urachus Presenting as Acute Abdomen After birth, that cord dries out further and becomes the median umbilical ligament, a thin band of tissue running from the bladder dome to the back of the belly button. You have one right now, tucked behind the muscles of your lower abdominal wall. It does nothing. It is simply a leftover.
What the Median Umbilical Ligament Actually Is
The median umbilical ligament sits in the space between the inner lining of your abdominal cavity and the muscle wall, sandwiched between two other cords called the medial umbilical ligaments, which are the dried-up remains of the umbilical arteries that once carried blood to the placenta. All three converge toward the belly button like spokes of a wheel. You might encounter these structures on an anatomy diagram or, occasionally, during abdominal surgery. Surgeons performing laparoscopic procedures sometimes see the median umbilical ligament as a faint ridge on the inner surface of the abdomen. It is so unremarkable that it usually goes unmentioned in operative notes.
The ligament is not hollow. It contains no urine, no blood, and no fluid of any kind. For the vast majority of adults, there is zero functional connection between the belly button and the bladder. The idea that poking your belly button might somehow affect your bladder is a common folk belief, possibly reinforced by the strange tugging sensation some people feel low in the abdomen when they press on their navel. That sensation is real but has more to do with the thinness of the tissue at the umbilicus and the sensitivity of the peritoneum (the membrane lining the abdomen) than with any active plumbing running to the bladder.
When the Connection Doesn’t Fully Close
In a small number of people, the urachus fails to seal off completely before or after birth. These are called urachal remnant anomalies, and they come in several varieties depending on which part of the tube stayed open. A review of imaging findings describes four main types:3PubMed Central. The urachus revisited: multimodal imaging of benign & malignant urachal pathology
- Patent urachus: The entire tube from bladder to belly button remains open. This is the rarest and most dramatic form. In a newborn, urine can literally leak from the belly button.
- Urachal cyst: Both ends of the tube seal, but a pocket in the middle stays open, forming a fluid-filled sac buried in the abdominal wall.
- Urachal sinus: The belly-button end stays open while the bladder end seals. This creates a blind pouch that opens at the navel, accounting for about 18% of cases in one surgical series.4PubMed Central. Incidental discovery of an infected urachal diverticulum mistaken for an umbilical hernia: a case report
- Vesicourachal diverticulum: The bladder end stays open while the belly-button end seals, creating a small outpouching at the top of the bladder.
Of these four, the urachal cyst is the most common malformation.5PubMed Central. An Infected Urachal Cyst With Umbilical Granuloma in an Adult Patient Many people live their entire lives with a small urachal remnant and never know it, because it causes no symptoms until it gets infected or is spotted incidentally on an imaging scan done for some other reason.
Patent Urachus in Newborns
A fully patent (open) urachus is the scenario that most literally answers the title question: in these babies, the belly button really is connected to the bladder, and urine drains from the umbilical stump. It is rare and tends to show up within the first few weeks of life. One case report describes a 15-day-old girl who presented with persistent leakage from the umbilical site.6PubMed. Her belly button is leaking: a case of patent urachus Wet or weeping umbilical stumps in newborns are not always a patent urachus; other things, including umbilical granulomas and omphalomesenteric duct remnants (leftover tissue from a different embryonic structure that connected the yolk sac to the gut), can look similar. Differentiating between these requires imaging or sometimes a simple dye test.
A patent urachus in a newborn usually needs surgical repair. Left untreated, the open channel creates a direct route for bacteria to travel from the outside world into the bladder or abdominal cavity, raising the risk of urinary tract infections and, in severe cases, sepsis.
Urachal Cysts and Infections in Adults
Adults can go decades without knowing they have a urachal remnant, and then something triggers an infection. An infected urachal cyst is the scenario doctors encounter most often in older patients. The cyst itself is typically buried somewhere along the midline of the lower abdomen, between the belly button and the bladder. When bacteria colonize it, the symptoms can be confusing: lower abdominal pain, fever, a palpable lump near the midline, and sometimes blood in the urine or signs that mimic a urinary tract infection.7PubMed Central. An infected urachal cyst forming an abscess: A case report Roughly a third of patients with urachal remnant disease show up with some combination of those complaints.
The tricky part is that these symptoms overlap with a lot of other conditions. Appendicitis, a hernia, an ovarian cyst, or a bladder tumor can all produce similar pain and imaging findings. Case reports describe patients initially misdiagnosed with umbilical hernias or peritonitis before someone thought to look for a urachal remnant.8PubMed Central. An Adult with a Remnant Urachus Anomaly Diagnosed in the Emergency Department When a cyst ruptures or forms an abscess, the presentation can look like an acute surgical emergency.
An infected urachal cyst that goes untreated can lead to sepsis, fistula formation (where the infection burns a new channel to the skin surface or into the bladder), or rupture that mimics peritonitis.5PubMed Central. An Infected Urachal Cyst With Umbilical Granuloma in an Adult Patient Prompt recognition matters, and it starts with a doctor thinking to ask whether the midline location of the problem could point to a urachal origin.
How Urachal Remnants Are Found
Ultrasound and CT scanning are the main tools. On ultrasound, a patent urachus shows up as a tube running between the bladder and the belly button. A urachal cyst appears as a fluid-filled pocket in the midline lower abdominal wall, not communicating with either the bladder or the navel. A vesicourachal diverticulum looks like a small pouch protruding from the top of the bladder.9PubMed. Urachal remnant diseases: spectrum of CT and US findings CT provides sharper detail and is particularly useful when infection is suspected, though both ultrasound and CT can struggle to tell an infected cyst apart from a urachal cancer, because both can produce thick-walled, mixed-density lesions on imaging.10PubMed Central. The primary considerations and image guided diagnosis of an infected urachal cyst in a pediatric patient
This overlap between infected cysts and cancers on imaging is one reason surgeons tend to recommend removing urachal remnants rather than simply draining them and hoping for the best. A tissue sample examined under a microscope is the only way to rule out malignancy with certainty.
Urachal Cancer
Cancer arising from the urachus is extremely rare, but it does happen and tends to be aggressive when it does. Nearly all urachal cancers are adenocarcinomas, a type of cancer that originates in glandular tissue.11Exploratory Research and Hypothesis in Medicine. Diagnosis, Treatment, and Prognosis of Urachal Carcinoma: A Case Series of Eleven Patients Urachal carcinoma accounts for a tiny fraction of all bladder cancers, but because of its midline location between the bladder and the abdominal wall, it can quietly grow before producing symptoms. Blood in the urine, a mucus-like discharge, or a hard mass felt above the pubic bone are typical warning signs. Treatment involves surgical removal of the urachus, a portion of the bladder dome, and surrounding tissue, often followed by chemotherapy if the cancer has spread.
The rarity of this cancer means that most people with urachal remnants will never face it. But it does underscore why surgeons prefer to excise symptomatic urachal tissue rather than leave it in place after treating an infection.
Surgery for Urachal Remnants
When a urachal remnant is causing trouble, the standard treatment is surgical excision of the remnant along with a small cuff of bladder tissue at its base. Historically, this was done through an open incision. More recently, laparoscopic approaches have become common and show comparable outcomes with shorter recovery. One series of pediatric patients reported that laparoscopic removal took about 50 minutes on average, with patients going home within two to four days and no postoperative complications.12PubMed Central. Laparoscopic management of urachal cysts A separate study of 25 children found similarly good results: no conversions to open surgery, minimal blood loss, and no recurrences on follow-up ultrasound over a period of up to two years.13PubMed. The efficacy analysis of laparoscopic treatment of pediatric urachal cysts
In adults, especially those whose cysts are infected at the time of diagnosis, the process is sometimes staged: drain the infection first, control it with antibiotics, then schedule the definitive excision once things have cooled down. A series of adult patients treated laparoscopically reported no recurrences over a mean follow-up of nearly four years.14PubMed Central. Laparoscopic management of complicated urachal remnants Some surgical teams have developed techniques that route the entire operation through the belly button itself, using specially designed incisions to minimize visible scarring.15PubMed. Three-flap umbilicoplasty: a novel and preliminary method of laparoendoscopic single-site transumbilical surgical approach for urachal remnants
Other Things Your Belly Button Used to Connect To
The urachus was not the only embryonic structure attached to the umbilicus. The belly button was essentially a multi-port docking station during fetal life. Two umbilical arteries carried deoxygenated blood from the fetus to the placenta, and a single umbilical vein carried oxygen-rich blood back. After birth, the arteries shriveled into the medial umbilical ligaments (flanking the median umbilical ligament from the urachus on either side), and the vein became the round ligament of the liver, a cord of tissue running from the belly button up toward the underside of the liver. Occasionally, calcification can develop in the remnants of the obliterated umbilical arteries, visible on X-ray as incidental spots in the pelvis.16PubMed. Dystrophic calcification in obliterated umbilical artery
There was also the omphalomesenteric duct (sometimes called the vitelline duct), which connected the developing gut to the yolk sac. Like the urachus, it normally closes and disappears. When it doesn’t, the result can be a Meckel diverticulum (a small blind pouch off the small intestine, present in roughly 2% of people), an omphalomesenteric fistula, or fibrous bands that can occasionally cause bowel obstruction. A weeping belly button in a newborn can be caused by a persistent omphalomesenteric duct rather than a patent urachus, and the two look similar enough on initial examination that imaging is often needed to tell them apart.
Patent Urachus in Animals
Humans are not the only species that deals with urachal problems. Patent urachus is a well-known condition in newborn foals, where it occurs at a higher rate than in human babies. A large retrospective study of equine neonates found a patent urachus frequency of about 8% of all foals within the first two weeks of life, with colts affected far more often than fillies.17PubMed Central. Equine Patent Urachus and Associated Comorbidities in 101 Newborn Foals: A Retrospective Study The classic sign is urine dripping from the umbilical stump during urination. Most affected foals were treated conservatively (chemical cauterization of the stump, antibiotics), while about 30% needed surgical resection. The condition is taken seriously in equine medicine because an open urachus is a direct route for bacteria to enter the abdomen, and neonatal foals are already vulnerable to infection.
The evolutionary backdrop here is interesting. The allantois, the fetal structure the urachus connects to, has been a feature of amniote vertebrates for hundreds of millions of years. In egg-laying reptiles and birds, the allantois handles gas exchange and waste storage inside the egg. In mammals, it was repurposed as part of the placental system.18PubMed. Evolution and development of fetal membranes and placentation in amniote vertebrates The urachus is essentially the last visible trace of that ancient plumbing, a reminder that your bladder’s connection to the outside world once ran straight through what became your belly button.
That Weird Feeling When You Poke Your Belly Button
Many people report an odd sensation, sometimes described as a tingle or a pulling feeling deep in the pelvis or even near the urethra, when they press firmly on their belly button. This is not evidence of a secret connection to the bladder. The belly button is one of the thinnest spots on the abdominal wall, and pressing on it pushes almost directly against the peritoneum and the structures just behind it, including the median umbilical ligament. That ligament runs straight down to the bladder dome, so pressure at the navel can tug on it and create a referred sensation in the lower abdomen. Some of the nerves serving the skin around the belly button also supply sensation to the lower abdominal region and parts of the urogenital tract, which further explains why the feeling seems to travel downward.
This is completely harmless and does not mean you have a patent urachus. If, on the other hand, pressing on or cleaning your belly button produces an actual discharge of clear fluid, cloudy fluid, or anything that smells like urine, that would be worth mentioning to a doctor. Persistent wetness at the navel in a child or adult is the kind of finding that prompts an ultrasound to check for a urachal sinus or, less commonly, a remnant of the omphalomesenteric duct.
In adults, an infected urachal sinus can sometimes masquerade as a recurring belly-button infection. If you have had multiple episodes of redness, discharge, or pain at the navel that don’t respond well to topical treatment, a urachal remnant is one of the less obvious possibilities a doctor might investigate with imaging.