The belly button, also known as the navel or umbilicus, is a scar on the abdomen marking the original site of the umbilical cord. When a baby is developing in the womb, the umbilical cord connects it to the placenta and allows nourishment and oxygen from the mother to reach the fetus. At birth, the umbilical cord is cut, leaving behind the belly button as a remnant of this connection.
So what lies directly behind the belly button inside the abdomen? The answer is the urinary bladder.
Anatomy Behind the Belly Button
The urinary bladder sits right behind the belly button in the lower abdomen. It is a hollow, muscular organ that stores urine before it exits the body. Some key facts about the bladder:
- Located in the pelvis behind the pubic bone
- Surrounded by pelvic floor muscles
- Has a capacity of around 16 fluid ounces (500 ml) when fully distended
- Connected to the kidneys via the ureters
- Empties urine into the urethra
In both men and women, the bladder sits in the same anatomic position behind the navel. However, due to differences in pelvic anatomy, the bladder may sit slightly lower in women than in men.
Relation of the Bladder to Other Abdominal Organs
Several other major organs are located in proximity to the bladder in the lower abdomen:
- Small intestine: The coiled tubes of the small intestine wrap around the bladder.
- Large intestine: Parts of the large intestine, including the sigmoid colon and rectum, sit just behind or beside the bladder.
- Uterus: In women, the uterus sits just above the bladder in the pelvis.
- Prostate gland: In men, the prostate gland wraps around the neck of the bladder.
This complex web of organs fills the lower abdominal cavity below the belly button. The bladder’s location can be visualized as centrally positioned within this web, right behind the navel.
Why the Bladder Sits Behind the Belly Button
The bladder’s positioning behind the navel is the result of human anatomy and development:
- The bladder develops from the upper part of the urogenital sinus, an embryonic precursor structure.
- As the fetus grows, the bladder moves upward into the abdomen, while the pelvic floor descends below it.
- This positions the bladder centrally in the lower abdomen, where it is anchored by surrounding muscles and ligaments.
- The navel forms at the original site of the umbilical cord attachment on the abdominal wall in front of the bladder.
Therefore, the belly button ends up directly in front of the bladder due to the bladder’s upward growth and the navel’s position on the midline of the abdomen.
How a Full Bladder Relates to the Belly Button
Since the bladder sits right behind the navel, a full bladder can put pressure on the abdominal wall at this point. Signs that the bladder is full and pressing on the belly button may include:
- A distinct bulging of the lower abdomen around the navel
- A noticeable protrusion of the belly button itself
- Discomfort or a feeling of fullness behind the navel
These sensations are signals that the bladder is getting full and putting pressure on surrounding structures. Urination provides relief by emptying the bladder.
In summary, a full bladder can temporarily cause the belly button to pop out as it exerts pressure from behind. This is a harmless effect from the bladder’s proximity behind the abdominal wall at this location.
Conclusion
The urinary bladder sits directly behind the belly button or navel in the lower abdomen. This positioning occurs because the bladder moves upward into the pelvis during development, while the umbilical cord leaves the navel on the abdominal wall as a marker after birth. A full bladder may cause a bulge around the navel, which can be relieved by urinating. So the next time you feel a twinge around your belly button, know that your bladder is likely the culprit!