Belly Button (Navel) Anatomy: Function, Conditions, and Care

The navel, also known as the belly button or umbilicus, is a small, round, or oval indentation or bump in the middle of the abdomen (belly). It marks where the umbilical cord once connected a baby to the parent in the womb.

Each person’s navel is unique, varying in size, shape, and depth. Many people refer to it as an “innie” or “outie,” depending on whether it dips inward or sticks out. The navel can affect body image and hygiene and is a common site for decorative piercings. Although it doesn’t serve a purpose after birth, the navel can be susceptible to infections or hernias.

The navel is a small scar left where the umbilical cord once connected a fetus to the pregnant parent’s placenta, supplying essential nutrients during pregnancy. After birth, the person who delivers the baby clamps and cuts the cord. They leave a small stump that typically dries up and falls off within the first two weeks, creating the belly button on the baby.

Structure

The navel consists of skin, connective tissue, and underlying abdominal muscle, all contributing to its shape and appearance. It also has some leftover connections from before birth, like small ligaments that once supported the umbilical cord. These ligaments attach to nearby tissue layers called fascia, which provide structure in the abdominal wall. 

Location

The navel is in the center of the abdomen, between the chest and pelvis, near the waist. Internally, it sits just above parts of the digestive system. However, it no longer connects to any organs. 

Anatomical Variations

The most noticeable difference in navels is whether they are “innies” (inward indentations) or “outies” (slight outward protrusions), with innies being more common. Other variations include T-shaped, vertical, and funnel-shaped navels, influenced by body type, muscle structure, and scarring from later surgeries.

A navel’s appearance can vary due to skin elasticity, scar tissue, and how the cut umbilical cord falls off and heals. 

The navel has no internal function. It’s a healed scar from where the umbilical cord was once attached. However, it plays a role in fetal development, cultural symbolism, and as a surgical landmark.

Umbilical Cord

The umbilical cord forms around five weeks into pregnancy. It’s a flexible cord that connects the fetus’s belly button to the placenta, delivering essential nutrients and oxygen to the fetus. Typically, the cord is about 20-24 inches (50-60 centimeters) long and 0.4 inches (1 centimeter) wide. It contains Wharton’s jelly, a cushioning, jelly-like substance that protects the blood vessels as the fetus moves.

Body Landmark

Healthcare providers often use the navel as a helpful landmark to guide them during exams and surgical procedures. For example, during laparoscopic surgeries, surgeons may use the navel to place an incision and insert a tiny camera into the abdomen to examine internal organs. Making an incision in the navel leaves a less noticeable scar. 

Cultural Significance

The navel can also be a cultural symbol, representing life, beauty, and connection across different societies. For some, it signifies a center of energy or a link to one’s origins. Many pregnant parents feel a deep emotional bond with their unborn child through the cord, leading some poets to call it the ‘string of life.’ 

In cultures where “innies” are more common, people with an “outie” may feel self-conscious about their appearance. Some people and cultures may find specific navel shapes, such as T-shaped or vertical ones, especially appealing. Some people also decorate their navels with jewelry or piercings, which can boost self-image and help them feel more attractive.

Though primarily cosmetic in adults, the navel can be susceptible to certain conditions, injuries, or infections. 

Umbilical Hernia

An umbilical hernia occurs when part of the intestine pushes through a weak spot in the abdominal muscles, causing a soft bulge. Umbilical hernias are more common in infants but can affect adults. Symptoms include a visible bulge near the belly button and sometimes discomfort or pain, especially when straining.

Infection 

Bacteria, fungi, or yeast can cause infections in the navel, particularly in deep belly buttons that trap dirt and moisture. Common signs include redness, swelling, itching, and a discharge with an unpleasant smell. Proper cleaning is essential to help prevent infections.

Navel Stone

A navel stone is a rare, hard lump that can form in the belly button from a buildup of skin oils and dead skin cells, often appearing dark brown or black. It’s different from belly button lint, which is soft and fuzzy. Navel stones are more likely in people with deep belly buttons or people who have trouble cleaning their belly buttons.

Usually, navel stones don’t cause problems, but if they get big, they might irritate the skin, causing redness or itching. They may also cause an infection with signs like swelling, pain, or discharge. In that case, a healthcare provider can safely remove the stone with a simple procedure.

Umbilical Fistula

An umbilical fistula is a rare condition in which an abnormal connection forms between the belly button and other organs, like the bladder or intestines. This can cause fluids, such as urine or intestinal contents, to leak from the belly button and often requires surgery. Symptoms include unusual discharge, pain, and skin irritation.

Endometriosis

Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside the uterus (womb). While it commonly affects pelvic organs, it can also show up in other areas, like the navel. It can lead to pain, especially during menstruation, and may require hormonal treatments or surgery.

Umbilical Granuloma

An umbilical granuloma is a small, red bump that can form on a baby’s belly button after the umbilical cord falls off. It’s about the size of a pencil eraser.

The bump can keep growing or get infected, and requires treatment. Providers use a small amount of silver nitrate to shrink it. If it doesn’t go away, it may require more evaluation because it can sometimes look like polyps (non-cancerous growths) that may need surgery.

Belly Button Pain

While navel pain isn’t a condition on its own, it can be a sign of a health problem. For example, if you have a stomach bug, the irritation might cause pain around the navel.

Some conditions, like appendicitis (an inflamed or infected appendix), also start with pain near the belly button before moving to other areas. If you experience severe or ongoing pain, it’s important to seek emergency medical care.

When navel issues arise, healthcare providers begin with a physical examination to check for signs of infection, inflammation, discharge, or hernias. This exam may include gentle pressing around the area to detect tenderness or bulges. If further investigation is necessary, they may order the following diagnostic tests to identify underlying problems or confirm a diagnosis. 

Swab Culture

If there is discharge from the navel, a healthcare provider may take a swab sample for lab testing. A culture test identifies specific bacteria or fungi causing the infection. This helps determine if treatment should include antibiotics or antifungal medications.

Ultrasound

An ultrasound is an imaging test that uses sound waves to create pictures of the structures beneath the navel. Ultrasounds are especially useful for identifying umbilical hernias, abnormal tissue growths, or fluid-filled spaces that may indicate infections or fistulas.

A Computed Tomography (CT) Scan

A computed tomography (CT) scan provides a more detailed image of the abdomen and navel area. Providers use CT scans to investigate complex issues, like fistulas or abscesses, which may not be visible on an ultrasound.

Magnetic Resonance Imaging (MRI)

Healthcare providers can also use magnetic resonance imaging (MRI) if more detail is necessary. An MRI uses strong magnets and radio waves to make clear images of soft tissues in the body.

Umbilical Cord Diagnostics

Diagnostic tests on the umbilical cord can help monitor a fetus’s health during pregnancy and after delivery. An umbilical artery ultrasound can measure blood flow during pregnancy to ensure the fetus receives enough oxygen. After birth, an umbilical cord blood gas analysis can provide information about the baby’s oxygen levels.

To maintain a clean navel, follow these tips:

• Wash regularly: Wash your hands and gently clean your navel with a mild soap and water. 
• Dry the area: Dry the area thoroughly after washing to avoid trapping moisture.
• Avoid using sharp objects: Using sharp objects or cotton swabs to clean the navel can cause irritation, leave behind residue, or introduce infection.
• Keep piercings clean: If you have a navel piercing, follow proper aftercare guidelines, including using saline solution or antiseptic to prevent infection. 
• Wear breathable fabrics: Choose cotton or other fabrics that allow your skin to breathe. Tight or synthetic fabrics can trap moisture, which can lead to bacterial growth.
• Check for changes: Watch for unusual redness, discharge, or pain around your navel. If you notice these signs, consult a healthcare provider.

The navel, or belly button, is the small scar left after the umbilical cord is cut at birth. While it has no function after birth, its central position on the abdomen makes it a distinctive feature, often appearing as an ‘innie’ or ‘outie.’ For some, the navel is also a site for jewelry or piercings.

In medicine, it can serve as a landmark for exams and surgical procedures. Conditions that may affect the navel include infections, umbilical hernias, and fistulas. Gentle cleaning can help prevent navel infections.