The navel is a roundish notch, which lies approximately in the middle of the abdomen. In medical terminology the navel is called umbilicus. It is a scarred remnant of the umbilical cord that connects the fetus to the mother during pregnancy.
Anatomy of the navel
The belly button is what remains of the umbilical cord created during pregnancy even after birth. The umbilical cord supplies the baby with oxygen and nutrients until birth. At birth, the umbilical cord is clamped and cut off.
What remains is a stump which recedes within several days to a few weeks and finally falls off. The navel consists of connective tissue scar tissue, which is covered by the so-called “papilla“. The papilla is the inwardly bulging rest of the umbilical cord.
Scar and papilla are additionally surrounded by an umbilical ring. A rough distinction is made between two forms of the navel. The more frequent concave, inwardly turned and the convex, outwardly turned navel.
In overweight people the navel often has a deep, slit-like shape. The navel roughly divides the abdomen into four quadrants, which are used in medicine for rough orientation and localisation. Its function is completed with the completion of the birth process, which is why the navel only plays a visual role in adults.
Function of the navel
For the adult the navel has no function anymore, but is actually nothing more than a scar, which can only cause problems due to certain diseases. The navel is the scarred remnant of the umbilical cord that connects the fetus with the mother’s placenta during pregnancy. The placenta, also known as the placenta, develops from the lining of the uterus and consists of a maternal and a fetal part.
Figuratively speaking, the maternal part of the placenta represents a pot containing maternal blood. The fetal part represents the matching pot lid. The pot lid is connected to the umbilical cord and above it to the child.
The exchange of substances can take place through the contact of the fetal tissue with the mother’s blood. This means that the child takes everything it needs from the mother’s blood, namely oxygen and nutrients, and releases carbon dioxide and other waste products back to the mother. After birth, however, the placenta becomes superfluous because the baby can now breathe for itself and dispose of its waste products such as carbon dioxide and urea by itself.
Therefore the umbilical cord between mother and child is cut, the remains of the umbilical cord recede and leave the navel as a scar. Diseases or injuries can occur at the belly button in the course of life. Besides diseases, there are also anomalies, which are congenital abnormalities.
The term includes minor malformations which generally have no disease value. These include, for example, the amniotic and the meat beak. In the case of the amniotic navel, the amniotic sheath covers the abdominal skin.
This results in a skin defect, which usually heals without complications. The amniotic sac is the innermost skin of the egg and thus part of the amniotic sac. The reverse is true for the meat beak.
The umbilical cord is covered with abdominal skin, so that after the umbilical cord has regressed, a blunt navel is formed, which is slightly higher than the skin level. In addition to the umbilical anomalies, injuries or bleeding of the navel can occur. This can occur especially in infancy after the cutting of the umbilical cord.
Mostly they are not very strong and therefore not dangerous. In rare cases, however, more severe bleeding may occur, but this is usually caused by a general tendency to bleed due to infections (e.g. blood poisoning), or the infant suffers from a coagulation disorder such as vitamin K deficiency. In addition, there are other malformations resulting from embryonic development, which are usually detected shortly after birth.
These include the umbilical cord hernia (omphalocele), the urrachus and umbilical fistula and the umbilical hernia, which can also occur in adults. The omphalocele is usually already visible in the ultrasound before birth, and a urachus fistula can also be displayed sonographically (with ultrasound). Umbilical fistulas are best seen on X-rays.
In childhood, many diseases can also be accompanied by red spots on the navel. As mentioned above, umbilical cord fracture, uracic fistula and navel fistula are due to embryonic development. The umbilical cord hernia is a hernia, a hernia of the viscera, which occurs at the base of the umbilical cord between the 4th and 10th week of pregnancy.
During this period, the embryo undergoes a physiological umbilical hernia, i.e. one that corresponds to normal life processes. The reason for this is that the intestine grows so quickly during development that it no longer has enough room in the foetus’ abdomen and moves outwards into the amniotic sac. This hernia normally recedes by the 10th week of pregnancy.
If this is not the case, it is called an omphalocele or umbilical cord hernia. This means that internal organs such as the intestines, stomach or liver come out through the abdominal wall. During development in the womb, other connections besides the umbilical cord are formed which serve to supply the embryo, but which regress after birth because they are no longer needed.
Therefore, they do not really play a role – unless they are regressed incompletely or incorrectly. One of these connections is the yolk duct, which connects the yolk sac with the intestine. This yolk duct (Ductus omphaloentericus) runs from the navel to the intestine.
If this duct is not completely reduced in the area of the navel, a navel fistula is formed. A deficient regression in the area of the intestine leads to a so-called Meckel’s diverticulum. Another embryonic duct is the urachus, the urethra.
This connects the bladder with the navel. This means that the embryo releases its urine through this passage via the navel. Normally, the urchus atrophies after birth; if it does not, a urinary fistula can develop.
But enough of the embryonic ducts and connections, even in adults, diseases of the navel can occur. The most important one is the umbilical hernia. This is a hernia, but it can also occur in babies, especially if they are born prematurely.
In addition, it can also lead to inflammation of the belly button in babies and infants. In adults, women are more frequently affected than men because they have more risk factors. These include obesity (adiposity), water in the abdomen (ascites), which is a chronic pressure load on the abdominal wall. Furthermore, heavy physical exertion and (past) pregnancies are factors that can contribute to the development of an umbilical hernia.
All articles in this series:
