A newborn baby's fontanel: when it overgrows, pathologies

The fontanelle in children is the place where the bones of the skull meet at the place of their supposed fusion. The anatomical features of the structure of the bones of the skull of a newborn child are arranged in such a way that the physiological process of childbirth occurs as best as possible. But by changes in the normal appearance and condition of the fontanelle in a child, one can say a lot about the state of his health.

What is a fontanelle and why is it needed?

The fontanelle is the place on the baby's head where the skull bones do not fuse tightly together and connective tissue is formed. Why do children need a fontanelle, and why is the structure of the head of children different from that of adults? The answers are actually very simple. After all, nature has thought of everything perfectly so that the child goes through gradual changes in the mother's tummy and is born normal and healthy. When the bones of the skull of a newborn are formed, the processes of osteogenesis are not yet perfect. Therefore, the bones are soft and pliable in their structure. At the junction of the bones, there should be seams of dense bone tissue, which in children are represented by the fontanelle. This is explained by the fact that during childbirth, when passing through all the planes of the pelvis, the head performs the most important function and regulates the process of passing the child through the birth canal. Therefore, the load and pressure on the bones of the skull is maximum. The fontanelles allow the bones of the skull to move freely along the birth canal, the bones can overlap each other, which significantly reduces the pressure and load on the brain itself. Therefore, if the child did not have fontanelles, the birth process would be very complicated.

How many fontanelles does a child have?

A full-term newborn baby has only one open fontanelle – the large one.

It is located between the frontal bone and two parietal bones, which is why it has an irregular diamond shape. If we talk about the total number of fontanelles in a child, there are six of them. One anterior or large, one posterior, and two lateral on each side. The posterior fontanelle is located between the occipital bone and two parietal bones. The lateral fontanelles are located at the same level - the first between the parietal, temporal, and sphenoid bones, and the second between the parietal, temporal, and occipital bones. But the lateral fontanelles should be closed in a full-term child, while the anterior fontanelle is normally open after birth and in the first year of life. Sometimes a full-term child may have an open posterior fontanelle, but more often it is closed. The sizes of fontanelles in children vary. The largest fontanelle is the anterior one and it is about 25 millimeters long and wide. Next comes the small or posterior one, which is less than 10 millimeters. The lateral fontanelles are the smallest and are no more than five millimeters. In order to monitor the child's condition and the rate of closure of these fontanelles, you need to know how to measure the fontanelle in a child. This procedure is performed by a doctor every time during an examination of a child and the result is always recorded in the newborn's development chart. This allows you to monitor the dynamics of fontanelle closure. But the mother can also measure at home and this does not require special skills or tools. The large fontanelle has the shape of a rhombus, so the measurement is not from corner to corner, but from one side of the rhombus to the other side. That is, to measure, you need to place three fingers of the mother's right hand in the projection of the large fontanelle not in a straight direction at the corners of the rhombus, but slightly obliquely along the sides of the rhombus. One mother's finger is approximately equal to one centimeter, and therefore there is no need to measure with a ruler or anything else. Thus, the normal size of the fontanelle in a child should not exceed the width of three fingers of the mother.

The norms for fontanelle closure in children vary depending on individual characteristics. After all, one child is breastfed and has enough minerals and vitamins for early fontanelle closure, while another child is formula fed and was born in the winter without rickets prophylaxis, so the fontanelle closure is later. But there are still normal closure thresholds, exceeding which indicates a possible problem. The large fontanelle closes by 12-18 months of a child's life, and the posterior or small fontanelle, when it opens after birth, should close by the end of the second month of the child's life. If the lateral fontanelles are open in a child, they should close within six months. When a child's fontanelle closes, a dense bone is formed, which will forever be the same as in an adult.

Pathology of fontanelles in children

Naturally, there are certain norms for the closure of fontanelles, but each child may have its own characteristics that affect these terms. Considering that the large fontanelle is the most indicative and has the most delayed closure terms, it is always a guide to the health of the infant.

If the fontanelle closes early in a child, then we can think about a metabolic disorder, especially calcium and vitamin D. But we must remember that the concept of "early" is very relative, because if the norm is 12 months, and the fontanelle closed at 11 months, then this is not so bad. In this case, you should always monitor the dynamics of the fontanelle size throughout the child's life, because he could be born with a small fontanelle. But if we are talking about the closure of a large fontanelle at 3 months or earlier, then you clearly need to consult a doctor. This does not always pose a danger, because you need to assess the general condition of the baby. Sometimes small children have constitutional features of the structure of the head and all parts of the body, in which children will be small in stature and miniature. Then, for the growth of the brain and head, there is no longer a need for further increase in the volume of the head, so the fontanelle can close earlier. Therefore, it is necessary for the doctor to assess the child's condition comprehensively, taking into account the constitutional features of the development of the parents during this period. If we talk about pathology, then early closure of the fontanelle in children can be caused by congenital pathologies of the skeletal system. If there is a pathology of the thyroid gland or parathyroid glands, then fusion of the skull bones can be observed against the background of a violation of the level of calcium metabolism. If we talk about congenital defects, then pathologies of the brain with violations of the structure and size of the skull can cause early fusion of bones. But if the child was born healthy and developed normally, then mothers should not look for some kind of defect in him due to a simple early closure of the fontanelle.

If a child's fontanelle does not close well, there may be more reasons than the mother can assume. But even in this case, it is important to remember that the time it takes for the fontanelle to close may vary. If a child's fontanelle has not closed by one year, this is normal if there has been positive dynamics since birth. For example, if at one month the fontanelle was 2.5 by 2.5 centimeters, and at one year it was 1.5 by 1.5 and did not close, then this is an absolutely normal time frame and by the end of the second half of the child's life it will completely close. But if there is no positive dynamics, then you need to think about pathology. The reasons for the fontanelle not closing in a child may be associated not only with calcium metabolism disorders, but there may also be other disorders. Rickets can be considered the most common cause of untimely closure of the fontanelle. This is a disease characterized by vitamin D deficiency, which disrupts the absorption and metabolism of calcium. This directly affects the state of the child's skeletal system, and as a direct sign of pathology, the structure of the fontanelle is disrupted. Calcium deficiency in the child's body leads to the fact that, first of all, normal ossification of the skull bones does not occur, and the child's entire process is disrupted in the place where bone sutures should already be formed. This is accompanied by a delay in the closure of the fontanelle. Another less common but more serious problem can be considered congenital hypothyroidism. This is a disease that is characterized by the lack of synthesis of thyroid hormones. These hormones ensure active reproduction of all cells and growth of the body in utero and after birth. Therefore, the deficiency of these hormones leads to inhibition of active cell growth. Therefore, with a delay in the overgrowth of the fontanelle, along with other symptoms, thyroid pathology must be excluded.

If a child has a large fontanel, this may be a manifestation of hydrocephalus. This is also accompanied by an increase in the size of the head against the background of an increase in the volume of its circumference. This pathology develops due to a violation of the outflow of cerebrospinal fluid through the spinal canal, which is accompanied by the accumulation of this fluid in the brain. But this pathology has a characteristic clinical picture that is difficult to miss.

If the child's fontanelle is pulsating and tense, then one should think about neurological pathology. It often happens with children who are born in hypoxia or after complicated births, after some time the child becomes restless. His fontanelle begins to pulsate, especially when he is picked up. This may be due to increased intracerebral pressure, which especially increases in an upright position and causes such pulsation. But if the child sleeps peacefully, eats normally and is not capricious, then an attentive mother can sometimes notice a slight pulsation of the fontanelle. This is not an absolute pathology, but may be a simple pulsation of the vessels, which is normal for such a baby. Therefore, any pathology of the fontanelle is conditional and a doctor's consultation is required.

Sometimes a child may have a sunken fontanelle, which often develops against the background of infection and severe dehydration. The concept of "severe" dehydration for a newborn or infant is somewhat relative, since even three episodes of diarrhea in such a child can cause symptoms of dehydration. Considering that they are systemic in nature, a decrease in the volume of circulating blood leads to a decrease in the volume of intracerebral fluid and a decrease in pressure, so the fontanelle becomes sunken. This is a very characteristic symptom that cannot be ignored.

Parents are often concerned about a bump near the fontanelle in their child. This may be a simple feature of the fusion of the skull bones, or it may be a serious neurological pathology. If the bump is small and there are no symptoms of concern, then it is possible that these are features of bone fusion. But if the child is restless or the defect itself is large, then developmental anomalies are possible that require intervention. Therefore, it is imperative to consult a pediatric neurologist.

The fontanelle in premature babies has its own characteristics, since the period of its overgrowth may be a little longer. A premature baby may be born with all fontanelles open, depending on the gestational age. It may be tense and pulsate strongly due to frequent neurological symptoms in such babies. In any case, the fontanelle and care for it in premature babies require special attention.

The fontanelle in children is the place of future fusion of the skull bones, which assumes the normal process of birth of the baby and further growth of the brain. But although the fontanelle itself consists of connective tissue, its condition can indicate many problems in the child's body. Therefore, it is very important to monitor the condition of the fontanelle, the dynamics and timing of its closure and undergo a timely examination by a pediatrician.