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A large fontanel in a child: sizes, closing dates. The structure of the skull of a newborn

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A large fontanel in a child: sizes, closing dates. The structure of the skull of a newborn
A large fontanel in a child: sizes, closing dates. The structure of the skull of a newborn

At birth, a child has elastic and at the same time strong cranial bones that connect the large and small fontanels, as well as sutures, they also act as natural shock absorbers. According to their condition, it is possible to determine the presence of ICP or the nature of the course of labor. When passing through the birth canal, the skull of a newborn is significantly deformed due to the superimposition of bones on top of each other. This reduces the risk of injury for both the baby and the mother. The irregular shape of the head may scare young parents a little, but do not worry, because after a while it will take on its usual shape.

large fontanel in a child

Why do we need a fontanelle

A large fontanel in a child ensures the unhindered development of the brain. And its most active growth, as is known, falls on the first year of life, precisely at the time when the skull has a space closed by a membrane.

Thanks to the fontanel, it is possible to conductbrain examinations without the use of complex techniques and with the least discomfort for the baby. Neurosonography allows you to identify the consequences of trauma, hemorrhage, various neoplasms, changes in brain structures at a very early stage. Among other functions, it is worth noting the provision of thermoregulation. A large fontanel in a child, in particular the membrane covering it, cools the body when the body temperature reaches 38 degrees. The additional mechanism of thermoregulation significantly reduces the likelihood of cerebral edema and seizures, which can be caused by high temperature. It also acts as a kind of shock absorber during falls, without which the first steps are indispensable.

fontanel in the chest

Terms for closing a large fontanel in children

The average size is 2x2 cm, the fontanel is located on the top of the head and has a diamond shape. With age, the cranial bones grow together and by the year it disappears. But all children have different development, so this process can last up to 18-20 months. This should not cause concern, provided other indicators are in line with the norm.

The skull of a newborn is distinguished by the presence of a small fontanelle at the back of the head, which is much smaller. In almost all children, it is closed immediately after birth, it can be found in infants who were born before the due date. In this case, its complete fusion is noted after 4-8 weeks.

The pulsation and size of the fontanel are of particular importance and allow doctors to assess the conditionchild. Due to its functional load, late or vice versa earlier overgrowth in some cases may be a symptom of pathological growth of the cranial bones.

newborn skull

The course of pregnancy

Feeding a woman during pregnancy affects the phosphorus-calcium metabolism of the child, which accordingly affects the time of overgrowth of the fontanel. A large fontanel in a child can be dense, small in size and have a tendency to close quickly if the expectant mother consumed too much dairy products while taking vitamins. This is one of the reasons for the need for strict adherence to the established norm, selected by the gynecologist depending on the gestational age. It is also worth noting that an excess of calcium contributes to early aging of the placenta.

In addition, due to the volume limitation for brain growth, there is an effect on its development.

Calcium-phosphorus metabolism

Excess calcium in most cases is the cause of early overgrowth of the fontanel, with its deficiency, it closes later than the deadline. Both cases are a reason for additional examination, since low calcium levels are caused by insufficient amounts of vitamin D, and its deficiency also contributes to the development of a disease such as rickets. Because of it, the bone tissues begin to change, the legs become less even and the gait is disturbed. Other symptoms include baldness at the back of the head, profuse sweating, characterized by a sour smell, poordream. Normalization of the exchange of calcium-phosphorus elements prevents premature fusion of the fontanel edges.

large fontanel in newborns

Influencing factors

If the large fontanelle in newborns closes too early, this may indicate the likelihood of microcephaly, craniostenosis, and if the divergence after closure is worth paying special attention to possible increased cranial pressure.

A large fontanel in newborns should be between 1-3 cm in size. Exceeding this parameter may indicate the presence of infectious diseases, injuries sustained during childbirth, hypoxia during pregnancy and impaired outflow of fluid in the cerebral ventricles. In addition, children born prematurely, as well as those with malformations, endocrine disorders and improper metabolism, can also have a large fontanel.

fontanel size

When to see a doctor

If a discrepancy occurs, tests are required to determine the level of calcium in the urine and blood and an additional medical examination is required. This is due to the fact that rickets, which is a common cause of an incorrect size of the fontanel, leads to bone deformity, a decrease in overall muscle tone and changes in the functioning of the nervous system. In this case, constipation may occur due to general muscle weakness. The child must be shown to a neurologist, if the psychomotor development and the fontanel do not correspond to age, more often the reason for this is intracranial hypertension,which is eliminated by special preparations. At the same time, parents should monitor the development of the child and, if there is any doubt, contact the pediatrician. The doctor should be aware of any non-compliance with the norms and alarming symptoms. For example, frequent crying in your sleep and loud screams when you wake up can indicate a headache caused by high intracranial pressure. The fontanel in the baby becomes tense when crying, arterial pulsation is felt under it.

The depressed surface also requires a medical examination, this indicates dehydration due to frequent vomiting or diarrhea.

small spring

What mothers are afraid of

Newly-made parents are often afraid to even accidentally touch the “soft” top of the head and ask the pediatrician about the need for specific care. The fontanel in the baby, in particular its membrane, cannot be damaged by combing the hair or stroking the head, since it is much stronger than it seems. At the same time, in some cases, it is undesirable for a child to dive, even under the supervision of qualified specialists, since the brain is exposed to pressure differences.

When observing the development of the crumbs, the pulsation of the fontanel should not cause anxiety for parents. Many people are of the opinion that it can be accelerated by increasing the daily dose of vitamin D and calcium in the diet. But such actions will not have any effect if there is a genetic predisposition.

the timing of the closure of a large fontanel in children


In conclusion of the above, it is worth noting the main reasons for the fontanel's non-compliance with established standards:

  • Rickets is the most widespread. But you should not search for the symptoms of this disease only if the crown of the head is not overgrown for a long time. The main additional symptom is skeletal deformity, in particular changes in certain parts of the body, for example, legs or chest.
  • A large fontanel in a child can also be caused by hypothyroidism. But such a violation of the thyroid gland manifests itself at the age of 1.5-2 years is quite rare.
  • Hereditary factor. In this case, the terms of fusion are very blurred and can reach up to 2.5 years. Its presence can be said in the absence of other signs and simultaneous development in accordance with age.

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