What is this hole behind my baby's head?

For parents, there is nothing happier than seeing their child being born. Of course, after the baby is born, it is necessary to observe carefully to see if there are any problems with the baby's body. If there are any problems, they must be treated immediately. Many young people have no experience in this area, and even feel horrified when seeing the "pit" behind the newborn's head. So, what is the pit behind the baby's head?

The fontanelle, commonly known as the "zenith", is a boneless diamond-shaped space formed between the baby's two frontal bones and the parietal bones, with only meninges, scalp and subcutaneous tissue, namely the anterior fontanelle; the boneless small triangle formed between the baby's two parietal bones and the occipital bone is called the posterior fontanelle.

The fontanelle that people often refer to is the anterior fontanelle. Simply put, the fontanelle is the place on the top of the baby's head that looks like it's jumping around.

The average anterior fontanelle of a newborn is 2.5×2.5 cm, but there are also individual differences. If the baby's anterior fontanelle is smaller than 1 cm, or larger than 3 cm, it should be taken seriously, because a too small anterior fontanelle is common in microcephaly, while an too large anterior fontanelle is common in hydrocephalus, rickets, and cretinism.

As the baby develops, the fontanelle will slowly close. The anterior fontanelle usually ossifies and becomes smaller within 6 months after birth, and usually closes at the latest by the age of one and a half. The posterior fontanelle usually closes 2 to 3 months after birth.

1. Is the late closure of the fontanelle due to calcium deficiency?

For most babies, the anterior fontanelle should close 18-24 months after birth. Some babies may close a little later, but there is no need to worry as long as their height, weight, head circumference and nervous system development are normal.

Don't pay too much attention to the size of the fontanelle, but instead continue to monitor the growth of the child's head circumference. If the growth of head circumference is normal, it is actually okay if the child's fontanelle closes earlier or later.

However, there is a certain time limit for early closure and late closure. The average time for the anterior fontanelle to close is 18 months, but it is normal for it to close between one and two years old. If the child's fontanelle closes within two years, then parents do not need to worry too much, as it has nothing to do with calcium deficiency. If the fontanelle has not closed by the time your child is almost 2 years old, you need to see a doctor.

2. Will early closure of the fontanelle affect the baby's intellectual development?

Some children's fontanelles close early, and parents are very worried that their children's brain growth will be affected, which will affect their intellectual development in the future. Generally, the anterior fontanelle closes at around one and a half years old, but some children close early. If the head circumference is normal, and the head circumference increases at a normal rate every month (see the head circumference growth value in the growth and development table), it means that the cranial sutures of the skull have not closed. The continuously enlarging head will not affect brain development, so parents do not have to worry that the early closure of the anterior fontanelle will affect intellectual development.