In the top of the little baby’s head there is a small “heaven’s gate”, usually look closely, you can also see a pulse jump, this is the baby’s fontanelle. It is a diamond-shaped gap formed by the frontal and parietal bones in the baby’s skull, where the two frontal bones and the two fast parietal bones are connected to each other and not yet fully ossified, commonly known as the “sky gate cover”, located in the front center of the top of the head. In the first few months of life, the fontanelle will expand with the increase of the head circumference, and generally shrink after 6 months with the gradual ossification of the frontal and parietal bones, and close at around 18 months of age. In addition to the fontanelle, the baby has a posterior fontanelle, which is a triangular gap formed by two parietal bones and one occipital bone, located in the occipital area. Under normal circumstances, the unclosed fontanelle has a flat, slightly sunken appearance. Although most babies’ fontanelles close by 18 months, some babies’ fontanelles are late in closing and parents are very anxious. Generally speaking, there are some diseases that affect the closing of fontanel, such as rickets, which causes problems with calcium nutrition in the body, resulting in incomplete calcification of the bones, and eventually causing the late closing of fontanel; cretinism, which is a congenital hypothyroidism in the body, and the lack or reduced secretion of thyroid hormones affects the deposition of calcium and phosphorus in the bones, causing problems with bone calcification and resulting in difficulties in closing the fontanel; hydrocephalus, which is a condition in which water in the brain affects the closing of fontanel. Hydrocephalus, which affects the closure of fontanelle due to the accumulation of water in the brain. In addition to these disease factors, some babies may be born with poorly calcified skull bones due to poor calcium nutrition of the mother during pregnancy, and their fontanels may be too large at birth, about 3-4 cm, so these babies may have their fontanels close later than normal, despite normal calcium nutrition after birth. In addition to worrying about the late closure of fontanelle, some parents worry that the baby’s fontanelle will close too early, and that the baby’s fontanelle will be closed by 6-7 months of age, so will this affect the development of intelligence? They even ask whether they should take cod liver oil pills and calcium powder again. Although the fontanelle normally closes at around 18 months, the fact that some children close their fontanelle early does not mean that the head stops growing because the head circumference stops growing until the fusion of the bones between the bones at 13-14 years of age. Therefore, although some infants have early closure of fontanelle, the head circumference will continue to grow as the brain develops and generally will not affect the development of intelligence. However, there is a situation in which children with small malformed heads, whose fontanels close early, have poor brain development and therefore have delayed intellectual development. Therefore, the most appropriate way to determine whether the early closure of fontanelle affects the child’s intellectual development is to regularly measure the head circumference and follow up the child’s neuropsychiatric development process. If the growth rate of head circumference is within the normal range and the child’s neuropsychiatric development is in line with his or her age, then even if the fontanelle is prematurely closed, it will not affect the child’s intellectual development. So, what should parents pay attention to during the growth and closure of their baby’s fontanelle? First of all, we should pay attention to the protection of the baby’s fontanelle, and should not press it heavily, because it has not yet ossified and is only protected by a layer of skin. Secondly, during each health care session, you can ask your doctor about the size of your baby’s fontanel and the growth of the head circumference. If the fontanelle continues to grow and the head circumference is too large, you should suspect the possibility of hydrocephalus, and further cranial ultrasound or CT examination is needed to confirm the diagnosis. Thirdly, when the baby is sick, the fontanelle is also an important window to observe the progress of the baby’s disease. A full and inflated fontanelle should be especially alerted to indicate an increase in intracranial pressure, which is an important clinical sign of meningitis and encephalitis; while when the fontanelle is sunken, attention should be paid to whether the baby is dehydrated.