The time it takes for the baby’s head to close is related to the child’s development, physical condition and nutritional status, and cannot be generalized. The place where the bones at the top of the baby’s head are not closed at birth is called fontanelle, and there are fontanelle and bregma. As the baby’s brain develops, the volume of the brain will gradually increase, and the fontanelle will widen slightly, generally at around 6 months of age, the fontanelle is the widest, after which the fontanelle becomes smaller and smaller, and most of them can gradually close at around 1 year old, and at the latest not later than 2 and a half years old. The fontanelle is closed at birth or is very small, and closes at the latest 6-8 weeks after birth. If the fontanelle closes too early, you should consider whether there is brain dysplasia; if the fontanelle closes too late, you should suspect rickets, hydrocephalus, intracranial tumors and other diseases. If your baby’s fontanelle closes too early or too late, you should go to the pediatric neurosurgery department of a regular hospital in a timely manner to determine the situation through medical examination by a specialist and then give the necessary treatment.