Under normal circumstances, the fontanelle closes around one and a half years old, so some children can see the beating of the fontanelle before it closes. The beating of fontanelle is mainly caused by the pulsation of blood vessels in the skull, and it is normal for some babies to not see the beating of fontanelle. Whether or not the fontanelle is beating is related to the size of the fontanelle and the child’s activity. For example, when the child is calm, the fontanelle may not be seen to be throbbing, but when the child is crying or moving more vigorously, the beating of the fontanelle will be more obvious. Even if the fontanelle is not throbbing, you can still feel the pulsation of the fontanelle when you touch it with your hand. If you can’t feel the beating of the fontanelle with your hand, you should be alert to the possibility of microcephaly, the most common cause of microcephaly is a viral infection.