Diagram of infant fontanel development Before discussing the development of infant fontanels, we need to first understand what fontanelles are. Fontans are grooves in the human skull. Fontanelles are found in the skulls of newborns and infants and serve to support the brain. Understanding the development of a baby\’s fontanels is crucial to ensuring normal development of the baby. Stages of fontanel development: When a newborn is born, there are two fontanelles on the skull, namely the anterior fontanel and the posterior fontanel. The anterior fontanel is located directly in front of the skull and is shaped like a rhombus with a size of approximately 2.5 cm x 2.5 cm.