The fontanel is a diamond-shaped bony defect formed by the frontal bones on both sides, the parietal bones on both sides, and the frontal suture, coronal suture, and sagittal suture.
During labor and delivery, the cranial suture and fontanel give the cranial plate some room to move, the fetal head is squeezed when passing through the birth canal, and the cranial sutures mildly overlap, making the fetal head deformed and smaller, which is conducive to the delivery of the fetus. Therefore, a newborn baby’s skull will have such a gap, which is called fontanel.
The fontanel is a diamond-shaped bony defect in the center of the front part of the infant’s head, formed by the frontal bones on both sides, the parietal bones on both sides, and the frontal, coronal, and sagittal sutures. Because there is no bone mass present here, it is soft to the touch. The oblique diameter at birth is about 2. 5 cm.
The normal fontanel closes between 12 and 18 months after birth. It closes no later than about 2 years of age. Early closure is seen in microcephaly and premature closure of the cranial sutures. Late closure of the fontanel or an oversized fontanel can be seen in hydrocephalus and chondrodysplasia. With increased intracranial pressure, the fontanels are tense and bulging in addition to being enlarged.
Infants with developmental problems are advised to go to regular hospitals for further examination and treatment to avoid delaying the condition and causing serious consequences.