A fontanel or soft spot is a space between the bones of the skull in an infant or fetus. Typically, ossification or hardening of the bone is not complete and the sutures have not fully formed.
The purpose of the fontanelles are protection of the human brain. It also allows the baby’s head to pass through the birth canal. The major bones that compose the skull of a newborn include the following: (2) frontal bones, (2) parietal bones, and (1) occipital bone. These bony plates cover the brain and are held together by fibrous material called sutures. These bony plates eventually fuse and harden to become the skull. There are six fontanelles. The anterior fontanelle, posterior fontanelle, (2) sphenoidal, and (2) mastoid fontanelle.
The posterior fontanelle generally closes 1-3 months after birth. The sphenoidal fontanelle is the next to close around 6 months after birth. The mastoid fontanelle closes next from 6 to 18 months after birth.
The anterior fontanelle is usually the last to close around 24 months however it may close earlier.
Premature closure and ossification is called craniosynostosis. This can lead to complications for an infant. An anterior bulging fontanelle may be indicative of increased intracranial pressure (ICP). It can occur due to encephalitis or inflammation of the brain. This is most often due to infections.
Hydrocephalus is a build-up of fluid inside the skull. Another cause may be meningitis which is an inflammation of the meninges, a membrane covering the brain and the spinal cord. Tumor and/or space occupying lesion must be included in the differential diagnosis. This is an emergency situation. It is important to consult your pediatrician immediately.
A sunken fontanelle may be indicative of dehydration or malnutrition. It is important to consult your pediatrician immediately.
Other conditions which may affect the anterior fontanelle and may cause premature closure of sutures include: achondroplasia, congenital hypothyroidism, Down syndrome, and Rickets. Parents who suspect a bulging fontanelle, a sunken fontanelle, or premature closure of a suture should notify their pediatrician immediately.
5 years ago / Comments Off on Fontanelles