Everything You Need To Know About Fontanelles

Your bundle of joy is here, and you can’t help but marvel at his or her tiny delicate features, including that soft, throbbing part at the top of the head. Your heart may skips a beat at the thought of things going wrong, but worry not, we’ll shed some light on everything you need to know about that soft, throbbing part of the head- the fontanelle.

What are Fontanelles?

A fontanelle is a soft open area on the baby’s skull where the skull bones are yet to grow and join together. Some Kenyan mums may tell you that this part controls your baby’s breathing and heart rate. This is, however, not true. 

Importance of fontanelles

The fontanelle is important as it performs various functions. These include:

  • Easy vaginal delivery – During birth, fontanelles make it possible for the bones of the skull to move, so as to allow the baby’s head to change shape at birth. Since the birth canal is quite narrow, the movement of the bones enables the head to move smoothly.
  • Expansion during growth – Babies are born with very tiny heads which grow superfast during the first two years of life. Fontanelles allow for the fast expansion of the head and brain by leaving sufficient room for that to happen.

How Many Fontanelles Does a Baby Have?

A baby has 6 fontanelles, namely:

  • Anterior fontanelle – found on the top of the head.
  • Posterior fontanelle – located at the back of the skull.
  • Sphenoid fontanelles – they are two, and are on each side of the head, near the temples.
  • Mastoid fontanelles -they are two, and are on each side of the head, behind the ears.

When Do Fontanelles Close?

Fontanelles close at different times to allow the brain and the head enough time to grow. Once growth has taken place, the open spaces seal up and can no longer be felt. The aforementioned fontanelles close in the following order:

  • Anterior– it starts to close at 6 months and can’t be felt between 18 months and 2 years.
  • Mastoid-between 6 and 18 months.
  • Posterior-between 6 weeks and 3 months.
  • Sphenoid-by 6 months.

Fontanelles can close earlier or later than the above estimate, and still be normal.

Precautions to Consider Before the Fontanelles Close

  • Ensure that your baby sleeps on his back at night this also helps avoid SID.
  • Reposition your baby’s head from time to time. This helps his neck muscles grow stronger too.
  • Constant monitoring of your baby’s fontanelles and reporting anything that seems unusual to the doctor.
  • Be gentle when bathing your baby’s head or scalp.
  • Monitor your other children closely every time they hold the baby.

Common Concerns

It is important to frequently have a good look at your baby’s fontanelles. This is because they speak volumes about your baby’s health. Take a look:

  • Sunken fontanelle –generally fontanelles, are slightly curved inwardly. However, if they appear sunken deep into your infant’s head, it could be that your baby is dehydrated. Dehydration comes about when your baby does not breastfeed well, has diarrhea, a fever or is vomiting, or even spends lots of time in hot and dry environments. To avoid this, ensure that your baby is well fed, and is in good health, and does not spend too much time exposed to hot environments.
  • Bulging fontanelle – if your baby’s fontanelle bulges slightly whenever he cries, it doesn’t mean that something is wrong. However, if the fontanelle persists to bulge after the baby stops crying, or even feels swollen and hard to touch when he is relaxed, then that could be a sign of ill health. Bulging fontanelles are most probably brought about by swelling or fluid-retention in the brain. Once you spot this, please consult a doctor for immediate treatment.
  • Abnormally large fontanelle – fontanelles that are abnormally large and do not fuse within the approximated time, are signs of conditions such as rickets, down syndrome and hypothyroidism. 



#Please note that development differs from one child to another. 

#Content intended for educational purposes only, and should not be substituted for medical advice from your doctor.

Last reviewed January 2019

Sources: medlineplus, babycenter, columbianeurosurgery, news-medical, verywellfamily

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