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Fontanelles. Fringes for the Great Frontier

Reticular nuclei synapse in a rostral desiccation....What!? Neuroscience is filled with scary language. As we explore new and eerie parts of the brain, it seems an even more intimidating word is coined. But do not fear, fellow amygdalae! Place a hand on each side of your head. Every word describes what is now in between your hands, and learning them will give you an edge on understanding the brain you own. This series, Semantics, seeks to clarify all of these words and their meanings in a short, quirky and memorable blurb. After all, what use is a word if it carries no meaning?


Birth is traumatic. Mothers know this. Babies proclaim this. The cacophony of wailing from both sides of the generation gap may just contend with those at a funeral.

BRAIN Infant Fontanelles

Today, we will explore one masterful tool you were employed with that kept your birth from becoming a funeral. Tragically, this is not true for everyone . I am referring to the fontanel.

While the word may induce imagery of a pretentious French fountain, it has little to do with its namesake.

Fontanelles are actually the soft cracks of a baby's skull that do not completely disappear until around 22 years of age. Fusion of these sutures quite literally account for the 'hard headness' of adults. A comparable analogy would be to crack a hard-boiled eggs without peeling it, and observe the membrane directly beneath each crack.

BRAIN Inside the Womb

Why did/do you have fontanelles? Skull flexibility. The birth canal is a relatively small diameter of space. The average female pelvic outlet, providing the narrowest corridor for the baby's large head, has a diameter of only 11 cm . A little over a third of 1 foot. These fontanelles allowed your skull to contract without damaging your brain and your mother. The same flexibility allows for the brain to grow in volume. While your fontanelles fuse at 22, your brain interestingly does not stop growing in volume until age 40.

Forget not the fontanel!

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