via Scientific American Blogs

When we are born, all of our body is adapting to the new environment we are taken to. From chemical reactions to instinctive reflexes, babies experience incredible changes in the first weeks and years of their lives, and one of them is the transition to losing some bones.

Maybe you don’t know, but a lot of the bones we normally have are the product of the fusion and merging of other structures, this is a normal and particular phenomenon.


But, Why Do Babies Have More Bones On Their Bodies?

via Baby Won’t Sleep?

There is an easy explanation for why this happens. Normally as adults, we have 206 bones, but babies can be born with around 300, that is a big difference. Basically, they need several structures to be able to go out through the birth canal.

A lot of those structures are flexible and kind of separated before they weld together into the ones we know. This also explains why their heads are so soft and fragile, they need elasticity so their skull is made from cartilage before it ossifies when they are about 6 years.

In the 8th week of gestation, the baby starts to develop all the tissues until its body is completely formed. A big part of their skeleton is made from cartilage, which is an elastic tissue that allows them to go out easily and without any damage. That’s one of the reasons why babies are so fragile.

If you see the skeleton of a baby you will notice a lot of differences such as 3 or 4 vertebrates instead of the sacrum, the humerus divided into three parts, or the skull formed by 8 bones when as adults we only have 4. It can be years before all the bones calcify and become the definite skeleton. This calcification is a long and slow process that turns cartilage tissue into the bone and is completed when the skeleton weighs about 12% of the body.

The bones grow when the cells of the cartilage divide and start to multiply in the growing plaques. Eventually, those cells die and are replaced for proper bone cells, once they are fully grown out. Meanwhile, the fusion of the structures is made by the capillary vases that take the nutrients to the bone cells, called osteoblasts, which are responsible for the ossify.

The growth of the body doesn’t stop until puberty is completely done, which can be even when people are 20 or 25 years old. Calcium is an important factor for this process to be developed well, so it is important that babies and children consume it regularly so their bones are strong and healthy for the rest of their lives.