20/04/2026
The "Flexible" Beginning
Babies aren't born with a rigid skeleton because they need to be flexible enough to pass through the birth canal. Instead of solid bone, much of a newborn's skeleton is made of cartilage—the same firm, flexible stuff in your ears and nose.
The Fusion Process
As a child grows, a process called ossification takes over. This is where the cartilage is replaced by actual bone, and separate pieces begin to join together.
The Skull: A baby’s skull starts as several plates with "soft spots" (fontanelles) that eventually fuse into one solid structure.
The Sacrum: Your lower spine is a single bone as an adult, but it starts as five separate vertebrae in infancy.
Why it Matters
If we were born with 206 solid bones, we’d be far too brittle. The "extra" pieces allow for the rapid growth spurts of childhood. By the time you hit your late teens or early 20s, the fusion is complete, and you're down to the "standard" 206.