The standard fact you’ll hear is that the adult human body has 206 bones. That’s accurate, but it’s only half the story. Babies are actually born with around 300 separate bones. That’s almost 100 more.
What happens? As babies grow, certain small bones gradually fuse together into bigger ones. A newborn’s skull, for example, comes in several separate plates with soft “fontanelles” between them - perfect for squeezing through the birth canal and for letting the brain grow rapidly afterward. By age 2-3, those plates have fused into one solid skull. Throughout childhood and adolescence, other bones in the spine, pelvis, and limbs similarly fuse.
This is also why young children’s bones heal so much faster than adults’. Their bones are growing, fusing, and remodeling constantly. By around age 25, most of the fusion is finished and the adult bone count of 206 has settled in. Even then, your bones are still alive - they constantly break down and rebuild themselves throughout your life.
