You may have heard that a person has 206 bones. That’s sort of true: Most adults have somewhere around that number. You’ll never know exactly how many you have, anyway, since a lot of them are little bitty bones like sesamoids in your finger joints.
Babies, though? They have even more. The average baby has about 300 bones. That’s because a lot of things that are one bone in an adult are actually multiple separate bones, joined by cartilage, in little ones. Take the skull, for example: babies’ “soft spot” is just the cartilage in between some of the head bones that haven’t fused together yet.