The parasite without kneecaps

What do adults have that children don't?

Would you believe that babies aren’t born with kneecaps? And would you also believe that toddlers and young children don’t all have kneecaps either? In fact, some children don’t have fully developed kneecaps until they’re 10-12 years old.

I first heard about babies and their lack of kneecaps a few months ago. I had never really thought much about about the skeletal development of children. Now I cannot stop thinking about this, so naturally I had to tell other people. It seems obvious that babies don’t have bone kneecaps since they’re little sacks of cartilage when they’re evicted from the womb.

As I learned more, what threw me a little is how late in adolescence kneecaps fully form (despite the development timing making sense). Toddlers look like petite drunks with how unstable their walking is, so from a design standpoint it makes sense that their kneecaps are cartilage on it’s way to ossification (process of going from cartilage to bone*). Between the ages of two and six, the cartilage cosplaying as a kneecap begins to harden, but it can take until a child is basically finished with elementary school before they have kneecaps that are bone.

Thinking about this, I can’t believe I played soccer for five to seven years without kneecaps. I would blame the presence of kneecaps for the pain my body feels after falling on my knees playing soccer, but really it’s the age paired with the lack of a strong mobility routine.

I hope you learned something new about the human body. Don’t go touching random peoples’ children’s knees, that’s weird. If you enjoyed this fun fact, send this newsletter to a friend and join me next week for another long-form fun fact.

*I learned this new word while researching this kneecap discovery.