Eli5: Why do knees have kneecaps, but elbows dont have elbowcaps?

Question

Eli5: Why do knees have kneecaps, but elbows dont have elbowcaps?

In: Biology

Answer 1

What does it look like if someone is missing a kneecap? Can someone live without a kneecap? When I imagine missing a kneecap, my brain melts. I don’t think I want to live missing a kneecap.

Edit: prior to reading this post, I read another post about why repeating words makes the word feel and sound weird.

Now kneecap doesn’t sound right.