The Extra Bone You Might Have...

We're going to start a series of fascinating facts on the blog now, going a bit deeper than you'd get from a quiz or one of those factoid soundbites. Here's one about an extra bone you just might have and not even know it!

A fairly mundane fact that any good quizzer will know is that the human body has 206 bones. Except, that’s not always true. For starters, babies are born with quite a lot more, up to 300 as it happens. As an infant grows, some of these bones fuse together to make precisely 206 bones in fully grown adults. Except even that isn’t at all precise. Some people are born with an extra rib, or vertebrae, or extra fingers or toes, so it is more accurate to say that adult humans have between 206 and 213 bones. Still, these extra appendages are quite rare - only 1 in 200 of us have an extra rib, and it is even rarer to get an extra finger or thumb. So, almost every adult you meet will have the standard 206 bones, right? Well, no, that’s not true either which brings us on to our mysterious bonus bone.

The fabella is an extra bone that some of us have in our knee. Once upon a time in our evolutionary family tree this was common – the fabella can be found in old world monkeys and it can give a mechanical advantage if they’ve got it. However the ancestors of humans and great apes grew out of the need for it, and it disappeared or so it seemed. Now though, it is making a comeback. Academic studies have shown that in 1918, around 11% of humans had a fabella bone, but by 2018, almost 40% of humans had it. Why this strange little bone is making a comeback, nobody knows, but there’s a good chance that you have it too – which is unfortunate because it is a troublesome bone that increases the chance of arthritis and other knee problems.

So, next time you get asked how many bones you have, you can just say, it depends!

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