Why Don't We Have Elbowcaps?
Arms and legs are pretty similar, from the amount of bones they have to the way their joints bend, but your legs have one thing your arms don't: kneecaps.
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Have you ever taken a good, long look at your arms? You might've noticed that they're similar to your legs in a lot of ways: in both your arms and legs, there's a single bone in the top half connected to two bones in the bottom half by a joint that only bends back and forth. But there's at least one key difference: legs have kneecaps, whereas elbows don't have any kind of cap. The reason why is actually pretty simple – you don’t need elbowcaps because you don’t walk on your hands. Your knees face forward and bear your weight when you walk, so they need a little extra help and protection. The kneecap – or as biologists call it, the patella – is a sesamoid bone, a bone that’s only connected to tendons instead of other bones. One of those tendons is connected to t...
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Have you ever taken a good, long look at your arms? You might've noticed that they're similar to your legs in a lot of ways: in both your arms and legs, there's a single bone in the top half connected to two bones in the bottom half by a joint that only bends back and forth. But there's at least one key difference: legs have kneecaps, whereas elbows don't have any kind of cap. The reason why is actually pretty simple – you don’t need elbowcaps because you don’t walk on your hands. Your knees face forward and bear your weight when you walk, so they need a little extra help and protection. The kneecap – or as biologists call it, the patella – is a sesamoid bone, a bone that’s only connected to tendons instead of other bones. One of those tendons is connected to t...
