Useless Body Organs
Plica semilunaris ( Third eyelid )
You may not know it , but you have a third eyelid. Pull open the two more noticeable eyelids and take a look - it's located right in the corner by the tear duct.
The third eyelid is left over from what's known as a " nictitating membrane ," which is still present in animals like chickens , lizards and sharks.
Doctors don't really know much about sinuses, only that we have a lot of them. Possibilities for their function range from insulating our eyes to changing the pitch and tone of our voice.
Also prone to swelling and infection. If you have them by your 30s , it's almost an accomplishment.
When were hairier , the erector pili made the hairs stand on end when we needed to appear bigger and scarier. Now , it just gives us goose bumps.
Back in the day , when we ate meat off the bone and didn't floss afterward , our teeth tended to fall out.
Therefore , when those reserve molars , aka " wisdom teeth ," came in they were welcomed. Nowadays , fluoride and dental plans have just made them a huge pain.