Fainting

This is the left knee.

Just where that arrow is pointing?  That ligament connecting the femur and the fibula?  Imagine finding out that that spot is precisely at the height of the corner of your coffee table, and slamming that spot forcibly into that corner.

That pain will be so agonizing you feel like you are going to faint.  You have to lie down for several minutes to catch your breath and for the pain to subside.

Happened to me today.  I don't recommend you try this particular adventure.