This question crossed my mind the other night as
I put some of that wonderful, soothing gel on my
shoulder. Why doesn’t Polar Ice/Icy Hot/etc. al
affect the palms of your hand? Seems like you’d
find your palms hot and numb after you use the
stuff, right?
Anyone got the Straight Dope? 
I believe the answer is that the skin on your hands is callussed and toughened from use.
I have heard that a jellyfish can not sting the palm of your hand from a scuba diving instructor - I never carred to test that though.
Actually, I think it is that there are fewer nerve endings in the fingers than most skin. Wouldn’t do do have your primary feelers being as sensative as… well, some other protrusions.
no way erislover,
We did an experiment in school a few years back usin a paper clip. You bent it so you had two ends and poked them on your skin. You recorded if you could feel one or two pokes. The fingers were defenatly the closest together where you can feel two pricks.
Well, try using your genetalia to unscrew a tough screw and get back to me.