In some particular days, it seems that my car is somehow at a different potential from the ground. When I get out my car and I wear my sneakers (that I think are better insulators than other kind of shoes) and I touch the metallic gate with my hand or with a key I am holding, I can feel (and see, if it is night) the electric discharge.
I noted that, when it happens, I can feel it not only on my skin but also somewhere inside my knuckle, approximately between finger bones, just before the last phalanx.
My question is: could this be explained from a physical point of view? Could it be that there is a change in the resistance of my finger or something similar to a capacitor in my knuckle?
If this is exclusively related to my sensation of the discharge, then maybe this question is more related to biology. Please excuse me if you consider this question an off-topic.
Thinking again to my question, I experienced the same effect (but through my elbow) when I touched the conducting grid of a mosquito racket (even when it is off, there is a certain voltage, I discovered). Therefore, I don't think it is just a matter of sensations.
This can be related to Factors affecting pain of static electricity shock, even if it is a quite different question.
Edit (23/01/2017): After Squid's comment, I have tried to change clothes, shoes and even to drive another car; in every case, especially in dry and cold days, the electric discharge were produced. Therefore, I think that this static electricity is due to my movements driving, but I still have no idea of why I feel the discharge in my knuckles and not elsewhere.