Why do I feel my phone vibrating on the wrong leg?

We here at the Naked Scientists wouldn't like to comment on whether or not Tommy is weird, but if he is, he's in good company! Our very own Dr Chris experiences something similar:

Chris - What I have got is, on the outside edge of each elbow, if I pinch the outer skin of my elbow I feel a pain on a strip of skin on my trunk (about, if I laid my arm down by my side, where my elbow would be on my trunk). I feel that hurting there too. On both sides.

This is interesting. I think it's a sort of miswiring of the nervous system and it's got an embryological basis to it.

When the body develops, you start off as this flat plate of cells and that then rolls up into a tube. It's split up into segments a bit like a centipede. Well, we're very similar, we have segments to our body. And some of those segments are specialised.

Two segments produce arms at the top and two segments down below produce legs. They bud out from the body segment and they pull the nerve supply from that segment with them.

You end up with a sort of extension of the nervous system down into the two limbs: upper and lower.

然后进入中枢神经系统informs your spinal column as to what's going on in that bit of the body.

It's possible, I suppose, that some of the nerves, as well as being connected to the hand and the spinal cord area encoding the hand, could also be routed to the bit of the body that original bulge came out of to form the limb.

So in the case of the questionner, I suspect there's a sort of a crossover going on in his nervous system where something has not crossed properly and the nerves from one side of the body are triggering nerves for the other side of the body. So it's a sort of referred sensation phenomenon.