If someone has their fingers crossed while they say something, that means that they are lying. This phrase can also be used in the sense of "we'll keep our fingers crossed", meaning that you are hoping for something.

hinge

Phalanges.

When fingers are very sore and it is hard to open and close your hand, it could signify something as simple as over working your hand. This could also signify a break in the hand.

Why? (I think I know, I'm not so sure) Her friend betrayed her.