String puppet behaviour

I have a humanoid model used as a ragdoll and a hand model of which I move the fingers separately. Now I want to emulate a puppet string behaviour. As if there were strings attached from the fingers to the puppet. So if I, for example, would like to move the head up and down, I move my middle finger up and down.

How would I achieve this effect? I've tried with different sorts of joints, but they're too fixed to a certain point to resemble strings.