Position/Displacement sensor

Hi,
I'm working on a project where I control a robot hand with my own. I use a glove with some flex sensors attached to it for measuring bending of the fingers. Now I need a sensor to measure the rotation of the fist. It should be something to put on the glove, that measures fist rotation relative to the rest of the arm. This way I don't limit the hand movement.
thank you

Accelerometer, perhaps?