Yoga help for "Writer's Cramp"?

Sorry for the repeat message.

I have trouble with Writer's Cramp. It's NOT a cramping of the hand, but rather some of the hand muscles lose their tension and it's hard if not impossible to write properly. Does anyone know if there's any yoga help for this condition. I think it might be a problem with pinching either in the shoulder, elbow or wrist.

Thanks for any help.