Here is a better explanation and a pic attached to show what I'm trying to achieve.

I'm trying to figure a way where my character is getting up off a rock and have his elbow (and hand possibly) locked to the rock and not have his elbow slide all over the place. I figure he'll be using his elbow to help him get up, but how do you set it up? I have a hand controller to move the main arm and a wrist controller (locator) for rotating the hand. I'm attaching a pic to show what it is I'm trying to do. I've had no luck and just can't figure out what it is that I need to do. At the moment whenenver I rotate the body to twist or turn a certain way, the arm goes straight the rock. Any help much appreciated - thanx.