3ds Max :: Need To Stretch Mesh Around A Corner

Imagine you have a a box, say 1 foot square. You attach a fat rubber band in the center of one side and then you pull the rubber band up to an edge and around it to the center of the next face. It stretches and the corner is the only spot that controls the change of direction. If you raise one end (the segment from your finger to the corner) it raises, but the segment from the corner to where the other end is attached stays flat on the box until you move your hand far enough away so that there is now no wrap around the edge. Now if you pull and relax, it acts like any normal rubber band. But then if you lower your fingers with the end you are holding and go back down to the face, you wrap around that corner again and can pull and relax around the corner.
 
What I'm actually doing is animating a muscle that goes around a bone when it's stretched out. But when it's contracted, one end moves out away from that bone it's wrapped around and it's now just a straight line. I need to animate that muscle from that contracted and straight position to the extended position but have the end of the muscle bend around the bone when it hits it.