User in Autodesk Area forum search for Stretchy & Bendy Arm Rig tutorial similar to this one (Maya tutorial) or this one (Softimage). Well, I`m too not found similar tutorial for the 3ds Max. This is strangely, right? This is can be done using Physique by Spline-based floating bones. In Max help (F1) search for "Spline-Based Physique Deformation" .