Ragdoll Part4: ragdoll shapes follow target joints, visible joints follow ragdoll shapes

If you enable this option in the menu:   Developer -->Avatar_Options-->Collide_As_Ragdoll  then the avatar's skeleton's collision shapes will self collide and the visible positions of the joints will try to follow the positions of the skeleton's shapes.

To see the shapes being used for collisions enable:  Developer-->Avatar_Options-->Skeleton_Collision_Shapes.
Adding these extra constraints help make the visible hand joints stable since they help keep the first segments of the finger collision shapes aligned correctly.