skinning help request.

so i have been working on skinning this kratos model. The thing i cant seem to understand is how to skin are shoulder twists and clavicle bones. I just hope that you can take a look at the model and tell me if i skinned it correctly please. file is in 3ds max 2012 format.

here is the link for the model.

http://www.filedropper.com/kratosmax2012facepunch