biped hand movement affecting verts on other hand

I have a biped using skin to link to mesh. With biped in figure pose (arms
apart) I tilt the left hand down and a bunch of vertices in the opposite hand
stretch down with it. Also one vert from the torso moves as well. The envelopes
do not encompass these verts. Why is this happening and how do I fix? Using
Max9.

thanks,