how do i fix a vertice that isn't selected?

i’ve been working on rigging up my character following the stellatutorial.

here’s the problem i’ve having. the stomach is deforming in a spot where there is no vert selected i’ve triple checked everything. the same thing happens to the other side too.
here’s the images.

http://members.cox.net/pdottz/armshoulderstomach.jpg

the weight painting shows that nothing else is selected.

http://members.cox.net/pdottz/painted.jpg

go into edit mode and check the vertex group.

MacBlender

how do you know it isn’t part of the thumb group, or something else child of that bone?

z3r0 D.
i never thought of that. thanks. now i remember earlier when checking for the deforming the hand groupd was deforming the stomach also. thanks guys.