too much moves in armature - pose

Question

in pose also the ribs move although I only move the arm

I have nothing parent

unfortunately I don't know how to get this fixed

My Blender file: https://1drv.ms/u/s!Amok31-g9Vyoid1QzxhrViaikey4_A?e=DdsUhv

Answer 1

You've parented the the ribs to the armature, so accidentally the arm acts on the ribs and you need to correct that:

• Select the arm to know its name:

• Select the ribs, go in the Properties panel > Object Data > Vertex Groups, find the vertex groups that has the same name, click on Remove:

The lower arm influences the ribs as well so do the same. You can also do it in Weight Paint mode.