Stand up and hold a pencil in each one of your hands. Hold it in your fist so it points out in front of you.

Just hold them there naturally and then look down and see which way your pencil is pointed.

If it is pointed inward, you have TOS. If it is pointed straight out or outward, then you don't.

Not scientific but I think consciously trying to hold your pencils straight or out, will help posture, hehe.