hello and welcome,
I am not really sure what info you need??
Are you asking what kind of a work up you need to find out if you have TOS??? because the carpel tunnel and other sx could be coming from a compression higher up than just the arm......neck area at the brachial plexus where a bundle of vessels and nerves are that supply the arm and neck with all the blood and nerve supply. so your issues may be higher up than just your lower arm.

You may like to have an EMG done to assess your Brachial plexus (BP) to see if you hve problems there.....although most of us have normal EMG unless you are in realllllllly bad shape and have had tos for so many years that permenant damage has been done.......a veinogram is a good test to see if your blood vessels are being blocked or not due to the decreased space in your BP as a result of your extra cervial rib....as was/is my case.
A neurologist who is familiar with TOS is also a bonus as there are some who do not believe in the diagnosis as it is a diagnosis of exclusion....ie we think of everything else then if nothing else makes sense then TOS may.

An ultrasound to your brachial plexus could tell you if you have vascular blockages in the area......in my case I had 90-100% blockage in a provocative position.

let us know more if you still want some more help!!!!

happy to answer questions and you can always PM me with them if you don't want to put them here....but the more answers the better here as we all have such different experiences!

take care and I hope some of what I have written helps....
hugs
Victoria
ps re SSI if you can't work then this is always an option but a good US member will answer that question better than I can as I am in Canada.....I am on the equivilant which is CPP canadian pension plan disability pension.

so always remember that with ssi it is a battle and then the US guys will for sure tell you that too....I had to appeal and was lucky to get it.
take care,
Victoria