I was diagnosed based on symptoms and nerve conduction studies, but what really confirmed the thoracic outlet as the place of compression...for my peace of mind anyhow...was opening up that space briefly and experiencing heavenly moments of relief. Before my surgery I was asked to complete 2 months of the Edgelow Protocol - a specialized physical therapy just for TOS. The protocol never produced lasting relief, but there was one part of the therapy I could do that would give me profound relief for a few brief moments...maybe you could try this one technique and see if it works for you.

• Lay on your back on carpeted floor with knees bent.
• Take some nice deep breaths to relax.
• Once you are a bit relaxed, begin arching your back as you breath in (visualize shortening your spine).
• As you breath out, flatten your back and really "pull" your rib cage down. I would dig in my heels and use my legs to physically pull my pelvis down and really pull the ribs down. Visualize that top rib coming down and opening up that thoracic space.

For me, doing this would bring total relief to my arms. As soon as I would breath in again and my ribs went back up, the symptoms would return, but this really helped me know for certain that the thoracic space was the area of compression.

Hope this helps you...and perhaps others.