Hi,
the others already wrote everything essential - but from my own story I can tell you, that we needed some time to find it out. I have arterial TOS and the artery is squeezed when my shoulder blades go together (fi when I am in a very right and good posture) - "normally" the tos testing consits in holding up the arm, but this was without a result.

I remember that in the beginning I went from one doctor to the other and I had to hear a lot of stupid answers and I was often down. But I knew, there was something wrong and I didn`t imagine the pain and the weakness. The members of this forum gave me a lot of energy to continue my way. Now I have found a vascular surgeon who is a good and competent doctor and a therapist who understands a lot about TOS, too.

Even it is a long walk through the medical jungle - don`t give up, go your way!!! TOS has many faces and in combination with other problems (cervical, shoulder,....)a case is not exacly as an other.

I wish you all the best!
Barbara