You are both right; I think most doctors know very little about TOS, if they've heard of it at all. After my cervical ribs were discovered and I started researching cervical ribs, I found several sites that mentioned TOS. As this was my introduction to TOS, I studied it fiercely so that I could talk to my doctor intelligently about it. I have had no fewer than three doctors say, almost verbatim, the information found on the first couple of websites that pop up when you google "thoracic outlet syndrome." I'm pretty sure they were googling it, too. ;-) And I have talked to several doctors (not as a patient, but in social situations) who freely admit they have never heard of it, some of whom become quite intrigued when I tell them what I know about it.

Since it's not really common, and it's often a diagnosis of exclusion (i.e. you rule out a zillion other things first, as there is no definitive "TOS test,") it's not something that is covered extensively in med school or even in Continuing Education courses. A doctor has to make a concentrated effort just to become educated about it, much less treat it. I will say that for all the nonsense I've endured for the last 3 years - I have learned to be my own patient advocate and take a far more active role in discussions, decisions and treatment plans. It is rare for a doctor to admit, in front of a patient, that he or she is largely ignorant of the subject at hand - they're trained not to; a doctor should always appear calm and confident for the benefit of the patient, after all. :-)