The breakdown is roughly 90-95% neuro, 5% venous, 1-2% arterial. Although I think these percentages are based on the definitions of venous and arterial TOS meaning those who have had a clot. You can have venous and arterial symptoms without a doctor giving you that official diagnosis.

One thing to note about the EMG: I have learned from docs and reading others' experiences that many people with neuro TOS actually have a normal EMG.

I have had multiple venous doppler tests. The standard test is looking at your whole chest/arm area from collarbone to wrist to see if there are any clots. The TOS doppler test is where the tech places a transducer over your subclavian vein (and sometimes axillary as well) and puts your arms in different positions to see if and in what positions you have diminished blood flow. From what I understand, only vascular surgeons who really specialize in TOS order this type of study. I would ask your doc about performing both.

As far as other tests, ultrasounds are really the standard right now. There are more invasive tests (venograms for veins and angiograms for arteries) and tests with high radiation (CT scans) but those really only come into play if the ultrasound shows something that needs further investigation. One thing you could ask about is getting a C-Spine x-ray that can show if you have any cervical ribs or abnormalities of the first rib.