FrenchFri - Glad to hear you are slowly improving.

Regarding a double crush, how it was explained to me is to think of a water hose. You get a kink in the hose (say at the neck), it takes less pressure to get a kink (compression) in the hose further down the line (say in the thoracic outlet or elbow). You can even have a triple crush => neck, elbow and wrist. If the nerve is slightly compressed above, it doesn't take as much to compress the nerve further down the line. None of the sites may be compressed enough to show up on EMG or physical testing on a standalone basis.

Cathy - Have they ruled out TOS as a possibility for your ulnar nerve? I've had surgery for it and I wouldn't be able to work today if I hadn't had surgey as I'd lost the use of that hand before surgery. So I know what you're going through regarding considering getting re-trained for another field.