This is from our first forum 8 years ago.....Hope it helps new folks

This response submitted by Allen Togut MD> on 3/28/99.

EMG is a very insensitive way of diagnosing TOS. The EMG looks at muscle fibers, which are supplied by large, myelinate nerve fibers which more often than not involved late in the course of TOS. TOS usually first affects the small unmyelinated
sensory fibers, and the little large myelinated sensory fibers which an EMG does not see.

(I give the example if feeling heat from a candle flame; small sensory nerves feel the heat and the burn hurting, the larger nerves make the muscle move to jerk your arm away from the heat
Dianne)
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Double and triple crush
This response submitted by Allen Togut MD. on 4/17/99.

To understand why people devlope entrapment at more than one level-that is TOS, ulnar cubital tunnel, and carpal tunnel syndromes, one needs to know that the nerve cell body-sensory nerve extends from just a little outside the spinal column all-all-all-all the way to the place where it receives sensation. That is a long way.

That is a long cell and therefore it can be affected at one or more places-brachial plexus, ulnar at the elbow, median nerve at the wrist. And frequently what causes a problem at one level will also cause a problem at the second level. And moreover, when one area of the cell is affected this facilitates a second area. And lastly, diabetics are more prone to have double crush syndromes.
Sincerely, Allen Togut MD.