Hi HIpGranny!
I'm so sorry your post slipped to the 2nd page.
My guess is that they each play a role (good guesser aren't I - ha/ha). Seriously, what limitations are you experiencing with each? That will provide the clues as to what role those nerves typically play.
Going to give this a bump to see if anyone is available and versed.
How are you getting along with your MS?
-Shell