Sorry for being so dense about this, but how would a doc go about doing electrophysiological tests on the phrenic nerve? I'm assuming it isn't part of a routine test unless they suspect something is up with the nerves innervating the diaphragm. Is this correct?

Can anyone tell me how this would be done? Where on the body would they do electrophysiological testing for the phrenic nerve?

Thanks so much in advance.