yes- upper is different nerves according to dr brantigan. (c5 and c6 maybe?)
lower is c7/c8 i think. Upper plexus symptopms are the headaches, tingly half of face, tingly ear and some others. Lower plexus symptoms are the hand stuff.

dr brantigan thinks upper responds to complete scalenectomy better....lower=rib resection needed.
I posted a Brantigan and roos peper somewhere on this, i think...you might be able to find it if you search my posts.

dr ahn told me he could not find a difference in surgical success doing complete scalenectomy for upper plexus symptoms...and rib resection is useful for relieving many many kinds of entrapment. My upper plexus symptoms were the first to go when I had rib resection surgery on the left side.

sorry quick answer...hand hurting. got to get off this dumb computer./