The counter force of the vacuum resists {HEAD ~ tissue movement} in {TAIL ~ the direction} of electrode penetration 
in
The counter force of the vacuum resists { HEAD ~ tissue movement } in { TAIL ~ the direction } of electrode penetration
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH