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