a plurality of {HEAD ~ electrodes} in {TAIL ~ an array} and adapted to be in electrical contact with the body 
in
a plurality of { HEAD ~ electrodes } in { TAIL ~ an array } and adapted to be in electrical contact with the body
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH