Furthermore, {HEAD ~ the stabilizing effects} of {TAIL ~ the covering} make the mattress stationary for surgical operations 
of
Furthermore , { HEAD ~ the stabilizing effects } of { TAIL ~ the covering } make the mattress stationary for surgical operations
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH