The lower jaw is attached near its inner end on its backside to the dipper stick by a linkage for operative pivotal movement of {HEAD ~ the upper jaw} relative to {TAIL ~ the lower jaw} 
relative to
The lower jaw is attached near its inner end on its backside to the dipper stick by a linkage for operative pivotal movement of { HEAD ~ the upper jaw } relative to { TAIL ~ the lower jaw }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL