This collar rotation can be accomplished by a surgical assistant or the chief surgeon without having to individually adjust and check {HEAD ~ the tilt angles} of {TAIL ~ the individual microscopes} 
of
This collar rotation can be accomplished by a surgical assistant or the chief surgeon without having to individually adjust and check { HEAD ~ the tilt angles } of { TAIL ~ the individual microscopes }
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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL