The arm rotates about axis A with {HEAD ~ an angular range} of {TAIL ~ rotation} of the order of 60 degrees 
The arm rotates about axis A with { HEAD ~ an angular range } of { TAIL ~ rotation } of the order of 60 degrees
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH