The outer part 12b of {HEAD ~ the base joint} is fixed to {TAIL ~ one end} of a lower arm 14 
The outer part 12b of { HEAD ~ the base joint } is fixed to { TAIL ~ one end } of a lower arm 14
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH