A lower arm has {TAIL ~ one end} connected to {HEAD ~ the base rotatable} joint member and another end connected to a central joint member 
A lower arm has { TAIL ~ one end } connected to { HEAD ~ the base rotatable } joint member and another end connected to a central joint member
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH