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