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