The front wheel is a caster wheel pivotally attached to {HEAD ~ an arm} directly or indirectly connected to {TAIL ~ the wheelchair frame} 
indirectly connected to
The front wheel is a caster wheel pivotally attached to { HEAD ~ an arm } directly or indirectly connected to { TAIL ~ the wheelchair frame }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL