{HEAD ~ Pathway} 88 is defined by upper surface 90 of stop 72 and {TAIL ~ a parallel wall section} 92 beneath cover plate 78 
is defined by
{ HEAD ~ Pathway } 88 is defined by upper surface 90 of stop 72 and { TAIL ~ a parallel wall section } 92 beneath cover plate 78
HEAD HEAD HEAD HEAD HEAD OTH REL REL REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH