said main portion and {HEAD ~ tubular portion} having an inner surface and {TAIL ~ a generally arcuate shaped outer surface} 
having
said main portion and { HEAD ~ tubular portion } having an inner surface and { TAIL ~ a generally arcuate shaped outer surface }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL