{HEAD ~ A transition} or tapered portion 50 extends from {TAIL ~ the portion} 48 to an enlarged portion, shown as a spherical cap 52 
extends from
{ HEAD ~ A transition } or tapered portion 50 extends from { TAIL ~ the portion } 48 to an enlarged portion , shown as a spherical cap 52
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH