The ribbon has a small thickness to prevent obstruction of the elements bordering the top flange and {HEAD ~ the upper surface} of {TAIL ~ the top flange} 
of
The ribbon has a small thickness to prevent obstruction of the elements bordering the top flange and { HEAD ~ the upper surface } of { TAIL ~ the top flange }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL