In the case of a U shaped staple, the plug of filler material would be joined to {HEAD ~ the cross member} joining {TAIL ~ the staple legs} 
In the case of a U shaped staple , the plug of filler material would be joined to { HEAD ~ the cross member } joining { TAIL ~ the staple legs }
OTH 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