In {TAIL ~ the case} of a nail, {HEAD ~ the plug} of filler material would be joined to the nail head 
In { TAIL ~ the case } of a nail , { HEAD ~ the plug } of filler material would be joined to the nail head
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH