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