{HEAD ~ The lower portion} is recessed relative to {TAIL ~ the upper portion} in a direction toward the opposite cutting edge 
is recessed relative to
{ HEAD ~ The lower portion } is recessed relative to { TAIL ~ the upper portion } in a direction toward the opposite cutting edge
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH