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