The circuit board has a groove in {HEAD ~ a section} of {TAIL ~ a surface} of the circuit board 
of
The circuit board has a groove in { HEAD ~ a section } of { TAIL ~ a surface } of the circuit board
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH