These openings can be {HEAD ~ holes} or small bores extending from the top surface through {TAIL ~ the bottom surface} of the base member 
extending through
These openings can be { HEAD ~ holes } or small bores extending from the top surface through { TAIL ~ the bottom surface } of the base member
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH