The hook is disengageable from {HEAD ~ the hook anchor} only by sliding {TAIL ~ movement} transverse to vertical and through the channel opening 
by sliding
The hook is disengageable from { HEAD ~ the hook anchor } only by sliding { TAIL ~ movement } transverse to vertical and through the channel opening
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH