The wall limits {HEAD ~ vertical movement} of a hook connected to {TAIL ~ the hook anchor} to prevent inadvertent disengagement by vertical movement 
The wall limits { HEAD ~ vertical movement } of a hook connected to { TAIL ~ the hook anchor } to prevent inadvertent disengagement by vertical movement
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH