Saline is used to clean head wounds.
"To be big-headed" - to be overly full of oneself"To come to a head"  to reach a critical stage and require immediate action"To bite someone's head off"  to criticize someone strongly"Can't make head or tail of something"  cannot understand something"A head start"  an early start that provides an advantage over others"Head and shoulders above someone or something"   better than someone or something in some way"To want someone's head on a platter"  to want someone severely punished"To bang your head against a brick wall"  to continually try to achieve something without success"To have one's head in the clouds"  to not pay attention to what is happening around one because one is so absorbed by one's own thoughts=== Engineering and scientific fields ===The head's function and appearance play an analogous role in the etymology of many technical terms
 Heads develop in animals by an evolutionary trend known as cephalization

