The phrase "to protect the head" means to take measures to keep the head safe and out of harm's way from potential injuries or dangers. Full definition
Many of us are diligent with making sure kids wear sunscreen, but we somehow trust hair to be «enough» in terms of protecting their heads from the sun. (modernmom.com)
This feature helps protect the heads of both front and rear passengers in a severe side - impact collision. (edmunds.com)
As a result, the curtain can remain upright and help protect the head in an effective way even if the window is open. (topspeed.com)