RULES
Targeting and Initiating Contact With the Crown of the Helmet (Rule 9-1-3)
No player shall target and initiate contact against an opponent with the crown (top) of his helmet. When in question, it is a foul.
Targeting and Initiating Contact to Head or Neck Area of a Defenseless Player (Rule 9-1-4)
No player shall target and initiate contact to the head or neck area of a defenseless opponent with the helmet, forearm, fist, elbow or shoulder. When in question, it is a foul. (Rule 2-27-14)