Re: Good article on commonly misunderstood NBA rules. Good read.
A defender may not be in contact with an extended forearm to an offensive player with the ball at any time above the free throw line extended. Below the free throw line extended and outside the lower defensive box, a defender may use an extended forearm to the back/side of an opponent with the ball to maintain his legally obtained position. Inside the lower defensive box, a defender may use an extended forearm at anytime to maintain his position against a payer with the ball. At no time may the forearm be used to dislodge, reroute or impede the offensive player.
Hear is a foul rule that ref's can make a call and players go 'what?'