As as assistant referee focusing on an offside situation I am mostly looking for the scoring part of the player in determining offside most time the head is the farthest point ahead. With that in mind as I am looking at players lined up along the center half I am looking for the same thing. So if a head is over the line and the feet may not be is this technically an offsides call? Many people seem to think that where feet are is an issue but referees aren’t typically looking at feet for offsides calls.
USSF answer (July 2, 2010):
Your first sentence has it all: When judging the offside position, we look solely at the body parts that can score a goal in a legal play on the ball: the head and the feet, but NOT the hands.
There is, of course, no offense called “offsides.”