A fan broke his arm when he fell over a railing above an outfield wall before the Mets-Giants game at Citi Field Saturday.The fan, identified as Nick Gambacorta, was standing in the area called the Party City deck over an 8-foot wall when he leaned over the railing and fell. Gambacorta was reportedly trying to get the attention of a Giants player who had just caught a flyball.“It just looked like he was reaching for something and then just fell over,” Giants pitcher Matt Cain said. “I don’t know if it was for a foul ball or what.”Gambacorta’s arm was “terribly” bloody, said Cain, and he saw bone protruding through skin.A witness said Gambacorta — who was on outing with local bus operators, supervisors and their families — tried stopping his fall by grabbing the railing with his right hand as he went over the waist-high railing. The twisting motion seemed to break his arm.Security and medical staff attended to the injured man on the warning track in left field. They placed him on a backboard then put him on a stretcher before wheeling him though a gate in the left-field wall.The Mets released a statement saying a fan fell from the stands and was taken to a hospital. The team didn't provide additional details.