STILLWATER, Okla. – After an annual football game they call Bedlam, thousands of Oklahoma State fans jumped and pushed their way onto the field in joy. The Cowboys had just taken apart the Oklahoma Sooners, their bitter and often more successful rivals. The Cowboys’ first national championship suddenly seemed within reach.

But fans were pressing toward the field, which is separated from the stands by a 9-foot brick wall. The crowd pulled down the goal posts, and in the 45 minutes or more it took police to restore order Saturday night, some fans were trampled as the crowd struggled to reach the exits.

At least 12 people were injured.

“You couldn’t move, there were so many people,” said Michael Authement, who heads the command post at emergency medical provider LifeNet EMS. “It was a nasty deal.”

The field is not designed to allow huge crowds to get in or out. Narrow staircases are the only ways to reach the field from the seating areas. To get back off the field, fans were crunched together and pushing to make their way to the exits.

The announcer had warned fans not to storm the field, but “we just laughed,” said Alex Lillibridge, a 19-year-old freshman from Belton, Texas. Fans started jumping the wall in the last seconds of Oklahoma State’s 44-10 win, and Lillibridge said he followed.

Some people said they were forced to jump because of the crush of fans.

“A girl pushed me over the wall,” said Jennifer Payne, 21, a junior from Stillwater. “Luckily, I didn’t get injured, but I didn’t have control of when I jumped off the wall. You just moved with the crowd.”

Jerry Nevils of Sapulpa, who was at the game but did not storm the field, said Sunday that the security force surrounding the field was no match for the “slow, steady avalanche” of students and other fans.

Oklahoma State spokesman Gary Shutt said two people were airlifted to Oklahoma City for treatment, including one adult who had a medical problem before the end of the game. Eight people were taken to Stillwater Medical Center — including two who were having surgery Sunday on broken ankles. Three others were treated at the field.