ST. LOUIS — Another opponent put the St. Louis Rams hopelessly behind by halftime. This time, it was the Chicago Bears’ turn to roll up some big numbers.

Matt Forte scored on two long runs and Marc Bulger lasted only five plays before sustaining a concussion against a defense that had three of a season-best five sacks by the break, helping the Bears build a 21-point cushion in a 27-3 victory Sunday.

Kyle Orton set a franchise record by throwing 185 consecutive passes without an interception, helping the Bears (6-5) rebound from a 37-3 blowout loss at Green Bay last week and keep a share of first place in the balanced NFC North.

“We go into every game saying, ‘Start fast,”’ quarterback Kyle Orton said. “Start fast and finish strong, and I thought for the most part we did that.”

In a repeat of recent games, the Edward Jones Dome appeared to have a 50-50 mix — or worse — of Rams and Bears fans. Rams guard Richie Incognito, who was critical of fan support during the practice week, was booed after he drew a false start penalty in the second quarter.

Before leaving the field, he set down his helmet and cupped both hands to his ears, waving on fans to boo some more. He later denied it.

“I was just trying to get off the field as quick as possible,” Incognito said. “I don’t know what you saw.”

The Rams (2-9) have lost five straight since Steven Jackson injured his thigh late in a win over the Cowboys and were booed off the field at halftime as the Bears departed to cheers. St. Louis has been routed by a 99-6 score in the first half of the last three setbacks, and outscored 123-13 in the first half the last four games.

Bears coach Lovie Smith, the defensive coordinator with the Rams from 2001-03, said it felt as if he was at Soldier Field.

“We have super fans,” Smith said. “You don’t want to disappoint them. It seems like every win we’ve had our fans have had something to do with it, and they definitely did today.”

Coach Jim Haslett said the Rams didn’t quit, but were “terrible” in play-execution, ball security and tackling.

“I will do anything I can to help these guys be successful. Anything,” Haslett said. “But I can’t tackle for them anymore. I can’t take care of the football.”

Bulger took a blow to the head when Ogunleye came in untouched on a stunt on the Rams’ first series. At halftime, the Rams said Bulger was done for the day — just like the rest of the Rams, who totaled 14 rushing yards on 19 carries.

The Bears intercepted the 38-year-old Green four times in the second half, two by Lance Briggs with Brian Urlacher adding his second of the year, to keep the Rams from rallying.

Forte, one the NFL’s top rookies, had a career-best 132 yards on 20 carries and his third 100-yard rushing game. He lost his first fumble of the year early in the second quarter, but more than made up for it with a 13-yard scoring run to cap the Bears’ effortless opening drive and a 47-yarder in the second quarter in which he faked out one safety and shrugged off a tackle attempt by the second safety.

“I just run through the holes, and they do the dirty work up front,” Forte said. “That’s where it starts.”

Danieal Manning’s 50-yard kickoff return opened the game, giving the Bears a short field. After Forte cruised into the end zone, the chant was clearly audible: “Let’s go Bears!”

The Rams have allowed five touchdowns and two field goals on the opening possession this season. The Bears scored TDs on two of three drives in the first quarter, with fullback Jason McKie going untouched on a 7-yard reception when two Rams defenders followed Devin Hester into the end zone.

Orton was 18-of-29 for 139 yards with one touchdown, giving him 11 TDs and only four interceptions. He broke the previous franchise record of 174 consecutive passes without an interception set by Erik Kramer in 1995 and has gone without a pick in eight games.

Ogunleye and Tommie Harris each had two sacks, and Ogunleye also downed Green in his first series after replacing Bulger. The Bears’ pass rush totaled 17 sacks in the first 10 games, none against the Packers, but spent a lot of time in St. Louis’ backfield.

Notes: Before the game, the Rams added former owner Carroll

Rosenbloom to their ring of honor. … The Bears had a number of injuries, losing safety Mike Brown (leg) in the first half, and tight end Desmond Clark (knee) and cornerback Nathan Vasher (thumb) in the third quarter. Smith said he didn’t know the extent of any of the injuries. … Both teams opened with a reverse. Hester gained 20 yards for the Bears and Donnie Avery lost a yard for the Rams.