"I'm not sure what difference (a broken seat belt) made," said Dr. Patrick Lantz, medical examiner for Forsyth County and one of three experts who reviewed Earnhardt's autopsy report for The Charlotte Observer.
The idea that the seat belt break was responsible for Earnhardt's death was advanced Friday by Dr. Steve Bohannon, head of emergency medical services at Daytona International Speedway. The theory is consistent with measurements of the driver, the car's cockpit and how he hit his chin on the steering wheel, Bohannon said.
"(But) this is only one theory," he said.
Earnhardt, 49, died Sunday in a crash at the last turn on the last lap of the Daytona 500 in Florida. Bohannon said Earnhardt had no vital signs when rescuers arrived.
NASCAR officials confirmed Friday that the left lap seat belt in his car was found in two pieces when rescuers arrived at the crash.
Earnhardt died as a result of a ring fracture around the base of the skull, according to a preliminary autopsy report released by the Volusia County (Fla.) medical examiner's office. The fracture, described as a circular break in the skull, around the connection of the head to the spine can instantly destroy the brain's control of the body's heartbeat and respiration.
Earnhardt also had a scrape on the right side of his chin, a bruise on the left side of his scalp, broken ribs on the left side of his chest, a fractured sternum and a broken left ankle, the report said.
"The injuries Mr. Earnhardt sustained are consistent with a seat belt being loose or broken," said Dave Byron, a spokesman for the medical examiner's office.
Asked if he was referring to Earnhardt's fatal injuries, Byron replied: "You can assume that's what we meant."
But the three outside experts said they have questions about what role if any a broken seat belt played in the driver's death.
Ring fractures are customarily seen in two situations, said two medical examiners, one from North Carolina and one from Florida.
One occurs when someone falls from a great height and lands on their buttocks. The force of the ground contact drives the spine up into the skull, causing the fracture, they said.
The other occurs in a high-speed wreck in which the body is restrained but the head is not. The force pulls the head away from the neck in a motion that may end with a blow on top of the head.
The seat belts apparently worked well enough to at least partially restrain the body and enable that kind of action to occur, said one medical examiner, who spoke on condition of anonymity to avoid appearing critical of a colleague.
Bil Simpson of Simpson Performance Products, the Mooresville company that made the belts, denied that that the way the belt was made caused Earnhardt's death.
"This company has no responsibility with respect to what happened. None," Simpson told the Observer.
Simpson told the newspaper that he inspected Earnhardt's wrecked car Wednesday night in Hickory with NASCAR officials and Winston Cup drivers Rusty Wallace and Ken Schrader. He declined to describe what they found.
Simpson also said he had received death threats since NASCAR officials announced the discovery of the broken belt.
"My conscience is totally clear," he said. "I'm telling you, it has nothing to do with Simpson."
While attention has focused on the seat belt, one of the medical examiners said a better helmet would not have altered the outcome. "You would need clamps to hold his helmet on to his shoulders to make a difference," he said.
Earnhardt's lower body might be expected to have suffered more injuries if the seat belt had broken, two of the experts said. If the lap belt had completely failed, they would have expected to see more injuries to his lower body than a broken ankle, and perhaps more damage to his torso than a few broken ribs.
Without seeing the damaged car and other accident evidence, it's hard to know if even the broken ankle was related to a broken seat belt, because the engine block may have been forced up into the passenger area, Lantz said.
Photographs of the car wreckage do not show evidence of the engine being forced up.
Bohannon noted that Earnhardt's car suffered not only a head-on crash, but also a hit from the right side. If it was simply a head-on crash, the victim might have suffered the kind of lower body injuries other medical examiners expected. But the combination of impacts, along with a break of one seat belt and resulting loss of tension in the others, could have twisted Earnhardt's body in an unexpected way.
Bohannon said he believes the driver hit his chin on the steering wheel. Earnhardt's jaw was not broken and his teeth were intact, but it's possible the energy from the blow was transferred through the jaw and along the sutures that connect sections of the skull. The ring fracture was along suture lines farther back in the skull, he said.
"You're going to get a lot of opinions on this thing. I'm not a pathologist, but the pathologist on the autopsy did notice the abrasion on the skin (of Earnhardt's chin)," Bohannon said.
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