After performing an autopsy, the New York City medical examiner's office has ruled actress Natasha Richardson died of an epidural hematoma due to blunt impact to the head.
Spokeswoman Ellen Borakove says the death was ruled an accident.
Richardson, 45, died Wednesday after falling on Monday while taking a beginners ski course in Canada.
The lights will be dimmed on Broadway in New York City on Thursday night in tribute to the fallen star.
Meanwhile, questions have arisen about the actress' care following her fall.
The first ambulance sent to the ski resort where Richardson fell during a ski lesson was turned away, a paramedic told a Canadian newspaper Wednesday.
Yves Coderre, director of operations at the emergency services company that sent the medics to the Mont Tremblant resort in Quebec, told The Globe and Mail newspaper Wednesday that ski patrollers requested an ambulance for Richardson.
The paramedics who responded were told they were not needed, said Coderre, whose company, Ambulances Radisson, serves Mont Tremblant, about 80 miles northwest of Montreal.
"They never saw the patient," Coderre told the Globe and Mail. "So they turned around."
Coderre said another ambulance was called later to Richardson's luxury hotel, after her condition had worsened, and she was rushed to a hospital.
It wasn't immediately clear who sent the first ambulance away, or why, but a resort spokeswoman said Tuesday that Richardson initially said that she was fine.
The resort also issued a statement Tuesday that said Richardson didn't appear hurt and was walking around shortly after the incident.
"She did not show any visible sign of injury but the ski patrol followed strict procedures and brought her back to the bottom of the slope and insisted she should see a doctor," the resort said in its statement.
The ski resort said the instructor and a ski patroller accompanied the actress to her hotel, where they again recommended she should be seen by a doctor.
Coderre said victims of head trauma often believe they are fine, a mistake that can cost them their lives.
"When you have a head trauma you can bleed. It can deteriorate in a few hours or a few days," he told the newspaper.
Richardson, 45, was married to Liam Neeson and was the daughter of Vanessa Redgrave. She and Neeson have two sons.
Alan Nierob, publicist for the Richardson family, confirmed her death Wednesday night.
Funeral arrangements will be handled by the Greenwich Village Funeral Home.
The Associated Press contributed to this report.