The New York City medical examiner's office said Thursday that Natasha Richardson died from a blunt impact to the head, a day after the actress succumbed from injuries sustained in a Quebec skiing accident.
The 45-year-old Tony Award-winning actress fell on the Mont Tremblant slope on Monday during a ski lesson on the resort's bunny hill.
The autopsy also found that the blunt impact caused bleeding in Richardson's brain.
Richardson appeared to be fine after the fall on Monday, and refused to see paramedics who were at the scene within 20 minutes of the fall, the Globe and Mail reports.
But the newspaper says 911 records show that emergency workers were not called again for another two hours. Initially, the luxury resort where Richardson was staying said that an ambulance was called only an hour after the fall.
The actress was originally rushed to a local hospital and then was driven to a trauma clinic in Montreal. She was later flown to New York on Tuesday, where she died in hospital.
Montreal does not have an air ambulance service, and questions are being raised as a helicopter would have greatly reduced the one hour drive to Montreal.
Mount Tremblant issued a statement on Thursday extending "its most sincere condolences to Ms. Richardson's family and friends at this sad and difficult time."
The statement went on to say that "our staff at Tremblant intends to fully co-operate with any resulting investigations."
Richardson was the mother of two children and was married to actor Liam Neeson.
A spokesperson for Neeson confirmed the death on Wednesday, but gave no details about the cause.
Neeson was seen late Wednesday night going into the family's New York apartment, where he was greeted by people offering their condolences. In response, the worn-looking Neeson gave a single wave and said "thank you."
A statement issued by the family Wednesday evening requested privacy.
"Liam Neeson, his sons, and the entire family are shocked and devastated by the tragic death of their beloved Natasha," said the statement.
"They are profoundly grateful for the support, love and prayers of everyone, and ask for privacy during this very difficult time."
There is no word yet on when a funeral or memorial service will be held.
Tributes begin to pour in
Richardson's death was described as a "tragic" loss by actress Lindsay Lohan, who worked with Richardson on a remake of "The Parent Trap" in 1998.
"She was a wonderful woman and actress and treated me like I was her own," said Lohan. "My heart goes out to her family. This is a tragic loss."
Actress Jane Fonda recalled meeting a young Richardson on the set of "Julia," the 1977 film Fonda starred in opposite Richardson's mother, Vanessa Redgrave.
"She was a little girl but already beautiful and graceful. It didn't surprise me that she became such a talented actor," Fonda wrote on her blog.
"It is hard to even imagine what it must be like for her family. My heart is heavy."
Broadway productions dimmed their lights for one minute in honour of Richardson Thursday evening, while a number of well-wishers lined the street.
Neeson made a brief public appearance to thank people for their support.
Acting legacy
Hailing from one of Britain's most illustrious theatrical dynasties, Richardson was the elder daughter of Oscar-winning actress Vanessa Redgrave and the late director Tony Richardson.
Her other famed relations included sister and "Nip/Tuck" star Joely Richardson, aunt Lynne Redgrave, uncle Corin Redgrave, and Richardson's maternal grandparents, Sir Michael Redgrave and Rachel Kempson.
Richardson's career highlights included the film "Patty Hearst" and a Tony-winning performance in a stage revival of "Cabaret."
Professionally, she divided her time between stage and screen. She won a Tony for her performance as Sally Bowles in a 1998 Broadway revival of "Cabaret."
She also appeared in New York in a production of Patrick Marber's "Closer" (1999) as well as a 2005 revival of Tennessee Williams' "A Streetcar Named Desire," in which she played Blanche opposite John C. Reilly as Stanley Kowalski.
Born on May 11, 1963 in London, England, the flaxen-haired beauty made her film debut at age four in 1968's "The Charge of the Light Brigade," a film directed by her father. Richardson played a flower girl to the film's star, her mother Vanessa Redgrave.
Trained at London's Central School of Speech and Drama, the acclaimed stage actress launched her career in regional theatre in Leeds, England in 1983. Her first professional performance in London's West End followed in 1985 when the 22-year-old actress appeared in a revival of Anton Chekhov's "The Seagull."
Determined to distinguish herself from other starlets saddled with a famous last name, Richardson appeared in winning stage productions of "High Society" (1987), "Fat Man and Little Boy" (1989) and "Anna Christie" (1993) - a role that earned her a Tony Award nomination.
She seamlessly shifted characters on screen, from the seductress to a cool terrorist, to a caring scientist and a neurotic Southern belle.
