Broadway dimmed the marquee lights Thursday night in memory of Natasha Richardson, the Tony award-winning actress who died the day before.

The medical examiner ruled Thursday that Richardson died from a from a brain hemorrhage caused by blunt impact to her head.

She is one of an estimated 55,000 people who will die this year from a traumatic brain injury.

"It's a true tragedy. I feel awful for the husband, for the children, for the whole family. It was so unnecessary," Jane Rothchild, fan of Natasha Richardson said.

She hit her head while skiing and initially she felt fine. But an hour later she had a headache, was admitted to the hospital, and died a short time later.

"You can have a traumatic brain injury from a small bump or a big bump on the head what may have happened to her, though, is she had this fall, struck her head, and there may have been this period of time when blood was clotting and collecting and pushing on her brain," a New York City doctor said.

Richardson was not wearing a helmet at the time of her accident.

Wearing a helmet is the best way to prevent a head injury. Parents should make sure their children have a well-fitting helmet before they go outside to ride bikes, skateboard, roller-blade, ski, anything where they could sustain a serious blow to the head.

But helmets are not just for kids.

"I wouldn't come skiing. I wouldn't let my family come skiing without helmets," skier Dave Hunniford said.

But helmets don't protect against all head trauma. So when you hit your head hard, regardless of whether you're wearing a helmet, go to the emergency room if you're vomiting, sleepy, have a bad headache, have a seizure, are unusually irritable, lose balance or have slurred speech. Doctors will perform a CT scan to see if you have any neurological problems.

Natasha Richardson was the mother of two, daughter of actress Vanessa Redgrave and the wife of actor Liam Neeson.