In January 2014, a woman in San Diego, California, went to a local salon to get her hair done. What happened next sounds like the most nightmarish of urban legends: the angle and degree she was tilted in the chair and the way her head tipped back over the sink while the stylist was washing her hair caused Elizabeth Smith to have a stroke two weeks later:

“I vomited, my head became hot and I couldn’t stand. I had weakness in my arms and legs. They didn’t think I was going to live,” said Smith, choking back tears. Smith says she could hardly believe what nearly killed her. Her doctors pointed to her time in the shampoo chair. Beauty Parlor Stroke Syndrome is what they called it. It’s a rare but documented condition. Multiple doctors who saw Smith say when her neck was bent backwards, it hyperextended, her vertebrae slicing an artery. A clot began forming, later causing a stroke. “Several of Ms. Smith’s neurologists confirmed with her that the stroke was caused by the vertebra dissecting her artery during her hair wash,” said Smith’s attorney Carree Nahama.

The danger is real, although the probability of it happening is low. A study that came out in 1993, subsequently covered by the New York Times, found that older people have a higher risk of a stroke during or after a visit to the beauty salon (Smith was in her late 40s at the time):

The patients suffered from a variety of complaints attributable to poor blood flow in arteries leading through the neck to the back of the brain, including severe dizziness, imbalance and facial numbness. Four out of five suffered strokes leading to permanent neurologic damage. “In older people, neck motion beyond a certain degree can be extremely dangerous, particularly hyperextension and rotation,” said Dr. Weintraub, chief of neurology at Phelps Memorial Hospital in North Tarrytown, N.Y., referring to backward arching and twisting. He and others have suggested that patients receiving anesthesia or undergoing prolonged dental work may also be vulnerable, since they too have their necks arched back abnormally for prolonged periods.

A 2006 study also looked into the issue, saying while it probably occurred more than previously thought, the risk of stroke in these cases was easily alleviated:

Taken together, hyperextension combined with hanging the head backwards in a hair washbasin can be seen as a risk factor for posterior circulation ischemia. It probably occurs more often than assumed and a number of patients may report about previous dizziness episodes under the same conditions when asked specifically. It can be prevented by changing the shampoo routine from the hanging head position to a flexed or neutral position.

Dr. Scott Olson, a vascular neurologist at the University of California, San Diego, told us that while he hasn’t seen this specific case, he has seen this particular injury (more commonly called a “vertebral artery dissection,” which can lead to subsequent clotting and stroke) and it’s not unprecedented:

It’s pretty much a fluke. I have seen people who’ve had this happen while surfing, they happen after dental visits. I had an auto mechanic who was working on a car for a day and had his head hanging over a creeper… I had a patient fall asleep in a movie theater and ended up having a dissection. [But] …It’s like a lot of things in life where it’s the same thing you’ve done. I think people should not be inordinately worried about it. I mean, tens of thousands of people across this country have their hair washed at salons every day. It’s very statistically uncommon.

He says there are signs to watch for after a potential injury:

Things people should pay attention to, should be concerned about? Pain on one side of the neck after extension, and obviously, any neurologic symptoms like vertigo. There’s some genetic disorders, like Marfan Syndrome, hyperextensible joints, or connective tissue disease that will make you more prone.

Elizabeth Smith says she racked up $250,000 in medical bills and has permanently lost part of her vision and mobility. She is now suing the salon for damages.

On 30 March 2016, we spoke to Smith. She told us: