Having your hair washed professionally can be a luxurious treat—the best part of getting your haircut, even. Who doesn't like a great head and neck massage? But when your stylist forgets to prop your head up with a towel or two, it can be painful. Your neck falls backwards and the sink digs into your skin. Ouch. As it turns out, this position isn't only uncomfortable, it can also prove dangerous.
As Peter Gloviczki, M.D., a vascular surgeon at the Mayo Clinic in Rochester, Minnesota, told Self, "beauty parlor stroke syndrome is caused when there is an injury, tear, or blood clot in one of the four major arteries that go to the brain." If your neck isn't properly supported while your stylist shampoos your hair, it can be hyperextended, and that can compress one of those four major arteries. According to Gloviczki, a tear in the blood vessel could result "in a blood clot, which can travel to your brain and cause a stroke." This syndrome, officially called iatrogenic vertebral artery injury, is rare, but it has happened.