 of your head on top of your neck. As I sit here, 73 years old, half my life under this care, I can turn and look backward over both shoulders. I know I have at least 270 degrees of vision. I got to move my head both ways to see it. Not quite as good as a chameleon, but I can turn my head both directions without a single sound coming out of my head and neck. And I haven't had 30 headaches in the last 30 years.