It doesn't happen often.. but my daughter (3 years) had it happen to her today! So i'm curious.. and googling didn't seem to help. It happens when i turn my head to either side and ..the best way to describe it, is that it feels like my brain caught on my skull or something haha. On the back/top 'corner' of my head. It clicks then hurts.. then sends a cold, numb feeling down the back of my head to the base of the skull. Does anyone have any idea what this is? What causes it? Or the medical name so i can look it up? =)