Apparently, you can. Twenty-eight-year-old Monique Jeffrey of Melbourne, Australia, sneezed so hard that she actually dislocated two vertebrae in her neck:
She's lucky not to have been paralyzed, according to her doctors: Link - via Arbroath
Monique—of Melbourne, Australia—who was alone at home with her 10-month-old baby, said it was incredibly painful after she sneezed: "I just knew something was wrong. I felt something move and I was in excruciating pain."
She was able to text her husband with a simple "Help can't move pls call." Emergency personell came to the rescue, taking her to Sandringham Hospital. Doctors told her she had a "wry neck" and asked her to do some exercises to move it again. But when her left arm went numb and started to tingle, the doctors immediately sent her to The Alfred hospital's spinal trauma unit, where they discovered that her two top vertebrae were dislocated.