The Mayo Clinic defines torticollis, also called cervical dystonia, as a painful condition in which neck muscles contract involuntarily. The head twists to one side, forward or back.
The New York Times Health Guide distinguishes between three forms of torticollis. --Idiopathic torticollis occurs without a cause. Faulty genes or an underlying condition may be at fault. --Congenital torticollis (present at birth) may occur "if the fetus' head is in the wrong position while growing in the womb, or if the muscles or blood supply to the fetus' neck are injured." --Acquired torticollis occurs as a result of damage to the nervous systems or muscles.