Anatomy and cervical dystonia : "Dysfunction follows form".

At first glance, cervical dystonia might be an illustration of the well-known proposition "function follows form". Nevertheless, cervical dystonia is a highly non-physiological condition, which cannot be reproduced by healthy subjects and does not respond to the usual physiological rules. "Dysfunction follows form" might be the most accurate aphorism to define cervical dystonia. Taking into account this situation and recent insights, the anatomic approach needs to be adapted to allow a better understanding of semiology and to improve botulinum toxin therapy. In this review dealing with a new approach to cervical dystonia, we develop some practical anatomical concepts concerning the head and neck complex. Knowledge of cervical spine and muscular dysfunctions in cervical dystonia is an essential stage in treating cervical dystonia patients with botulinum toxin.