In cervical dystonia (CD), outcome of treatment with botulinum neurotoxin (BoNt), is highly dependent on the correct identificationof the muscles involved. There are “simple” (in one plane) and “complex” (in two or more levels) forms of CD. The difficulty lies in the treatment of complex CD, requiring a more extensive analysis. For such analysis, different diagnostic methods are used. These include: ultrasound, CT neck soft tissue imaging (particularly the deep muscles of the neck), electromyography (EMG) of neck muscles, and standardized photographs of patients with measurements of angles (head, neck, thorax).

Cervical dystonia may occur in principle in three axes (rotation, lateral flexion and sagittal flexion). The head or the neck can be affected alone in each of these planes of movements. Therefore, eight clinical forms can be distinguished: torticollis, laterocollis, antecollis, retrocollis, torticaput, laterocaput, antecaput and retrocaput. In this chapter, involved muscles, their origins and insertions are presented in a table for each of these clinical forms. Injection under CT guidance is described.