Symmetry of the face: Review of a complex matter

Facial symmetry is one of the most important characteristics in the perception of a human face. Facial asymmetry means that both facial sides are not identical. Mild facial asymmetry is very common in the general population. Most people have slight facial asymmetry, and this is the normal biological situation in humans. Abnormalities of soft tissue, dental and skeletal elements result in facial asymmetry. Asymmetry has many causative factors and its etiology includes both congenital and acquired disorders. Extended knowledge of the embryology and anatomy of each branchial arch derivative is mandatory for the diagnosis, grading, treatment and followup of postoperative patients. In this review, we focus on the broad differential diagnosis of facial asymmetry. Treatment is multidisciplinary and must be related to the underlying cause. When formulating a treatment plan, complete knowledge of the etiological factors and character of the asymmetry plays a crucial role. The timing of treatment should be based on functional criteria, growth, the expected stability of the result and the patient's wishes. Patients in a functional crisis situation should be treated early.