ABSTRACT
Developmental abnormalities of the face, mouth and jaws are relatively rare and because of the complexity of developmental abnormalities an ideal classification system is not available. Consequently, there are a number of different systems available, some purely descriptive (e.g. Tessier’s classification of clefts), while others apply only to single conditions, such as the OMENS (O, orbital alteration; M, mandibular deformity; E, ear deformity; N, nerve involvement; and S, soft tissue alterations) classification of hemifacial (craniofacial) microsomia, which has utility in instituting treatment protocols. Van der Meulen and his colleagues proposed a classification that has significant utility in helping to understand the variety and complexity of craniofacial malformations.
