Craniofacial malformations are a ¿difficult-to-define group¿ of congenital anomalies named after the anatomical location of a given defect present at birth. According to working definitions, it could include any etiologic category (chromosomal, environmental, Mendelian, multifactorial, etc.), as well as any pathogenetic mechanism (malformation, deformation, disruption, dysplasia), or any clinical category (developmental field complex, isolated defect, sequence, syndrome, etc.). There is a general tendency in the vertebrates to form bilateral structures as mirror images of each other over the midline (symmetry). Symmetry is described as correspondence in size, shape and relative position of parts on opposite sides of a dividing line or median plane. Asymmetry is defined as a lack or absence of symmetry. When applying this to the human face, an imbalance or disproportionality between the right and left sides shall be noted. A degree of asymmetry is normal and acceptable in a normal face. It has, however, become evident that there are many phenomena associated with laterality or asymmetry during growth and development explainable only by complex.