Facial asymmetry: type, extent and range of normal values.

For analysis of facial asymmetry (signed, absolute, relative) a group of 720 normal children aged 6-18 years was examined. Twelve direct dimensions measured on both sides of the face were assessed. The results revealed that the extent of facial asymmetry is the same in both sexes and does not change with age. Facial asymmetries have mostly a fluctuating character, usually with slight predominance of the right side. With the help of double standard deviations of signed asymmetry, the range of normal asymmetry for lateral facial dimensions was determined as 4-5 mm. The definition of the borderlines or normal and abnormal asymmetries may be of practical value in some medical disciplines.