A proportional analysis of some facial height and depth variables in 10 to 16 year old children.

A method for analysing the horizontal and vertical proportions of the face is described, based on natural head orientation (NHO). It demonstrates how individual deviations from the mean proportions can be quantified both horizontally and vertically. Correlation between facial depth to height (index 1) and the mandibular plane angle was determined and found to be fairly strong and highly significant (r = 0.5, P < 0.001). Facial depth to height and lower facial height to total facial height (index 2) relationships were found to be strongly correlated at each age between 10 and 16 years, with only small mean differences. For this reason the norm values presented for 12-year-old children for indices 1 and 2 should be applicable to orthodontic patients within this age range. The relationship between mandible and maxilla (index 3) increases continually between 10 and 16 years in boys, and between 10 and 14 years in girls, about 0.3 units a year. It can provide supplementary information for individual case analysis. For boys the increase was 2.2 units per year between 14 and 16 years of age.