Morphometry of the normal human ear : a cross-sectional study from adolescence to mid-adulthood

The objective of this study was to supply information about: (1) normal gender-based dimensions of ears (linear distances and ratios, area); (2) left-right symmetry; and (3) growth changes between adolescence and mid-adulthood. The three-dimensional co-ordinates of several soft-tissue landmarks on the ears and face were obtained by an electromagnetic digitizer in 40 male and 33 female adolescents aged 12-15 years, 73 young female and 89 young male adults aged 19-30 years, and 41 male and 38 female adults aged 31-56 years. From the landmarks, paired ear width and length were calculated and averaged for age and gender, as well as the relevant ratios, ear areas and angles relative to the facial midline, and indices of left-right symmetry. Comparisons were performed by factorial analysis of variance. All ear dimensions were significantly larger in men than in women (P < 0.005). A significant effect of age was found (P ( 0.005), with larger values in older individuals. On average, the three-dimensional position of ears was symmetric, with symmetry coefficients ranging between 94 and 96%. Data collected in the present investigation could serve as a database for the quantitative description of human ear morphology during normal adolescent and adult growth.