Table 1.
Age distribution of the sample with its statistical indicators.
N–number of subjects; SD–standard deviation. Age groups: A (20–39.99 y), B (40–59.99 y), C (60–79.99 y). SD = standard deviation.
Fig 1.
Shows the localization of the 28 used 3D landmarks.
Table 2.
A list of the 28 3D landmarks.
Landmarks 1–8 were unpaired. Landmarks 9–28 were paired–the same landmark was digitized on the right and left sides.
Fig 2.
Mean facial asymmetry from the frontal view for males (blue wireframe graph) and females (red wireframe graph).
The grey wireframe graph shows the mean symmetrical shape for the whole group. The blue and red wireframe graphs show the specific directional asymmetry in shape beside the group-specific symmetrical shape. The green arrows show the direction and range of the asymmetrical shifts from the mean facial symmetry. Age groups: A (20–39.99 y), B (40–59.99 y), and C (60–79.99 y). Numbers 1 to 28 represent 3D landmark numbers. The scale factor for mean facial asymmetry was set at 5 (the default scale factor was 1).
Table 3.
The asymmetry results from 6 Procrustes ANOVAs for sexes and age categories separately with effects of individual variable (individual effect), and directional asymmetry (DA effect).
SS = Procrustes sum of squares; MS = Procrustes mean squares; df = degrees of freedom; F = Goodall´s F statistic; p = p value.
Fig 3.
A PCA scatter plot visualizing the variability of shape directional asymmetry in the space of the PC1 and PC2 for males with percentage of variance.
The 95% confidence ellipses represent age groups (A, B, C) in years of age. The wireframe graphs show shape asymmetry (blue lines) versus shape symmetrical mean (grey lines) for PC1 (from negative value -0.03 to positive value 0.04) and PC2 (from negative value -0.04 to positive value 0.04).
Fig 4.
A PCA scatter plot visualizing the variability of shape directional asymmetry in the space of PC1 and PC2 for females with percentage of variance.
The 95% confidence ellipses represent age groups (A, B, C) in years of age. The wireframe graphs show shape asymmetry (red lines) versus shape symmetrical mean (grey lines) for PC1 (from negative value -0.06 to positive value 0.04) and PC2 (from negative value -0.04 to positive value 0.04).