Three-dimensional characterization of zygomatic arch morphology and its relation to the articular eminence in a Brazilian population

Zygomatic arch and articular eminence are structures from the human skull involved in jaw muscle activity. The aim of the study was to evaluate three-dimensional morphological patterns of the zygomatic arch and its relationships with articular eminence in a Brazilian population. 122 computed tomography scans of human skulls were evaluated. The Mimics 18.0 software (Materialise, NV, Belgium) was used to perform segmentation of images from CT scans. 3D reconstructions of CT scans were imported into Rhinoceros 5.0 software (McNeel & Associates, Seattle, USA), in which linear measurements (mm) were obtained. Statistical analysis was performed in GraphPAD Prism v.8 (San Diego, CA, USA). The normality of the sample was checked by Shapiro-Wilks and significance level of 5% was considered. Based on cross-sectional area classification, out of 116 male zygomatic arches the incidence was 59% of type elliptical (E) and 41% of type blade-like (Bl). Out of 102 female zygomatic arches the incidence was 38% of type E and 62% of type Bl. There was no incidence of type cylindrical (C). Based on the classification proposed in the present study, the incidence for males was 58% of type parentheses (P), 38% of type bracket (B) and 4% of type M-shaped (M); and the incidence for females was 33% (type P), 66% (type B) and 1% (type M). The elliptical and convex body of the zygomatic arch prevailed in males and the blade-like and straight body of the zygomatic arch prevailed in females. There is no relationship between zygomatic arch type and zygomatic arch and articular eminence distances.