Anatomy of the pterygopalatine fossa: an innovative metrical assessment based on 3D segmentation on head CT-scan.

Abstract

The pterygopalatine fossa is an important anatomical structure for several surgical and anaesthesiologic procedures; yet, very few data are available about its size. This study aims at providing a metrical assessment of pterygopalatine fossa through an innovative 3D segmentation procedure on head CT-scans. CT-scans from 100 patients (50 males and 50 females) aged between 18 and 85years were chosen for the study. Right and left pterygopalatine fossae were segmented through ITK-SNAP open source software. Height and volume were calculated on the acquired 3D models. In addition, anterior-posterior nasal spine distance, upper facial height (nasion-prosthion) and biorbital breadth (ectoconchion-ectoconchion) were measured as well. Statistically significant differences of height and volume according to sex and side were assessed through two-way ANOVA test: sexually dimorphic measurements were further assessed through one-way ANCOVA test using the three cranial measurements as covariates (p < 0.05). On average pterygopalatine fossa height was 24.1 ± 3.5mm in males, and 22.8 ± 3.4mm in females, whereas volume was 0.930 ± 0.181cm3 in males and 0.817 ± 0.157cm3 in females, with statistically significant differences according to sex (p < 0.05), but not to side (p > 0.05); interaction was negligible for both the measurements. ANCOVA test verified that sexual dimorphism of both measurements is independent from general cranial size (p < 0.05). The present study highlighted the sexual dimorphism of pterygopalatine fossa: results may improve the knowledge of this anatomical structure difficult to explore, but crucial in several fields of clinics and surgery.