Nasal Profile Assessment Using Geometric Morphometrics in a Sample of Chilean Population. Clinical and Forensic Implications

Abstract

The search of morphological patterns of nasal profile using traditional morphometrics has been the goal of several studies aiming to orient therapeutical planning and forensic techniques such as facial reconstruction. The present study aims to find and describe such patterns with geometric morphometric tools in a sample of Chilean population with geometric morphometric tools. We used the lateral X-rays of 156 individuals (men and women) and 14 landmarks in bone and soft tissues. Procrustes analysis was performed followed by principal component analysis to assess general shape variation, regression of shape components against centroid size to study to allometric effect and discriminant analysis by sex with cross-validation test. Our results show the lack of shape patterns, and that the size, followed by sex, explains within a limited scope the shape changes which suggests the presence of uncontrolled variables and a high effect of inter-individual variation. In general terms bigger profiles, more frequent in men, show a lower Pronasal point, a more prominent nasal dorsum with a thicker layer of soft tissue, and a vertically expanded upper lip. We suggest the reassessment of the importance of individual aesthetic evaluation for clinical purposes, and recommend caution in concluding results based on forensic reconstruction techniques