Nasal Septal Deviation and Facial Skeletal Asymmetries

Abstract

During ontogeny, the nasal septum exerts a morphogenetic influence on the surrounding facial skeleton. While the influence of the septum is well established in long snouted animal models, its role in human facial growth is less clear. If the septum is a facial growth center in humans, we would predict that deviated septal growth would be associated with facial skeletal asymmetries. Using computed tomographic (CT) scans of n 5 55 adult subjects, the purpose of this study was to test whether there is a correlation between septal deviation and facial asymmetries using three-dimensional (3D) geometric morphometric techniques. We calculated deviation as a percentage of septal volume relative to the volume of a modeled non-deviated septum. We then recorded skeletal landmarks representing the nasal, palatal, and lateral facial regions. Landmark data were superimposed using Procrustes analysis. First, we examined the correlation between nasal septal deviation and the overall magnitude of asymmetry. Next, we assessed whether there was a relationship between nasal septal deviation and more localized aspects of asymmetry using multivariate regression analysis. Our results indicate that while there was no correlation between septal deviation and the overall magnitude of asymmetry, septal deviation was associated with asymmetry primarily in the nasal floor and the palatal region. Septal deviation was unassociated with asymmetries in the lateral facial skeleton. Though we did not test the causal relationship between nasal septal deviation and facial asymmetry, our results suggest that the nasal septum may have an influence on patterns of adult facial form. Anat Rec, 299:295-306, 2016. V C 2015 Wiley Periodicals, Inc. Key words: ontogeny; geometric morphometrics; facial skeletonCraniofacial and occlusal asymmetries are commonly observed in populations and can result from a number of causative factors. These include the early loss of primary teeth, loss of permanent teeth, genetic or congenital malformations (e.g., hemifacial microsomia, unilateral clefts, etc.), environmental factors (e.g., habits and trauma), and functional deviations (Bishara et al., 1994;Burstone, 1998

Fluctuating Asymmetry of Human Populations: A Review

“…Long bones of the upper limbs, for example, have a right bias in most populations [49][50][51]. Furthermore, parts of the cranial skeleton can also be directionally asymmetric [32,52,53]. One can either remove the directional component [48,54] or decompose a mixture distribution into fluctuating, directional, and antisymmetric components [55].…”

“…Facial asymmetry, for example, is related to deviation of the nasal septum [52], which may be related, in turn, to asymmetry of the brain [53]. Moreover, some directional asymmetry may be present.…”

Morphological interaction between the nasal septum and nasofacial skeleton during human ontogeny

“…As the anterior component of the chondrocranium, the nasal septal cartilage is thought to act as a key growth center influencing the development of the nasofacial skeleton (Scott, 1953;Wexler & Sarnat, 1961;Latham, 1970;Siegel et al 1990;Wealthall & Herring, 2006;Holton et al 2011;Hall & Precious, 2013;Hartman et al 2016). During ontogeny, the expanding septum exerts a mechanical force on surrounding skeletal tissues, inducing a morphogenetic response at key sutural growth sites (e.g.…”

“…Copray, 1986;Al Dayeh et al 2013). While the influence of the nasal septum on facial skeletal growth has been demonstrated primarily in long-snouted animal models, there is evidence that the septum also has a significant influence on the development of the human facial skeleton (Pirsig, 1984(Pirsig, , 1992Precious et al 1988;Verwoerd & Verwoerd-Verhoef, 2010;Holton et al 2012;Hall & Precious, 2013;Hartman et al 2016).…”

“…Given the developmental influence of the nasal septum as a facial growth center, deviated septal growth appears to have significant consequences for skeletal development. For example, deviation of the expanding nasal septum is associated with asymmetrical development of the palatal, nasal, and lateral regions of the facial skeleton (Gray & Brogan, 1972;Gray, 1983;Kim et al 2011;Reitzen et al 2011;Hartman et al 2016). Moreover, septal deviation has an indirect influence on lower facial skeletal development resulting from altered patterns of respiratory function, which subsequently affects the growth of the upper and lower jaws (e.g.…”