Three‐Dimensional Geometric Morphometric Analysis of the Nasopharyngeal Boundaries and Its Functional Integration with the Face and External Basicranium Among Extant Hominoids

Abstract

The nasopharynx is a centrally located but understudied upper respiratory tract component. This study tested hypotheses related to the functional integration of the nasopharyngeal boundaries with the facial skeleton and external basicranium over the course of development in humans and nonhuman hominoids. It was hypothesized that facial morphology (width, length, and kyphosis) is related to nasopharyngeal width and choanal morphology, whereas relative external basicranial proportions are related to nasopharyngeal depth. Human infants were used as models of extreme orthognathy and external basicranial retroflexion, whereas nonhuman hominoids were used to model greater relative prognathism and external basicranial retroflexion. Both of these groups were contrasted against adult humans, who exhibit both extreme orthognathy and external basicranial flexion. Three-dimensional landmark coordinate data were collected from age-graded series of Homo, Pan, Gorilla, Pongo, and Hylobates. Generalized Procrustes Analysis was performed, and multivariate shape differences were evaluated via principal components analysis. Additionally, linear measures were extracted from the Procrustescorrected sets of landmark data. Results indicate that human adults are indeed distinct from all groups in possessing a relatively shallow nasopharyngeal roof and shorter, more flexed external basicranial axis. Human adults and infants both exhibit greater relative choanal and nasopharyngeal width. Nonhuman hominoid faces tended to become airorhynch into adulthood, whereas humans exhibited the opposite trend. When pooling all the hominoids, facial width and palate length were strongly correlated with choanal and nasopharyngeal width, whereas facial kyphosis was strongly correlated with choanal orientation. The hypotheses were supported as the results indicated a morphologic rela-

Ecogeographic variation across morphofunctional units of the human nose

“…Our finding that the nasopharynx exhibits no evidence of climatemediated morphology across humans is consistent with findings that the nasopharynx contributes relatively little to respiratory thermal and moisture modification in comparison to the nasal fossa (Elad et al, 2008;Ingelstedt, 1970;Naftali, Schroter, Shiner, & Elad, 1998;Wolf, Naftali, Schroter, & Elad, 2004). Accordingly, our study appears to further support recent studies (Bastir, 2008;Bastir & Rosas, 2013Holton et al, 2014Holton et al, , 2016bPagano & Laitman, 2015;Rosas & Bastir, 2002) demonstrating that variation in modern human nasopharyneal morphology is predominantly related to energetic demands for sufficient oxygen intake (i.e., volume) relative to body size.…”

Differential Scaling Patterns in Maxillary Sinus Volume and Nasal Cavity Breadth Among Modern Humans

“…An important note to consider is that climate and other respiratory demands are not the only factors influencing the craniofacial skeleton. While several studies note stronger relationships with climate for midfacial structures (Smith et al, 2007;Hubbe et al, 2009;Evteev et al, 2014), other factors such as overall craniofacial architecture (Koppe et al, 1999;Pagano and Laitman, 2015), biomechanical influences (Hylander, 1977;Spencer and Demes, 1993;Preuschoft et al, 2002;Noback and Harvati, 2015), and neutral sources of variation (e.g., population structure, geographic distance) (Rothhammer and Silva, 1990;Relethford, 2004;Roseman, 2004;Harvati and Weaver, 2006;Smith, 2009;Betti et al, 2010) all play a role in shaping the midface. While the primary purpose of the current study was to simply establish whether a broader range of samples exhibit differences in the scaling relationships among the maxillary sinus, nasal cavity, and overall craniofacial size, additional studies are needed to confirm whether these established differences relate to climate.…”

Reconstructing the Neanderthal Eustachian Tube: New Insights on Disease Susceptibility, Fitness Cost, and Extinction

“…These allow for the direct assessment of CET size and orientation without scaling over any single univariate measure. Tests of inter‐ and intra‐observer error for these data are described by Pagano and Laitman ().…”

“…The baseline comparator for the Neanderthal sample was an extant human growth series ranging from newborns to adults (Pagano and Laitman, 2015;Pagano et al, 2017). Much of the materials and assessment methods has been published previously in Pagano et al (2017) and will be summarized here.…”

“…These allow for the direct assessment of CET size and orientation without scaling over any single univariate measure. Tests of inter-and intraobserver error for these data are described by Pagano and Laitman (2015). In Analysis 1, a GPA was performed using 21 right side and midline landmarks on the facial skeleton and basicranium (Table 2).…”