title: 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 Procrustes-corrected 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 relationship among nasopharyngeal boundaries, the facial skeleton, and the external basicranium.
authors.affiliation: Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York; New York Consortium for Evolutionary Primatology (NYCEP), Department of Anthropology, CUNY Graduate Center, New York, New York; Department of Cell Biology, New York University School of Medicine, New York, New York.
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Pagano
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Laitman
mesh_terms: D000328:Adult; D000717:Anatomy, Comparative; D000818:Animals; D015509:Developmental Biology; D005145:Face / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D015186:Hominidae / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D008297:Male; D008433:Mathematics; D008445:Maxillofacial Development; D008954:Models, Biological; D015999:Multivariate Analysis; D009305:Nasopharynx / Q000033:anatomy & histology* / Q000254:growth & development / Q000502:physiology*; D012737:Sex Factors; D019291:Skull Base / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology
keywords: external basicranial flexion; human development; nasopharynx; three-dimensional geometric morphometrics; upper respiratory tract