A model of developmental canalization, applied to human cranial form.

Developmental mechanisms that canalize or compensate perturbations of organismal development (targeted or compensatory growth) are widely considered a prerequisite of individual health and the evolution of complex life, but little is known about the nature of these mechanisms. It is even unclear if and how a "target trajectory" of individual development is encoded in the organism's genetic-developmental system or, instead, emerges as an epiphenomenon. Here we develop a statistical model of developmental canalization based on an extended autoregressive model. We show that under certain assumptions the strength of canalization and the amount of canalized variance in a population can be estimated, or at least approximated, from longitudinal phenotypic measurements, even if the target trajectories are unobserved. We extend this model to multivariate measures and discuss reifications of the ensuing parameter matrix. We apply these approaches to longitudinal geometric morphometric data on human postnatal craniofacial size and shape as well as to the size of the frontal sinuses. Craniofacial size showed strong developmental canalization during the first 5 years of life, leading to a 50% reduction of cross-sectional size variance, followed by a continual increase in variance during puberty. Frontal sinus size, by contrast, did not show any signs of canalization. Total variance of craniofacial shape decreased slightly until about 5 years of age and increased thereafter. However, different features of craniofacial shape showed very different developmental dynamics. Whereas the relative dimensions of the nasopharynx showed strong canalization and a reduction of variance throughout postnatal development, facial orientation continually increased in variance. Some of the signals of canalization may owe to independent variation in developmental timing of cranial components, but our results indicate evolved, partly mechanically induced mechanisms of canalization that ensure properly sized upper airways and facial dimensions.

EBV infection is associated with histone bivalent switch modifications in squamous epithelial cells.

Epstein-Barr virus (EBV) induces histone modifications to regulate signaling pathways involved in EBV-driven tumorigenesis. To date, the regulatory mechanisms involved are poorly understood. In this study, we show that EBV infection of epithelial cells is associated with aberrant histone modification; specifically, aberrant histone bivalent switches by reducing the transcriptional activation histone mark (H3K4me3) and enhancing the suppressive mark (H3K27me3) at the promoter regions of a panel of DNA damage repair members in immortalized nasopharyngeal epithelial (NPE) cells. Sixteen DNA damage repair family members in base excision repair (BER), homologous recombination, nonhomologous end-joining, and mismatch repair (MMR) pathways showed aberrant histone bivalent switches. Among this panel of DNA repair members, MLH1, involved in MMR, was significantly down-regulated in EBV-infected NPE cells through aberrant histone bivalent switches in a promoter hypermethylation-independent manner. Functionally, expression of MLH1 correlated closely with cisplatin sensitivity both in vitro and in vivo. Moreover, seven BER members with aberrant histone bivalent switches in the EBV-positive NPE cell lines were significantly enriched in pathway analysis in a promoter hypermethylation-independent manner. This observation is further validated by their down-regulation in EBV-infected NPE cells. The in vitro comet and apurinic/apyrimidinic site assays further confirmed that EBV-infected NPE cells showed reduced DNA damage repair responsiveness. These findings suggest the importance of EBV-associated aberrant histone bivalent switch in host cells in subsequent suppression of DNA damage repair genes in a methylation-independent manner.

Anatomy of teleost fish immune structures and organs.

The function of a tissue is determined by its construction and cellular composition. The action of different genes can thus only be understood properly when seen in the context of the environment in which they are expressed and function. We now experience a renaissance in morphological research in fish, not only because, surprisingly enough, large structures have remained un-described until recently, but also because improved methods for studying morphological characteristics in combination with expression analysis are at hand. In this review, we address anatomical features of teleost immune tissues. There are approximately 30,000 known teleost fish species and only a minor portion of them have been studied. We aim our review at the Atlantic salmon (Salmo salar) and other salmonids, but when applicable, we also present information from other species. Our focus is the anatomy of the kidney, thymus, spleen, the interbranchial lymphoid tissue (ILT), the newly discovered salmonid cloacal bursa and the naso-pharynx associated lymphoid tissue (NALT).

Development of the nasopharynx: A radiological study of children.

The relation between pharyngeal tonsil and the bony nasopharynx determines the nasopharyngeal airway patency. Despite its importance, an anatomical study utilizing advanced imaging has not been conducted. The aim of the study was to evaluate the pharyngeal tonsil and bony nasopharynx depth and their ratio (adenoid-nasopharyngeal ratio [ANR]) with relation to sex and age in the general pediatric population. After excluding reported history of adenoidectomy, acute upper airway illness, allergy, and poor quality, 200 randomly selected head computed tomographies (CTs) of children were evaluated. CTs were divided into five age groups (0-5, 5.1-8, 8.1-11, 11.1-14, and 14.1-17 years). For each CT scan, the pharyngeal tonsil, bony nasopharynx and ANR values were calculated. A significant difference was found in the bony nasopharynx and pharyngeal tonsil depth between the five age subgroups (P < 0.001). Both bony nasopharynx and pharyngeal tonsil depth significantly increased between the age groups of 0-5 years to 5.1-8 years (4.17 mm increase, P < 0.001 and 3.47 mm increase, P < 0.009, respectively). The pharyngeal tonsil depth gradually decreases following the age of 8 years. No difference was found between age groups beyond age of eight for both the pharyngeal tonsil tissue and the bony nasopharynx. The ANR has an upward trend in the age group of 5.1-8 years. No sexual predilection was found. The bony nasopharynx and the pharyngeal tonsil tissue both grow during childhood. Different growth rates result in the narrowest airway in the age group of 5.1-8 years (ANR peak). These growth curves should be taken under consideration when treating pediatric pharyngeal tonsil hypertrophy. Clin. Anat., 33:1019-1024, 2020. © 2019 Wiley Periodicals, Inc.

Relationship between oro and nasopharynx permeability and the direction of facial growth.

AIM: Most scientific literature relates vertical growth to individuals with decreased upper airway permeability. However, we often find subjects with a long face and a normal breathing pattern, most likely caused by other aetiological factors. And, frequently, we also find decreased upper airway permeability with horizontal growth. The aim of the study was to compare the cephalometric measurements of the oro and nasopharynx permeability with the facial growth direction and to identify the most common facial growth direction in individuals with decreased upper airway permeability. MATERIALS AND METHODS: Cephalometric analysis was carried out in 158 pre-adolescent patients at the Orthodontic appointment, using facial profile teleradiographs. Parameters used were Jabarak's ratio and measurement of oro-nasopharynx space. Data collected were submitted to statistical treatment. RESULTS: This study points to the presence of an intermediate growth in individuals with diminished oro and nasopharynx permeability, either simultaneous or separate. The number of individuals with diminished permeability and vertical growth is close to the number of individuals with horizontal growth. CONCLUSIONS: The individuals with diminished permeability of the upper airway present an intermediate growth direction, representing the most frequent type. In the less common growth directions, there is a slight tendency to horizontal facial growth verified in individuals with diminished nasopharynx permeability. Also, a light tendency to vertical facial growth is present when oropharynx permeability is reduced.

Morphometric growth changes of the nasopharyngeal space in subjects with different vertical craniofacial features.

INTRODUCTION: The purpose of this study was to morphometrically investigate the growth pattern of the adenoids in growing subjects with hyperdivergent and hypodivergent vertical craniofacial features. METHODS: In this retrospective study, we used a longitudinal sample of lateral cephalometric radiographs of 28 hyperdivergent and 30 hypodivergent subjects from 4 to 13 years of age. The radiographs were obtained from the American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection. Measurements were made using digital tracings of the lateral cephalograms and point distribution models. Mixed-model analyses were used for statistical analysis. RESULTS: The mean distance between the sphenoid bone and the posterior nasal spine increased up to 5.3 mm over a 9-year span (95% CI, 4.1-6.5 mm; P <0.001). Furthermore, the mean distance between the sphenoid bone and the posterior nasal spine differed significantly (P = 0.029) between facial types; it was consistently greater (1.8 mm; 95% CI, 0.2-3.3 mm) in the hyperdivergent group. The nasopharyngeal airway area showed a trend to increase with age up to 12-fold (P <0.001). A significant interaction (P = 0.004) was found between age and facial type. Assessment of the adenoid shapes showed greater convexities in the hyperdivergent group, which were observable from an earlier age and for a longer duration. CONCLUSIONS: Clear differences in the morphometric growth pattern of the adenoids were found between facial types. Evaluation of adenoid shapes showed more prominent convexities that lasted longer in the long facial types than in the short facial types.

Increase in sagittal depth of the bony nasopharynx following maxillary protraction in patients with unilateral cleft lip and palate.

Objective : To study the change in the sagittal depth of the bony nasopharynx in patients with unilateral cleft lip and palate (UCLP), following maxillary protraction using reverse headgear. Methods : Nineteen patients (14 male, five female; aged 9.36 ± 2.89 years) with repaired complete UCLP underwent maxillary protraction with a Delaire type reverse headgear at a tertiary-care referral teaching hospital. Control data were taken from five patients (four male, one female; aged 8.25 ± 2.25 years) who did not receive any orthopedic/orthodontic treatment for a similar duration of time as the treated patients. Average treatment/observation period was 11.71 ± 3.39 months for the treated patients and 12.40 ± 2.60 months for the untreated subjects. Changes in the sagittal bony nasopharynx depth were measured by comparing pretreatment (T1) and posttreatment (T2) lateral cephalograms. Correlations between the changes in the bony nasopharynx depth and in other variables measured in the treated patients were analyzed. An exploratory analysis of differences in the changes from T1 to T2 between the treated patients and untreated subjects was also conducted. Results : The favorable skeletal changes seen in SNA and ANB following maxillary protraction were accompanied by a significant increase in the sagittal depth of bony nasopharynx (1.74 ± 1.10 mm; P < .001). This change was significant when compared with the data from the untreated subjects (P = .004). Correlations between the increase in bony nasopharynx depth and changes in other variables studied in the treated patients were weak and not statistically significant. Conclusion : Sagittal depth of the bony nasopharynx in patients with repaired UCLP increased following maxillary protraction therapy using reverse headgear.

Upper airway changes in Pierre Robin sequence from childhood to adulthood.

OBJECTIVES: To investigate pharyngeal airway changes in patients with Pierre Robin sequence (PRS) longitudinally from childhood to adulthood. SETTING AND SAMPLE POPULATION: Cleft Lip and Palate Unit, Clinic of Orthodontics, University of Zurich. Twenty-four patients born between 1970 and 1990 with non-syndromic PRS. MATERIALS AND METHODS: Lateral cephalograms at age 5 (T1), 10 (T2), 15 (T3) and 20 (T4) years were available. Variables describing pharyngeal airway dimensions, soft palate morphology, tongue and hyoid position, skeletal morphology and head posture were assessed. RESULTS: A significant increase in nasopharyngeal depth was found over the entire observation period (T1 10.7 to T4 19.1 mm, p < 0.001), especially between T2 and T3 (change 3.8 mm, p < 0.001), and was mainly due to adenoid recession (r = -0.75, p < 0.001; variation explained by 56%). Increase in velopharyngeal depth mainly took place between T3 and T4 (change 2.3 mm, p < 0.01). It was due to more anterior tongue posture (r = 0.65, p < 0.001; 42.5% of variation explained), in turn allowing the soft palate to take a more vertical position (r = -0.52, p < 0.001). Increase in oropharyngeal depth was associated with head extension and anterior mandibular positioning (36% of variation explained). However, significance was not reached (T1 8.3 to T4 9.8 mm, p > 0.05). CONCLUSIONS: Upper airway dimensions in children with PRS improve with time, except for the oropharyngeal airway. Despite large interindividual variation, the mean remained in the lower reaches of normality described in other studies. Thus, further research should investigate the prevalence of obstructive sleep apnoea in adults with PRS.

Choanal atresia and stenosis: Development and diseases of the nasal cavity.

Proper craniofacial development in vertebrates depends on growth and fusion of the facial processes during embryogenesis. Failure of any step in this process could lead to craniofacial anomalies such as facial clefting, which has been well studied with regard to its molecular etiology and cellular pathogenesis. Nasal cavity invagination is also a critical event in proper craniofacial development, and is required for the formation of a functional nasal cavity and airway. The nasal cavity must connect the nasopharynx with the primitive choanae to complete an airway from the nostril to the nasopharynx. In contrast to orofacial clefts, defects in nasal cavity and airway formation, such as choanal atresia (CA), in which the connection between the nasal airway and nasopharynx is physically blocked, have largely been understudied. This is also true for a narrowed connection between the nasal cavity and the nasopharynx, which is known as choanal stenosis (CS). CA occurs in approximately 1 in 5,000 live births, and can present in isolation but typically arises as part of a syndrome. Despite the fact that CA and CS usually require immediate intervention, and substantially affect the quality of life of affected individuals, the etiology and pathogenesis of CA and CS have remained elusive. In this review I focus on the process of nasal cavity development with respect to forming a functional airway and discuss the cellular behavior and molecular networks governing this process. Additionally, the etiology of human CA is discussed using examples of disorders which involve CA or CS. This article is categorized under: Signaling Pathways > Cell Fate Signaling Comparative Development and Evolution > Model Systems Birth Defects > Craniofacial and Nervous System Anomalies.

Fibroblast growth factor receptor 2 plays an essential role in telencephalic progenitors.

We used loss-of-function analysis to determine the role of fibroblast growth factor receptor 2 (FGFR2) in telencephalic progenitors, and also to examine interactions between FGFR and Notch signaling. While the telencephalon of FGFR2 mutants appears grossly normal, mutant telencephalic progenitors exhibit altered proliferative behavior in vivo and in vitro. Based upon our prior finding that Notch1 activation increased neurosphere frequency in FGF2, we tested whether this effect is mediated by FGFR1 or FGFR2. We found that Notch1 activation increased neurosphere frequency in cells mutant for either FGFR1 or FGFR2, but had no effect on the reduced size of neurospheres mutant for those receptors. Additional analyses revealed biochemical changes in the adult neocortex mutant for the IIIc isoform of FGFR2, and essential roles for FGFR2 in nasopharynx, eyelid, and cornea development.

IL-33/ST2 immune responses to respiratory bacteria in pediatric asthma.

Here we investigated the relationship between local bacterial colonization and anti-bacterial immune responses in pre-school asthmatic and control children within the EU-wide study PreDicta. In this cohort of pre-school asthmatic children, nasopharyngeal colonization with Gram-negative bacteria such as Haemophilus influenzae and Moraxella catarrhalis was found to be associated with the highest interferon beta (IFNß) and IL-33 levels in the nasal pharyngeal fluids (NPF). IL33R-ST2 was found induced in the blood of asthmatic children with additional Gram + bacteria in the nasopharynx (Gr+/-). Furthermore, asthmatic children had more episodes of infection that required antibiotic therapy than the control group. Treatment with antibiotics associated with reduced ST2 in blood cells of both asthmatic and control children and reduced IL-33 levels in the airways of asthmatic children. In the absence of Staphylococcus (S.) aureus in NPF, antibiotic therapy associated with decreased IL-33 levels in the NPF and lower ST2 values in the blood of control children but not of asthmatic children. These data suggest that, in asthmatic children, Gram- bacteria, which persist after antibiotic therapy, contributes to IL-33 locally and associated with Gr + bacteria colonization in the airways, inhibited IFN-ß and in the absence of Staphylococcus (S.) aureus, induced ST2 bearing cells in their blood.

Postnatal morphological and lectin histochemical observation of the submucosal glands of rat nasopharynx.

The development of submucosal glands of rat nasopharynx was studied with respect to their morphological maturation and glycoprotein alterations during the postnatal period. This study examined the histological morphology with hematoxylin-eosin and the binding pattern of lectins, soybean agglutinin (SBA), Dolichos biflorus agglutinin (DBA), Vicia villosa agglutinin (VVA), Ulex europaeus agglutinin-I (UEA-I), peanut agglutinin (PNA), wheat germ agglutinin (WGA), and succinylated WGA (sucWGA) on frozen sections from newborn into adulthood. At birth, nasopharyngeal glands consisted of rudimentary secretory units which by postnatal day 3 (PN3) showed the characteristic features of salivary glands comprised of mixed mucous and serous cells. With maturation, serous cells increased in number and were arranged in clusters. Lectin reactivity at birth was detected at the acinar cell basal membranes for DBA, SBA, VVA, UEA-1 and PNA. At PN3, lectins labeled the apical cytoplasm and basolateral membranes of mucous cells and progressively with maturation, extended from the apical to basal portions of the cytoplasm with variable reactivity of VVA, PNA and sucWGA. Serous cells were labeled by UEA-1 starting from PN10 and also by PNA in adults. Ducts showed variable lectin reaction on the luminal membrane with strong reactivity of DBA and UEA-1 at PN21. Taken together, lectin histochemistry indicated the transitional occurrence of glycoproteins depending on the stage of maturation of the glands. Moreover, these results emphasize the difference in the morphology and lectin histochemistry between the nasopharyngeal and palatine glands.

[Nasopharyngeal changes in 8-13 years old healthy children in China: a longitudinal study].

Objective: Nasopharynx is an important compartment of the upper airway. It is closely associated with the characteristic craniofacial skeletal pattern related to sleep breathing. The present study aimed to investigate the growth pattern of the nasopharynx during rapid puberty growth period. Methods: Thirty non-snoring children (aged 8 to 11 years old) were selected by means of questionnaires and clinical examination. Periodic yearly follow up using MRI, lateral cephalogram, and polysomnograph (PSG) was done in these children. Fifty-one final mixed longitudinal samples were consisted of 23 children completed three consecutive follow-up, and 5 children completed two consecutive follow-up. The yearly changes of the nasopharynx and craniofacial structures were measured. ANOVA was used to evaluate the yearly growth of the nasopharynx. Correlated analysis was used to explore the potential influencing factors of craniofacial structures. Results: The rapid growth period of the nasopharynx located in the age range of 8-10 years old, during which the transverse dimension of the nasopharynx developed rapidly, while the rapid development of the sagittal dimension of the nasopharynx was around 12-13 years old. The growth of the nasopharynx was continuous. The changes in the cross-sectional area of the nasopharynx (⊿CSA) was positively correlated with the changes in distance between mandible of glossopharyngeus (⊿M), distance of hyoid to cervical anterior surface (⊿H-CVP), and anterior pharyngeal distance of glossopharyngeus (⊿AD) (r=0.363, 0.363, 0.323, respectively, all P<0.05). The changes in the volume of the nasopharynx (⊿V) was positively correlated with the changes in upper facial height (⊿N-ANS), ⊿M, and ⊿AD (r=0.336, 0.413, 0.478, respectively, all P<0.05). The changes in the sagittal dimension of the nasopharynx (⊿S) was negatively correlated with angulation in supramental and anatomical horizontal line (⊿SNB) (r=-0.322, P=0.045). The changes in the transverse dimension of the nasopharynx (⊿T) was negatively correlated with the changes in adenoid (⊿A) (r=-0.411, P=0.009). Conclusions: The growth and development of the nasopharynx was early and continuous, which could be affected by the development of either maxilla or mandible.

Three-dimensional geometric morphometric analysis of the nasopharyngeal boundaries and its functional integration with the face and external basicranium among extant hominoids.

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.

Postnatal development of palatal and laryngeal taste buds in the hamster.

Mammalian taste buds are distributed within several distinct subpopulations, innervated by branches of three cranial nerves. These taste bud populations originate and mature at different times in various mammalian species and are thought to play differential roles in the control of taste-mediated behaviors. The hamster is a common animal for the electrophysiological study of the gustatory system, and it has been shown that taste buds innervated by the IXth nerve develop postnatally in this species. To delineate further the development of the gustatory system of hamsters, we quantified the number of taste buds appearing on the palatal, nasopharyngeal, and laryngeal epithelium from birth through 120 days of age. Taste buds are present in almost adult numbers on the soft palate at birth, but only 39% of these are mature. Distinct taste pores, indicative of mature taste buds, increase in number until about 20-30 days of life, at which time all of the taste buds on the soft palate and on the nasoincisive papillae are fully developed. Taste buds are concentrated primarily on the posterior and medial portions of the soft palate. Taste buds located on the laryngeal surface of the epiglottis and the aryepiglottal folds are absent at birth and originate and mature over the following 120 days. Laryngeal taste buds are more concentrated on the aryepiglottal folds than on the epiglottis. On the soft palate and in the epiglottal region, the maturation of taste buds is well characterized by a logarithmic function (Y = a log X + B) relating the number of mature taste buds to postnatal age. On the soft palate, the length of the taste buds from base to apex correlates with the thickness of the epithelium, which increases with development. The diameter of mature taste buds on the soft palate does not change with age. In contrast to many mammalian species, in rodents taste bud development occurs mostly after birth. Rapid postnatal development progresses at a time when ingestive behavior is undergoing a number of significant changes. Taste buds in the larynx have been implicated in a number of laryngeal reflexes (i.e., apnea, swallowing) in several nonrodent species. The electrophysiological properties of superior laryngeal nerve fibers would suggest a similar function for epiglottal taste buds in the hamster.

A longitudinal study of the growth of the nasopharynx and its contents in normal children.

The areas of the nasopharynx and its contents have been measured on the lateral cephalometric radiographs of 41 normal children who had been examined at yearly intervals for a minimum of 12 years between the ages of three and 19. The means and standard deviations of the areas of the nasopharynx, the soft tissues and the airway have been calculated for each year from three to 11 and for alternate years to age 19. The size and shape of the soft tissues of individual children are shown to vary from year to year, and the anterior convexity changes to a concave shape with maturity. The soft tissues appear to grow more rapidly from three to five than does the nasopharynx, with a consequent decrease in size of the airway at this period. Subsequently the soft tissue area remains relatively constant whilst the nasopharynx increases in size so that the airway progressively enlarges. There is a significant difference between the sexes in nasopharyngeal area from 13 onwards (p less than 0.005).

A cephalometric study by multivariate analysis of growth of the bony nasopharynx in patients with clefts and non-cleft controls.

To clarify the characteristics of growth of the nasopharynx, comparison of the cephalometric growth of bones surrounding nasopharynx between 61 patients with complete unilateral cleft lip and palate (UCLP group) and 82 non-cleft controls (NCC group) was carried out. All of the subjects were divided into four developmental stages (i.e. stage 1 at 4 years of age, stage 2 at 8 years of age, stage 3 at 12 years of age and stage 4 at 17 years of age). Measurements on the antero-posterior and the vertical dimensions were derived from a coordinate system and points on bones surrounding the nasopharynx on lateral X-ray cephalograms, and results were analyzed by multivariate analysis and t-test. The results showed that (a) the posterior maxillary point (PMP) in the UCLP group was located more postero-superiorly than that in the NCC group, and this was the main factor that allows discrimination between the two groups and (b) the cranial base, posterior maxilla and the cervical vertebrae were found to be in independent in growth, however, the nasopharyngeal triangle connecting three points on these three bones (Ho: cranial base; PMP: posterior maxillary point; At: atlas) showed harmonious growth in both the UCLP and NCC groups.

Velopharyngeal function following maxillary advancement.

In a series of 40 patients who had maxillary advancements, none developed velopharyngeal incompetence. Unlike the cleft palate patient who is more at risk, there are distinct anatomical characteristics in craniofacial dysostosis which favor maintenance of the integrity of the velopharyngeal mechanism. Hyponasality was eliminated in 5 patients with Crouzon's disease. On cephalometric study, it was observed that after maxillary advancement the nasopharyngeal volume was expanded and the angle formed by the hard and soft palates was increased. On phonating cephalograms, the velopharyngeal contact became more physiological after maxillary advancement in the craniofacial dysostosis patient. The only postoperative articulatory changes after maxillary advancement were in the production of the /s/ sound, which is particularly sensitive to changes in dentoalveolar relationships.

Dental development and the pharyngeal lymphoid tissue.

Because the teeth are housed and develop within the jaws, skeletal development of the maxilla and mandible is a primary factor in the consideration of any problems pertaining to the developing dentition. Growth of the posterior nasal choanae, the maxilla, and the nasopharynx should be evaluated as a unit in assessing the favorable or unfavorable character of the nasopharyngeal region. Both large and small adenoidal tissues should be examined in light of the morphologic character of the nasopharynx (be it small, large, narrow, or wide) and related to the developing maxilla. Variables in size and location of the maxilla and the pharynx will play an important role in the impact that lymphoid tissue will have on the patency of the nasopharyngeal isthmus. Synchronized growth between the normally developing adenoids and the migration of the maxilla away from the cranial base will produce a balanced environment that precludes nasal obstruction by the presence of adenoids. With time, the changes in spatial relationships between the posterior border of the maxilla and the posterior pharyngeal wall plus atrophy of the adenoidal tissue will generally minimize or eliminate the problems of nasal obstruction and mouth breathing. Growth data may be used to evaluate the status, assess progress, measure comparability, determine inheritance patterns, and confer individuality. Unit-trait inheritance of the teeth, alveolar processes, maxilla, mandible, soft-tissue profile, tongue, pharynx, and lymphoid tissues may well produce more definitive answers to the question of the developing dentition and the pharyngeal lymphoid tissue. Finally, at present, no clinician can categorically state that enlarged tonsils or adenoids per se are responsible for abnormal dentition in the absence of other factors.

Does nasal septal deviation influence adult posterior choanal size?

Despite the development of modern imaging techniques, no study has been carried out to establish the normal size (particularly the area) of the adult posterior choanae. In this study we present our findings of the normal anatomical sizes of the adult posterior choanae and its relationship to septal deviation, by analysing MRI images of 70 patients. Coronal sections through the sphenoid rostrum and axial sections through the nasal septum were used. There were 32 males and 38 female patients. The age ranged between 18 and 73 years (mean 35.6). Our results show that the posterior choanal dimensions were as follows: right area: 1.35-6.1 cm2 (mean 2.7 cm2); left area: 1.4-5.9 cm2 (mean 2.7 cm2); right width: 0.9-2.1 cm (mean 1.5 cm); left width: 0.9-2.2 cm (mean 1.5 cm); right height: 2.5-4.0 cm (mean 2.6 cm); and left height: 1.5-4.0 cm (mean 2.5 cm). Chi-square analysis showed no statistically significant differences between left- and right-sided measurements. Twenty-three patients had a deviated septum towards the left side, 22 patients towards the right side, and 25 patients had no septal deviation. Chi-square analysis showed no statistical correlation between deviation of the nasal septum and any of the three dimensions of the posterior choanae studied.