Cranial Base Morphology Research Articles

Three-Dimensional Analysis of the Cranial Base Structure in Patients with Facial Asymmetry.

Facial asymmetry is often seen in patients with skeletal mandibular prognathism and is associated with deformities in the maxillofacial and head regions. The maxillofacial deviation is three-dimensional and affects not only the lateral deviation of the mandible and midface, but also the cranium. This study conducted a three-dimensional morphological evaluation of the cranial base morphology of patients with skeletal mandibular prognathism (ANB < 0°, Wits < 0 mm) with the aim of examining the relationship between deformities of the head region and facial asymmetry. Data obtained from computed tomography conducted during the initial examination of patients with and without skeletal mandibular prognathism with facial asymmetry were used. Differences in the position of structures present in the cranial base were measured, and the association between cranial deformities and mandibular deviation was assessed. The middle cranial base area and the lateral deviation of the mandibular fossa were significantly larger in patients with facial asymmetry compared to those without facial asymmetry. In addition, a correlation between the amount of mandibular deviation and the area of the anterior cranial base was identified in patients with significant cranial deformity (p = 0.012). Given the identified association between the structure of the head region and facial asymmetry, further studies are needed to determine the factors implicated in the growth process.

Assessment and comparison of cranial base morphology in individuals with long face and short face.

The objectives of the study was to assess and compare the cranial base morphology in long face and short face. The study comprises 64 individuals (32 in each group). Group I consists of individual's with long face and group II comprises individuals with short face. Individuals were classified into groups with the help of lateral cephalometric parameters like Gonial Angle, Anterior facial height, Posterior facial height, Jarabak's Ratio, and Y-axis. Linear and angular measurement in the cranial base was taken. The results showed statistically significant difference in Sella-Nasion, Sella-Basion and Nasion-Sella-Basion between the two groups. Sella-Spinoethmoidal suture, Nasion-Spinoethmoidal suture, Spinoethmoidal suture-Sella-Basion, Frankfurt Horizontal-Sella-Nasion, Frankfurt horizontal-Sella-Basion, Frankfurt horizontal-Sella-Spinoethmoidal suture showed no statistically significant difference among the groups. The study concluded that individuals with long face have a greater Sella-Nasion, Sella-Basion, Nasion-Sella-Basion compared to individuals with short face.

Neurocranial Growth in the OIM Mouse Model of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a disorder of type I collagen characterized by abnormal bone formation and weakened bone architecture. Human patients with OI have larger cranial vaults (macrocephaly), altered cranial base morphology including basilar invagination and platybasia (skull base flattening), and midfacial underdevelopment. The neurocranial changes may affect both underlying nervous tissue and growth patterns of the facial skeleton. However, we still do not fully understand how and when these divergent morphologies occur. The aims of this study are: (1) to investigate the integrated development of the skull and the brain in a mouse model of OI; and (2) to identify the developmental trajectories of these structures to facilitate future therapeutic interventions. We hypothesize that compared to unaffected mice, mice with OI will have decreased brain volumes due to an overall reduction in cranial size and decreased cranial base angles (CBA) due to platybasia.To test these hypotheses, we used the osteogenesis imperfecta murine (OIM or B6C3FE a/a‐Col1a2oim/J), a model for the severe type III OI in humans, and unaffected wild‐type (WT) littermates. Mice were imaged using in vivo micro‐computed tomography (micro‐CT) at the juvenile (week 4; 10 OIM/14 WT) and adult (week 16; 9 OIM/11 WT) stages. All measurements were taken in 3D Slicer software. 82 cranial landmarks were used to calculate centroid size, an estimate of overall head size. The segmentations tool was used to create virtual endocasts as a proxy for brain volume. The angle tool was used to measure CBA in the midsagittal plane using three landmarks: foramen cecum, midsphenoidal synchondrosis, and basion. Mann‐Whitney U tests were used to compare centroid sizes, brain volumes, and CBA between the genotypes.Both juvenile (p=0.008) and adult (p=0.003) OIM mice were found to have absolutely smaller brains than WT mice. However, OIM mice also have significantly smaller cranial centroid sizes compared to WT mice (p=0.003, p&lt;0.001). When scaled to cranial size, juvenile mice had relatively larger brain volumes (p=0.016) but adult OIM relative brain volumes were not significantly different from WT. No significant difference was seen in CBA at the juvenile (p=0.065) or adult (p=0.171) stages, however a trend was observed for decreased CBA at the adult stage.These results suggest that neurocranial dysmorphologies in OI may be more severe at earlier stages of postnatal development. Previous analyses of these mice have documented relative skeletal macrocephaly in both juvenile and adults, however here we document an increase in relative endocranial volume only at the juvenile stage. A reduction in CBA during growth, possibly due to platybasia, may underlie this decoupling between external and internal cranial morphology. Future work will investigate the effect of CBA on facial growth and midfacial underdevelopment in these mice. A better understanding of the integration and growth trajectory of the neurocranium is foundational for formulating treatments to manage basicranial instabilities in patients with OI.

Differences in craniofacial morphology between platybasic and nonplatybasic patients with velopharyngeal dysfunction and control subjects

This study aimed to identify the characteristics of cranial-base morphology in platybasic and nonplatybasic patients with palatal anomalies and velopharyngeal dysfunction (VPD) compared with control subjects to investigate structural factors related to craniofacial morphology that affect the nasopharyngeal space and may influence velopharyngeal function, and to develop precise treatments for specific patients with VPD. Three hundred eighty-six patients with VPD and various palatal anomalies were studied retrospectively. The control group included 126 healthy patients with normal speech. Lateral cephalometric images assessed craniofacial morphology. Nonplatybasic patients and control subjects had larger SNA, S-Ba-Ptm, and N-Ba-PP angles (in the craniomaxillary complex), and platybasic patients had larger nasopharyngeal ANS-Ptm-Ve and Ba-S-Ptm angles and longer Ve-T and Ve-Ba distances than the nonplatybasic patients. All study patients had larger ANB, Gn-Go-Ar, and PP-MP angles (in the craniomandibular complex). Nonplatybasic patients had smaller Ba-SN angles than platybasic patients and controls because of more acute N-S-Ptm angle. Among the nonplatybasic patients, Ve-T length tended to be shorter (with no significant difference between groups) and located more inferiorly (because of the smallest ANS-Ptm-Ve angle) in relation to the maxilla. Thus, the nasopharynx was narrower horizontally but longer vertically than in patients with platybasia. Cranial-base flexure influences the shape of the skull base and facial-skeletal structure and may alter the pharyngeal space between them. This finding should help improve preoperative planning regarding the effect of the pharyngeal flap height relative to the nasopharynx and oropharynx ratio that affects surgical outcomes, such as resonance and residual VPD. In patients with Class III malocclusion and maxillary constriction, careful planning of presurgical orthodontic treatment is needed in maxillary advancement procedures. Orthodontic and surgical collaboration can help prevent postoperative VPD, especially in platybasic patients.

Is there a correlation between skull base flexure and palatal anomalies in patients with 22q11 deletion syndrome and velopharyngeal dysfunction?

The study aimed at assessing the relationship between skull base morphology, represented by skull base and nasopharyngeal angles, and palatal anatomy among patients with 22q11DS and velopharyngeal dysfunction.Retrospective analysis of patients with 22q11DS and velopharyngeal dysfunction. Age, sex, severity of velopharyngeal dysfunction, type of cleft (overt cleft palate, submucous cleft palate, occult submucous cleft palate, or no-CP, and cephalometric skull base angles were reviewed. Correlations between type of palatal anomaly and the angles were assessed.Among 132 patients, 71 were male (53.8%) and 61 were female (46.2%), ages 3.3–40.0 years (mean 8.3 ± 6.10). No difference in the mean cranial-base angle (P = 0.353) or in the distribution of the three types of cranial base angle sizes was found among the palatal anomaly groups (P = 0.137). More men had normal cranial base angles and more women had acute angulation (P = 0.008). A positive correlation was found between the skull base and nasopharyngeal angles (P = 0.001, r = −0.590).No direct correlation was found between cranial base morphology and palatal anomalies in patients with 22q11DS, and velopharyngeal dysfunction. This is probably because skull base and palate morphology contribute independently to velopharyngeal dysfunction.

Correlation Between Cranial Base Morphology and Skeletal Maloclusion in a Sample of Sudanese Orthodontic Patients

Objective: This study aimed to evaluate the relationship between the cranial base and jaw base in a sample of Sudanese orthodontic patients. Material and methods: one hundred and twenty lateral Cephalograms from university of Khartoum orthodontic department archive 60 males, 60 females, age 18.3 ± 4.3 years old, were classified into 3 sagittal malocclusion groups (40 individuals each) according to their ANB angle. A cephalometric analysis of the study variables of the cranial base (NSBa, N-S, S-Ba, N-Ba) and jaws bases (SNA, SNB, ANB, A-Co, Gn-Co) was carried out, the morphological characteristics of the cranial and jaw bases in the three groups were compared using One-way ANOVA test and Pearson’s coefficient correlation analysis. Results: Cranial base angle and cranial base lengths did not show significant differences between the main classes of malocclusion studied. However, jaw size was statistically significant different between the 3 groups, longer maxilla was found in Class II group and the mandible was longer in Class III group. Strong significant relation was found between SNA, SNB and NSBa in the three groups. Positive correlation was found between cranial base lengths and maxillary and mandibular lengths among the three groups. Conclusion: Cranial base angulation and lengths has no major role in developing malocclusion.

Discussion: What Is the Difference in Cranial Base Morphology in Isolated and Syndromic Bicoronal Synostosis?

Discussion: What Is the Difference in Cranial Base Morphology in Isolated and Syndromic Bicoronal Synostosis?

Effects of reduced connexin43 function on skull development in the Cx43I130T/+ mutant mouse that models oculodentodigital dysplasia.

Oculodentodigital dysplasia (ODDD) is a disease caused by mutations in the GJA1 gene that encodes the gap-junctional protein connexin43 (Cx43). ODDD affects multiple organs, but craniofacial anomalies are typical. However, details on the timing of phenotypic presentation of these abnormalities and their correspondence with potential cellular changes are incomplete. Here, we perform the first assessment of the development of the ODDD craniofacial phenotype in the Cx43I130T/+ mouse model and show that the phenotypic features commonly found in patients with the disorder arise in mice between E17.5 and birth and become more profound with age. Using mice heterozygous for the I130T mutation of Gja1, we provide a detailed analysis of the craniofacial phenotype in this ODDD model using shape analyses based on micro-CT images. Results show that in addition to differences in facial bone morphology, there are significant shape differences in the cranial base. Mutant mice display delayed ossification at E17.5 and birth, particularly in bones of the face and cranial vault but ossification is normal at three months. Our immunohistochemical analyses of the palatine bone indicate that osteoblast differentiation is delayed in Cx43I130T/+ mice compared to their wildtype littermates, which likely contributes to the phenotypic variations observed in the facial bones. Our histological and immunohistochemical analyses of the synchondroses of the cranial base show no differences in molecular indicators of chondrocyte differentiation in mutant mice, suggesting that the differences to cranial base morphology displayed by Cx43I130T/+ mice are not due to differences in chondrocyte proliferation or differentiation. Together, our findings suggest that Cx43I130T/+ mice represent a surrogate model to not only inform about the craniofacial anomalies found in ODDD patients but also to show that reduced Cx43 function leads to phenotypic changes that are largely due to osteoblast defects.

Evaluation of Cranial Base Morphology of Pakistani Population in Skeletal Class I, II and III Malocclusions

Introduction: Cranial Base integrate different patterns of growth in various regions of the skull such as the nasal cavity, the oral cavity, and the pharynx. Anteroposterior jaw position is thought to be affected by cranial base growth. Although scientific literature shows conflicting results regarding both positive and negative correlation between the cranial base and skeletal malocclusions.&#x0D; Materials &amp; Method: 138 patients selected according to the Inclusion criteria were divided into three major categories depending upon ANB angle. Class I, class II group and class III group. Pretreatment lateral cephalometric radiographs were taken. Linear and Angular measurements were measured. All the data was entered in SPSS version 25 and then analyzed by using descriptive statistics including mean, standard deviation and by using inferential statistics including Pearson correlation and ANOVA test.&#x0D; Result: No significant differences were recorded between cranial base deflection angles (N-S-Ar and N-S-Ba) and malocclusions groups while Anterior cranial base length S-N was found to be maximum in class III and posterior cranial base length S-Ba was greater in class I.&#x0D; Conclusion: Cranial base angles N-S-Ar and N-S-Ba did not demonstrate any statistically significant correlation with three malocclusion groups i.e. Class I, Class II and Class III and their correlation was negative.

Evaluation of the cranial base and sella turcica morphology in patients with unilateral cleft lip and palate

Objective: The aim of this study was to investigate the size and morphology of the sella turcica and cranial base in individuals with unilateral cleft lip and palate (UCLP), and to compare it with individuals showing Class III discrepancy due to maxillary deficiency (CL3) and with individuals having normal (CL1) craniofacial development. Materials and Method: This retrospective study was carried out on the lateral cephalogram tracings of UCLP (10 females, 4 males; 12.05±1.14 years), CL3 (10 females, 5 males; 11.73±0.89 years) and CL1 (10 females, 5 males; 13.11±1.11 years) patients. Linear and angular measurements related to sella turcica and cranial base were performed. Intergroup comparisons were either made with one-way ANOVA followed by Tukey’s test or with Kruskal-Wallis test with Bonferroni adjustment (p&amp;lt;0.05). Spearman correlation coefficient was used for correlations (p&amp;lt;0.01). Results: The length of the maxilla (Co-A) was shorter in UCLP (p=0.035) and CL3 (p=0.001) than in CL1. Total cranial length (Ba-N) was greater in UCLP than in CL3 (p=0.012) and CL1 (p=0.016). Cranial base angle (N-S-Ar°) was less in CL3 than in UCLP (p=0.001) and CL1 (p=0.009). Ba-N (p=0.003) and anterior cranial length (S-N) (p=0.000) were positively correlated with Co-A. Posterior cranial length (S-Ba) was positively correlated with ramus height (Ar-Go) (p=0.001). The diameter of sella was bigger in CL1 than in CL3 (p=0.025). The prevalence of morphologic variations of sella turcica in UCLP was higher (71.4%) than in control groups. Conclusion: Although there was a Class III tendency in UCLP due to maxillary deficiency, cranial base flexure characteristic to CL3 anomalies was not seen in this group. The existence of UCLP or CL3 did not alter dimensions of sella turcica, but morphologic variations were more common in UCLP.

Variation of Cranial Base Morphology among Different Sagittal Skeletal Malocclusion – A Cephalometric Study in Nepalese Population

Introduction: Variation of cranial base morphology among different sagittal skeletal malocclusion has been evaluated previously by many studies. However, the findings of these studies conducted in different population differ due to racial/ ethnic differences. Objective: To obtain measurement data for various cranial base parameters and evaluate the variation in cranial base morphology among different sagittal skeletal malocclusion in Nepalese population. Materials and Methods: Manual tracing and measurement of 4 different cranial base parameters [linear- Anterior Cranial Base Length (ACBL), Posterior Cranial Base Length (PCBL) and Total Cranial Base Length (TCBL); angular - Cranial Base Angle (CBA)] were done on 90 pretreatment lateral cephalogram of healthy adult orthodontic patients. Study samples were matched for age and were equally distributed among three different sagittal skeletal malocclusion group using ANB angle. [skeletal Class I: 30, skeletal Class II: 30 and skeletal Class III: 30]. Analysis Of Variances [ANOVA] followed by Least Significant Difference (LSD) post hoc test was used to determine difference in cranial base measurements among three sagittal skeletal group. Results: While comparing the cranial base parameters among different sagittal skeletal class, mean value for all the parameters reduced systematically from skeletal Class II, via skeletal Class I, to skeletal Class III group. However, a statistically significant difference was found only for TCBL between skeletal Class II and skeletal Class III (p &lt; 0.01). Conclusions: A significant difference in TCBL among different sagittal skeletal malocclusion was observed in Nepalese adults.

Effects of Palate Repair on Cranial Base and Maxillary Morphology in Patients With Unilateral Complete Cleft Lip and Palate.

To identify the effects of palate repair on cranial base and maxillary morphology in patients with unilateral cleft lip and palate (UCLP) and to discover the relevance between cranial base and maxilla through cephalometric analysis. Retrospective. Thirty-seven UCLP patients with operated lip (OL) and unoperated palate constituted OL group and were classified into 5 cervical vertebral maturation (CVM) stages. Thirty-seven UCLP patients with operated lip and palate (OLP) and 37 noncleft people with skeletal class I malocclusion were CVM- and sex-matched with the OL group as OLP group and control group, respectively. CVM stage I and II were combined into group 1, CVM stage III to V were combined into group 2. Lateral cephalograms of all participants were obtained. Cephalometric analysis was employed, and data were compared among groups. Length of posterior cranial base (Ba-S) of the OL group was shorter than controls in group 1; Ba-S and the ratio between length of posterior and anterior cranial base (Ba-S/S-N) of the OL and OLP groups were smaller than controls in group 2. No significant differences in cranial base were found between the OL and OLP groups. In group 1, patients of the OLP group showed smaller SNA, ANS-Ptm, and ANS-Ptm/S-N, and patients of the OL group showed smaller ANS-Ptm. In group 2, both OL and OLP groups had smaller sella-nasion-A point angle (SNA), projection distance between ANS and Ptm points on FH plane (ANS-Ptm), and the ratio between ANS-Ptm and anterior cranial base length (ANS-Ptm/S-N). Palate repair seems to have no obvious effects on cranial base morphology in patients with UCLP. Those patients with lip operated, whether cleft palate operated or not, tend to have a smaller length of maxilla sagittally and this deformity progresses with age.

Three-dimensional analysis of cranial base morphology in patients with hemifacial microsomia

BackgroundMany researchers have studied the relationship between facial asymmetry and cranial base morphology, but they have failed to reach a consensus. In this study, we aimed to verify whether the cranial base is involved in hemifacial microsomia (HFM). MethodsWe included 66 patients with HFM who were treated at the Plastic and Reconstructive Surgery Department of Shanghai Ninth People's Hospital from January 2013 to October 2016. The patients were divided into three groups according to Pruzansky and OMENS classifications, separately. The controls were 20 patients diagnosed with mandibular angle hypertrophy but with no facial asymmetry. Angular and linear measurements of the cranial base were obtained for all patients. ResultsThe two classification methods yielded similar results. The intersection angle between two planes showed differences in the severe group. In the moderate and severe groups, the middle and posterior cranial angles were significantly different and the CIP and SP lengths were shorter in the affected side. Landmarks such as the carotid canal and internal acoustic canal could be considered as references. ConclusionsThe cranial base is involved in hemifacial microsomia. This relationship supports the hypothesis of HFM pathogenesis and opens new avenues to classification methods.

Study Regarding the Applications of Imaging Technology in Cranial Base Morphology in Angle Class II Division 1 and 2 Malocclusions

The aim of the research is to investigate the characteristics of cranial base morphology in class II division 1 and class II division 2 malocclusions. The study group consisted of 40 patients aged 11 years treated at the Orthodontic Department of �Carol Davila� University. Both gender and both malocclusion types were equally represented. Lateral cephalograms were traced and 22 linear and angular cephalometric parameters were calculated: four parameters for the cranial base (N-S-Ba, N-Op-Ba angles, N-S, S-Ba lengths) and 18 parameters for the maxillofacial complex Nsa-Nsp, Go-Gn, Kdl-Go, S-Nsp, N-Nsa, Nsa-Gn, N-Gn, Nsp-Go, SNA angle, ANB angle, SN � NsaNsp angle, SN-GoGn angle, N-Nsa-Gn angle, S-Nsp-Go angle, N-Nsa-Pg angle, gonial angle, FMA angle, NsaNsp � GoGn. Statistical significant differences between cranial base parameters in the two malocclusions groups were depicted, in particular for feminine gender. Regardless of gender, the sphenoidal angle values were mainly increased in both malocclusion groups, when compared to normal population values. The S-Ba lengths were decreased in both malocclusion groups, regardless of gender. More significant alterations of cranial base morphology were depicted in patients with Class II Division 2 malocclusions then in patients with Class II Division 1 malocclusion. The study�s results sustain the existence of some cranial base alterations in Class II malocclusions.

An Examination of the Differential Effects of the Modern Epidemiological Transition on Cranial Morphology in the United States and Portugal.

This research examines the pattern of secular change in the cranial morphology of two populations experiencing the epidemiological transition associated with decreased mortality rates in children, followed by declines in infant mortality and subsequent increases in adult longevity. The two samples examined in this study come from US and Portuguese individuals. The epidemiological transition occurred at different times in the United States and Portugal, with Portugal entering into the transition later than the United States. The results of the study show that the US and Portuguese samples experienced significant changes in cranial morphology during the approximately 150 years under study. In all of the samples the cranial base morphology changes significantly over time. However, the pattern of change in the US and Portuguese samples varies in the other regions of the crania. The US samples exhibit significant changes associated with the posterior cranial fossa, which experiences the greatest growth during the fetal period and the first year of life. Conversely, in the Portuguese samples the region of the cranium that shows the greatest change is in the face and lateral cranial base, which experiences the greatest growth from three to nine years. This differential pattern may reflect differences in changing mortality patterns in the two countries. During the period under study the United States had already proceeded through the early stages of the epidemiological transition, and improvements in the juvenile mortality and juvenile growth had occurred previously. Subsequently, the United States experienced significant declines in infant mortality, and the regions of the crania that exhibit the greatest changes occur in area with maximum growth velocity under one year. However, Portugal entered into the epidemiological transition later than the United States and therefore the greatest changes in growth occurred during the juvenile period, which is reflected in the adult morphology in this group. This study demonstrates the utility of variation in growth patterns in different cranial regions to document changes in the demographic parameters in two different populations.

Do functional demands associated with locomotor habitat, diet, and activity pattern drive skull shape evolution in musteloid carnivorans?

A major goal of evolutionary studies is to better understand how complex morphologies are related to the different functions and behaviours in which they are involved. For example, during locomotion and hunting behaviour, the head and the eyes have to stay at an appropriate level in order to reliably judge distance as well as to provide postural information. The morphology and orientation of the orbits and cranial base will have an impact on eye orientation. Consequently, variation in orbital and cranial base morphology is expected to be correlated with aspects of an animal's lifestyle. In this study, we investigate whether the shape of the skull evolves in response to the functional demands imposed by ecology and behaviour using geometric morphometric methods. We test if locomotor habitats, diet, and activity pattern influence the shape of the skull in musteloid carnivorans using (M)ANOVAs and phylogenetic (M)ANOVAs, and explore the functional correlates of morphological features in relation to locomotor habitats, diet, and activity pattern. Our results show that phylogeny, locomotion and, diet strongly influence the shape of the skull, whereas the activity pattern seems to have a weakest influence. We also show that the locomotor environment is highly integrated with foraging and feeding, which can lead to similar selective pressures and drive the evolution of skull shape in the same direction. Finally, we show similar responses to functional demands in musteloids, a super family of close related species, as are typically observed across all mammals suggesting the pervasiveness of these functional demands.

Phylogeny, Ecology, and Morphological Evolution in the Atelid Cranium

Reconstructing evolutionary relationships of living and extinct primate groups requires reliable phylogenetic inference based on morphology, as DNA is rarely preserved in fossil specimens. Atelids (family Atelidae) are a monophyletic clade and one of the three major adaptive radiations of south and central American primates (platyrrhines), including the genera Alouatta, Ateles, Brachyteles, and Lagothrix, and are diverse in morphology, body and brain size, locomotion, diet, social systems, and behavioral ecology. Molecular phylogenetic relationships of the extant atelid genera are well resolved, yet morphological analyses often support alternative phylogenetic relationships to molecular data. We collected geometric morphometric data from the crania of atelid taxa for phylogenetic analysis of the cranium, cranial base, and face and tested the hypotheses that cranial data maintain a phylogenetic signal, cranial base morphology most closely reflects the atelid molecular phylogeny, and facial and overall cranial morphology are shaped by diet and have experienced greater homoplasy. All analyses supported genus monophyly, and facial morphology maintained a strong phylogenetic signal inferring the atelid molecular phylogeny and a sister relationship between Brachyteles and Lagothrix, whereas results from the cranial base and whole cranium supported Ateles–Lagothrix and/or Alouatta–Brachyteles clades reflecting homoplasy and ecological and dietary similarities. A phylogenetic signal in the atelid face is important for future studies integrating fossil taxa and supports evidence that congruence between molecular and morphological phylogenetics in primates is module and clade specific.

Encephalization and diversification of the cranial base in platyrrhine primates

The cranial base, composed of the midline and lateral basicranium, is a structurally important region of the skull associated with several key traits, which has been extensively studied in anthropology and primatology. In particular, most studies have focused on the association between midline cranial base flexion and relative brain size, or encephalization. However, variation in lateral basicranial morphology has been studied less thoroughly. Platyrrhines are a group of primates that experienced a major evolutionary radiation accompanied by extensive morphological diversification in Central and South America over a large temporal scale. Previous studies have also suggested that they underwent several evolutionarily independent processes of encephalization. Given these characteristics, platyrrhines present an excellent opportunity to study, on a large phylogenetic scale, the morphological correlates of primate diversification in brain size. In this study we explore the pattern of variation in basicranial morphology and its relationship with phylogenetic branching and with encephalization in platyrrhines. We quantify variation in the 3D shape of the midline and lateral basicranium and endocranial volumes in a large sample of platyrrhine species, employing high-resolution CT-scans and geometric morphometric techniques. We investigate the relationship between basicranial shape and encephalization using phylogenetic regression methods and calculate a measure of phylogenetic signal in the datasets. The results showed that phylogenetic structure is the most important dimension for understanding platyrrhine cranial base diversification; only Aotus species do not show concordance with our molecular phylogeny. Encephalization was only correlated with midline basicranial flexion, and species that exhibit convergence in their relative brain size do not display convergence in lateral basicranial shape. The evolution of basicranial variation in primates is probably more complex than previously believed, and understanding it will require further studies exploring the complex interactions between encephalization, brain shape, cranial base morphology, and ecological dimensions acting along the species divergence process.

Cranial base pathology in pediatric osteogenesis imperfecta patients treated with bisphosphonates.

Cranial base pathology is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze whether bisphosphonate treatment, used to improve bone strength, could also prevent the development of craniocervical junction pathology (basilar impression, basilar invagination, or platybasia) in children with OI. In this single-center retrospective study the authors analyzed the skull base morphology from lateral skull radiographs and midsagittal MR images (total of 94 images), obtained between the ages of 0 and 25 years in 39 bisphosphonate-treated OI patients. The results were compared with age-matched normative values and with findings in 70 OI patients who were not treated with bisphosphonates. In addition to cross-sectional data, longitudinal data were available from 22 patients with an average follow-up period of 7.6 years. The patients, who had OI types I, III, IV, VI, and VII, had been treated with zoledronic acid, pamidronate, or risedronate for 3.2 years on average. Altogether 33% of the 39 bisphosphonate-treated patients had at least 1 cranial base anomaly, platybasia being the most prevalent diagnosis (28%). Logistic regression analysis suggested a higher risk of basilar impression or invagination in patients with severe OI (OR 22.04) and/or older age at initiation of bisphosphonate treatment (OR 1.45), whereas a decreased risk was associated with longer duration of treatment (OR 0.28). No significant associations between age, height, or cumulative bisphosphonate dose and the risk for cranial base anomaly were detected. In longitudinal evaluation, Kaplan-Meier curves suggested delayed development of cranial base pathology in patients treated with bisphosphonates but the differences from the untreated group were not statistically significant. These findings indicate that cranial base pathology may develop despite bisphosphonate treatment. Early initiation of bisphosphonate treatment may delay development of craniocervical junction pathology. Careful followup of cranial base morphology is warranted, particularly in patients with severe OI.

Cranial-base morphology in adults with skeletal Class III malocclusion

The objectives of this study were to clarify the characteristics of cranial-base morphology in adults with skeletal Class III malocclusion and investigate factors relating to the establishment of a skeletal Class III malocclusion. Initial lateral cephalograms of women were examined. Subjects with an ANB angle of 0° to 4°, normal overjet and overbite, and a Class I molar relationship were classified as Class I (n = 86). Those with an ANB angle less than -1°, a Wits appraisal less than 2 mm, a negative overjet, and a Class III molar relationship were the Class III group (n = 86) in this study. Angular, linear, and coordinate measurements were made. Multivariate analysis of variance and the Student t test were used to analyze significant differences between the 2 groups. Discriminant analysis, logistic regression analysis, and decision analysis were used to identify which cranial-base and maxillomandibular variables influenced the establishment of a skeletal Class III malocclusion. The Class III group had smaller values for NSBa, SeSBa, FH-SSe, and FH-SBa. Sphenoidale and basion were more inferior and anterior than those of the Class I group. There was no difference in the anterior and posterior cranial-base lengths between the groups. Greater mandibular length was the first major characteristic in the Class III group, followed by smaller values for SeSBa and NSBa. Cranial-base morphology in adults with a skeletal Class III malocclusion is different from that in a skeletal Class I malocclusion. Smaller cranial-base angles, steeper posterior cranial bases, more inferiorly positioned sphenoidale, and more anteriorly positioned basion are major characteristics of skeletal Class III malocclusions. These characteristics play important roles in the establishment of a skeletal Class III malocclusion.