Comparative endocranial vascular changes due to craniosynostosis and artificial cranial deformation

The processes of craniosynostosis (premature fusion of one or more of the calvarial sutures) and artificial cranial deformation are similar since both can alter the shape of the craniofacial complex. Most research exploring these processes has focused on the ectocranium, although it is obvious that these processes also modify the endocranium. Endocranial changes due to either craniosynostosis or artificial cranial deformation have not been as thoroughly examined. Silicone rubber endocasts were made from 11 craniosynostotic archaeologically derived specimens from North and South America. For comparative purposes, endocasts were made from 22 normal and 17 occipitally deformed crania that were archaeologically derived from North and South America. With all samples, middle meningeal vessel patterns and venous sinus impressions were qualitatively and quantitatively analyzed. Depth, width, and convolution of the middle meningeal vessels were recorded, and the direction of vessel branches was noted. Both artificial cranial deformation and craniosynostosis altered the endocranial vasculature. Middle meningeal vessel and venous sinus impressions of the craniosynostotic group differed when compared to both the undeformed and artificially cranially deformed samples. Sinuses traversing under synostosed sutures became wider and deeper. In contrast, sinuses directly underneath the greatest artificial deformational stress were shallower, while there was compensatory enlargement of sinuses further away from the greatest deformational effects. Such compensatory enlargement also was shown by the high incidence of enlarged occipital/marginal sinuses in artificially deformed skulls. Increased intracranial pressure is hypothesized to be the cause of the venous sinus changes found in craniosynostotic individuals. Middle meningeal vessel patterns from craniosynostotic and artificially deformed specimens were similar in that their direction paralleled the direction of altered cranial growth. These findings demonstrate that the endocranial vasculature is developmentally plastic and responds to deformation in a predictable pattern. © 1996 Wiley-Liss, Inc.     

Sutural bone frequency in synostotic rabbit crania

This study tests the hypothesis that crania with synostosed sutures will have a significantly higher incidence of calvarial sutural bones than normal crania. Sutural bones were counted in seven calvarial sutures and compared among four groups of adult New Zealand white rabbit skulls: normal in-colony (NI) controls (N = 14), normal out-colony (NO) controls (N = 12), skulls with familial delayed onset (DO) coronal synostosis (N = 25), and skulls with experimentally immobilized coronal sutures (EI) (N = 20). Comparisons among groups were made with a Kruskal-Wallis one-way ANOVA and between groups with a Mann-Whitney U-test, using a Bonferroni correction for multiple comparisons. Significant differences (P > 0.05) were noted only in the coronal and sagittal sutures, with EI crania having the greatest number of coronal sutural bones; between group differences were undetectable for sagittal sutural bones. A post hoc two-sample binomial test for equal proportions showed that the distribution of coronal sutural bones among individuals across groups was even, while the distribution of sagittal sutural bones was significantly higher in EI crania. These results suggest that altered sutural forces of the calvaria contribute to an increased occurrence of sutural bones. However, the influence of inheritance on increased occurrence of sutural bones cannot be discounted, as reflected in the equivalent number of individuals across groups that possessed coronal sutural bones. Am J Phys Anthropol 102:555–563, 1997. © 1997 Wiley-Liss, Inc.     

Effects of fronto-occipital artificial cranial vault modification on the cranial base and face.

Artificial reshaping of the cranial vault has been practiced by many human groups and provides a natural experiment in which the relationships of neurocranial, cranial base, and facial growth can be investigated. We test the hypothesis that fronto-occipital artificial reshaping of the neurocranial vault results in specific changes in the cranial base and face. Fronto-occipital reshaping results from the application of pads or a cradle board which constrains cranial vault growth, limiting growth between the frontal and occipital and allowing compensatory growth of the parietals in a mediolateral direction. Two skeletal series including both normal and artificially modified crania are analyzed, a prehistoric Peruvian Ancon sample (47 normal, 64 modified crania) and a Songish Indian sample from British Columbia (6 normal, 4 modified). Three-dimensional coordinates of 53 landmarks were measured with a diagraph and used to form 9 finite elements as a prelude to finite element scaling analysis. Finite element scaling was used to compare average normal and modified crania and the results were evaluated for statistical significance using a bootstrap test. Fronto-occipitally reshaped Ancon crania are significantly different from normal in the vault, cranial base, and face. The vault is compressed along an anterior-superior to posterior-inferior axis and expanded along a mediolateral axis in modified individuals. The cranial base is wider and shallower in the modified crania and the face is foreshortened and wider with the anterior orbital rim moving inferior and posterior towards the cranial base. The Songish crania display a different modification of the vault and face, indicating that important differences may exist in the morphological effects of fronto-occipital reshaping from one group to another.     

Exploring artificial cranial deformation using elliptic Fourier analysis of Procrustes aligned outlines

The anatomical effects of artificial cranial deformation on the face and the base have been subject to various metric approaches, including standard linear as well as finite element techniques, and have produced controversial results (Antón [1989] Am. J. Phys. Anthropol. 79:253-267; Kohn et al. [1993] Am. J. Phys. Anthropol. 90:147-158). It can be argued that diverging observations partly result from methodological constraints. The present study compares samples of intentionally deformed and undeformed human crania, using elliptic Fourier analysis (EFA), a morphometric approach which has been shown to be particularly appropriate for characterizing the shape of two-dimensional outlines and associated shape changes. We improve the standard EFA approach by adding a preliminary orientation of the outlines following the rotation parameters of a Procrustes superimposition, using multiple homologous landmarks called control points. The results confirm that circumferentially deformed skulls exhibit modifications of the basioccipital region, together with increased anterior and inferior facial projection. However, the degree to which basioccipital flattening is modified in circumferentially deformed Peruvians was found to be less marked than changes observed in the face. Some of the modifications observed here can be related to morphological trends existing in the population from which our sample was taken. The observation of other modifications may be subject to methodological constraints of standard morphometric approaches.     

Intentional cranial deformation in the preColumbian populations of ecuador

Using 151 crania, 8 Preceramic, 86 Formative, 29 Regional Developmental, 28 Integration Period and some isolated skulls from Ecuador I can clarify some origins and diffusion of American cranial deformation. To Imbelloni's classification of Tabular erecta, Tabular obliqua, and Annular I add a new type, Cuneiform, marked by flattening of the entire occiput (not just the upper, membraneous-derived bone) without evidence of counter pressure in front. The Cuneiform type starts in Guayas about 2000 B.C. (perhaps the earliest in America) with diffusion to coastal Peru in Chavin times. Tabular erecta, of coastal origin between Manabi province and the Guyas river basin, about 1,000 B.C. , also spreads to coastal Peru. Tabular obliqua appears in Esmeraldas province probably from Mexico 2000 years ago, and diffuses south into Chile. Annular type starts early in the Southern Andes and appears late in the highlands of Ecuador.     

Test of the relationship between sutural ossicles and cultural cranial deformation: Results from Hawikuh,New Mexico

A number of researchers have hypothesized that the biomechanical forces associated with cultural cranial deformation can influence the formation of sutural ossicles. However, it is still difficult to make definitive conclusions about this relationship because the effects appear to be quite weak, and contradictory results have been obtained when specific sutures and deformation types are compared across studies. This research retests the hypothesis using a single archeological sample of lamdoidally deformed, occipitally deformed, and undeformed crania from Hawikuh, New Mexico (AD 1300–1680). Our results show no significant difference in either the prevalence or number of ossicles between deformed and undeformed crania, suggesting that the abnormal strains generated by cranial shape modification during infancy are not a factor in ossicle development for this population. One significant relationship was detected at the right lambdoid suture in crania with asymmetrical occipital deformation. Crania that were more deformed on the left side showed greater numbers of ossicles on the right side, but the effect was small. Furthermore, the relationship may well reflect a sampling error, due to the small number of crania with greater left side deformation and scorable right side lambdoid ossicles (n = 11). Although it is possible that forms of cranial deformation other than the posterior tabular types examined here may affect ossicle expression, our review of the literature suggests that the relationship in humans is complex and incompletely understood at this time. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.     

Assessing cranial plasticity in humans: The impact of artificial deformation on masticatory and basicranial structures

Artificial cranial deformations (ACD) are a widespread cultural practice found in numerous historical and prehistoric contexts. Their study can yield valuable insight into craniofacial growth, specifically into the interactions between neurocranial and basicranial modules. This study seeks to reinvestigate the presumed effect of ACD on basicranial and masticatory elements by applying a 3D geometric morphometric approach to CT scans. A total of 51 French and Bolivian skulls, representing anteroposterior and circumferential deformations and including undeformed individuals, were scanned, and 3D landmarks were submitted to between-group principal components analysis and two-block partial least-squares analysis. Our results illustrate changes in basicranial shape and in cranial base angles induced by ACD, as well as in masticatory geometry, namely in the relative position of the mandibular fossae. Furthermore, our findings highlight differential effects of the various deformation types, which suggest that patterns of covariation between modified vaults and their associated basicrania are more complex than previously assumed, thereby stressing the degree of plasticity in human craniofacial growth.     

A comparative study of metric and non-metric traits in a series of modern crania

The purpose of this study is to question the utility of non-metric traits as predictors of age, race, and sex by comparing a group of non-metric variables with a group of metric variables. Twelve metric variables and 15 nonmetric variables were scored on 317 crania from the Terry Collection at the U. S. National Museum, and later statistically evaluated with a number of multivariate analysis programs and a stepwise discriminant program. The metric variables were found to be significant sex and race discriminators, where-as the non-metric variables were non-significant. The non-metric variables were found to be better age discriminators than the metric variables, even though neither could be classified as highly significant. It was concluded that non-metric traits by themselves have very little discriminatory value and should be used instead to supplement other osteological measurements and observations.     

Growth and sexual dimorphism in orangutan crania: a three-dimensional approach

New insights may be gleaned by taking an ontogenetic approach to investigations of adult dimorphism. Previous work in this area relied on traditional, caliper-based, morphometric methods, and produced conflicting results. This study uses a three-dimensional (3-D) approach for both local and global form comparisons of sex-specific growth and growth patterns. 3-D coordinate data were collected for 20 landmarks on 94 orangutan crania divided into five developmental stages. Data were analyzed using Euclidean distance matrix analysis (EDMA). Results indicate that differences in growth patterns between male and female orangutans exist in the youngest age intervals. Dimorphic patterns are strongest in the face and basicranium at the youngest age intervals, and in the face and neurocranium during adult stages. Females grow substantially more in the cranial base and face during the youngest age groups, while males grow more than females in all anatomical regions later in development. Growth in the palate was similar between sexes. Sexual dimorphism may be produced through the continued growth of one sex relative to the other, representing differences in timing, or growth duration. Dimophism may also result from different growth rates between sexes, where one sex develops faster than the other sex in the same time interval. Orangutan males and females differ in both the rate and duration of their craniofacial development. The data analysis technique used here, EDMA, was integral in identifying dynamic growth processes rather than just the static end results of each developmental stage.     

Growth-related shape changes in the fetal craniofacial complex of humans (Homo sapiens) and pigtailed macaques (Macaca nemestrina): a 3D-CT comparative analysis

This study investigates whether macaques and humans possess a common pattern of relative growth during the fetal period. The fetal samples consist of 16 male pigtailed macaques (mean age, 20.5 gestational weeks) and 17 humans (9 males and 8 females; mean age, 29.5 gestational weeks). For each individual, three-dimensional coordinates of 18 landmarks on the skull were collected from three-dimensional computed tomographic (CT) reconstructed images and two-dimensional CT axial slices. Early and late groups were created from the human (early mean age, 24 weeks, N = 8; late mean age, 34 weeks, N = 9) and macaque samples (early mean age, 17.7 weeks, N = 7; late mean age, 23 weeks, N = 9). Inter- and intraspecific comparisons were made between the early and late groups. To determine if macaques and humans share a common fetal pattern of relative growth, human change in shape estimated from a comparison of early and late groups was compared to the pattern estimated between early and late macaque groups. Euclidean distance matrix analysis was used in all comparisons. Intraspecific comparisons indicate that the growing fetal skull displays the greatest amount of change along mediolateral dimensions. Changes during human growth are primarily localized to the basicranium and palate, while macaques experience localized change in the midface. Interspecific comparisons indicate that the two primate species do not share a common pattern of relative growth, and the macaque pattern is characterized by increased midfacial growth relative to humans. Our results suggest that morphological differences in the craniofacial skeleton of these species are in part established by differences in fetal growth patterns.     

Relationship between non‐ulcerative functional dyspepsia,occlusal pairs and masticatory performance in partially edentulous elderly persons

doi: 10.1111/j.1741‐2358.2010.00377.x
Relationship between non‐ulcerative functional dyspepsia, occlusal pairs and masticatory performance in partially edentulous elderly persons Objective: To relate occlusal state, masticatory performance and non‐ulcerative functional dyspepsia. Background: In spite of the relationship between gastric disturbances and number of present teeth being recognised, the influence of the number of occlusal pairs and masticatory performance, expressed as median particle size, has not been considered. Materials and methods: Thirty‐eight subjects (mean age = 71.8 ± 7.7 years) diagnosed with non‐ulcerative functional dyspepsia were selected. A further 38 healthy subjects (mean age = 71.9 ± 7.0 years) acted as controls. Subjects were subdivided according to their number of occlusal pairs: (1) 0–4, (2) 5–9 and (3) 10–14. Masticatory performance was evaluated by using the sieving method. Data were analysed using 2‐way anova and Bonferroni post‐hoc, Chi‐square and Odd ratio tests. Results: Subjects presenting with non‐ulcerative functional dyspepsia and 0–4 occlusal pairs showed the lowest masticatory performance (p < 0.01). No association between the dyspepsia and the number of occlusal pairs (χ² = 0.48, p = 0.785) was observed, however results showed association between functional dyspepsia and masticatory performance (χ² = 4.07, p = 0.0437) presenting an odds ratio = 3.46 (Confidence Interval = 0.99–12.10). Conclusion: Changes in masticatory performance were associated with the presence of non‐ulcerative functional dyspepsia.     

Intentional cranial vault deformation and induced changes of the cranial base and face

Three morphologically distinct populations of Peruvian crania (n = 130) were metrically analysed to quantify changes resulting from intentional artificial vault deformation. Two of these samples are artificially deformed (anteroposterior [AP] and circumferential [C] types). Measurements taken from lateral radiographs demonstrated that alternative forms of the cranial base angle (N-S-Ba, planum angle, planum sphenoidale to plane of the clivus and PANG angle, planum sphenoidale to basion-sella plane) and the orbital and OANG angles (orbital roof to plane of the clivus and basion-sella plane, respectively) of both deformed groups increased while the angle S-Ba-O decreased significantly with respect to the undeformed (N) sample. Changes in the AP group are largely due to anteroinferior displacement of the basion-sella plane. Similar changes in group C are amplified by this group's posterosuperior frontal migration. This migration results in a relatively shallow orbit at the orbital plate/frontal squama interface. Unlike the deformation experienced by the external vault plates, the basion-sella plane orientation remains stable with respect to the Frankfort Horizontal. Additionally, nasal region measurements such as maximum nasal aperture breadth and nasal height were largely stable between each deformed group and the undeformed group. However, facial (bimaxillary and bizygomatic), basicranial, cranial, and frontal breadths decreased significantly from group AP to group N to group C. Thus, gross morphological facial changes between each undeformed group and the control group are largely accounted for by dimensional changes in peripheral structures. These results stress the importance of the dynamic interrelationship between the cranial vault and base in the development of the craniofacial complex.     

Brief communication: Artificial cranial modification in Kow Swamp and Cohuna

The crania from Kow Swamp and Cohuna have been important for a number of debates in Australian paleoanthropology. These crania typically have long, flat foreheads that many workers have cited as evidence of genetic continuity with archaic Indonesian populations, particularly the Ngandong sample. Other scientists have alleged that at least some of the crania from Kow Swamp and the Cohuna skull have been altered through artificial modification, and that the flat foreheads possessed by these individuals are not phylogenetically informative. In this study, several Kow Swamp crania and Cohuna are compared to known modified and unmodified comparative samples. Canonical variates analyses and Mahalanobis distances are generated, and random expectation statistics are used to calculate statistical significance for these tests. The results of this study agree with prior work indicating that a portion of this sample shows evidence for artificial modification of the cranial vault. Many Kow Swamp crania and Cohuna display shape similarities with a population of known modified individuals from New Britain. Kow Swamp 1, 5, and Cohuna show the strongest evidence for modification, but other individuals from this sample also show evidence of culturally manipulated changes in cranial shape. This project provides added support for the argument that at least some Pleistocene Australian groups were practicing artificial cranial modification, and suggests that caution should be used when including these individuals in phylogenetic studies. Am J Phys Anthropol 155:173–178, 2014. © 2014 Wiley Periodicals, Inc.     

Transverse masticatory movements, occlusal orientation, and symphyseal fusion in selenodont artiodactyls

Based on extensive experimental work on primates, two masticatory loading regimes have emerged as the likely determinants of mandibular symphyseal fusion-dorsoventral shear and lateral transverse bending (wishboning) (Ravosa and Hylander, 1994; Hylander et al., 1998, 2000). Recently, however, it has been argued that, rather than functioning to strengthen the symphysis during mastication, fusion serves to stiffen the symphyseal joint so as to facilitate increased transverse jaw movements during occlusion (Lieberman and Crompton, 2000). As part of this transverse stiffness model, it has been suggested that taxa with fused symphyses should also exhibit more horizontally oriented occlusal wear facets. Using a series of univariate and bivariate analyses, we test predictions of these three models in a sample of 44 species of selenodont artiodactyls. Consistent with the wishboning and transverse stiffness models, taxa with fused symphyses (camelids) have more horizontally oriented M(2) and M(2) occlusal wear facets, anteroposteriorly (AP) elongate symphyses, and relatively wider corpora. Contrary to the dorsoventral shear model, camelids do not have relatively deeper corpora (due to greater parasagittal bending). While taxa with ossified symphyses have relatively larger symphysis cross-sectional areas, this appears to be the byproduct of an increase in AP symphysis length due to greater lateral transverse bending of the mandible. Theoretical consideration of the biomechanics of mastication further suggests that strength, not stiffness, is the critical factor in determining symphyseal ossification. Thus, like anthropoid primates, fusion in selenodont artiodactyls appears to function in resisting increased wishboning stresses arising from an emphasis on transverse occlusal/mandibular movements and loads.