Twenty years of functional cranial analysis

Septoplasty During Primary Cleft Lip Reconstruction: A Historical Perspective and Scoping Review

BACKGROUND

Traditional surgical approaches excluded septoplasty at primary cleft lip reconstruction due to concerns about restricted nasal and midfacial growth. Modern opinion in the treatment of cleft lip has increasingly employed primary septoplasty; this scoping review and historical perspective aims to chronicle the evolution of septoplasty in patients born with cleft lip and palate and discuss current evidence.

METHODS

The historical perspective explicitly contrasts American and European perceptions of septoplasty in cleft lip deformity and the competing anatomical theories of the role of the septum on midfacial and nasal growth. For the scoping review, articles were extracted from Embase, PubMed, and Medline, as well as manual searches of reference lists. Results were compiled, grouped, and appraised by date, outcomes, and historical significance. Inclusion criteria consisted of children who underwent primary septoplasty for any indication and were followed up on outcomes of facial growth and nasal function. Literature reviews, opinion articles, case reports, guidelines, or studies not available in English or online were excluded.

RESULTS

Evolving anatomical theories relating to midfacial growth in the mid-late 20th century underpinned a progressive ideological shift on the safety and efficacy of septoplasty in children. This is supported by our scoping review, which included 23 articles mutually selected for inclusion by 2 blinded assessors. Several competing methods have been employed to measure endpoints on facial growth and nasal function, but generally indicate primary septoplasty is successful in improving nasal function and preserving midfacial growth.

CONCLUSION

Perceptions towards septoplasty on facial growth in the pediatric population have transformed significantly and suggest a growing acceptance of primary septoplasty techniques in patients born with a cleft lip.

The influence of biological relatedness on sexual dimorphism and sex classification based on external morphology of the frontal bone

The most significant sexual differences in the human skull are located in the upper third of the face (the frontal bone), which is a useful research object, mainly in combination with virtual anthropology methods. However, the influence of biological relatedness on sexual dimorphism and frontal bone variability remains unknown. This study was directed at sexual difference description and sex classification using the form and shape of the external surface of the frontal bones from a genealogically documented Central European osteological sample (nineteenth to twentieth centuries). The study sample consisted of 47 cranial CT images of the adult members of several branches of one family group over 4 generations. Three-dimensional virtual models of the frontal bones were analyzed using geometric morphometrics and multidimensional statistics. Almost the entire external frontal surface was significantly different between males and females, especially in form. Significant differences were also found between this related sample and an unrelated one. Sex estimation of the biologically related individuals was performed using the classification models developed on a sample of unrelated individuals from the recent Czech population (Čechová et al. in Int J Legal Med 133: 1285 1294, 2019), with a result of 74.46% and 63.83% in form and shape, respectively. Failure of this classifier was caused by the existence of typical traits found in the biologically related sample different from the usual manifestation of sexual dimorphism. This can be explained as due to the increased degree of similarity and the reduction of variability in biologically related individuals. The results show the importance of testing previously published methods on genealogical data.

INFLUENCE OF BAD HABITS ON THE DEVELOPMENT OF ACQUIRED DEFORMATIONS IN THE MAXILLOFACIAL AREA

OBJECTIVE

The aim: Identifying the relationship between the presence of oral habit and acquired maxillomandibular anomalies, influence of oral habits on the skeleton and muscular system formation in children.

PATIENTS AND METHODS

Materials and methods: We conducted clinical, radiological methods of examination of 60 patients aged 9-12 with acquired maxillomandibular anomalies, 15 persons aged 9-12 years without maxillomandibular anomalies and acquired deformities (norm group) and 15 persons aged 9-12 years with hereditary syndromes, which are combined with bone deformities in the maxillofacial area (comparison group).

RESULTS

Results: Clinical examination showed that oral habits were manifested in 98.3% of patients. The results of clinical and radiological examination, analysis of cephalometric parameters and data on the thickness of the masticatory muscles on symmetrical areas of the face confirm the relationship between chronic oral habits and formation of acquired maxillomandibular anomalies; confirm the presence of acquired rather than congenital deformity of the facial skeleton, which is associated with changes in the thickness of the masticatory muscles on the part of the deformation та compensatory muscle hypertrophy on the opposite side.

CONCLUSION

Conclusions: The oral habit should be considered as one of the triggers in the development of acquired deformities of the maxillofacial area.

Comparison of Genial Tubercule Anatomy Based on Age and Gender

Objective

In our study, it was aimed to determine whether there were differences in genial tubercle dimensions depending on age and gender.

Methods

In this study, 220 cone beam computed tomography (CBCT) images of patients (110 female and 110 male) between the ages of 20-80 years were obtained from the archive of İzmir Katip Çelebi University Faculty of Dentistry. All patients were divided into decade groups according to their age, and each decade group was divided into two subgroups according to gender. The genial tubercle was defined radiologically using axial, coronal and sagittal sections as well as 3D reconstruction image with NNT software program. Sagittal, vertical and horizontal dimensions of the genial tubercle were measured and statistically analyzed.

Results

There was a weak negative correlation between age groups and vertical values (r=-0.142; p=0.036) whereas the correlation coefficients between age groups and sagittal and horizontal values were not statistically significant (r=-0.043; p=0.530 and r=-0.039; p=0.563). There was a strong positive correlation between vertical and sagittal values in men (r=0.705, p<0.001) and women (r=0.714, p<0.001) in the whole group. There was a weak positive correlation between horizontal and sagittal, horizontal and vertical values in men (r=0.362, p<0.001; r=0.231, p<0.001) and women (r=0.304, p<0.001; r=0.257, p=0.007) in the whole group.

Conclusion

The vertical and horizontal dimensions of genial tubercle of men were higher than that of women. As the age of the patients increased, a decrease in the vertical values of the genial tubercle was observed.

The relationship between masseter muscle thickness measured by ultrasonography and facial profile in young Korean adults

Purpose

The purpose of this study was to evaluate the relationship between masseter muscle thickness, facial morphology, and mandibular morphology in Korean adults using ultrasonography.

Materials and Methods

Ultrasonography was used to measure the masseter muscle thickness bilaterally of 40 adults (20 males, 20 females) and was performed in the relaxed and contracted states. Facial photos and panoramic radiography were used for morphological analyses and evaluated for correlations with masseter muscle thickness. We also evaluated the correlations of age, body weight, stature, and body constitution with masseter muscle thickness.

Results

In the relaxing, the masseter was 9.8±1.3 mm in females and 11.3±1.2 mm in males. In the contracted state, it was 12.4±1.4 mm in females and 14.7±1.4 mm in males. Facial photography showed that bizygomatic facial width over facial height was correlated with masseter muscle thickness in both sexes in the relaxed state, and was statistically significantly correlated with masseter muscle thickness in males in the contracted state. In panoramic radiography, correlations were found between anterior angle length and posterior angle length and masseter muscle thickness in females, and between body length and posterior angle length, between anterior angle length and body length, between ramal length and body length, and between body length and condyle length in males.

Conclusion

Masseter muscle thickness was associated with facial and mandibular morphology in both sexes, and with age in males. Ultrasonography can be used effectively to measure masseter muscle thickness.

Costochondral Graft Versus Total Alloplastic Joint for Temporomandibular Joint Reconstruction

Presently, there are 2 options for the replacement of the temporomandibular joint for end-stage pathology: autogenous bone grafting or alloplastic joint replacement. This article presents evidence-based advantages and disadvantages for each of these management options to assist both surgeons and their patients in making that choice.

Ontogeny of the Postorbital Region in Tarsiers and Other Primates

Bony structure of the postorbital region is a key trait distinguishing major clades of primates. Strepsirrhines share a postorbital bar, and anthropoids share a complete postorbital septum. At issue is whether the partial postorbital septum of tarsiers unites living tarsiers more closely with anthropoids than with certain large-eyed Eocene fossils. Previously we reported incomplete postorbital closure in tarsiers at birth. In this article, we document comparative analyses of the postorbital region in a broad range of perinatal primates. Virtual reconstructions of microCT data were used to study three-dimensional structure of the perinatal cranium in these taxa. We also describe and illustrate formation of the tarsier partial postorbital septum through the perinatal period using a growth series of Tarsius syrichta. Our results support the hypothesis that partial postorbital septation in the tarsier is secondary to eye hypertrophy. Based on these observations, we propose a structural hypothesis for phylogenetic differences observed in the primate postorbital region. Specifically, we propose that key postorbital traits, including the frontal spur in strepsirrhines and the posterior lamina of the zygomatic in anthropoids, develop as a result of the spatial relationships of brain, eyes, and teeth. Haplorhines are united by expansion of the anterior cranial fossa and loss of the frontal spur. Anthropoids are further united to the exclusion of tarsiers by expansion of the temporal lobes and associated formation of the posterior lamina of the zygomatic. Mechanical forces related to these spatial relationships may be modulated by deep fascia of the orbit to induce formation of the postorbital septum. Anat Rec, 299:1631-1645, 2016. © 2016 Wiley Periodicals, Inc.

Mandibular volumetric increase following distraction osteogenesis

INTRODUCTION

Mandibular distraction osteogenesis (MDO) for the treatment of Pierre Robin sequence (PRS) enables mandibular lengthening and improves airway and feeding function. It remains unknown how the post-distracted mandibular volume compares to a normal control population. The aim of this study was to analyze mandibular volume and symmetry following bilateral MDO and compare post-distraction measurements to a non-distracted, normal age- and sex-matched control cohort.

METHODS

Demographic information and three dimensional-computed tomographic (CT) images were obtained from normal control and distracted PRS patients. Mandibular volume and symmetry indices were calculated and results statistically analyzed. P values ≤0.05 were considered statistically significant.

RESULTS

24 CT scans and 48 hemimandibles were analyzed (8 control patients: mean age = 5.6 months, 3 females; 8 distracted patients: mean age pre-distraction = 1.8 months, mean age post-distraction = 5.3 months, 3 females). No complications were encountered in the distracted group. The mean pre- and post-distraction volume in the MDO group measured 7238.1 mm(3) and 15,360.6 mm(3), respectively (P = 0.0003) and the mean percent increase in mandibular volume following distraction was 113.3%. The mean symmetry index increased after distraction from 0.91 to 0.95 (P = 0.31). Matched normal control mandibles measured 13,488.6 mm(3) versus post-distraction mandibles at 15,360.6 mm(3) (P = 0.40). Normal control and post-distraction symmetry indices were 0.99 and 0.95, respectively (P = 0.68).

CONCLUSION

Distraction resulted in a significantly increased mandibular volume and an observed preservation in mandibular symmetry. Post-distraction volume was increased compared to normal controls but remained less symmetrical.

The aponeurotic tension model of craniofacial growth in man

Craniofacial growth is a scientific crossroad for the fundamental mechanisms of musculoskeletal physiology. Better understanding of growth and development will provide new insights into repair, regeneration and adaptation to applied loads. Traditional craniofacial growth concepts are insufficient to explain the dynamics of airway/vocal tract development, cranial rotation, basicranial flexion and the role of the cranial base in expression of facial proportions. A testable hypothesis is needed to explore the physiological pressure propelling midface growth and the role of neural factors in expression of musculoskeletal adaptation after the cessation of anterior cranial base growth. A novel model for craniofacial growth is proposed for: 1. brain growth and craniofacial adaptation up to the age of 20; 2. explaining growth force vectors; 3. defining the role of muscle plasticity as a conduit for craniofacial growth forces; and 4. describing the effect of cranial rotation in the expression of facial form.Growth of the viscerocranium is believed to be influenced by the superficial musculoaponeurotic systems (SMAS) of the head through residual tension in the occipitofrontalis muscle as a result of cephalad brain growth and cranial rotation. The coordinated effects of the regional SMAS develop a craniofacial musculoaponeurotic system (CFMAS), which is believed to affect maxillary and mandibular development.

Middle cranial fossa anatomy and the origin of modern humans

Anatomically, modern humans differ from archaic forms in possessing a globular neurocranium and a retracted face and in cognitive functions, many of which are associated with the temporal lobes. The middle cranial fossa (MCF) interacts during growth and development with the temporal lobes, the midface, and the mandible. It has been proposed that evolutionary transformations of the MCF (perhaps from modification of the temporal lobes) can have substantial influences on craniofacial morphology. Here, we use three-dimensional (3D) geometric morphometrics and computer reconstructions of computed tomography-scanned fossil hominids, fossil and recent modern humans and chimpanzees to address this issue further. Mean comparisons and permutation analyses of scaled 3D basicranial landmarks confirm that the MCF of Homo sapiens is highly significantly different (P < 0.001) from H. neanderthalensis, H. heidelbergensis, and Pan troglodytes. Modern humans have a unique configuration with relatively more anterolateral projection of the MCF pole relative to the optic chiasm and the foramen rotundum. These findings are discussed in the context of evolutionary changes in craniofacial morphology and the origins of modern human autapomorphies. In particular, the findings of this study point to variations in the temporal lobe, which, through effects on the MCF and face, are central to the evolution of modern human facial form.

Genetic, geographic, and environmental correlates of human temporal bone variation

Temporal bone shape has been shown to reflect molecular phylogenetic relationships among hominoids and offers significant morphological detail for distinguishing taxa. Although it is generally accepted that temporal bone shape, like other aspects of morphology, has an underlying genetic component, the relative influence of genetic and environmental factors is unclear. To determine the impact of genetic differentiation and environmental variation on temporal bone morphology, we used three-dimensional geometric morphometric techniques to evaluate temporal bone variation in 11 modern human populations. Population differences were investigated by discriminant function analysis, and the strength of the relationships between morphology, neutral molecular distance, geographic distribution, and environmental variables were assessed by matrix correlation comparisons. Significant differences were found in temporal bone shape among all populations, and classification rates using cross-validation were relatively high. Comparisons of morphological distances to molecular distances based on short tandem repeats (STRs) revealed a significant correlation between temporal bone shape and neutral molecular distance among Old World populations, but not when Native Americans were included. Further analyses suggested a similar pattern for morphological variation and geographic distribution. No significant correlations were found between temporal bone shape and environmental variables: temperature, annual rainfall, latitude, or altitude. Significant correlations were found between temporal bone size and both temperature and latitude, presumably reflecting Bergmann's rule. Thus, temporal bone morphology appears to partially follow an isolation by distance model of evolution among human populations, although levels of correlation show that a substantial component of variation is unexplained by factors considered here.

Reformation of the sagittal suture following surgery for isolated sagittal craniosynostosis

OBJECT

Data from animal studies have shown that in experimentally induced craniosynostosis, removal of the involved calvaria results in the formation of new calvaria with time, and sutures redevelop in their normal anatomical positions. However, the pattern of suture reformation following surgery in humans with craniosynostosis remains ill-defined. The aim of this study was to determine the pattern of postoperative suture reformation in children who have undergone surgery for isolated sagittal synostosis and assess possible factors related to suture reformation.

METHODS

Records were retrospectively reviewed for 42 consecutive infants who had surgery for isolated sagittal synostosis between 1987 and 2000 and for whom postoperative skull radiographs were available. The radiographs were evaluated for sagittal suture morphology and patency of the coronal and lambdoid sutures. Surgery involved at a minimum 1) a vertex craniectomy, characterized by removal of the sagittal suture and a 1.5- to 2.5-cm piece of adjacent parietal bone with the attached pericranium bilaterally, and 2) parietal osteotomies and/or craniectomies. The median age at surgery was 3.9 months (range 1.9-7.6 months). The mean duration of follow up was 32.2 months (range 6-144 months). The sagittal suture had reformed in only seven (16.7%) of the children at follow up. In the other 35 (83.3%), the craniectomized bone defects had reossified without any part of the sagittal suture being visible on the radiographs.

CONCLUSIONS

There is a very low incidence of suture reformation in children after surgery for isolated sagittal craniosynostosis. Genetic predisposition, inclusion of undiagnosed syndromic patients, and current operative techniques may be some of the factors responsible for the low incidence of suture reformation seen in this series.

Skull base growth in craniosynostosis

INTRODUCTION

The interrelationship of skull base growth and craniosynostosis is one that is not often taken into account in the clinical management of patients with craniofacial disorders by neurosurgeons and craniofacial surgeons. Very early on in our medical training we are taught the anatomical differences between the calvarial unit and skull base portion of the skull. The inherent differences in both underlying tissue components and the different growth characteristics of these two uniquely different structures are critical in understanding skull base growth in craniosynostosis and the inherent potential craniofacial growth in these unique children.

REVIEW

This paper will review some of the basic anatomy of these zones of growth plus review some of the prevalent theories of the effect of skull base growth on craniosynostosis and the converse.

CONCLUSION

While the theories of these growth patterns have yet to be finalized an understanding of their potential influences and abnormal growth patterns remain key to providing a good surgical outcome in surgery for craniosynostosis.

Three-dimensional dental arch and palatal form changes after extraction and nonextraction treatment. Part 1. Arch length and area

The purpose of this study was to investigate changes in arch length, arch area, and irregularity index in patients treated with and without premolar extractions. Records collected at pretreatment, at bracket removal, at the end of retention, and 5 years out of retention were examined. Stone casts were mounted on an articulator with an anatomic face-bow and a central wax record, and measurements were made with a 3-dimensional digitizer. In general, the maxillary arch exhibited less relapse tendency than did the mandibular arch for both patient groups. In general, the extraction group showed the same relapse tendency as the nonextraction group.

Malformations of the craniofacial region: evolutionary, embryonic, genetic, and clinical perspectives

Malformations of the craniofacial region are reviewed with respect to evolutionary, embryonic, genetic, and clinical perspectives under the following headings: How Old Is Our Head?, Head Organization Genes, Genetics of Craniofacial Anomalies, Craniofacial Derivatives, Anencephaly, Cephalocele, Holoprosencephaly, Craniosynostosis, Hypertelorism, Branchial Arch Anomalies, and Orofacial Clefting.

Relationship in hypoplasia between the masticatory muscles and the craniofacial skeleton in hemifacial microsomia, as determined by 3-D CT imaging

The purpose of this study, based on three-dimensional (3-D) computed tomographic (CT) reconstructions, was to evaluate the relation between underdevelopment of masticatory muscles and hypoplasia of the craniofacial skeleton in hemifacial microsomia (HFM). In 25 patients with HFM and 19 control patients the volumes of the masseter, the temporal, and the medial-pterygoid and lateral-pterygoid muscles were measured on the basis of CT scans, using three-dimensional segmentation and voxel addition. The size and shape of the craniofacial structures were classified, using three-dimensional imaging based on CT scans. Contiguous 1.5-mm computed tomography scans were made with a Philips Tomoscan 350 and processed by a Cemax 1500X 3-D workstation. Using the Pearson product moment correlation coefficient, the Pruzansky/Kaban classification system, the new Craniofacial Deformity Scoring System, Cranial Deformity Scoring System, and Mandibular Deformity Scoring System (MDS) demonstrated correlation coefficients with the "masseter muscle percentage" varying from 0.71 to 0.81 (P < 0.05), with the medial pterygoid muscle percentage correlation coefficient varying from 0.43 to 0.56 (P < 0.05), with the lateral pterygoid muscle percentage correlation coefficient varying from 0.55 to 0.61 (P < 0.05), and with the temporal muscle percentage correlation coefficient varying from 0.67 to 0.84 (P < 0.05). The normal right/left difference in volume of the masticatory muscles of the control patients, calculated as a percentage of the total, demonstrated small differences of 3.4% to 4.8%. Bony malformations are associated with underdevelopment of the masseter and the temporal muscles, and demonstrate a tendency toward a clear relationship. The degree of muscular underdevelopment of the different muscles of mastication in one patient could vary widely. The normal right/left difference of the masticatory muscles of the control patients is minimal. The volume of the masticatory muscles of the non-affected side does not demonstrate a compensatory effect in patients with HFM.

Genetic aspects of dental disorders

This paper reviews past and present applications of quantitative and molecular genetics to dental disorders. Examples are given relating to craniofacial development (including malocclusion), oral supporting tissues (including periodontal diseases) and dental hard tissues (including defects of enamel and dentine as well as dental caries). Future developments and applications to clinical dentistry are discussed. Early investigations confirmed genetic bases to dental caries, periodontal diseases and malocclusion, but research findings have had little impact on clinical practice. The complex multifactorial aetiologies of these conditions, together with methodological problems, have limited progress until recently. Present studies are clarifying previously unrecognized genetic and phenotypic heterogeneities and attempting to unravel the complex interactions between genes and environment by applying new statistical modelling approaches to twin and family data. Linkage studies using highly polymorphic DNA markers are providing a means of locating candidate genes, including quantitative trait loci (QTL). In future, as knowledge increases; it should be possible to implement preventive strategies for those genetically-predisposed individuals who are identified to be at risk.

The functional matrix hypothesis revisited. 4. The epigenetic antithesis and the resolving synthesis

In two interrelated articles, the current revision of the functional matrix hypothesis extends to a reconsideration of the relative roles of genomic and of epigenetic processes and mechanisms in the regulation (control, causation) of craniofacial growth and development. The dialectical method was chosen to analyze this matter, because it explicitly provides for the fuller presentation of a genomic thesis, an epigenetic antithesis, and a resolving synthesis. The later two are presented here, where the synthesis suggests that both genomic and epigenetic factors are necessary causes, that neither alone is also a sufficient cause, and that only the two, interacting together, furnish both the necessary and sufficient cause(s) of ontogenesis. This article also provides a comprehensive bibliography that introduces the several new, and still evolving, disciplines that may provide alternative viewpoints capable of resolving this continuing controversy; repetition of the present theoretical bases for the arguments on both sides of these questions seems nonproductive. In their place, it is suggested that the group of disciplines, broadly termed Complexity, would most likely amply repay deeper consideration and application in the study of ontogenesis.

The functional matrix hypothesis revisited. 2. The role of an osseous connected cellular network

Intercellular gap junctions permit bone cells to intercellularly transmit, and subsequently process, periosteal functional matrix information, after its initial intracellular mechanotransduction. In addition, gap junctions, as electrical synapses, underlie the organization of bone tissue as a connected cellular network, and the fact that all bone adaptation processes are multicellular. The structural and operational characteristics of such biologic networks are outlined and their specific bone cell attributes described. Specifically, bone is "tuned" to the precise frequencies of skeletal muscle activity. The inclusion of the concepts and databases that are related to the intracellular and intercellular bone cell mechanisms and processes of mechanotransduction and the organization of bone as a biologic connected cellular network permit revision of the functional matrix hypothesis, which offers an explanatory chain, extending from the epigenetic event of muscle contraction hierarchically downward to the regulation of the bone cell genome.

Relationship between bone and muscles of mastication in hemifacial microsomia

The relationship between the bone and muscles of mastication in hemifacial microsomia was studied using three-dimensional volumetric computed tomography scans and image processing techniques. High resolution head computed tomography scans were obtained from 31 patients with unilateral hemifacial microsomia and eight normal patients. Using three-dimensional volume renderings of bone, mandibular deformities in patients with hemifacial microsomia were classified using the Pruzansky system. For each patient, specific craniofacial bones (temporal bone, maxilla mandible) and the muscles of mastication (masseter, temporalis and lateral and medial pterygoid) were segmented bilaterally from the image volume for independent display and volume measurement. Volumes were expressed as the ratio of the affected: unaffected sides. For the masseter and temporalis, the relationship between muscular hypoplasia and osseous hypoplasia in its origin and insertion was studied by plotting affected:unaffected bone volume as a function of affected:unaffected muscle volume for each muscle, bone of origin, bone of insertion triplet. The volumes of the pterygoid muscles were compared with hemimandibular volumes. The precision of object segmentations was examined by repetitive definition tasks, whereas the accuracy of volume measurement was tested by scanning custom-made phantom objects and comparing digital to physical object volume measurements. Volume measurements performed using these techniques were both accurate and precise. In hemifacial microsomia, the extent of hypoplasia of specific muscles of mastication predicted the extent of dysplasia in their osseous origin and insertion. However, the reverse was not true. The extent of hypoplasia of the facial bones did not necessarily predict the extent of hypoplasia in the attached muscles of mastication. Pruzansky grade of the mandible described the degree of mandibular hypoplasia on the affected side, but was inconsistent in its prediction of volume decrease of the other facial bones.

Hypertelorism: interorbital growth, measurements, and pathogenetic considerations

Normal pre- and post-natal changes in the interorbital distance are described. Causes of illusory hypertelorism include flat nasal bridge, epicanthic folds, exotropia, widely-spaced eyebrows, narrow palpebral fissures, and dystopia canthorum. Measurements of hypertelorism may involve soft tissues or bone, and a number of indices have also been proposed. Various types of measurements are evaluated and recommendations suggested. Possible pathogenetic mechanisms for hypertelorism include: early ossification of the lesser wings of the sphenoid; failure in nasal capsule development allowing the primitive brain vesicle to protrude into the space normally occupied by the capsule resulting in morphokinetic arrest in the position of the eyes; and disturbances of the cranial base in Apert syndrome. Associations with increased interorbital distance are also discussed: orofacial clefting, nonprotruding lipomas of the corpus callosum, calcification of the falx cerebri, duplication of the crista galli, wrinkling of the nose, and tissue tags of the nose. Finally, experimental models of hypertelorism in animals are discussed.

Superimposition and reconstruction in forensic facial identification: a survey

Forensic facial reconstruction, is the reproduction of the lost or unknown facial features of an individual, for the purposes of recognition and identification. It is generally accepted that facial reconstruction can be divided into four categories: (1) replacing and repositioning damaged or distorted soft tissues onto a skull; (2) the use of photographic transparencies and drawings in an identikit-type system; (3) the technique of graphic, photographic or video superimposition; (4) plastic or three-dimensional reconstruction of a face over a skull, using modelling clay. This paper sets out to review work done on both superimposition and plastic reconstruction, however, the authors believe that only the latter category can correctly be termed facial reconstruction. The survey is divided according to work done through anthropological evaluation of the skull, clinical examination and dissection of the soft tissues, as well as methods of measuring soft tissue thicknesses using tissue puncture, ultrasound, cephalometric radiography and magnetic resonance imaging. In addition, a method of the combined use of ultrasound and radiography to collect a wider range of facial soft tissue depths and a method of producing skull and face profiles are outlined.

Oro-maxillofacial skeletal deformities resulting from burn scar contractures of the face and neck

The deforming forces of the scar contracture associated with burns of the head and neck region involve primarily the skin and secondarily the facial musculoskeletal structures. A case of severe face and neck burn accompanied by extreme facial skeletal deformity is reported. Best results are obtained in patients treated properly and promptly by a team including plastic and maxillofacial surgeons as well as orthodontists.

Development of the neurocranium after transsutural fixing by new, resorbable poly-L-lactide miniplates. A comparison to fixing with the common titanium miniplates

The right coronal sutures of twelve (12) newborn rabbits were fixed with commercially available, self-reinforced poly-L-lactide miniplates, with eight (8) rabbits sham treated with titanium miniplate fixation as reference experiments, in order to demonstrate the possible effects on skull growth. After six (6) months follow-up, both types of plate were detected to have caused a similar asymmetry in the neurocranium. Therefore, in our opinion, fixing across growing sutures, even with the new biodegradable devices, should be avoided.

Basicranial flexion, relative brain size, and facial kyphosis in nonhuman primates

Numerous hypotheses explaining interspecific differences in the degree of basicranial flexion have been presented. Several authors have argued that an increase in relative brain size results in a spatial packing problem that is resolved by flexing the basicranium. Others attribute differences in the degree of basicranial flexion to different postural behaviors, suggesting that more orthograde animals require a ventrally flexed pre-sella basicranium in order to maintain the eyes in a correct forward-facing orientation. Less specific claims are made for a relationship between the degree of basicranial flexion and facial orientation. In order to evaluate these hypotheses, the degree of basicranial flexion (cranial base angle), palate orientation, and orbital axis orientation were measured from lateral radiographs of 68 primate species and combined with linear and volumetric measures as well as data on the size of the neocortex and telencephalon. Bivariate correlation and partial correlation analyses at several taxonomic levels revealed that, within haplorhines, the cranial base angle decreases with increasing neurocranial volume relative to basicranial length and is positively correlated with angles of facial kyphosis and orbital axis orientation. Strepsirhines show no significant correlations between the cranial base angle and any of the variables examined. It is argued that prior orbital approximation in the ancestral haplorhine integrated the medial orbital walls and pre-sella basicranium into a single structural network such that changes in the orientation of one necessarily affect the other. Gould's ("Ontogeny and Phylogeny." Cambridge: Belknap Press, 1977) hypothesis, that the highly flexed basicranium of Homo may be due to a combination of a large brain and a relatively short basicranium, is corroborated.

The use of twins in dentofacial genetic research

A literature review is given on the different results obtained with twin and family studies in relationship to the development and structure of the dentofacial complex. Recent advances in twin and family studies are mentioned. Attention is focused on functional components considered to be of primary importance in craniofacial growth.

Progressive hemifacial atrophy (Romberg's disease): skeletal involvement and treatment

Progressive hemifacial atrophy (Romberg's disease) manifests variable involvement of the skin, soft tissue and underlying cranio-facial skeleton. Significant bony deformation has been identified in those patients with early onset disease, the result of factors both intrinsic to the disease process and secondary to the abnormal environment in which the skeleton develops (functional matrix). Treatment demands combined osteotomy and augmentation of the skeleton in concert with conventional approaches to soft tissue correction.

Facial dysmorphology in the neglected paediatric head and neck burn

The morphological distortion of the facial skeleton induced by untreated paediatric burns of the head and neck reinforces the theories of craniofacial growth and the modern principles of acute burn management and post-burn facial reconstruction.

Thickness of the lateral surface of the temporal bone in children

The placement of implantable auditory prostheses in children has raised questions concerning the thickness of the temporal bone in the region of implantation. The purpose of this study is to describe the thickness at specific sites of the lateral surface of the temporal bone in children of different ages. One hundred twenty-five intact temporal bones from 83 children of known sex, race, and age between birth and 20 years were measured. Thickness was measured with a specially designed micrometer at specific locations from a fixed reference point by use of a surface projected grid for site identification. Thickness was plotted against age on scattergraphs for each site, and regression analysis revealed a bimodal linear relationship. Sites medial to the temporalis muscle were the thinnest; sites associated with the posteroinferior insertion of the temporalis muscle, along the supramastoid crest, were the thickest. However, wide interindividual variability was the rule.

Sutures and forces: a review

This review gives a description of the biologic significance of craniofacial sutures with respect to growth and to growth corrections. Sutural growth and its regulation are discussed briefly. Morphogenesis of sutures, sutural morphology, both microscopic and macroscopic, the structure and function of the sutural periosteum and secondary cartilages, and the biochemical composition of sutures are described. Furthermore, in vivo and in vitro experiments, including transplantation experiments, are discussed. The relationship between extrinsic mechanical forces and the resulting tissue responses in sutures is given special attention. The present article describes the state of our knowledge on the interaction between sutures and forces, and indicates problems that need to be investigated.

Statistical evaluation of the position of the mandibular foramen

The position of the mandibular foramen and its importance to successful inferior alveolar anesthesia has been well documented. The current study attempts to use position of the narrowest AP width of the ramus and the gonial angle as the important parameters in locating MF, rather than using isolated measurements of the bony mandible proper.

The control of condylar growth: an experimental evaluation of the role of the lateral pterygoid muscle

The present study used 21 male albino rats to test the hypothesis that lateral pterygoid traction regulates the growth of the mandibular condyle. The condyles, the rami, and the top of each glenoid fossa were marked with metallic implants, and, following bilateral section of the condylar neck, one lateral pterygoid muscle was extirpated. On the basis of the literal details of Petrovic's cybernetic model, it was assumed that the continued forward growth of the midface and the backward translation of the glenoid fossa would combine to produce a progressive disturbance in the buccal occlusion that would, in turn, generate a reflex contraction of the remaining lateral pterygoid muscle. Initially, however, growth of the isolated condyles would have little impact on the spatial position of the rest of the mandible. As a result, the condyles on the side with the intact lateral pterygoid should grow for a time at a maximal, open-circuit rate, whereas the experimental condyle, deprived of all muscle traction, should show only a minimal "commanded" rate of growth. The serial change in the position of the condylar and ramal implants was assessed cephalometrically for 6 weeks, and between-sides differences were analyzed by randomized block analysis of variance. The presence or absence of the lateral pterygoid muscle had no significant effect on the anteroposterior position of the condylar implants and only a slight, transitory effect on their vertical position. The translation of the ramal implants, however, was greatly affected by the condylotomy. On both control and experimental sides, the mandible collapsed upward and backward until contact between the growing condyle and ramus had been achieved, whereupon a downward and forward pattern of translatory growth was re-established. Although it could not be shown that lateral pterygoid traction per se is a significant factor in the growth of isolated condyles, it was concluded that the condyle is vitally important to the translatory growth of the mandible as a whole. On the basis of these data and the current literature, a simple hypothesis was advanced for the control of condylar growth by the ongoing pattern of functional loading and for the role of this growth in the normal downward and forward displacement of the rest of the mandible.

The growth of the first cervical vertebra in the rat

With the help of in vivo marking with alizarin red S, the patterns of growth of the first cervical vertebra are demonstrated. Major parts of the developmental events which take place during growth (differential bone formation on the bone ends facing the synchondroses, closure of the dorsal synchondrosis at 14 days, closure of the ventral synchondroses at 35 to 40 days) may be explained by the influence that a capsular matrix exerts on its protecting and supporting skeletal unit. A demonstrated continued increase of the dorsoventral diameter of the bone is suggested to be an adjustive growth process related to the translative movements of foramen magnum, a topic that has been poorly understood and incompletely investigated.

Mandibular rotation and Class III malocclusion

The purpose of this investigation was to examine Class III cases with reverse overjet and low maxillo-mandibular planes angle, before, during and following treatment. Several methods, including Björk's structural method, are used to assess any rotation occurring and the effects of such rotation on vertical facial dimension and antero-posterior jaw relationship. From these observations comments are made on the possible existence of overclosure in these cases.