Differences In Facial Shape Research Articles

Quantitative analysis of facial shape in children to support respirator design

The COVID-19 pandemic demonstrated the need for respiratory protection against airborne pathogens. Respirator options for children are limited, and existing designs do not consider differences in facial shape or size. We created a dataset of children's facial images from three cohorts, then used geometric morphometric analyses of dense and sparse facial landmark representations to quantify age, sex and ancestry-related variation in shape. We found facial shape and size in children vary significantly with age from ages 2 to 18, particularly in dimensions relevant to respirator design. Sex differences are small throughout most of the age range of our sample. Ancestry is associated with significant facial shape variation in dimensions that may affect respirator fit. We offer guidance on how to our results can be used for the appropriate design of devices such as respirators for pediatric populations. We also highlight the need to consider ancestry-related variation in facial morphology to promote equitable, inclusive products.

Face-brain correlates as potential sex-specific biomarkers for schizophrenia and bipolar disorder

Given the shared ectodermal origin and integrated development of the face and the brain, facial biomarkers emerge as potential candidates to assess vulnerability for disorders in which neurodevelopment is compromised, such as schizophrenia (SZ) and bipolar disorder (BD).The sample comprised 188 individuals (67 SZ patients, 46 BD patients and 75 healthy controls (HC)). Using a landmark-based approach on 3D facial reconstructions, we quantified global and local facial shape differences between SZ/BD patients and HC using geometric morphometrics. We also assessed correlations between facial and brain cortical measures. All analyses were performed separately by sex.Diagnosis explained 4.1 % - 5.9 % of global facial shape variance in males and females with SZ, and 4.5 % - 4.1 % in BD. Regarding local facial shape, we detected 43.2 % of significantly different distances in males and 47.4 % in females with SZ as compared to HC, whereas in BD the percentages decreased to 35.8 % and 26.8 %, respectively. We detected that brain area and volume significantly explained 2.2 % and 2 % of facial shape variance in the male SZ - HC sample.Our results support facial shape as a neurodevelopmental marker for SZ and BD and reveal sex-specific pathophysiological mechanisms modulating the interplay between the brain and the face.

ZFACE: facial analytics from a coordinate extrapolation system for morphometric phenotyping of developing zebrafish.

Facial development requires a complex and coordinated series of cellular events, that when perturbed, can lead to structural birth defects. A quantitative approach to quickly assess morphological changes could address how genetic or environmental inputs lead to differences in facial shape and promote malformations. Here we report on a method to rapidly analyze craniofacial development in zebrafish embryos using Facial Analytics based on a Coordinate Extrapolation system, termed zFACE. Confocal images capture facial structures and morphometric data is quantified based on anatomical landmarks present during development. The quantitative morphometric data can detect phenotypic variation and informs on changes in facial morphology. We applied this approach to show that loss of smarca4a in developing zebrafish leads to craniofacial anomalies, microcephaly and alterations in brain morphology. These changes are characteristic of Coffin-Siris syndrome (CSS), a rare human genetic disorder associated with mutations in SMARCA4. Multivariate analysis of zFACE data facilitated the classification of smarca4a mutants based on changes in specific phenotypic characteristics. Together, zFACE provides a way to rapidly and quantitatively assess the impact of genetic alterations on craniofacial development in zebrafish.

Can we combine 3D data obtained with a MicroScribe digitising arm and photogrammetry to address bioarchaeological research questions?

Virtual methods for studying human remains are becoming increasingly popular in bioarchaeology, and the rate of technological innovation in the last few years has been such that we now have multiple options to choose from when collecting data. This raises the question of whether datasets generated with different methods are transposable. In the study reported here, we investigated whether it is valid to combine 3D data obtained with a MicroScribe digitising arm and 3D data collected via photogrammetry. We did so by simulating a population-based analysis similar to those commonly undertaken in bioarchaeology. Our sample comprised 19 crania from two ethnic groups, Ancient Egyptians and Guanches, and the landmarks we employed pertained to facial shape.The analyses yielded several findings. First, we found that photogrammetry was significantly more precise than the MicroScribe digitising arm. Second, the photogrammetry-based method revealed the existence of facial shape differences between the two ethnic groups that were not captured by the MicroScribe-based method. Third, we found that the two methods did not consistently capture the same facial shapes—they did for one of the ethnic groups but not for the other. Fourth, the analyses indicated that using the two methods can result in ethnic group-level differences in facial shape when they are applied to individuals from a single ethnic group. Lastly, the two methods of data collection yielded different patterns of variation in facial shape. Together, these findings suggest that combining 3D landmark coordinates collected with a MicroScribe and those obtained via photogrammetry may introduce considerable error into an analysis, and, consequently, bioarchaeologists should be cautious about doing so.

Sex Differences in Adult Facial Three-Dimensional Morphology: Application to Gender-Affirming Facial Surgery.

Background: Gender-affirming facial surgery (GFS) is pursued by transgender individuals who desire facial features that better reflect their gender identity. Currently, there are a few objective guidelines to justify and facilitate effective surgical decision making. Objective: To quantify the effect of sex on adult facial size and shape through an analysis of three-dimensional (3D) facial surface images. Materials and Methods: Facial measurements were obtained by registering an atlas facial surface to 3D surface scans of 545 males and 1028 females older than 20 years of age. The differences between male and female faces were analyzed and visualized for a set of predefined surgically relevant facial regions. Results: On average, male faces are 7.3% larger than female faces (Cohen's D = 2.17). Sex is associated with significant facial shape differences (p < 0.0001) in the entire face as well as in each sub-region considered in this study. The facial regions in which sex has the largest effect on shape are the brow, jaw, nose, and cheek. Conclusions: These findings provide biologic data-driven anatomic guidance and justification for GFS, particularly forehead contouring cranioplasty, mandible and chin alterations, rhinoplasty, and cheek modifications.

Spatial normalization of facial thermal images using facial landmarks

Human–computer interaction (HCI) is an interaction for mutual communication between humans and computers. HCI needs to recognize the human state quantitatively and in real-time. Although it is possible to quantitatively evaluate the human condition by measuring biological signals, the challenge is that it often requires physical constraints. There is an increasing interest in a non-contact method of estimating physiological and psychological states by measuring facial skin temperature using infrared thermography. However, due to individual differences in face shape, the accuracy of physiological and psychological state estimation using facial thermal images was sometimes low. To solve this problem, we hypothesized that spatial normalization of facial thermal image (SN-FTI) could reduce the effect of individual differences in facial shape. The objective of this study is to develop a method for SN-FTI and to evaluate the effect of SN-FTI on the estimation of physiological and psychological states. First, we attempted spatial normalization using facial features. The results suggested that SN-FTI would result in the same face shape among individuals. Since there are individual differences in facial skin temperature distribution, the inter-individual correlation coefficient is suggested to be lower than the intra-individual correlation coefficient. Next, we modeled the estimated drowsiness level using SN-FTIs and compared it with Normal. The results showed that SN-FTI slightly improved the discrimination rate of drowsiness level. SN-FTIs were suggested to reduce the effect of individual differences in facial structure on the estimation of physiological and psychological states.

Analyzing Facial Asymmetry in Children as a Function of BMI

Childhood obesity is a major public health concern in the US with a prevalence of nearly 19% for all children and adolescents. During growth, environmental factors such as poor diet can result in increased developmental stress. Given the symmetric patterning of facial growth in humans, any random deviations from symmetry, referred to as fluctuating asymmetry (FA), are considered a reflection of stress during growth. In this study, we examine whether childhood obesity serves as a source of developmental stress resulting in increased facial asymmetry. We hypothesize that a significant relationship between facial asymmetry and BMI exists, with higher BMI individuals demonstrating increased levels of facial asymmetry.To test our hypothesis, we obtained n=354 3D facial scans of children (age 3–19) from the University of Pittsburgh Center for Craniofacial and Dental Genetics. A total of n=286 facial scans represented children with a normal weight and n=68 faces were from children with obesity. Obesity status was determined using BMI values at or above the 95th percentile. Facial scans were digitized using 34 coordinate landmarks to capture asymmetry in the eyes, nose, mouth, and lower jaw. Coordinate data was submitted to a Generalized Procrustes Analysis (GPA) to align the facial landmarks and geometric morphometrics (GM) was then employed to quantify facial shape phenotypes in MorphoJ. Principal Component Analysis (PCA) was used to identify patterns of facial asymmetry throughout the entire sample. Canonical Variate Analysis (CVA) was then employed to identify differences in facial shape due to BMI. Lastly, a Procrustes ANOVA was ran to quantify levels of fluctuating asymmetry in the sample and the resulting FA scores were regressed against BMI percentile to test for a significant relationship.The results from the PCA identified 43 principal components (PCs), with the first three PCs accounting for 44.3% of total facial asymmetry. PC1 (accounting for 20.6% of facial asymmetry) identified asymmetry in the position of the eyes and a slight deviation of the nose, mouth and lower jaw to the left or right. PC2 (12.9%) demonstrated asymmetry primarily between the jaw and nose. PC3 (10.7%) further illustrated asymmetries through the eyes and jaw. The results of the CVA showed a significant difference (p=0.023) in overall asymmetry between normal weight children with children with obesity. Normal weight children demonstrated a trend toward facial symmetry while obese children showed marked asymmetry with respect to the eyes, nose, and chin. Finally, the results of the regression between FA scores and BMI percentile did not produce any significant association (p=0.72).While these results indicate a significant difference in the patterning of facial asymmetry between normal and obese children, evidence for increased FA levels (and therefore developmental instability) was not observed. Although we reject our hypothesis, the results demonstrate interesting facial asymmetries between BMI groups that may be promising for future analysis with longitudinal data.Support or Funding InformationGrant support: R01‐DE016148

A new 3D statistical model for treacher collins syndrome using machine learning techniques to quantify facial shape differences from the normal

Background: Treacher Collins syndrome (TCS) is an autosomal dominant congenital condition with variable penetrance characterized by orbital, auricular, nasal and orofacial deformity. Currently, clinical diagnosis based on phenotypical features is confirmed with genetic testing and radiographic findings. However, no validated classification tool based on phenotypical findings exists.

Whole-exome sequencing identified four loci influencing craniofacial morphology in northern Han Chinese

Facial shape differences are one of the most significant phenotypes in humans. It is affected largely by skull shape. However, research into the genetic basis of the craniofacial morphology has rarely been reported. The present study aimed to identify genetic variants influencing craniofacial morphology in northern Han Chinese through whole-exome sequencing (WES). Phenotypic data of the volunteers’ faces and skulls were obtained through three-dimensional CT scan of the skull. A total of 48 phenotypes (35 facial and 13 cranial phenotypes) were used for the bioinformatics analysis. Four genetic loci were identified affecting the craniofacial shapes. The four candidate genes are RGPD3, IGSF3, SLC28A3, and USP40. Four single-nucleotide polymorphism (SNP) site mutations in RGPD3, IGSF3, and USP40 were significantly associated with the skull shape (p < 1×10−6), and three SNP site mutations in RGPD3, IGSF3, and SLC28A3 were significantly associated with the facial shape (p < 1×10−6). The rs62152530 site mutation in the RGPD3 gene may be closely associated with the nasal length, ear length, and alar width. The rs647711 site mutation in the IGSF3 gene may be closely associated with the nasal length, mandibular width, and width between the mental foramina. The rs10868138 site mutation in the SLC28A3 gene may be associated with the nasal length, alar width, width between tragus, and width between the mental foramina. The rs1048603 and rs838543 site mutations in the USP40 gene may be closely associated with the pyriform aperture width. Our findings provide useful genetic information for the determination of face morphology.

Do Unaffected Parents of Children with Orofacial Clefts have Decreased Facial Integration Compared to Controls?

Orofacial clefts are the most common congenital craniofacial anomaly affecting humans. Non‐syndromic clefts may result from decreased integration of the palate during fetal facial growth. This study will investigate whether this pattern is detectable in individuals who do not have a cleft, but do have a child with an orofacial cleft (and therefore carry genetic risk factors for clefting). In order to examine this, we hypothesize that 1) facial shape differences exist between unaffected parents of children with clefts (cases) compared to adults with no history of clefting (controls), and 2) cases will have lower facial integration values compared to controls.For this study, 3D facial scans were obtained from the University of Pittsburgh Center for Craniofacial and Dental Genetics (CCDG). 34 landmarks were placed on n=230 case faces of unaffected parents from the Pitt Orofacial Cleft Study and n=490 control faces from the Pitt 3D Facial Norms Study. Landmarks were aligned using Generalized Procrustes Analysis (GPA) and geometric morphometrics were used for quantifying facial phenotypes. Facial shape differences as a function of age were removed prior to all analyses using linear regression. Canonical Variate Analysis (CVA) was employed to examine shape differences in three different subsets of facial landmarks: a midfacial nose and mouth dataset, a lower facial mouth and jaw dataset and a third dataset consisting of the nose and jaw. Two Block Partial Least Squares analysis (2B PLS) was used to measure the strength of integration by comparing RV coefficients between the case and control populations.Results from the CVA identify significant differences in facial morphology, including jaw width, chin projection, nasal height and mouth width, between cases and controls across all datasets (nose/mouth midfacial set p&lt;0.001, mouth/jaw lower facial set p&lt;0.001, and nose/jaw dataset p=0.028). 2B PLS results, however, showed overall equivalent or higher integration levels in case faces compared to the controls. When comparing levels of integration within the midface (nose and mouth dataset), case samples demonstrate significant (p&lt;0.001) overall higher integration levels (RV=0.352) compared to control samples (RV=0.301). This pattern is also seen within the nose and jaw dataset, with cases (RV=0.614) showing increased integration compared to controls (RV=0.554). Interestingly, integration levels within the lower facial mouth and jaw dataset were nearly identical in both case samples (RV=0.444) and controls (RV=0.447).While facial shape differences exist between unaffected cleft relatives and controls with no family history of clefting, integration values were actually higher in case samples compared to control samples. This indicates that integration in facial soft tissue structures may not serve as a good indicator of cleft risk. Future studies will examine skeletal structures (such as the maxilla and mandible) to test if differences in integration are quantifiable in the facial skeleton only.Support or Funding InformationNIDCR: R01‐DE016148, U01‐DE020078This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Facial shape differences between rats selected for tame and aggressive behaviors.

Domestication has been consistently accompanied by a suite of traits called the domestication syndrome. These include increased docility, changes in coat coloration, prolonged juvenile behaviors, modified function of adrenal glands and reduced craniofacial dimensions. Wilkins et al recently proposed that the mechanistic factor underlying traits that encompass the domestication syndrome was altered neural crest cell (NCC) development. NCC form the precursors to a large number of tissue types including pigment cells, adrenal glands, teeth and the bones of the face. The hypothesis that deficits in NCC development can account for the domestication syndrome was partly based on the outcomes of Dmitri Belyaev’s domestication experiments initially conducted on silver foxes. After generations of selecting for tameness, the foxes displayed phenotypes observed in domesticated species. Belyaev also had a colony of rats selected over 64 generations for either tameness or defensive aggression towards humans. Here we focus on the facial morphology of Belyaev’s tame, ‘domesticated’ rats to test whether: 1) tameness in rats causes craniofacial changes similar to those observed in the foxes; 2) facial shape, i.e. NCC-derived region, is distinct in the tame and aggressive rats. We used computed-tomography scans of rat skulls and landmark-based geometric morphometrics to quantify and analyze the facial skeleton. We found facial shape differences between the tame and aggressive rats that were independent of size and which mirrored changes seen in domesticated animals compared to their wild counterparts. However, there was no evidence of reduced sexual dimorphism in the face of the tame rats. This indicates that not all morphological changes in NCC-derived regions in the rats follow the pattern of shape change reported in domesticated animals or the silver foxes. Thus, certain phenotypic trends that are part of the domestication syndrome might not be consistently present in all experimental animal models.

Human Facial Shape and Size Heritability and Genetic Correlations.

The human face is an array of variable physical features that together make each of us unique and distinguishable. Striking familial facial similarities underscore a genetic component, but little is known of the genes that underlie facial shape differences. Numerous studies have estimated facial shape heritability using various methods. Here, we used advanced three-dimensional imaging technology and quantitative human genetics analysis to estimate narrow-sense heritability, heritability explained by common genetic variation, and pairwise genetic correlations of 38 measures of facial shape and size in normal African Bantu children from Tanzania. Specifically, we fit a linear mixed model of genetic relatedness between close and distant relatives to jointly estimate variance components that correspond to heritability explained by genome-wide common genetic variation and variance explained by uncaptured genetic variation, the sum representing total narrow-sense heritability. Our significant estimates for narrow-sense heritability of specific facial traits range from 28 to 67%, with horizontal measures being slightly more heritable than vertical or depth measures. Furthermore, for over half of facial traits, >90% of narrow-sense heritability can be explained by common genetic variation. We also find high absolute genetic correlation between most traits, indicating large overlap in underlying genetic loci. Not surprisingly, traits measured in the same physical orientation (i.e., both horizontal or both vertical) have high positive genetic correlations, whereas traits in opposite orientations have high negative correlations. The complex genetic architecture of facial shape informs our understanding of the intricate relationships among different facial features as well as overall facial development.

Using the 3D Facial Norms Database to investigate craniofacial sexual dimorphism in healthy children, adolescents, and adults.

BackgroundAlthough craniofacial sex differences have been extensively studied in humans, relatively little is known about when various dimorphic features manifest during postnatal life. Using cross-sectional data derived from the 3D Facial Norms data repository, we tested for sexual dimorphism of craniofacial soft-tissue morphology at different ages.MethodsOne thousand five hundred fifty-five individuals, pre-screened for craniofacial conditions, between 3 and 25 years of age were placed in to one of six age-defined categories: early childhood, late childhood, puberty, adolescence, young adult, and adult. At each age group, sex differences were tested by ANCOVA for 29 traditional soft-tissue anthropometric measurements collected from 3D facial scans. Additionally, sex differences in shape were tested using a geometric morphometric analysis of 24 3D facial landmarks.ResultsSignificant (p < 0.05) sex differences were observed in every age group for measurements covering multiple aspects of the craniofacial complex. The magnitude of the dimorphism generally increased with age, with large spikes in the nasal, cranial, and facial measurements observed after puberty. Significant facial shape differences (p < 0.05) were also seen at each age, with some dimorphic features already present in young children (eye fissure inclination) and others emerging only after puberty (mandibular position).ConclusionsSeveral craniofacial soft-tissue sex differences were already present in the youngest age group studied, indicating that these differences emerged prior to 3 years of age. The results paint a complex and heterogeneous picture, with different groups of traits exhibiting distinct patterns of dimorphism during ontogeny. The definitive adult male and female facial shape was present following puberty, but arose from numerous distinct changes taking place at earlier stages.Electronic supplementary materialThe online version of this article (doi:10.1186/s13293-016-0076-8) contains supplementary material, which is available to authorized users.

Influence of Age-independent Facial Traits on Adult Judgments of Cuteness and Infantility of a Child's Face

Traits that are characteristic of children's faces make a face appear to be cute. Therefore, infantile facial features have been considered a trigger for care-giving behavior. However, few studies have investigated the effect of age-independent traits of a child's face on adult preferences for a child. In this study, ninety-six Japanese undergraduates and ninety-six preschool children provided the facial images used in this study. We divided children's facial variations into age-related and age-independent traits using methodologies of geometric morphometrics. The age-independent variations were summarized using a principal component analysis. The facial pictures corresponding to theoretical values from −3SD to +3SD along with both the age-related dimension and age-independent principal components were made by warping the average facial texture of the children's faces. A pairwise comparison method was used to investigate the relationship between cuteness/infantility and facial shape differences along with the age-related and age-independent components using the facial pictures. The results suggest that an evaluation of a child's cuteness depends on both age-independent and age-related facial features.

Shape Differences Between the Faces of Homosexual and Heterosexual Men

Previous studies have shown that homosexual men differ from heterosexual men in several somatic traits and lay people accurately attribute sexual orientation based on facial images. Thus, we may predict that morphological differences between faces of homosexual and heterosexual individuals can cue to sexual orientation. The main aim of this study was to test for possible differences in facial shape between heterosexual and homosexual men. Further, we tested whether self-reported sexual orientation correlated with sexual orientation and masculinity-femininity attributed from facial images by independent raters. In Study 1, we used geometric morphometrics to test for differences in facial shape between homosexual and heterosexual men. The analysis revealed significant shape differences in faces of heterosexual and homosexual men. Homosexual men showed relatively wider and shorter faces, smaller and shorter noses, and rather massive and more rounded jaws, resulting in a mosaic of both feminine and masculine features. In Study 2, we tested the accuracy of sexual orientation judgment from standardized facial photos which were assessed by 80 independent raters. Binary logistic regression showed no effect of attributed sexual orientation on self-reported sexual orientation. However, homosexual men were rated as more masculine than heterosexual men, which may explain the misjudgment of sexual orientation. Thus, our results showed that differences in facial morphology of homosexual and heterosexual men do not simply mirror variation in femininity, and the stereotypic association of feminine looking men as homosexual may confound judgments of sexual orientation.

Evolutionary Relationships Among Robust and Gracile Australopiths: An “Evo-devo” Perspective

Hominin fossils of gracile and robust australopith groups were found both in East and in South Africa. It is unclear, however, whether all robusts belong to a monophyletic Paranthropus clade, as the craniofacial resemblance among robust australopiths might only be a superficial correlate of similar masticatory adaptations and not evidence of shared ancestry. It has been suggested that the East African Australopithecus/Paranthropus boisei and the South African A./P. robustus might be convergent allometric variants of their gracile geographical neighbors A. afarensis and A. africanus. Here we approach the phylogenetic questions about robust and gracile australopiths from an “evo-devo” perspective, examining how simple alterations of development could contribute to the shape differences among hominin species. Using geometric morphometrics we compare gracile and robust australopith crania in the context of the allometric scaling patterns of Pan troglodytes, P. paniscus, and Gorilla gorilla. We examine support for two alternative evolutionary scenarios based on predictions derived from quantitative genetics models: either (1) A./P. robustus evolved in South Africa from the gracile A. africanus, or (2) A./P. robustus is a local variant of the eastern African A./P. boisei. We use developmental simulations to demonstrate that some robust characteristics (wide faces, anteriorly placed zygomatics, and facial dishing) can be predicted by allometric scaling along the ontogenetic trajectory of the gracile A. africanus. We find, however, that the facial differences between A. africanus specimens (Taung, Sts 5, Sts 71, and Stw 505) and A./P. robustus specimen SK 48 cannot be explained by allometric scaling alone. Facial shape differences between A./P. robustus SK 48 and A./P. boisei (KNM-ER 732, KNM-ER 406, OH 5) and the A./P. aethiopicus specimen KNM-WT 17000, on the other hand, can largely be explained by allometric scaling. This is consistent with a close evolutionary relationship of these robust taxa.

Morphometric analysis and classification of the facial phenotype associated with fetal alcohol syndrome in 5‐ and 12‐year‐old children

Landmark-based morphometric analysis holds promise for quantitative assessment of craniofacial dysmorphology. We describe an application of facial shape analysis to characterize the facial anomalies associated with fetal alcohol syndrome (FAS) in a mixed ancestry population. Generalized Procrustes analysis, regression and discriminant function analysis were applied to stereo-photogrammetrically derived 3D coordinates of landmarks taken from 34 subjects (n = 17 FAS and n = 17 normal controls). Four shape analyses were carried out, namely a comparison of the FAS and control facial shapes at age 5, and one at age 12; a comparison of the FAS facial shapes at ages 5 and 12; and a comparison of control facial shapes at ages 5 and 12. The first two analyses showed that the FAS face is characterized by small palpebral fissures, a thin upper lip, and midfacial hypoplasia. Classification of subjects as having FAS using leave-one-out cross-validation showed that the 5-year-old group could be classified with 95.46% accuracy and the 12-year-olds with 80.13% accuracy. The third and fourth analyses revealed that the differences in facial shape between FAS individuals in different age groups were more pronounced than for control individuals, supporting the notion that FAS facial anomalies diminish with age. Geometric morphometric analysis of stereo-photogrammetrically derived 3D facial landmarks allows visualization of the facial anomalies associated with FAS, as well as classification of facial shapes.

Facial appearance affects voting decisions

Human groups are unusual among primates in that our leaders are often democratically selected. Faces affect hiring decisions and could influence voting behavior. Here, we show that facial appearance has important effects on choice of leader. We show that differences in facial shape alone between candidates can predict who wins or loses in an election (Study 1) and that changing context from war time to peace time can affect which face receives the most votes (Study 2). Our studies highlight the role of face shape in voting behavior and the role of personal attributions in face perception. We also show that there may be no general characteristics of faces that can win votes, demonstrating that face traits and information about the environment interact in choice of leader.

Exploring Variation in Three-Dimensional Shape Data

A variety of very useful methods of statistical shape analysis are available for landmark data. In particular, standard methods of multivariate analysis can often be applied after suitable alignment and transformation of the data. An important example is the use of principal components analysis to provide a convenient route to graphical exploration of the main modes of variation in a sample. Where there are many landmarks or shape information is extracted in the form of curves or surfaces, the dimensionality of the resulting data can be very high and it is unlikely that substantial proportions of variability will be captured in one or two principal components. Issues of graphical exploration are explored in this setting, including random tours of a suitable low-dimensional subspace, the comparison of different groups of data, longitudinal changes and the identification of the features which distinguish individual cases from a group of controls. A suitable software environment for handling these methods with three-dimensional data is outlined. Issues of comparing principal components across time are also tackled through appropriately constructed permutation tests. All of these techniques are illustrated on a longitudinal study of facial development in young children, with particular interest in the identification of differences in facial shape between control children and those who have undergone surgical repair of a cleft lip and/or palate.