Denver Growth Study Research Articles

Investigating femoral growth disruption in subadults from the 10th-13th century St. Étienne cemetery of Toulouse, France.

The skeleton embodies an individual's environment and lived experiences. Studying childhood growth disruption can, therefore, aid in understanding the experiences of children in the past. This study evaluates growth disruption in a medieval Toulousian subadult sample to explore factors that may have influenced childhood growth and mortality at this site and to assess the utility of Harris line (HL) interpretations in bioarchaeology. Femoral growth disruption was assessed in n = 71 subadults (0.125-12.42 years) from the 10th-13th century St. Étienne cemetery of Toulouse, France, using femoral length, total area, cortical area, and relative cortical area. Femoral radiographs were assessed for HLs. To determine the prevalence of growth disruption, z-scores were calculated using data from the Denver growth study. The majority of subadults in this sample suffered from femoral growth disruption. Young children (1.0-3.99 years) were the most affected, with >65% experiencing reduced appositional growth and linear growth stunting at time-of-death. Additionally, while many individuals presented with observable HLs, linear and appositional growth did not significantly differ between individuals with and without HLs. Maternal malnutrition and inadequate complementary feeding practices likely contributed to the high prevalence of growth disruption among the youngest individuals in the study. The older children and adolescents buried at St. Étienne experienced an amelioration in growth deficits, indicating an improvement in nutrition and/or disease load. The results of this study suggest that more consideration is required when interpreting the presence/absence of HLs, and that studies assessing HLs may benefit from using a more individualistic approach.

Craniofacial growth and SITAR growth curve analysis.

SITAR (SuperImposition by Translation And Rotation) is a shape invariant growth curve model that effectively summarizes somatic growth in puberty. To apply the SITAR model to longitudinal mandibular growth data to clarify its suitability to facial growth analysis. 2D-cephalometric data on two mandibular measurements (AP: articulare-pogonion; CP: condylion-pogonion) were selected from the Denver Growth Study, consisting of longitudinal records (age range: 7.9-19.0 years) of females (sample size N: 21; number of radiographs n: 154) and males (N: 18; n: 137). The SITAR mixed effects model estimated, for each measurement and gender separately, a mean growth curve versus chronological age, along with mean age at peak velocity (APV) and peak velocity (PV), plus subject-specific random effects for PV and mean size. The models were also fitted versus Greulich-Pyle bone age. In males, mean APV occurred at 14.6 years (AP) and 14.4 years (CP), with mean PV 3.1 mm/year (AP) and 3.3 mm/year (CP). In females, APV occurred at 11.6 years (AP and CP), with mean PV 2.3 mm/year (AP) and 2.4 mm/year (CP). The models explained 95-96 per cent of the cross-sectional variance for males and 92-93 per cent for females. The random effects demonstrated standard deviations (SDs) in size of 5.6 mm for males and 3.9 mm for females, and SDs for PV between 0.3 and 0.5 mm/year. The bone age results were similar. The SITAR model is a useful tool to analyse epidemiological craniofacial growth based on cephalometric data and provides an array of information on pubertal mandibular growth and its variance in a concise manner.

Environmental correlates of growth patterns in Neolithic Liguria (northwestern Italy)

ObjectiveThis study evaluates patterns of human growth in the Neolithic to make inferences about environmental correlates of developmental disturbances. Materials33 children/adolescents from the Neolithic of Liguria (Italy), 29 of which date between 4,800-4,400 cal BCE. MethodsNeolithic patterns of growth are compared with a modern sample (the Denver Growth Study; DGS). Dental development was used to determine age at death. Proxies for postcranial maturation are femoral length and proportion of mean adult femoral length attained. ResultsLigurian children show growth faltering compared to DGS, especially between 4 and 9 years of age. Between 1 and 2 years, and in later childhood and adolescence, values are more similar or higher than DGS, when using the proportion of adult femoral length attained. ConclusionsThe pattern of growth in Ligurian Neolithic children may reflect a deprived and highly-infectious environment: three individuals show skeletal lesions consistent with tuberculosis. The relatively faster growth in infancy may result from the buffering provided by maternal milk. Older children and adolescents may exhibit catch-up growth. SignificanceThis study contributes to our understanding of Neolithic selective pressures and possible biocultural adaptive strategies. LimitationsThe cross-sectional nature of the data and the small sample size make it unclear whether the observed pattern is representative of the growth patterns in the living population. The possibility that adults are stunted undermines the interpretation of optimal growth in the first years. Suggestions for Further ResearchRefine age estimates, increase sample size through the study of other bone elements.

Linear and appositional growth in children as indicators of social and economic change during the Medieval Islamic to Christian transition in Santarém, Portugal

AbstractThis study explores whether child growth has signalled periods of social change between the Medieval Islamic and post‐Islamic Christian Periods in Santarém, Portugal. The social change is associated with the Christian conquest of Iberia and the fall of the Islamic Empire in Europe, which ceased the regional influence of the Golden Age of Islam. This may have caused a deterioration in living conditions brought by the Christian conquest, compared with the social improvements brought by the Medieval Islamic Empire. Forty‐two juvenile skeletons were taken from three Medieval Islamic and three Late Medieval Christian sites excavated in the city of Santarém, Portugal. Age was estimated from tooth length. Linear growth for all long bones and appositional growth of the femur midshaft were compared with expected growth from the Denver Growth Study, using z scores. Significant growth deficit was found throughout the Medieval Islamic and Christian Periods in Santarém, as well as a deficit in apposition of cortical bone. Although children in the post‐Islamic Christian period showed a trend towards greater linear and appositional growth deficits, these differences were not statistically significant. Children in Medieval Islamic and Late Medieval Christian Periods show significant growth disruption, suggesting that in Santarém, the post‐Islamic Medieval Christian period may not have witnessed a decrease in living conditions after the fall of Islamic rule in the territory. Further studies that incorporate more samples from the Islamic and Post‐Islamic Periods as well as pre‐Islamic population samples are needed to explore the possibility that the Islamic Period was more favourable for child growth.

Craniofacial Growth Studies and Craniofacial Growth

Current understandings of human craniofacial growth are based on multiple historic longitudinal growth studies. The extent to which regional variation in growth patterns is present among the various growth studies even within the United States, however, is not well understood. The aim of this study is to compare growth patterns across six of the nation's largest growth studies.Lateral cephalographs were examined from the historical archives of the Denver Growth Study, Iowa Growth Study, and Oregon Growth Study (available via the AAOF Legacy Collection) as well as the Fels Longitudinal Study, the Michigan Growth Study, and the Bolton‐Brush Growth Study. A set of 44 two‐dimensional landmarks were collected on longitudinal series from participants 6–22 years old. A total of 5,622 cephalographs from 726 males and 5,514 cephalographs from 723 females were assessed. Fifth order polynomials were used to evaluate growth of 11 linear craniofacial measures for each growth study and by sex. Rates of growth and associated growth milestones were calculated from polynomial models and compared across study and by sex. In addition, geometric morphometric analyses were used to assess ontogenetic shape differences among studies using a regression of the shape variables on log centroid size, pooled by study, with subsequent evaluation of residual variation.Growth curves for the separate studies roughly parallel each other yet show differences in the timing of growth milestones and adult morphology. In general, for each linear trait participants in the Denver study are smaller and participants in the Iowa and Michigan studies are larger than participants in other studies at the same chronological age. Timing of onset and peak growth is similar in all 11 craniofacial measures, although trait values at those growth milestones differ by study. Preliminary results from the geometric morphometric analysis identify a common ontogenetic pattern shared across studies but demonstrate that, for a given size, individuals from the Denver study are more advanced along the common shape trajectory relative to other studies. Although ontogenetic trajectories are roughly similar, overall shape differences are present between study populations.Variations in growth and overall morphology among these six longitudinal growth study populations demonstrate regional differences in the rate and timing of growth that may be attributable to the ancestry and environmental conditions of study participants. Further study of the mechanisms for these differences in growth will improve the accuracy of craniofacial growth predictions, thereby improving the efficacy of growth modification interventions in pediatric craniofacial treatment.Support or Funding InformationFunding: NIH/NIDCR R03‐DE021435; NIH/NIDCR R01 DE024732This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A Preliminary Analysis of the Age of Full Expression of Sexually Dimorphic Cranial Traits.

Although high accuracy rates have been achieved for adult skeletal sex estimation, it is unclear at what age sexually dimorphic traits of the skull become fully developed and useful in subadults. Four linear distances that capture sexual dimorphism-the nuchal crest, mastoid process, glabella, and mental eminence-were measured in a longitudinal sample of lateral cranial radiographs from 10 males and 10 females in the Denver Growth Study (total n = 190). The age full trait expression was attained was compared to that of dental maturity (i.e., third molar eruption). The mental eminence reached full expression significantly earlier than dental maturity (p < 0.001), although a high degree of variability was observed. Ages of expression of the other traits did not differ significantly from dental maturity. These results suggest that in forensic cases, where misclassification can have substantial impacts, cranial traits cannot yet be used reliably for sex estimation prior to third molar eruption.

Evidence of secular trend in mandibular pubertal growth.

During puberty, mandibular growth follows a growth curve comparable to somatic growth. This study aimed to review the relationship between mandibular pubertal peak height velocity (PHV) and skeletal age, and to investigate the possibility of a secular trend. Retrospective analysis was performed of two historical craniofacial growth studies (Denver Growth Study; observational time: 1943-1965, and Zurich Growth Study; observational time: 1982-1984) of healthy untreated subjects. Two mandibular growth measures (Articulare-Pogonion [Ar-Pg], Condylion-Pogonion [Co-Pg]) were retrieved from cephalograms (n: 990) and corresponding skeletal age based on hand-wrist radiographs. Mandibular growth velocity was related to skeletal age, PHV was established by use of cubic smoothing splines and variability was calculated by bootstrap resampling for every growth study and gender separately. Sexual dimorphism in mandibular growth was apparent in both cohorts. In subjects of the Denver Growth Study, mandibular PHV occurred at a more advanced skeletal age than in subjects of the Zurich Growth Study. This trend was more pronounced in males, for whom PHV of Co-Pg shifted from 14.4 to 13.8 years and of Ar-Pg from 14.6 to 13.7 years. This tendency was more subtle in females: PHV of Co-Pg shifted from 12.7 to 12.4 years and of Ar-Pg from 12.6 to 11.8 years. Mandibular growth appears to be subject to a secular trend. When related to skeletal age, this secular trend seems to be more accentuated than the established secular trend for somatic pubertal growth.

Panel regression formulas for estimating stature and body mass from immature human skeletons: a statistical approach without reference to specific age estimates

Anthropologists require methods for accurately estimating stature and body mass from the human skeleton. Age-structured, generalized Least Squares (LS) regression formulas have been developed to predict stature from femoral length and to predict body mass in immature human remains using the width of the distal metaphysis, midshaft femoral geometry (J), and femoral head diameter. This paper tests the hypothesis that panel regression is an appropriate statistical method for regression modeling of longitudinal growth data, with longitudinal and cross-sectional effects on variance. Reference data were derived from the Denver Growth Study; panel regression was used to create one formula for estimating stature (for individuals 0.5–11.5 years old); two formulas for estimating body mass from the femur in infants and children (0.5–12.5 years old); and one formula for estimating body mass from the femoral head in older subadults (7–17.5 years old). The formulas were applied to an independent target sample of cadavers from Franklin County, Ohio and a large sample of immature individuals from diverse global populations. Results indicate panel regression formulas accurately estimate stature and body mass in immature skeletons, without reference to an independent estimate for age at death. Thus, using panel regression formulas to estimate stature and body mass in forensic and archaeological specimens may reduce second stage errors associated with inaccurate age estimates.

Infant growth patterns of the mandible in modern humans: a closer exploration of the developmental interactions between the symphyseal bone, the teeth, and the suprahyoid and tongue muscle insertion sites.

The ontogenetic development of the mental region still poses a number of unresolved questions in human growth, development and phylogeny. In our study we examine the hypotheses of DuBrul & Sicher (1954) (The Adaptive Chin. Springfield, IL: Charles) and Enlow (1990) (Facial Growth, 3rd edn. Philadelphia, PA: Saunders) to explain the presence of a prominent mental region in anatomically modern humans. In particular, we test whether the prominence of the mental region and the positioning of the teeth are both correlated with the developmental relocation of the tongue and the suprahyoid muscles inserting at the lingual side of the symphysis. Furthermore, we test whether the development of the mental region is associated with the development of the back of the vocal tract. Using geometric morphometric methods, we measured the 3D mandibular and tooth surfaces in a cross-sectional sample of 36 CT-scanned living humans, incorporating the positions of the tongue and the geniohyoid and digastric muscle insertions. The specimens' ages range from birth to the complete emergence of the deciduous dentition. We used multivariate regression and two-block partial least squares (PLS) analysis to study the covariation among the mental region, the muscle insertions, and the teeth both across and within age stages. In order to confirm our results from the 3D cross-sectional sample, and to relate them to facial growth and the position of the cervical column and the hyoid bone, we used 46 lateral radiographs of eight children from the longitudinal Denver Growth Study. The 3D analysis demonstrates that the lingual side of the lower border of the symphysis develops downwards and forwards. These shape changes are significantly correlated with the relocation of muscle insertion sites and also with the vertical reorientation of the anterior teeth prior to emergence. The 2D analysis confirms the idea that as the mental region prominence develops, the space of the laryngopharynx becomes restricted due to upper mid-face retraction and the acquisition of upright body posture. In agreement with the hypotheses of DuBrul & Sicher (1954) and Enlow (1990), our results suggest that the presence of a prominent mental region responds to the space restriction at the back of the vocal tract, and to the packaging of the tongue and suprahyoid muscles in order to preserve the functionality of the laryngopharynx during respiration, feeding and speech.

Estimating body mass in subadult human skeletons

Methods for estimating body mass from the human skeleton are often required for research in biological or forensic anthropology. There are currently only two methods for estimating body mass in subadults: the width of the distal femur metaphysis is useful for individuals 1-12 years of age and the femoral head is useful for older subadults. This article provides age-structured formulas for estimating subadult body mass using midshaft femur cross-sectional geometry (polar second moments of area). The formulas were developed using data from the Denver Growth Study and their accuracy was examined using an independent sample from Franklin County, Ohio. Body mass estimates from the midshaft were compared with estimates from the width of the distal metaphysis of the femur. Results indicate that accuracy and bias of estimates from the midshaft and the distal end of the femur are similar for this contemporary cadaver sample. While clinical research has demonstrated that body mass is one principle factor shaping cross-sectional geometry of the subadult midshaft femur, clearly other biomechanical forces, such as activity level, also play a role. Thus formulas for estimating body mass from femoral measurements should be tested on subadult populations from diverse ecological and cultural circumstances to better understand the relationship between body mass, activity, diet, and morphology during ontogeny.

Evaluation of juvenile stature and body mass prediction.

This investigation evaluates the performance of juvenile stature (from tibia and radius lengths) and body mass (from breadth of the femoral distal metaphysis) prediction equations based on the Denver Growth Study sample (Ruff C. 2007. Am J Phys Anthropol 133 698-716). The sample used here for evaluation is an independent sample of juveniles brought to the Franklin County (Ohio) Coroner in 1990-1991. The Ohio sample differs somewhat from the Denver reference sample: it includes approximately 25% African-Americans (rather than all European-Americans), a significant number of right limb bones were measured (rather than all left side), it includes a wider range of economic statuses and it includes individuals who died from disease and trauma. As such the composition and measures of the Ohio sample correspond more generally to that seen in skeletal samples so that the accuracy of the estimates from the present sample should approach those found in practical applications of these methods. Results indicate that both juvenile body mass and stature are estimated relatively accurately. Accuracy of body mass estimates for 1-13-year-old juveniles is similar for African-American and European-American males and females. The least accurate estimates are for individuals in the 8-13 years age class (excluding individuals with body mass indices greater than the age specific 95th percentile): n = 9, +/- 2.9 kg, 95% confidence interval 1.4-4.4 kg. Accuracy of stature estimates for 1-17-year-old juveniles is comparable for the tibia and radius and, as with body mass estimates, are similar for African-American and European-American males and females. For combined age, sex, and ancestry groups average accuracies are in the +/-3.5 to +/-6.5 cm range. Some limitations of the methods are discussed.

Body size prediction from juvenile skeletal remains

There are currently no methods for predicting body mass from juvenile skeletal remains and only a very limited number for predicting stature. In this study, stature and body mass prediction equations are generated for each year from 1 to 17 years of age using a subset of the Denver Growth Study sample, followed longitudinally (n = 20 individuals, 340 observations). Radiographic measurements of femoral distal metaphyseal and head breadth are used to predict body mass and long bone lengths are used to predict stature. In addition, pelvic bi-iliac breadth and long bone lengths are used to predict body mass in older adolescents. Relative prediction errors are equal to or smaller than those associated with similar adult estimation formulae. Body proportions change continuously throughout growth, necessitating age-specific formulae. Adult formulae overestimate stature and body mass in younger juveniles, but work well in 17-year-olds from the sample, indicating that in terms of body proportions they are representative of the general population. To illustrate use of the techniques, they are applied to the juvenile Homo erectus (ergaster) KNM-WT 15000 skeleton. New body mass and stature estimates for this specimen are similar to previous estimates derived using other methods. Body mass estimates range from 50 to 53 kg, and stature was probably slightly under 157 cm, although a precise stature estimate is difficult to determine due to differences in linear body proportions between KNM-WT 15000 and the Denver reference sample.

Variation in the development of postcranial robusticity: an example from Çatalhöyük, Turkey

AbstractWhile the study of variation in adult postcranial robusticity has a long history, few analyses have examined the acquisition of postcranial robusticity within an ontogenetic context. This research evaluates differences in the ontogenetic trajectories of immature femora from three samples, in order to assess the point at which differences in levels of adult postcranial robusticity arise during development. Femoral midshaft cross‐sectional properties were compared between three diverse samples: Neolithic agriculturalists from Çatalhöyük, Turkey (n = 42); Byzantine agriculturalists from Çatalhöyük, Turkey (n = 24); and urban Americans from the Denver Growth Study (n = 151). While the two adult samples from Çatalhöyük do not differ statistically, both Neolithic and Byzantine adults have relatively larger cortical and total areas than the American urban adults, and these differences are clearly established by the age of six. In addition, by the age of three, individuals from the Denver Growth Study have already attained a greater percentage of their adult length, total area, and cortical area relative to those in both the Neolithic and Byzantine samples. These results indicate that the differing levels of postcranial robusticity characterising adult populations appear relatively early during development, and that populations vary in the rate and pattern through which adult levels of postcranial robusticity are achieved. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Craniofacial levels and the morphological maturation of the human skull

It is well known that the human skull achieves adult size through a superior-inferior gradient of maturation. Because the basicranium matures in size before the face, it has been suggested that the form of the basicranium might have ontogenetic knock-on effects on that of the face. However, although sequential spatially organized maturation of size is well described in the cranium, the maturation of skull shape is not. Knowledge of the maturation of shape is important, nevertheless, because it is claimed that the early determination of the spatial configuration of basicranial components, where the facial skeleton attaches, is relevant in the spatio-temporal ontogenetic cascade from basicranium to face. This paper examines the ontogeny of various components of the human skull in 28 individuals from the longitudinal Denver Growth Study. Sixty-six landmarks and semilandmarks were digitized on 228 X-rays and analysed using geometric morphometric methods. Bootstrapped confidence intervals for centroid size support previous studies suggesting a supero-inferior gradient of growth maturation (size over time), while developmental maturation (shape over time) is more complex. A sequence of shape maturation is described, in which the earliest structure to mature in shape was the midline cranial base (7-8 years), followed by the lateral cranial floor (11-12), midline neurocranium (9-10) and facial and mandibular structures (15-16). The absolute ages of shape maturation of the latter three depended on the criterion of maturity used, which was not the case for the basicranial components. Additionally, ontogenetic dissociations were found between the maturation of size and shape of the midline cranial base and lateral floor, possibly underlining its role as structural 'interface' between brain and facial ontogeny. These findings imply potential for bidirectional developmental influences between the lateral cranial floor and the face until about 11-12 years. The findings are discussed with regard to their relevance for palaeoanthropology and especially the evolutionary and developmental bases of skull morphological variation.

Ontogeny of facial dimorphism and patterns of individual development within one human population

Based on a longitudinal study of radiographs of the Denver Growth Study, we investigated the morphological development of individual and gender differences in the anterior neurocranium, face, and basicranium. In total, 500 X-rays of 14 males and 14 females, each with 18 landmarks and semilandmarks, were digitized and analyzed using geometric morphometric methods. Sexual dimorphism in shape and form is already present at the earliest age stage included in the analysis. However, the nature of dimorphism changes with age. Four factors apper to contribute to cranial sexual dimorphism in human postnatal development: 1) initial, possibly prenatal, differences in shape; 2) differences in the association of size and shape; 3) male hypermorphosis; and 4) some degree of difference in the direction of male and female growth trajectories. Studying changes in individuals, we find a low correlation between newborn and adult morphology, while 3-year-olds already show a high correlation with their adult form. We conclude that the adult pattern of interindividual difference in facial form in a single human population is established within the first few years of life.

Ontogenetic adaptation to bipedalism: age changes in femoral to humeral length and strength proportions in humans, with a comparison to baboons

The increase in lower/upper limb bone length and strength proportions in adult humans compared to most other anthropoid primates is commonly viewed as an adaptation to bipedalism. The ontogenetic development of femoral to humeral proportions is examined here using a longitudinal sample of 20 individuals measured radiographically at semiannual or annual intervals from 6 months of age to late adolescence (a subset of the Denver Growth Study sample). Anthropometric data (body weights, muscle breadths) were also available at each examination age. Results show that while femoral/humeral length proportions close to those of adults are already present in human infants, characteristically human femoral/humeral diaphyseal strength proportions only develop after the adoption of bipedalism at about 1 year of age. A rapid increase in femoral/humeral strength occurs between 1 and 3 years, followed by a slow increase until mid-late adolescence, when adult proportions are reached. When age changes in material properties are factored in, femoral strength shows an almost constant relationship to body size (body mass·bone length) after 5 years of age, while humeral strength shows a progressive decline relative to body size. Femoral/humeral length proportions increase slightly throughout growth, with no apparent change in growth trajectory at the initiation of walking, and with a small decline in late adolescence due to later growth in length of the humerus. A sex difference in femoral/humeral strength proportions (females greater) but not length proportions, develops early in childhood. Thus, growth trajectories in length and strength proportions are largely independent, with strength proportions more responsive to actual changes in mechanical loading. A cross-sectional ontogenetic sample of baboons (n=30) illustrates contrasting patterns of growth, with much smaller age changes in proportions, particularly strength proportions, although there is some indication of an adaptation to altered limb loadings early in baboon development.

Ontogeny of postnatal hyoid and larynx descent in humans

Postnatal descent of the hyoid and larynx relative to the palate and mandible, which occurs uniquely in humans, is an anatomical prerequisite for quantal speech. This study tested the hypothesis that spatial constraints related to deglutition impose greater restrictions on the rate and degree of hyo-laryngeal descent than do adaptations for vocalization. Ontogenetic data on changes in the size and shape of the pharynx, the vocal tract, and the spatial positions of the larynx, hyoid, mandible and hard palate relative to each other and to the oral cavity were obtained for 15 males and 13 females from a longitudinal series of lateral radiographs (the Denver Growth Study) taken between the ages of 1 month and 14 years. To establish growth patterns, nine linear dimensions of the pharynx and 15 different pharyngeal and vocal-tract proportions were regressed against percentage growth. The results demonstrate that certain aspects of vocal-tract shape change markedly during ontogeny, especially in the first postnatal year and during the adolescent growth spurt. The ratio of pharynx height to oral cavity length (which is important for speech) decreases significantly ( P<0.001) from 1.5 to 1.0 between birth and 6–8 years, after which it remains stable. In contrast, regression analyses indicated that superoinferior spatial relations between the positions of the vocal folds, the hyoid body, the mandible and the hard palate do not change significantly throughout the entire postnatal growth period ( P<0.05). Sexual dimorphism in pharyngeal shape and size before the age of 14 years is very limited. The results suggest that the descent of the hyoid and larynx relative to the mandible is constrained by muscle function related to deglutition, highlighting the different functional roles of the hyoid during speech and oral transport.

A longitudinal cephalometric study of the soft tissue profile of short- and long face syndromes from 7 to 17 years

The longitudinal growth and development of the soft tissue drape for boys and girls with long and short vertical patterns was examined from age 7 to 17 years. The sample was taken from the Denver Growth Study and consisted of 32 subjects who were selected on the basis of their percentage of lower anterior vertical face height. All subjects were of northern European ancestry, and none had undergone orthodontic treatment. The sexual dimorphism was evident as anticipated for several soft tissue measurements. The boys showed continued growth through age 16 years in contrast to the girls who attained the adult size of the soft tissue integument around 14 years. A significant difference between vertical facial patterns was reported for all soft tissue variables with the exception of the soft tissue thickness at A point and the upper lip height. The boys and girls with long vertical patterns exhibited a thicker and longer soft tissue drape for the most variables when compared with those with short facial patterns. These soft tissue differences are believed to be compensatory mechanisms in long-face subjects, which may attempt to mask the vertical dysplasia, thereby producing a more normal facial profile. Individual growth assessments revealed that the perioral soft tissues follow a pattern similar to that of the mean group patterns. The subjects with long vertical facial patterns experienced their pubertal growth spurt earlier than the short-face subjects. This may have clinical implications in the timing of orthodontic intervention and treatment.

Cephalometric analysis of the Prader‐Willi syndrome

The Prader-Willi syndrome (PWS) is characterized by short stature, mild mental retardation, and a characteristic face. Approximately 75% of all patients have a del (15q). Cephalometric roentgenograms of 20 PWS patients of both sexes (12 adults, 8 children, age 4.5-50.0 years) were analyzed to determine if the facial appearance is reflected in changes in the bony architecture, a characteristic which might be useful in diagnosis and/or dental treatment of these individuals. PWS subjects were compared with chronologic age and sex-matched control individuals derived from the Denver Growth study using 52 point computer analyzed lateral head-plate tracings performed by the same individual (RS). The mean Z-score differences for mandibular and maxillary total length, ramus height, mandibular corpus length, posterior facial height, and mid-facial height were all significantly smaller in greater than 65% of the PWS subjects; this was more evident in the PWS children. The Z-score difference for posterior cranial base was very large in most PWS adults and children whereas lower facial height was small or normal in all subjects. No statistical difference in mean Z-score measurements was found for all these measures in PWS subjects with or without the 15q chromosome deletion. The overall small bony structures contrast with the relatively large soft tissue draping seen especially in obese adults. The data suggest that a characteristic bony model might be created for PWS which could be of use in diagnosis and in the treatment of PWS patients by their orthodontist.

Subcutaneous fat distribution in males and females from 1 to 39 years of age

Subcutaneous fat thicknesses measured in two longitudinal studies, the Denver Growth Study and the Melbourne Growth Study, were examined to determine 1) if one site of subcutaneous fat measurement is more representative than another of the body's subcutaneous fat layer, 2) if some measurements of subcutaneous fat from specific body areas are more representative of the subcutaneous fat layer than others, and 3) if there are sex and age differences in intersite relationships. Data from the Denver Study include skinfold thicknesses from 10 sites measured serially at annual ages from 4 to 39 yr and radiographic fat thickness measured at five sites at annual ages from 1 to 18 yr. In the Melbourne Study, five skinfold thicknesses were measured serially in children from 2 to 15 yr of age. Relatively low intersite communalities during the prepubertal years suggest a tendency in each sex for considerable site-to-site variation during this period. However, immediately before puberty and throughout adolescence, high communalities indicate that the thickness of subcutaneous fat at any site is highly related to thickness at all other sites. After puberty and into the mid-20's, there is a reoccurrence of greater site-to-site variability. This higher degree of variation continues into early middle age only in women, implying that more changes occur in their subcutaneous fat, that differentially affect various parts of the body, than in men.