Pattern Of Skeletal Development Research Articles

Tridimensional assessment of the mandibular angle in patients with different skeletal patterns by cone-beam computed tomography scans: a retrospective study

BackgroundSince the muscles of chewing are involved in the region of the mandibular angle, important structures in surgical and orthodontic procedures, to study its morphological aspects and the possible influence of different patterns of skeletal development would be of interest. Thus, this study aimed to assess the influence of patient characteristics - such as sex, skeletal malocclusion (Class I, Class II, and Class III) and facial type (brachycephalic, mesocephalic, and dolichocephalic) - on the width, height, thickness, and volume of the mandibular angle, using cone-beam computed tomography (CBCT) scans.MethodsCBCT scans were assessed − 144 men and 154 women, total of 298 - and classified according to skeletal patterns (skeletal malocclusions and facial types). Width, height, and thickness of the mandibular angle were measured using OnDemand 3D software. The volumetric measures of the mandibular angle were obtained using the ITK-SNAP software. Analysis of Variance (multiway ANOVA) with Tukey’s post-hoc test compared the data, with a 5% significance level.ResultsAmong the factors studied, sex significantly influenced all the analyzed variables (height, width, thickness, and volume of the mandibular angle) (p < 0.05); in general, male individuals presented higher values than females. In some cases, the skeletal malocclusion and facial type factors influenced only the width and height variables (p < 0.05); in general, the Class III and dolichocephalic individuals presented higher values in relation to the other types of skeletal malocclusions and facial types.ConclusionsVariations in the craniofacial growth pattern, considering the different skeletal malocclusions and facial types, had some influence in the width and height dimensions of the mandibular angle. Furthermore, sex influenced all the studied variables.

Classification and Morphological Analysis of the Hard Palate in Cone-Beam Computed Tomography Scans: A Retrospective Study

As the hard palate is a central structure of the skull and is involved in orthodontic and surgical procedures, it would be of interest to study the morphological aspects of this bone and its possible variations as per different patterns of skeletal development. Thus, this study aimed to develop a classification for the different morphological characteristics of the hard palate and to evaluate the relationship between these characteristics and the different skeletal patterns, using cone-beam computed tomography (CBCT). This retrospective and cross-sectional study used CBCT scans of patients seen from January 2014 to December 2016. Carestream Dental 3D Imaging software was applied to classify each patient according to vertical and sagittal skeletal patterns, and to evaluate the 3 morphological characteristics of the hard palate: depth (flat, regular, or deep), inclination (superior, parallel, or inferior), and presence of a bony projection (S-shaped). χ2 and Fisher's exact tests evaluated the relationship between the hard palate characteristics and the different skeletal patterns. A total of 298 CBCT scans (144 males and 154 females) were evaluated. The depth of the hard palate was significantly related to both skeletal patterns in males (P<.05), with Class II and dolichocephalics presenting a greater amount of deep palates, while classes I and III and brachycephalics had a greater amount of regular palates. The inclination of the hard palate was significantly associated with the facial type in females (P<.05), with brachycephalics and mesocephalics presenting a greater amount of parallel palates, whereas dolichocephalics had a greater number of inferiorly inclined palates. Regarding the presence of the S-shape in the hard palate, there was a greater number of this projection in Class II males and brachycephalic females. A morphological classification for the hard palate was developed. The morphology of the hard palate varied among the different skeletal patterns.

First species of Enantiornithes from Sihedang elucidates skeletal development in Early Cretaceous enantiornithines

The Sihedang locality of the Lower Cretaceous Yixian Formation is the only recognized ornithuromorph-dominated locality in the Jehol Group of north-eastern China. Here we report on the first enantiornithine from this locality and erect a new taxon Monoenantiornis sihedangia gen. et sp. nov. The holotype and only specimen preserves a rare ontogenetic stage in which the intermedium is ossified but free from the other proximal tarsals and the tibia, consistent with the pattern of ossification that occurs in neornithines. In order to explore the pattern of skeletal development in the enantiornithines, we select several published specimens inferred to represent different ontogenetic stages and document their degree of fusion in five key compound bones and the sterna. This provides a preliminary hypothesis for the sequence in which compound bones form in Early Cretaceous enantiornithines. From this hypothesis, most known specimens can be categorized into four major ontogenetic stages: all the compound bones unfused; synsacrum and pygostyle fused; tarsals fused; tibiotarsus and carpometacarpus formed.http://zoobank.org/urn:lsid:zoobank.org:pub:347485CA-87E6-4834-BEB5-687B6798644E

Developmental Pattern and Morphology of Salamandrella keyserlingii Limbs (Amphibia, Hynobiidae) Including Some Evolutionary Aspects

In this paper, we consider the pattern of skeletal development and morphology in the limbs of the hynobiid species, Salamandrella keyserlingii , with the overall aim of analyzing tetrapod limb evolution in context of the phylogeny. In comparison with anurans the urodeles demonstrate caenogenetic adaptation in distal structures of the limbs. As the most primitive family of Caudata hynobiids are of special interest since a study of early stages is likely to display some plesiomorphic features. In common with other larval salamanders Salamandrella has early development of digits 1 + 2. However, in contrast to them this species displays a number of distinctive characters, including larval adaptations and features which can be considered as phylogenetically primitive for caudates and sometimes for uniseriate sarcopterygians in general. The main peculiarities of Salamandrella can been summarized as follows: 1) early formation of the mesenchyme mass between the zeugopod bifurcation as the base for the proximodistal differentiation of preaxial, median and postaxial columns; 2) initial connection of the median column with postaxial one in the region of intermedium condensation; 3) early formation of the intermedium condensation in close contact with ulnar/fibular condensation; 4) dominance of the posterior or postaxial branch (ulnare/fibulare) in the early limb development; 5) comparatively late formation of the basale commune which arises primarily as a small distal 2 condensation at the base of the digit 2 and later fuses with distal 1 condensation; 6) fusion of the skeletal elements in longitudinal rather than in transverse direction; usually amalgamation of the median elements with postaxial than with preaxial ones; 7) frequent (in 75%) amalgamation of the intermedium with ulnare; 8) presence of two central elements in the standard morphology; 9) presence of a well developed, long temporary epidermal fin between first and second digits used in balance and locomotion of the larvae. This is caenogenetic adaptation. The comparison of Salamandrella with other caudates and some fossil sarcopterygians led us to conclusion that many developmental pattern of its limb (1 – 4) can been considered as an ancestral features. It may be supposed that such characters of urodeles as the precocious appearance of anterior digits and basale commune, the gap between them and proximal (zeugopod/stylopod) portion, distal-to-proximal sequence in development of carpal and tarsal elements have a secondary character, probably correlated with their caenogenetic adaptations, and do not support the hypothesis of the polyphyly of tetrapods.

Comparative ossification sequence and skeletal development of the postcranium of palaeognathous birds (Aves: Palaeognathae)

Palaeognaths constitute one of the most basal lineages of extant birds, and are also one of the most morphologically diverse avian orders. Their skeletal development is relatively unknown, in spite of their important phylogenetic position. Here, we compare the development of the postcranial skeleton in the emu (Dromaius novaehollandiae), ostrich (Struthio camelus), greater rhea (Rhea americana) and elegant crested-tinamou (Eudromia elegans), focusing on ossification. All of these taxa are characterized by element loss in the appendicular skeleton, but there are several developmental mechanisms through which this loss occurs, including failure to chondrify, failure to ossify and fusion of cartilages prior to ossification. Further evidence is presented here to support a reduction in size of skeletal elements resulting in a delay in the timing of ossification. This study provides an important first look at the timing and sequence of postcranial ossification in palaeognathous birds, and discusses the influence of changes in the pattern of skeletal development on morphological evolution.

Eggshell structure, mode of development and growth rate in birds

The shell of an egg contributes to successful embryogenesis in many ways, such as through protection, respiration and water exchange. The shell is also the major source of calcium for the development of high-calcium consuming organs, e.g. the skeleton, muscles and brain. Some studies show, moreover, that growth rate may play a fundamental role in the pattern of skeletal development in birds: the faster the growth the less ossified the skeleton is at hatching. We predicted, therefore, that slow (precocial) and fast (altricial) growing bird species should lay eggs encased in shells with different structures adapted to support different rates of calcium removal by developing embryos. We tested this prediction by comparing the fine structure of the inner eggshell surface (mammillary layer) from 36 bird species belonging to 18 orders ranging from Struthioniformes to Passeriformes. Using scanning electron microscopy, we compared the mammillary layer of both non-incubated eggs and eggs at the time of hatching, i.e., before and after embryonic development and the accompanying calcium removal. The results were consistent with the prediction, i.e., the number of mammillary tips per unit of surface area was associated with mode of development and growth rate. The number was higher, and calcium removal was also more extensive, in shells from precocial bird species than in shells from altricial bird species.

A description of the skeletal development pattern of the temperate coral Caryophyllia smithi based on internal growth lines

Scanning electron microscopy was used to study the microstructure and internal growth lines of the temperate ahermatypic coral Caryophyllia smithi (Cnidaria: Anthozoa). The arrangement of internal growth lines in combination with the orientation of aragonite crystals were used to describe the pattern of skeletal development in C. smithi. The observed pattern was verified using observations from another study on skeletal development in C. smithi, but which was based only on external observations of skeletons of living and dead specimens in different stages of development. The pattern of skeletal development in C. smithi is suggested to be subdivided into three stages, based on the deposition of specific skeletal elements during the development of the skeleton. In the first ‘juvenile’ stage, various primary skeletal elements are formed: the basal plate, the septa and a primary and secondary septotheca. The second ‘half full grown’ stage is characterized by development of apparently only an extended basal attachment, which enlarges the attachment area to the substratum. In the third ‘full grown’ stage, the edge zone of the polyp tissue is retracted from the extended basal attachment to the calice, and upward growth of the coral predominates followed by lateral thickening of the septotheca, costae, septa and columella. Internal growth lines were found throughout the skeleton and may be composed of, or resulting from the presence of organic matter. The septotheca and the extended basal attachment, which are important for a strong skeletal structure and a strong attachment to the substratum, respectively, are probably thickened faster than the other skeletal elements. Attachment scars were found in areas where attachment of the coral tissue to the skeleton is critical.

Prediction of Growth

We should like to be among the first to congratulate Stuart and Reed and their associates for their very significant contribution to child development research, which appeared in the November Supplement to Pediatrics (24:875, 1959). All who have dealt with the difficult problem of handling unwieldy, longitudinal data will particularly appreciate the careful organization and presentation of this valuable material and the original method here employed for its analysis. Of especial interest to us was the section on "Patterns of skeletal development in the hand." At the meeting of the Society for Research in Child Development, April 5, 1957, we discussed some of our experiences with patterns of skeletal development and we quote from this report:

PATTERNS OF SKELETAL DEVELOPMENT IN THE HAND

The first purpose of this presentation of patterns of skeletal development in the hand has been to demonstrate that essentially normal children, although passing through very similar steps or stages of skeletal development in the hand, do so in a variety of ways in respect to the rates of their progress through these stages or by age periods. The second objective has been to show the kinds of patterns which emerge and the relative frequency with which certain of these are encountered. This has been done by studying the consistency manifest by children in their rate of progress over the whole of childhood as well as by major subdivisions of the developmental period. This Study shows that few children are very irregular in progress or change frequently to any substantial degree in their rate of progress, but many make one or two substantial shifts in rate from one period to another. The most common, marked and understandable shift is the single one occurring roughly between childhood and adolescence. The years close to the dividing line between these two age periods, therefore, are the ones in which change in rate of skeletal development (hand) may be expected most commonly. The changes in rates occurring at other ages, as portrayed in patterns under III or IV (Figs. 15 to 20), are not readily explained on the basis of other features of development. Factors found associated with these different patterns of skeletal development in the children concerned, relating to nutrition, illness experiences, growth in height and other aspects of development will be considered in later reports on interrelationships. Aside from a preliminary report from this laboratory the only other report known to the authors which dealt longitudinally with patterns of skeletal development was published by Kelly in 1937. This concerned children 6 to 18 years of age and used an index derived from measurements of several bones or epiphyses in the hand and wrist; six patterns were derived from these indices and described as convex, linear, concave, convex-concave, linear-convex and concave-convex. Because of the fundamental differences in the data used in this Study, it is not possible to compare Kelly's results with those being reported.