Ossification Pattern Research Articles

Biologically structured materials

Biomimetics, biomechanics, and tissue engineering are three multidisciplinary fields that have been contemplated in this research to attain the objective of improving prosthetic implants reliability. Since testing and mathematical methods are closely interlaced, a promising approach seemed to be the combination of in vitro and in vivo experiments with computer simulations (in silico). An innovative biomimetics and biomechanics approach, and a new synthetic structure providing a microenvironment, which is mechanically coherent and nutrient conducive for tissue osteoblast cell cultures used in regenerative medicine, are presented. The novel hybrid ceramic-polymeric nanocomposites are mutually investigated by finite element analysis (FEA) biomimetic modeling, anatomic reconstruction, quantitative-computed-tomography characterization, computer design of tissue scaffold. The starting base materials are a class of innovative highly bioactive hybrid ceramic-polymeric materials set-up by the proponent research group that will be used as a bioactive matrix for the preparation of in situ bio-mineralized techno- structured porous nanocomposites. This study treats biomimetics, biomechanics and tissue engineering as strongly correlated multidisciplinary fields combined to design bone tissue scaffolds. The growth, maintenance, and ossification of bone are fundamental and are regulated by the mechanical cues that are imposed by physical activities: this biomimetic/biomechanical approach will be pursued in designing the experimental procedures for in vitro scaffold mineralization and ossification. Bio-tissue mathematical modeling serves as a central repository to interface design, simulation, and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesized for the use of the new biologically techno-structured hybrid materials.

Knee Bone Age using MRI: Validation of a Novel Method to Reduce Hand Bone Age Radiographs

Objectives:Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. This aim of this study was to create and validate a shorthand method of bone age determination using knee MRI.Methods:We identified patients who underwent both knee MRI and hand bone age radiograph within a ninety-day period. From the findings of Pennock et al., a stepwise algorithm for predicting bone age on knee MRI was developed for males and females separately, in collaboration with a pediatric musculoskeletal radiologist. Six raters at varying levels of training used the algorithm to assign a bone age to each knee MRI. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter- (two-way random, absolute agreement) and intra-rater (two-way mixed, absolute agreement ) reliability were also calculated using ICC.Results:Thirty-eight patients (44.7% females) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand algorithm was also shown to be a reliable predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee bone age and G&P hand bone age. All respondents also demonstrated consistency, with intra-rater ICCs between 0.85-0.93.Conclusion:This shorthand algorithm is a consistent, reliable and valid way to determine skeletal maturity using knee MRI in patients aged 10 to 15 and can be utilized across different levels of orthopaedic and radiographic expertise. We believe this method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.Figure 1.Table 1.Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Note: Intra-rater reliability has not been competed for “Resident 2” at this time. Validity of MRI Knee Bone Age and Hand Bone Age Intra-Rater Reliability Rater ICC 95% CI ICC 95% CI Student 10.750.57-0.860.930.79-0.97Student 20.730.53-0.860.930.87-0.97Resident 10.730.54-0.850.850.73-0.92Resident 20.780.60-0.88--Attending 10.740.54-0.850.860.70-0.93Attending 20.800.63-0.890.860.72-0.93

Development and evolution of regionalization within the avian axial column

AbstractThe origin of birds from their terrestrial antecedents was accompanied by a wholesale transformation of their skeleton as they transitioned from a terrestrial to aerial realm. Part of this dramatic transformation is the reduction of separate vertebral elements into regional fusions to limit axial flexibility. This is partially mirrored within the development of the axial column, with regions of the axial column experiencing increasing morphological modularity and the loss of skeletal elements through vertebral fusions. Using a detailed description of the morphological development of the axial column in the model domestic chicken, Gallus gallus domesticus, we present a map of axial ossification based on discrete characters. Delays in ossification are found to occur in conjunction with the formation of fusions. Our study shows that the pattern and sequence of fusion and ossification during development may reflect the presence of independent modules as subsets within the typical regions of the avian axial column. Interestingly, few of these fusion modules correspond to the initial axial Hox expression patterns, suggesting another patterning mechanism is driving axial fusion regionalization. Additionally, two regions of fusion are discovered in the synsacrum. The anterior region of seven fused synsacrals may correspond to the non-ornithuran pygostylian synsacrum of the same number of vertebrae.

A new jeholornithiform exhibits the earliest appearance of the fused sternum and pelvis in the evolution of avialan dinosaurs

A new jeholornithiform – Kompsornis longicaudus gen. et sp. nov. – is reported based on a nearly complete specimen from the Jehol Biota in western Liaoning, China. Comprehensive comparisons and phylogenetic analysis, including all published species of Jeholornithiformes, are provided and indicate that Shenzhouraptor sinensis, Jeholornis prima, Jixiangornis orientalis, Jeholornis palmapenis and Jeholornis curvipes are all valid species of this clade, but that Dalianraptor cuhe is regarded as a nomen dubium. In particular, K. longicaudus possesses completely fused sternum and pelvis, a combination of advanced features that is for the first time recognized among jeholornithiforms and non-pygostylian avialans. The osteohistological investigation suggests that the skeletal reinforcement occurred during the juvenile ontogeny in some Jeholornithiformes. Therefore, the new discovery further enriches the diversity of Jeholornithiformes and suggests an unexpected developmental disparity in ossification patterns along the lineage from non-avian dinosaurs to birds.

The pattern of medical clavicular epiphyseal ossification: preliminary study of a Sri Lankan population

Forensic Age Estimation (FAE) in living is required in many civil and criminal circumstances where documentary proof of age is unavailable. In Sri Lanka, 16-21 age range has many statutory age limits. Though international guidelines recommend CT scanning of medial clavicular epiphyses for forensic age estimations within this age range, Sri Lanka does not have any population-specific reference standards for this modality. The objective of this study was to describe the pattern of medial clavicular epiphyseal fusion among Sri Lankans aged 15-30 years. Chest, neck and pulmonary angiography CT scans of patients between 15-30 years performed in two tertiary hospitals were reported independently by two radiologists using the five-stage classification for medial clavicular ossification by Schmeling et al. (2004). Interobserver reliability was assessed using Cohen’s Kappa coefficient. A preliminary descriptive analysis of the first 46 cases was done using SPSS. There were 25 males and 21 females. Majority (80%) were 18 years and above. The oldest with stage 1 was 16 years. The youngest for stages 2 and 3 were both 17 years. Stages 4 and 5 were seen in 67% of cases and none were below 20 years. This trend was similar to previously published studies. From the preliminary results, it appears that only stages 4 and 5 can be used reliably to determine if a person is >18 years. Stages 2 and 3 are likely to indicate that the person is >16 years. Clavicular epiphyseal fusion shows good potential to be a reliable FAE method in Sri Lanka.

Normal Wrist Development in Children and Adolescents: A Geometrical Observational Analysis Based on Plain Radiographs.

To investigate the geometric development of the wrist in relation to the changes in its ossification pattern. This study will help the treating surgeon to identify early deviations from normal in children with musculoskeletal disorders and provide a template for anatomic reduction after trauma scenarios. A retrospective multicenter analysis was carried out of radiographs of 896 children (896 posteroanterior and 896 lateral views) with normal wrists from January 1996 till April 2016. We stratified patients into different yearly age groups; these included 16 age groups from 1 to 16 years, and 2 sex groups: males and females. We evaluated, depending on the wrist ossification pattern, the ulnar variance, radial and carpal heights, carpal height ratio, radial inclination, volar tilt, together with radiocarpal, scapholunate, and capitate-lunate angles and scapholunate distance. Our analysis showed that the ulna minus variance predominates in children. Radial height, radial inclination, and radiocarpal angle increase steadily during growth and reach their respective expected values at the beginning of the pubertal growth spurt. The scapholunate and capitolunate angles showed a downward trend with growth till reaching the adult values at puberty. Carpal height increased constantly, whereas the carpal height ratio was similar to that in adults. Volar tilt was not developed until the age of 12 years, when it started to increase gradually to reach the adult values by puberty. Both sexes have similar measurements. Most radiologic parameters showed reproducible anatomic changes till the 12-year-old time-point. After that, there are minimal changes till adulthood. The study findings offer a template of pediatric normal values guiding hand and pediatric surgeons in treatment of children with wrist pathology.

Point-of-Care Bone Age Evaluation: The Increasing Role of US in Resource-limited Populations

Point-of-Care Bone Age Evaluation: The Increasing Role of US in Resource-limited Populations

Histological development and integration of the Zebrafish Weberian apparatus.

The Weberian apparatus enhances hearing in otophysan fishes, including Zebrafish (Danio rerio). Several studies have examined aspects of morphological development of the Weberian apparatus and hearing ability in Zebrafish. A comprehensive developmental description including both hard and soft tissues is lacking. This information is critical for both interpretation of genetic developmental analyses and to better understand the role of morphogenesis and integration on changes in hearing ability. Histological development of hard and soft tissues of the Weberian apparatus, including ossicles, ear, swim bladder, and ligaments are described from early larval stages (3.8 mm notochord length) through adult. Results show a strong relationship in developmental timing and maturation across all regions. All required auditory elements are present and morphologically integrated early, by 6.5 mm SL. Dynamic ossification patterns and changes in shape continue throughout the examined developmental period. This study provides the first comprehensive histological description of Weberian apparatus development in Zebrafish. Morphological integration was found early, before increases in hearing ability were detected in functional studies (>10 mm total length), suggesting morphological integration precedes functional integration. Further research is needed to examine the nature of the functional delay, and how maturation of the Weberian apparatus influences functionality.

Embryonic development of skull bones in the Sahara horned viper (Cerastes cerastes), with new insights into structures related to the basicranium and braincase roof.

Ontogenetic studies are crucial for understanding functional morphology, origin and adaptation of skulls in vertebrates. However, very few studies have so far released complete embryonic series focusing on skull embryonic development in species showing diverse and extreme cranial morphologies such as snakes. The wide distribution and unique reproductive and ecological behaviors of venomous vipers, including the heterogeneity in breeding and egg incubation periods in oviparous species, make this group an excellent new model for studying the diversity of skull developmental processes in snakes. Here we present the first complete description of osteocranium development in a viperine snake, Cerastes cerastes, using detailed analysis of the ossification pattern of individual bones across different embryonic stages based on high-resolution micro-computed tomography data. Particularly, we describe in detail the development of the laterosphenoid from its dorsal and ventral components, dividing the trigeminal foramen into maxillary and mandibular foramina. Furthermore, our data help clarify some controversy concerning the presence and/or origin of structures related to the snake basicranium and braincase roof. For example, our detailed description of supraoccipital development suggests that this bone derived, at least in part, from the tectum posterius, although the involvement of the tectum synoticum cannot be totally excluded. Similarly, the epiotic centers of supraoccipital ossification are confirmed during braincase development, and the ancestral lacrimal bone primordium is observed as a ventral element at the early stages of prefrontal development. Finally, our embryonic C. cerastes data highlight a plausible asymmetry in snake skull development, mostly occurring in the basicranium region, but further investigations of embryonic samples and viper species would be required to confirm such phenomenon.

MRI KNEE BONE AGE: A NOVEL SHORTHAND APPROACH TO REDUCE BONE AGE RADIOGRAPHS IN CHILDREN

Background:Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency.Hypothesis/Purpose:We sought to validate and demonstrate reliability of a novel shorthand method of bone age determination using knee MRI across multiple levels of medical training.Methods:We identified patients who underwent knee MRI and hand bone age radiograph within a ninety-day period. In collaboration with a pediatric musculoskeletal radiologist, stepwise algorithms for predicting bone age on knee MRI were developed- one for males and one for females. Six raters at varying levels of training used the algorithm to assign a bone age for each patient. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter-rater reliability was also calculated using ICC.Results:Thirty-eight patients (44.7% female) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand methos was shown to be a good predictor of G&P hand bone age, both for each individual rater (ICC range: 0.73 – 0.80) and the mean knee MRI bone age across all raters (ICC 0.81; 95% CI 0.65 – 0.90). It was also shown to be a consistent predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee MRI bone age and G&P hand bone age.Conclusions:This novel shorthand algorithm is a reliable and valid way to determine skeletal maturity using knee MRI. It can be utilized clinically across different levels of radiographic and orthopaedic expertise and reduces the need for hand bone age radiographs and consequential radiation exposure in children.Figure 1.Shorthand Algorithm for Knee Bone Age Using MRI for MalesFigure 2.Shorthand Algorithm for Knee Bone Age Using MRI for FemalesTable 1.Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Rater ICC 95% CI Student 10.750.57 – 0.86Student 20.730.53 – 0.86Resident 10.730.54 – 0.85Resident 20.780.60 – 0.88Attending 10.740.54 – 0.85Attending 20.800.63 – 0.89Mean0.830.68 – 0.91

Mechanisms of Pisiform Reduction in Mammals

Most mammalian pisiforms are large, elongated carpal bones with two ossification centers and an associated growth plate, similar to the calcaneus in the ankle. Short pisiforms are rare among mammals, but can be found in humans, orangutans (Primates: Pongo sp.), two‐toed sloths (Pilosa: Choloepus sp.), and three‐toed sloths (Pilosa: Bradypus sp.). These groups utilize diverse forms of locomotion; humans are bipedal, orangutans are quadrumanous climbers, and sloths are suspensory quadrupeds. Human pisiforms form from a single ossification center and have likely lost a primary ossification center and the associated growth plate. Given the rarity of short pisiforms among mammals, little is known about the functional implications or developmental mechanisms underlying this convergent morphology in species with such diverse locomotor modes and evolutionary histories. The purpose of this study is to compare ossification patterns in orangutans and sloths with the mechanism underlying human pisiform truncation. We compare pisiform ossification data from human, orangutan, and sloth museum specimens. Unlike humans, orangutan pisiforms retain two centers of ossification but appear to form the secondary center of ossification later than other apes, possibly shortening the growth period for the pisiform. Sloths form a primary center of ossification with an unusual, pitted surface, which may represent an abnormal subchondral surface. In non‐human primates (including orangutans) and giant anteaters (Pilosa: Myrmecophaga tridactyla), which represent the closest living taxonomic group to sloths, pisiform and calcaneus ossification is generally correlated with epiphyses forming at similar times within individuals. In contrast, we found only a single ossification center corresponding to sloth pisiforms at all stages of calcaneal epiphyseal formation. Thus, the single pisiform ossification center appears to precede calcaneal epiphysis formation. This indicates that the sloth pisiform is homologous to the primary center of ossification of the calcaneus and other mammalian pisiforms, and that it fails to form a secondary center. This is in contrast to human pisiforms, which fail to form the primary ossification center. Humans, orangutans, and sloths are all unusual among mammals for having short pisiforms and each group achieves pisiform reduction through unique mechanisms.Support or Funding InformationThis research was funded by the National Science Foundation (BCS‐1540418 and BCS‐1638812).

Ontogeny of the distal femoral metaphyseal surface and its relationship to locomotor behavior in hominoids.

Distal femoral metaphyseal surface morphology is highly variable in extant mammals. This variation has previously been linked to differences in locomotor behavior. We perform the first systematic survey and description of the development of this morphology in extant hominoids. We collected 3D surface laser scans of the femora of 179 human and great ape individuals throughout all subadult stages of development. We qualitatively and quantitatively describe metaphyseal surface morphology. We find that the metaphysis is topographically simple in all hominoids during the fetal and infant periods relative to later developmental periods, and in apes it develops significant complexity throughout development. Humans, by contrast, retain relatively flat metaphyseal surfaces throughout ontogeny. Major shifts in morphology appear to coincide with major shifts in locomotor behavior, suggesting that metaphyseal morphology is developmentally plastic and highly dependent on the biomechanical loadings at the knee joint. This is consistent with a large body of biomedical research, which demonstrates the primacy of mechanical forces in determining growth plate ossification patterns. Additionally, specific metaphyseal morphology appears highly correlated with specific locomotor modes, suggesting that metaphyseal surface morphology will be useful for reconstructing the locomotor behavior of fossil primate taxa.

Growth of the capitellar ossification center and its relationship within the lateral condyle of the distal humerus in skeletally immature elbows: a study using MR images

To more accurately interpret the anterior humeral and radiocapitellar lines on simple radiographs of pediatric elbow, we investigated age-related changes of the capitellar ossific nucleus (CON) by using MRIs. Elbow MRIs from 79 children aged 1-16 years and free from demonstrable lesions in the distal humerus were retrospectively reviewed. On coronal images, the distal cartilaginous vertex of the capitellum, which articulates with the center of the radial head, was situated about 15%p laterally from the center of CON regardless of age. On sagittal images, the anterior humeral line passed the center of CON in older children (>6 years), but passed anteriorly in children with an age ≤6 years. Also on sagittal images, the anterior cartilaginous vertex of the capitellum was positioned within 10% of the level of the center of CON in all age groups. Recognition of the capitellar ossification pattern within the lateral condyle would aid in more accurate assessment of pediatric elbows on simple radiographs. Based on the results of the present MRI study, the following points were identified for the interpretation of simple radiographs: (1) The radiocapitellar line on anteroposterior views intersects the CON by about 15%p laterally regardless of age; (2) The anterior humeral line on lateral views intersects the center of the CON in older children, but passes anteriorly in younger (≤6 years) children; and (3) The radiocapitellar line on lateral radiographs invariably passes the center of CON regardless of the age.

Modeling of Neonatal Skull Development Using Computed Tomography Images

Neonatal skull anatomy and its evolution have received less attention with respect to the brain anatomy in neuroscience and neuroanatomy studies. Meanwhile, their influence on normal brain development and their impact on the results of functional brain studies have been demonstrated by several researches. Such disesteem is due to the weak appearance of the cranial bones, fontanels and sutures in images acquired by MRI which presents actually the only available aperture for observing the neonatal head volume in details. This paper presents an unprecedented retrospective CT-based study on modeling the neonatal skull and its development during the first weeks of life in a standard space defined by the available neonatal MRI model. We create two neonatal head atlases for the age ranges of 39-40 and 41-42 week's gestational age using symmetric group-wise normalization method. The created atlases allow direct observation of ossification patterns and precise three-dimensional measurement of anatomical features from neonatal skull during development. Development of the neonatal skull has been examined here using nineteen CT scans of neonates with two-week gestational age ranges of 39 to 40 and 41 to 42. Deformation-based morphometry method is applied with the use of Jacobian determinant maps to identify growth patterns and observe ossification during specified time interval. Precise three-dimensional measurements of anterior fontanel size, scalp eliminated head circumference and the area corresponding to the fontanel-sutures were performed by extracting fontanels and sutures.

Repair processes of flat bones formed via intramembranous versus endochondral ossification

ObjectivesAlthough fractures occur in various bones, including long, short, and flat bones, fracture repair investigations focus on the diaphysis of the long bone. The cell composition, osteogenic capacity, and bone matrix differ among osteogenesis patterns. However, the differences in the bone repair process have not been studied. Here, we compared the bone repair processes in the parietal bone and scapula of adolescent mice. MethodsBone apertures were created in the parietal bone and scapula. Samples were collected at indicated times after surgery, and the repair process was analyzed using micro-computed tomography, histological, immunohistochemical, and mRNA expression analyses. ResultsIn both repair processes, cartilage formation was not detected on the periosteum side. The parietal bone aperture was gradually filled with newly formed bone produced from the edge of the aperture by day 14 but was not completely repaired even by day 49. In the scapula, a bony callus was detected on the periosteum at day 7, and the aperture was bridged by day 14. Subsequently, the bony callus was remodeled to the original bone architecture. Alkaline phosphatase activity and osteocalcin synthesis occurred earlier in the repair region of the scapular periosteum, compared with that in the parietal periosteum. The mRNA expression of osteogenic markers in the periosteum was markedly upregulated in the scapula versus the parietal bone. ConclusionOur study findings clarify the differences between parietal bone and scapula repair and suggest that the bone repair process differs among ossification patterns.

Presents some Biologically Structured Materials

In this paper bio-tissue, mathematical modeling serves as a central repository to interface design, simulation and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesized for the use of the new biologically techno-structured hybrid materials.

Normal Glenoid Ossification in Pediatric and Adolescent Shoulders Mimics Bankart Lesions: A Magnetic Resonance Imaging–Based Study

The purpose of this descriptive study was to define patterns of ossification and fusion of growth centers around the pediatric and adolescent glenoid as a function of age using 3-dimensional, frequency-selective, fat-suppressed spoiled gradient recalled echo magnetic resonance (MR) imaging sequences, with a particular focus on the anterior glenoid rim because of its clinical relevance as a potential confounder of glenohumeral instability. Picture Archiving and Communication System records at an urban academic tertiary care orthopaedic facility from October 2005 to December 2018 were queried for shoulder MRI in patients aged 9 to 17years. Patients were excluded if they had any diagnoses that could alter glenoid development. All images were independently evaluated by a musculoskeletal fellowship-trained radiologist. Secondary ossification centers were characterized as cartilage anlage, ossified, or fused at 3 anatomic sites: the anterior glenoid rim, coracoid, and superior glenoid rim. A total of 250MR examinations (143 males, 107 females) were assessed in this study. The glenoid develops in a predictably sequential manner with ossification at the anterior glenoid rim lagging behind the coracoid and superior glenoid rim. The earliest age of anterior glenoid rim ossification was 11years for both males (range 11-17) and females (range 11-12). Anterior glenoid rim ossification peaked at age 16 among males (34.8%, 8/23) and age 11 among females (27.3%, 3/11). Glenoid ossification and fusion progress in a predictable and chronological manner. This pattern should be used as a guideline when interpreting pediatric shoulder MRI examinations. In particular, an anterior glenoid ossification center should not be confused with an anterior glenoid injury (e.g., Bankart lesion), particularly in males 11 to 17years old and females 11 to 12years old. IV (case series).

Identifying the homology of the short human pisiform and its lost ossification center

BackgroundThe pisiform and calcaneus are paralogous bones of the wrist and ankle and are the only carpal and tarsal, respectively, to develop from two ossification centers with an associated growth plate in mammals. Human pisiforms and calcanei have undergone drastic evolutionary changes since our last common ancestor with chimpanzees and bonobos. The human pisiform is truncated and has lost an ossification center with the associated growth plate, while the human calcaneus has expanded and retained two ossification centers and a growth plate. Mammalian pisiforms represent a wide range of morphologies but extremely short pisiforms are rare and ossification center loss is even rarer. This raises the question of whether the sole human pisiform ossification center is homologous to the primary center or the secondary center of other species. We performed an ontogenetic study of pisiform and calcaneus ossification patterns and timing in macaques, apes, and humans (n = 907) from museum skeletal collections to address this question.ResultsHuman pisiforms ossify irregularly and lack characteristic features of other primates while they develop. Pisiform primary and secondary center ossification timing typically matches that of the calcaneus of non-human primates, while the human pisiform corresponds with calcaneal secondary center ossification. Finally, human pisiforms ossify at the same dental stages as pisiform and calcaneal secondary centers in other hominoids.ConclusionsThese data indicate that the human pisiform is homologous to the pisiform epiphysis of other species, and that humans have lost a primary ossification center and associated growth plate while retaining ossification timing of the secondary center. This represents an exceptional evolutionary event and demonstrates a profound developmental change in the human wrist that is unusual not only among primates, but among mammals.

Biologically structured materials

In this paper bio-tissue mathematical modeling serves as a central repository to interface design, simulation, and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesized for the use of the new biologically techno-structured hybrid materials.

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics. The most frequently utilized methods to age bottlenose dolphins (Tursiops truncatus) include tooth extraction; counting dental growth layer groups and dental radiography. These methods are inaccurate in dolphins > 13 years old, due to overlapping of the growth layer groups in dolphins and worn teeth. Establishing a non-invasive method of accurately aging bottlenose dolphins across the entire age range is important to long term conservation efforts to understand health status, lifespan, reproduction and survivability. A database of 126 radiographs from 94 dolphins of known chronological age was utilized to establish the stages of skeletal ossification over time. A numerical score from -1 to 8 was assigned to 16 anatomic locations on the pectoral radiograph, to create a formula to estimate age. The most informative areas to evaluate morphologically were the metaphyseal regions of the radius and ulna, and the proximal and distal epiphysis of metacarpals II and III. Third order polynomial regression calculated separate age predictor formulas for male and female dolphins, with females reaching sexual maturity earlier than males. Completion of epiphyseal closure of the long bones correlated with average sexual maturity. Managed care dolphin ages could be properly estimated with decreasing precision from within 3 months in animals < 5 years old, to within 5 years in animals > 30 years old. This diagnostic tool could also be applied to diagnose atypical ossification patterns consistent with nutritional, developmental or growth abnormalities, and identifying subclinical health issues. In conclusion, knowledge of the lifespan and the onset of sexual maturity for each species will allow this model to be applied to other cetaceans, facilitating age estimation via pectoral radiography in future research.