scholarly journals Osteohistology of the Scapulocoracoid of Confuciusornis and Preliminary Analysis of the Shoulder Joint in Aves

2021 ◽  
Vol 9 ◽  
Author(s):  
Qian Wu ◽  
Alida M. Bailleul ◽  
Zhiheng Li ◽  
Jingmai O’Connor ◽  
Zhonghe Zhou

As key components of the tetrapod pectoral girdle, the scapula and coracoid have played a significant role in the evolution of forelimb locomotion among terrestrial vertebrates. The transition from a rigid fused scapulocoracoid in ancestral non-avian theropods to a presumably more flexible separated scapula-coracoid in early birds is considered to be one of the key morphological transitions related to the rapid refinement of flight. In most Mesozoic birds (e.g., Enantiornithes and Ornithuromorpha) and crown birds the scapula and coracoid are separate (unfused), with few exceptions (e.g., flightless paleognaths). In contrast, in Confuciusornis, a basal pygostylian from the Early Cretaceous Jehol Biota known from thousands of specimens, the scapula and coracoid remain plesiomorphically fused. This raises questions regarding the influence of shoulder girdle architecture on the early evolution and refinement of avian flight. The paravian scapula-coracoid joint has never previously been investigated using histology, and thus joint morphology has only been inferred superficially. In order to better understand the evolution of this joint in Mesozoic birds, we make the first histological study of the scapulocoracoid glenoid joint in Confuciusornis. The results demonstrate that the scapula and coracoid both consist of cancellous and compact bone, with both fibrolamellar and parallel-fibered structure. A thin layer of calcified cartilage is present on the glenoid fossa surface, representing remnants of the articular surface for the humerus. Both histology and computed tomography reveal that the scapulocoracoid of Confuciusornis is fully fused, forming a synostosis. Humeral histology suggests the studied individual was nearing completion of its first year of growth, suggesting the Confuciusornis scapulocoracoid fused before skeletal maturity was achieved, as in flightless paleognaths, whereas in the plesiomorphic condition fusion occurs late in ontogeny. We hypothesize the fused scapulocoracoid of Confuciusornis is secondarily evolved and suggest the primary factor responsible for this morphology may have been a decrease in mechanical stimulation at the glenoid of Confuciusornis relative to other volant birds, linked to the unique flight style of this taxon. Further investigation into the histology of the glenoid joint in other Mesozoic paravians and extant birds will help to clarify the morphological transition of the scapula-coracoid joint in early avian evolution.

2012 ◽  
Vol 37 (8) ◽  
pp. 765-771 ◽  
Author(s):  
A. S. Gavaskar ◽  
S. Muthukumar ◽  
N. Chowdary

The goal was to evaluate the efficacy of 2.4 mm column-specific plating for intra-articular distal radius fractures. In total, 105 patients with AO type C distal radius fractures were operated on using the locking distal radius system, Synthes. Follow-up assessments including clinical (wrist and forearm range of motion, grip strength), radiological (articular step, radial length and inclination, volar tilt, and ulnar variance), and functional scores (Disabilities of the Arm, Shoulder, and Hand; Patient Rated Wrist Evaluation) were made at regular intervals until 1 year. Union was obtained in all patients. Articular surface was anatomically reconstructed in 74 patients (70.5%). Clinical and functional evaluation showed significant continuous improvements over the first year. C1 fractures had a better chance of anatomical reduction compared with C2 and C3 fractures. Fracture type, quality of reduction, and presence of degenerative changes did not show a significant effect on functional outcome scores. Column-specific fixation of the distal radius can achieve satisfactory results in complex intra-articular fractures.


PEDIATRICS ◽  
1986 ◽  
Vol 77 (5) ◽  
pp. 664-669
Author(s):  
Michael K. Georgieff ◽  
Judy C. Bernbaum

To document the incidence of and neonatal factors associated with abnormal shoulder girdle muscle tone in premature infants at follow-up, we studied 125 consecutively admitted infants weighing < 1,750 g treated in The Children's Hospital of Philadelphia intensive care nursery and subsequently seen in the Neonatal Follow-up Program up to 18 months of age. Fifty-seven infants (46%) displayed abnormal shoulder girdle muscle tone which presented clinically as scapular retractions. These infants had significantly lower birth weights (P < .001) and gestational age (P < .001) as well as a higher incidence of acute and chronic pulmonary disease (P < 0.01) and CNS insults (P < .05) when compared with infants without scapular retractions. The 57 infants with scapular retractions were further divided into two groups: 42 infants (74%) in whom scapular retractions were associated with generalized mild hypertonicity and 15 infants (26%) in whom scapular retractions compensated for trunk and neck hypotonicity. The infants with scapular retractions and hypotonicity had a significantly higher incidence of neonatal neurologic morbidity including seizures, major resuscitations, and birth asphyxia (P < .01) when compared with the infants with scapular retractions and hypertonicity. Shoulder girdle tone abnormalities in the first year of life inhibit crawling, sitting, and object manipulation and, therefore, may manifest as delays in motor development. Identification of infants with significant neonatal risk factors for tone abnormalities is important to allow for earlier therapeutic intervention.


Fossil Record ◽  
2020 ◽  
Vol 23 (2) ◽  
pp. 191-196
Author(s):  
Chang-Fu Zhou ◽  
Jiahao Wang ◽  
Ziheng Zhu

Abstract. In the Jehol Biota, the filter-feeding ctenochasmatid pterosaurs flourished with a high biodiversity. Here, we report a new wing skeleton of the ctenochasmatid Forfexopterus from the Early Cretaceous Jiufotang Formation in Jianchang, western Liaoning, China. The specimen exhibits the sole autapomorphy, the first wing phalanx shorter than the second and longer than the third. Interestingly, it exhibits a skeletal maturity with co-ossified elements, but it is only about 75 % the size of the immature holotype. This discrepancy reveals developmental variation of Forfexopterus, but its relationship with sexual dimorphism needs to be certain by more available material.


2007 ◽  
Vol 17 (1) ◽  
pp. 82-90 ◽  
Author(s):  
M. Martiniaková ◽  
B. Grosskopf ◽  
R. Omelka ◽  
K. Dammers ◽  
M. Vondráková ◽  
...  

Bone ◽  
2021 ◽  
Vol 143 ◽  
pp. 115660
Author(s):  
Rasmus Klose-Jensen ◽  
Louise Brøndt Hartlev ◽  
Jesper Skovhus Thomsen ◽  
Jens Randel Nyengaard ◽  
Lene Warner Thorup Boel ◽  
...  

2020 ◽  
Vol 99 (12) ◽  
pp. 1377-1386 ◽  
Author(s):  
Y. Tang ◽  
C. Hong ◽  
Y. Cai ◽  
J. Zhu ◽  
X. Hu ◽  
...  

During the mandibular condylar growth, the absorption of calcified cartilage matrix induced by osteoclasts is crucial for the continuous endochondral osteogenesis. Meanwhile, recent studies showed that subchondral bone resided within the low-oxygen microenvironment, and our previous study revealed that hypoxia-inducible transcription factor 1α (HIF-1α) promoted osteoclastogenesis under hypoxia. However, whether HIF-1α regulates the function of osteoclasts in the mandibular condyle cartilage remains elusive. Our study indicated that severe deformity of the mandibular condyle was displayed in 10-wk-old osteoclast-specific HIF-1α conditional knockout (CKO) mice, accompanied by shortened length of condylar process and disorganized fibrocartilage. In 1-, 2-, and 4-wk-old CKO mice, the size of the hypertrophic layer and chondrocytic layer was significantly thickened. In the chondrocytic layer, chondrocytes were atrophied, showing a form of apoptosis in 4-wk-old CKO mice. Furthermore, an increase in the thickness of the fibrous and proliferating layer was observed in 10-wk-old CKO mice, as well as a significant decrease in that of the chondrocytic and hypertrophic chondrocyte layers. Interestingly, the articular surface of the condylar process abnormally presented a horizontal concave shape, and a disk-like acellular connective tissue appeared. In addition, genetic ablation of HIF-1α blunted cartilage matrix loss by subchondral osteoclast deficiency, resulting in a high subchondral bone mass phenotype, accompanied with a decreased number of blood vessels, alkaline phosphatase staining, and vascular endothelial growth factor (VEGF) expression. Mechanistically, the number of osteoclasts in the center of the condyle in CKO mice was significantly reduced by attenuated expression of adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling. These findings reveal a novel influence of HIF-1α function in osteoclasts on maintenance of osteoclast-induced resorption of calcified cartilage matrix via AMPK signaling, as well as subchondral bone formation through VEGF-dependent angiogenesis in bone marrow.


Paleobiology ◽  
2015 ◽  
Vol 41 (4) ◽  
pp. 503-527 ◽  
Author(s):  
Holly N. Woodward ◽  
Elizabeth A. Freedman Fowler ◽  
James O. Farlow ◽  
John R. Horner

AbstractFossil bone microanalyses reveal the ontogenetic histories of extinct tetrapods, but incomplete fossil records often result in small sample sets lacking statistical strength. In contrast, a histological sample of 50 tibiae of the hadrosaurid dinosaurMaiasaura peeblesorumallows predictions of annual growth and ecological interpretations based on more histologic data than any previous large sample study. Tibia length correlates well (R2>0.9) with diaphyseal circumference, cortical area, and bone wall thickness, thereby allowing longitudinal predictions of annual body size increases based on growth mark circumference measurements. With an avian level apposition rate of 86.4 μm/day,Maiasauraachieved over half of asymptotic tibia diaphyseal circumference within its first year. Mortality rate for the first year was 89.9% but a seven year period of peak performance followed, when survivorship (mean mortality rate=12.7%) was highest. During the third year of life,Maiasauraattained 36% (x=1260 kg) of asymptotic body mass, growth rate was decelerating (18.2 μm/day), cortical vascular orientation changed, and mortality rate briefly increased. These transitions may indicate onset of sexual maturity and corresponding reallocation of resources to reproduction. Skeletal maturity and senescence occurred after 8 years, at which point the mean mortality rate increased to 44.4%. Compared withAlligator, an extant relative,Maiasauraexhibits rapid cortical increase early in ontogeny, whileAlligatorcortical growth is much lower and protracted throughout ontogeny. Our life history synthesis ofMaiasaurautilizes the largest histological sample size for any extinct tetrapod species thus far, demonstrating how large sample microanalyses strengthen paleobiological interpretations.


2019 ◽  
Vol 13 (3) ◽  
pp. 318-323 ◽  
Author(s):  
B Danino ◽  
R. Rödl ◽  
J. E. Herzenberg ◽  
L. Shabtai ◽  
F. Grill ◽  
...  

Purpose To evaluate the temporal and spatial sequence of events following temporal hemiepiphysiodesis in idiopathic knee varus/valgus. Methods This is a retrospective multicentre study on 372 physes in 206 patients. The average rate of correction (ROC) was calculated; univariate and multivariate analysis were performed. Results In all, 92% of the femoral physes were followed for more than one year/reached skeletal maturity. Of those, 93% were corrected to a mechanical lateral distal femoral angle (mLDFA) of 85° to 89°; 2% did not, while 5% were over-corrected. A total of 92% of the tibial physes were followed for more than one year/reached skeletal maturity. Of those, 92% were corrected to a mechanical medial proximal tibial angle (mMPTA) of 85° to 89°; 2% did not, while 6% were over-corrected. Factors significantly influencing success and ROC were age, direction and magnitude of deformity. Femoral ROC was significantly faster than tibial ROC: 0.85° versus 0.78°/month, respectively (p = 0.05). Femoral valgus ROC was significantly faster than varus ROC: 0.90° versus 0.77°/month, respectively (p = 0.04). A constant was derived to calculate the amount of correction. Significant correlation was found between calculated and actual mLDFA in valgus deformity during the first year (r = 0.58 to 0.87, p < 0.01). Calculated mLDFA of varus deformity did not correlate with actual mLDFA. Significant correlation was found when calculating mMPTA correction in all deformities. Conclusions Femur corrects faster than tibia; valgus femoral deformities are corrected faster than varus. Valgus correction in the distal femur/proximal tibia as well as varus correction in the tibia in idiopathic patients is highly predictable. The constant derived is the first tool which enables predicting and monitoring amount of correction in hemiepiphysiodesis when correcting angular deformities around the knee. Level of Evidence IV


2015 ◽  
Vol 20 (3) ◽  
pp. 361 ◽  
Author(s):  
Luis Fernando Calixto ◽  
Rodrigo Penagos ◽  
Lina Jaramillo ◽  
María Lucia Guitierrez ◽  
Diego Garzón-Alvarado

The clavicle is the first bone to begin the process of ossification and the last one to complete it. Whilst histological studies of the clavicle have been focused mainly on embryonic events, our study focused on post natal clavicle development. The objective of this study was to perform a qualitative description of the clavicle’s epiphyseal growth to further shed light on the postnatal ossification process. Histological studies performed on clavicles obtained from cadavers confirmed medial and lateral extremities as true physes. Unlike the development of other long bones, no secondary ossification centre was present at the acromial end. Furthermore, appearance of the sternal end was observed after the age of 18, as evidenced in clavicles from a 19-year old individual. The articular surface of the clavicle’s acromial end was fibrocartilage. No histological studies have been performed before describing postnatal development of clavicular ends. Our data confirm the absence of an acromial secondary ossification centre, the late development of a secondary ossification centre at the sternal end, and the presence of fibrocartilage at the acromial end.


2020 ◽  
Vol 7 (48) ◽  
pp. 2811-2814
Author(s):  
Uday Kiran B ◽  
Divya Pothati

BACKGROUND Study of ossification of carpal bones in children indicates the level of structural maturity and age estimation. For the assessment of skeletal maturity in children, radiologists often use hand and wrist radiograph because of low level of radiation. Carpals are the most commonly used bones for determining the age of a child. We wanted to study the appearance of ossification centers in the carpal bones in age group of 3 - 14 years. METHODS This is a prospective observational study of one-year duration conducted between January 2019 and December 2020 in the Department of Forensic Medicine and Toxicology at Maheshwara Medical College and Hospital, Patancheru, Telangana. Children 3 to 14 years of age from nearby schools were randomly selected, and X-rays of the carpal bones were taken. Appearance of carpal bones and ossification were studied to estimate the age. RESULTS The study included 70 school children. We found that capitate and hamate carpals ossified during the first year of life in children of both sexes. Triquetral and lunate appeared at 3 - 4 years, trapezium, trapezoid and scaphoid carpals appeared between 5 and 8 years. Pisiform appeared at 9 years of age in females and at 13 years in males. CONCLUSIONS Capitate and hamate ossify at an early age. Triquetral and lunate carpals appear after capitate and hamate. Their appearance is slightly earlier in females than in males. KEYWORDS Ossification, Carpal Bones, Capitate, Hamate


Sign in / Sign up

Export Citation Format

Share Document