Multiple Ossification Centers Research Articles

A safe area for sternal puncture in children: an MSCT study based on sternal development.

PurposeMultislice spiral CT (MSCT) was used to investigate the anatomical characteristics of sternal development, and to provide anatomical basis for sternal puncture in children.MethodsWe retrospectively analyzed the thoracic MSCT data of 600 children who received thoracic MSCT from January to June 2020 with their age ranging from 1 month to 19 years. The distribution of sternal ossification centers and adjacent tissues and organs was observed. Subcutaneous soft tissue thickness and the distance between the skin and the posterior margin of the sternum were measured in the central areas of sternal manubrium and mesosternum (segments I and II), and the correlation between the two was calculated using linear correlation.ResultsA total of 600 patients were enrolled, the mean age was 9.87 years and the standard deviation was 8.28 years. The sternal manubrium and ossification centers at the I and II segments of the mesosternum were visible in all cases (100%). There was no ossification in segment III of the mesosternum in 15 cases (2.5%), including 12 cases (80%) adjacent to the posterior pericardium and 7 cases (46.7%) of lung tissue. There were 274 cases (45.7%) of segment IV without ossification, including 204 cases (74.5%) of adjacent pericardium and 95 cases (32.8%) of lung tissue. The xiphoid process was not ossified in 258 cases (43%), including 190 cases (73.6%) adjacent to the pericardium and 97 cases (37.6%) adjacent to the lung tissue. Correspondingly, the thickness of subcutaneous soft tissue of the sternal manubrium and the central region of the I and II segments of the mesosternum had a low positive correlation with age (P < 0.001), the distance between the skin and the posterior margin of the sternum showed a moderate positive correlation with age (P < 0.001), and the distance between the skin and the posterior margin of the sternum showed a high positive correlation with the thickness of subcutaneous soft tissue (P < 0.001).ConclusionsNonossification of the sternal ossification center usually occurs below segment III of the mesosternum and is usually adjacent to heart and lung tissue. Pediatric sternal puncture should be performed at the sternal manubrium and the mesosternum of segments I and II. However, attention should be paid to the space between multiple ossification centers. The thickness of subcutaneous soft tissue is a critical factor that determines the depth of the puncture.

A Biphasic Osteovascular Biomimetic Scaffold for Rapid and Self-Sustained Endochondral Ossification.

Regeneration of large bones remains a challenge in surgery. Recent developmental engineering efforts aim to recapitulate endochondral ossification (EO), a critical step in bone formation. However, this process entails the condensation of mesenchymal stem cells (MSCs) into cartilaginous templates, which requires long-term cultures and is challenging to scale up. Here, a biomimetic scaffold is developed that allows rapid and self-sustained EO without initial hypertrophic chondrogenesis. The design comprises a porous chondroitin sulfate cryogel decorated with whitlockite calcium phosphate nanoparticles, and a soft hydrogel occupying the porous space. This composite scaffold enables human endothelial colony-forming cells (ECFCs) and MSCs to rapidly assemble into osteovascular niches in immunodeficient mice. These niches contain ECFC-lined blood vessels and perivascular MSCs that differentiate into RUNX2+ OSX+ pre-osteoblasts after oneweekin vivo. Subsequently, multiple ossification centers are formed, leading tode novobone tissue formation by eightweeks, including mature human OCN+ OPN+ osteoblasts, collagen-rich mineralized extracellular matrix, hydroxyapatite, osteoclast activity, and gradual mechanical competence. The early establishment of blood vessels is essential, and grafts that do not contain ECFCs fail to produce osteovascular niches and ossification centers. The findings suggest a novel bioengineering approach to recapitulate EO in the context of human bone regeneration.

Pitfalls in MRI of the Developing Pediatric Ankle.

Normal skeletal development in the pediatric ankle is dynamic and often produces variable imaging appearances that are subject to misinterpretation. Radiologists must understand the underlying developmental phenomena, such as endochondral and membranous ossification and physeal fusion, and be familiar with their common and uncommon imaging manifestations unique to the pediatric ankle. This is especially true as the use of MRI in the evaluation of musculoskeletal trauma expands among younger populations. The authors focus on MRI evaluation of the skeletally maturing pediatric ankle and present pearls for accurately distinguishing normal findings and imaging pitfalls from true pathologic findings. The normal but often variable imaging findings of preossification, secondary ossification, and multiple ossification centers, as well as the range of bone marrow signal intensities that can be visualized within ossification centers, are described, along with tips to help differentiate these from true pathologic findings such as contusion, fracture, or tumor. The authors also review dynamic periosteal and physeal contributions to bone growth to highlight helpful distinguishing features and avoid misdiagnosis of common subperiosteal and periphyseal abnormalities. For example, the normal trilaminar appearance of the immature cortex and periosteum should not be mistaken for periosteal reaction, traumatic stripping, or subperiosteal hematoma. In addition, the physis can have several confusing but normal appearances, including normal physeal undulations (eg, Kump bump) or focal periphyseal edema, which should not be mistaken for pathologic findings such as physeal fracture, infection, or bar. ©RSNA, 2020.

Clinical Aspects and Current Therapeutic Approaches for FOP.

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare heritable disorder of connective tissues characterized by progressive heterotopic ossification in various skeletal sites. It is caused by gain-of-function mutations in the gene encoding activin A receptor type I (ACVR1)/activin-like kinase 2 (ALK2), a bone morphogenetic protein (BMP) type I receptor. Heterotopic ossification is usually progressive leading to severe deformities in the trunk and extremities. Early clinical diagnosis is important to prevent unnecessary iatrogenic harm or trauma. Clinicians should become aware of early detectable skeletal malformations, including great toe deformities, shortened thumb, neck stiffness associated with hypertrophy of the posterior elements of the cervical spine, multiple ossification centers in the calcaneus, and osteochondroma-like lesions of the long bones. Although there is presently no definitive medical treatment to prevent, stop or reverse heterotopic ossification in FOP, exciting advances of novel pharmacological drugs focusing on target inhibition of the activated ACVR1 receptor, including palovarotene, REGN 2477, rapamycin, and saracatinib, have developed and are currently in clinical trials.

Digital tomosynthesis of the pediatric elbow.

Imaging pediatric elbow trauma in the acute setting remains diagnostically challenging given difficult patient positioning, multiple ossification centers of the pediatric elbow, overlapping structures, and complex joint anatomy. Digital tomosynthesis is a technique where the X-ray source travels across a limited arc angle, obtaining a series of low-dose exposures that are in turn digitally reconstructed to produce high in-plane resolution at a relatively low overall radiation dose. Digital tomosynthesis is now more commonly integrated into standard radiographic machines and offers a new and exciting way to assess the pediatric elbow. In this review article we discuss the clinical applications of digital tomosynthesis in pediatric elbow trauma along with challenges related to technique, patient positioning and artifacts.

Successful Treatment of Painful Synchondrosis of Bipartite Patella after Direct Trauma by Operative Fixation: A Series of Six Cases.

Introduction:The patella is the largest sesamoid bone in the body and may have one (77%) or multiple (23%) ossification centres. Patellar and patellofemoral joint abnormalities are a common cause of anterior knee pain but symptomatic bipartite patella is an uncommon problem.Case Series:We report a series of six cases of painful synchondrosis in bipartite patellae, all in keen athletes following a direct blow to the anterior aspect of the knee. A complete rupture of the synchondrosis with evidence of retropatellar chondral separation was seen on MRI scan in all cases. Successful surgical fixation was undertaken with complete resolution of symptoms in all patients at an average of three months post-operatively.Conclusion:Painful synchondrosis of a bipartite patella in young and active individuals following direct trauma is a relatively rare cause of anterior knee pain, but may be associated with significant morbidity. In cases refractory to non-operative management, successful symptomatic treatment can be achieved by operative fixation.

Incidence and anatomical variations of accessory navicular bone in patients with foot pain: A retrospective radiographic analysis.

The accessory navicular (AN) is an accessory ossicle anatomically located on the medial side of the foot, proximal to the navicular and continuous with the tibialis posterior tendon. It is occasionally a source of pain and local tenderness. Knowledge of the AN and its morphological variations can help identify the source of a patient's symptoms and prevent misinterpreting them as fractures. Foot radiographs from 1,240 patients who presented in two centers with chronic foot pain, or persistent pain developed after trauma, were retrospectively reviewed to determine the incidence and variations of the AN in relation to gender. The AN was found in 20.9% (259/1240). Among 259 feet with AN, Type 1 was identified in 25.4% (66/259), Type 2 in 42.4% (110/259) (20.0% (52/259) Type 2 A and 22.4% (58/259) Type 2B), and Type 3 in 32.0% (83/259). After 13 patients with incomplete medical records had been excluded, the remaining records showed that foot pain was associated with an AN in 10.6% of patients (26/246). In 1.2% of cases, two additional ossicles were found proximal to the navicular, possibly the result of multiple ossification centers that did not unite at the time of development. Patient symptomatology was related to the presence of an AN in 2% of patients with chronic foot pain. The AN could vary morphologically. Our data can enhance our diagnostic skills in detecting these ossicles. Clin. Anat. 30:436-444, 2017. © 2017 Wiley Periodicals, Inc.

Elbow your way into reporting paediatric elbow fractures – A simple approach

The evaluation of X-rays of the paediatric elbow in the setting of trauma is challenging. The difficulty arises from the complex developmental anatomy of the elbow, with its multiple ossification centres and the differences in the pattern of injuries between adults and children. It is essential to evaluate the radiographs systematically. This review will provide an overview of the developmental anatomy, the range of soft tissue and skeletal findings, and demonstrate tips and pitfalls in radiographic interpretation in paediatric elbow trauma.

An Undiagnosed Fracture of the Radial Neck in a Young Child: The Radial Neck Fleck Sign: A Case Report.

In children, the development of the elbow involves multiple ossification centers that appear at variable stages of maturation. The unique anatomy makes radiographic evaluation of an elbow challenging in the presence of acute trauma. Understanding the developmental anatomy provides insight in terms of normal findings compared with abnormal findings on radiographs1,2. However, pediatric patients who have not undergone secondary ossification may not show the typical signs of a fracture. We report a rare case of a three-year-old boy with an undiagnosed completely displaced radial neck fracture associated with a nondisplaced olecranon fracture. The radial neck fracture was diagnosed when the follow-up radiograph showed a small, displaced ossified portion of the radial metaphysis, which we have termed the “radial neck fleck sign.” The child required closed reduction and intramedullary pinning under general anesthesia. The patient’s parent was informed that data concerning the case would be submitted for publication, and consent was provided. A three-year-old boy landed on the left elbow after jumping, and he was taken to another institution’s emergency department for evaluation and treatment. He was diagnosed with an olecranon fracture, which was treated with a long arm splint. The patient continued to have pain that was exacerbated by movement and, ten days later, presented to our orthopaedic clinic. Physical examination revealed a moderate amount of swelling at the anterior aspect of the elbow. The patient had no neurologic or vascular deficit. He refused active range of motion, but the arm was passively flexed to 90° and extended to 30°, …

An olecranon chondral flap and osteochondral coronoid fracture in a spontaneously reduced elbow dislocation in a child

Elbow injuries in children are very common and radiographs are often difficult to interpret because of the radiolucency of the cartilaginous anlage and the progressive appearance of multiple secondary ossification centres. Elbow dislocations are rare injuries in children. Coronoid fractures can occur during dislocation or relocation of the elbow and can be the only hallmark of a severe injury. The understanding of the mechanics of these injuries has undergone considerable evolution over the past decade. Intra-articular chondral flap fractures are a traumatic elevation of the hyaline cartilage from the subchondral bone. They are also rare injuries in children but should be included in the differential when examining an injured joint. The infrequency of these injuries provides little opportunity to become accustomed to the radiographic signs. We present a case report of a 4-year-old boy with both an olecranon chondral flap and coronoid cartilaginous fracture after a joint dislocation. We present his plain radiography and MRI with illustrated photographic records of the operative findings. This injury has been little described in the literature and never with such imaging to aid understanding of both the pathology and the injury mechanism.

Congenital sternal foramen in a stillborn Holstein calf

Congenital sternal foramen is an anomaly whose occurrence is rare in human but is especially unusual in animals. This defect was formed when fusion of multiple ossification centers was incomplete. It may be associated with other lesions in body organs especially cardiac anomalies. In the present study, we report a very rare case of congenital sternal foramen in a Holstein calf. The oval defect was like a gunshot wound and located at the lower third of the sternum. Apparently, the rest of skeleton system seems normal. The awareness of the anomaly is important for better diagnosis and treatment of diseases.

Radiology of acute elbow injuries

Elbow injuries are common and usually result from a fall onto an outstretched hand. Plain radiograph is the main modality used in the initial evaluation of these injuries. Clinical assessment can often be limited, especially in children who may be unable to communicate specific complaints and are sometimes difficult to examine reliably. Equally, interpretation of these radiographs is a daunting task as there are multiple ossification centres and normal variations. Therefore a good understanding of normal anatomy and common injury patterns is essential in evaluating elbow radiographs in the acute setting. This article reviews basic developmental anatomy, classical radiological signs and common elbow injuries.

Poly-epiphyseal overgrowth: description of a previously unreported skeletal dysplasia

A skeletal dysplasia with previously unreported features is presented. Its evolution was characterized by growth abnormalities of bones without involvement of other organs. Advanced bone age, increased stature and irregular epiphyseal ossification with stippling of the main long bones were documented. Physeal overgrowth was massive in the left proximal humerus and femur. Furthermore, the hip joint appeared fused with an abundant mass of pathological calcific tissue extending from the femur to the ilium. Pathological epiphyses were characterized by anarchic cartilaginous proliferation with multiple ossification centres, while lamellar bone apposition and remodelling were normal. The observed bone changes were different from those in any previously reported syndrome, metabolic defect or bone dysplasia. However, they clearly indicated a defect of endochondral ossification with some resemblance to phenotypes observed in dysplasia epiphysealis hemimelica.

Embryonic development of Python sebae – II: Craniofacial microscopic anatomy, cell proliferation and apoptosis

This study explores the microscopic craniofacial morphogenesis of the oviparous African rock python ( Python sebae) spanning the first two-thirds of the post-oviposition period. At the time of laying, the python embryo consists of largely undifferentiated mesenchyme and epithelium with the exception of the cranial base and trabeculae cranii, which are undergoing chondrogenesis. The facial prominences are well defined and are at a late stage, close to the time when lip fusion begins. Later (11–12 d), specializations in the epithelia begin to differentiate (vomeronasal and olfactory epithelia, teeth). Dental development in snakes is different from that of mammals in several aspects including an extended dental lamina with the capacity to form 4 sets of generational teeth. In addition, the ophidian olfactory system is very different from the mammalian. There is a large vomeronasal organ, a nasal cavity proper and an extraconchal space. All of these areas are lined with a greatly expanded olfactory epithelium. Intramembranous bone differentiation is taking place at stage 3 with some bones already ossifying whereas most are only represented as mesenchymal condensations. In addition to routine histological staining, PCNA immunohistochemistry reveals relatively higher levels of proliferation in the extending dental laminae, in osseous mesenchymal condensations and in the olfactory epithelia. Areas undergoing apoptosis were noted in the enamel organs of the teeth and osseous mesenchymal condensations. We propose that localized apoptosis helps to divide a single condensation into multiple ossification centres and this is a mechanism whereby novel morphology can be selected in response to evolutionary pressures. Several additional differences in head morphology between snakes and other amniotes were noted including a palatal groove separating the inner and outer row of teeth in the upper jaw, a tracheal opening within the tongue and a pharyngeal adhesion that closes off the pharynx from the oral cavity between stages 1 and 4. Our studies on these and other differences in the python will provide valuable insights into in developmental, molecular and evolutionary mechanisms of patterning.

The skull of the round Island boa, Casarea dussumieri Schlegel, based on high‐resolution X‐ray computed tomography

The skull of the rare bolyeriid snake Casarea dussumieri is described in detail based on high-resolution X-ray CT data. Bolyeriids are unique in their possession of a separate suborbital ossification and a maxilla subdivided into two movably jointed parts, which may be the result of paedomorphic truncation of the development of the maxilla from multiple ossification centers. Comparison of the skull of C. dussumieri to that of larger booids suggests additional paedomorphic features including reduction of the dorsal lamina of the nasal and prefrontal and reduction of their contacts with the frontal, limited posterior extent of the posterior free process of the supratemporal, and reduction of the coronoid and splenial. The observations herein do not resolve competing phylogenetic hypotheses based on morphology, which either place tropidophiids as the sister-taxon of bolyeriids, Acrochordus and colubroids, or place bolyeriids as the sister-taxon of the other three. But these observations provide no support whatsoever for the heterodox placement of tropidophiids at the base of alethinophidian snakes, as obtained recently with molecular data.

Pediatric elbow fractures: MRI evaluation.

Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies. Elbow injuries in children may be difficult to diagnose by routine clinical and radiographic techniques [1, 4, 12, 14]. Diagnostic difficulty is due to the presence of multiple ossification centers of the distal humeral epiphysis and proximal radius and ulna; these are mostly cartilaginous until the age of 11-12 years and therefore invisible on radiographs. Following distal radial and distal tibial physeal fractures, epiphyseal elbow injuries are the most frequent epiphyseal injuries [8, 16]. These fractures tend to be unstable and often require surgical intervention. In addition, lasting sequelae such as cubitus valgus and delayed ulnar nerve palsy can occur if these fractures are not treated properly [8].(ABSTRACT TRUNCATED AT 250 WORDS)

Dysplasia epiphysealis capitis femoris. Meyer's dysplasia

We made a prospective longitudinal clinical and radiological study of 18 children diagnosed as having dysplasia epiphysealis capitis femoris. Half the cases were bilateral. Boys were affected five times more often than girls. There were no symptoms or clinical signs in most but some of the bilateral cases had an inconsistent waddling gait. The imaging studies suggest that the cartilaginous proximal femoral epiphysis is hypoplastic, with delayed appearance of single or multiple ossification centres. Progressive improvement occurred and at an average age of five years and six months, there was complete fusion of all the ossific nuclei and normal density and texture of the epiphyseal bone. The end result was a round epiphysis with a slightly diminished height. The dysplasia is attributed to focal hypoplasia of the proximal femoral epiphysis.

Delta formation in foot polydactyly.

Congenital triangular deformity of the foot bones may occur in phalanges and metatarsals. As it resembles the Greek letter delta it is called "delta phalanx" and "delta metatarsal". We report on 19 delta formations in ten patients with foot polydactyly. Our long-term follow-up of these patients indicates four stages in the ossification process: no ossification of the epiphysis; appearance of single or multiple ossification centers; unification of the ossification centers with nonosseous tissue between the diaphysis and the epiphysis; and, finally, complete ossification. Pathogenetically, the delta formation may represent an intermediate stage in the bifurcation process of a polydactylic ray. Splitting longitudinally in a direction from distal to proximal, it is the root of the bifurcated toe ray.

Anomalous Multifocal Ossification of the Os Calcis

While accessory ossicles are relatively common in the feet, major developmental chondro-osseous variations in otherwise normal feet appear to be extremely unusual. The "bifid os calcis" has been reported infrequently since its first description by Sever in 1930. The majority of cases are fortuitously diagnosed, usually in children three years of age or older. The current case was diagnosed shortly after birth. The most obvious roentgenographic finding was punctate ossification in the anterior portion. As in other cases, this appeared to be a solitary, bilateral variation of chondro-osseous maturation. Foot development in the fetus includes considerable variation in the development of the calcaneal ossification center and at least two examples of multiple ossification centers.

Apophyseolysen, Abrißfrakturen und Osteochondropathie der Spina iliaca anterior inferior

Evulsion fractures of the anterior inferior iliac spine in adults usually are the result of sudden contraction of the rectus femoris muscle during sporting activities, particularly football. In children, before fusion of the apophysis, there may be an apophyseolysis. This may result in a chondropathy because of abnormal development of the frequently multiple ossification centres. In contrast to the relatively frequent evulsion fractures of the anterior superior iliac spine, such an event is very rare in the anterior inferior iliac spine. Three illustrative cases are described showing the typical combination of history, localisation, pain recurrence during exercise and x-ray changes, which usually consist of a curved osseous structure separate from the iliac bone. These findings permit a correct diagnosis.