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Rationale and Objectives To assess focal multiple myeloma bone lesions via dual-energy CT-based virtual noncalcium (VNCa) bone marrow imaging in relation to the overall hematological disease status and MRI findings. Materials and Methods We retrospectively evaluated 103 focal osteolytic lesions of the axial skeleton in VNCa bone marrow images of 32 patients. Region of interest-based attenuation measurements were correlated with T1w signal intensity and apparent diffusion coefficient (ADC). Results were compared between patients in active and inactive disease. Receiver operating characteristic analysis was performed to determine a cut-off value of VNCa attenuation for differentiation between the two groups. Standard of reference was the overall disease status according to International Myeloma Working Group response criteria. Results Mean attenuation difference between lesions and background bone marrow was significantly lower in inactive disease (16 HU, SD 30) compared to active disease (35 HU, SD 29). VNCa attenuation measurement allowed for differentiation between active and inactive disease with a sensitivity of 92% and a specificity of 58% at a cut-off value of -21 HU. VNCa attenuation was negatively correlated to T1w signal intensity (Spearman's ρ -0.617, p Conclusion Quantitative assessment of attenuation of focal osteolytic lesions in VNCa bone marrow images allows differentiation between overall active and inactive disease with higher attenuation signifying an increasing likelihood of active disease. This is supported by a significant positive correlation between the attenuation and the ADC, as well as a corresponding inverse correlation to T1w signal intensity.

Giant cell tumour of bone (GCTB) typically occurs in young adults from 20-40 years old. Although the majority of lesions are located in the epi-metaphyses of the long bones, approximately one third of tumours are located in the axial skeleton, of which only 4% in the sacrum. Sacral tumours tend to be large at the time of presentation, and they present with aggressive features such as marked cortical destruction and an associated soft tissue component. The 2020 World Health Organisation classification of Soft Tissue and Bone Tumours describes GCTB as a neoplasm which is locally aggressive and rarely metastasizing. The tumour contains three different cell types: neoplastic mononuclear stromal cells, macrophages and osteoclast-like giant cells. Two tumour subtypes were defined: conventional GCTB and malignant GCTB. Only 1-4% of GCTB is malignant. In this review article, we will discuss imaging findings at the time of diagnosis to guide the musculoskeletal radiologist in reporting these tumours. In addition, imaging for response evaluation after various treatment options will be addressed, such as surgery, radiotherapy, embolization and denosumab. Specific findings will be presented per imaging modality and illustrated by cases from our tertiary sarcoma referral center. Common postoperative and post-radiotherapy findings in GCTB of the sacrum on MRI will be discussed.

This case study demonstrates how animal abuse investigations can benefit from collaboration between forensic anthropologists and veterinary pathologists, especially in investigations involving trauma assessment of skeletal remains. In 2009, four deceased dogs were excavated from a residential property in conjunction with a case of suspected animal abuse. The decomposed remains were skeletonized to permit assessment of biological profiles, individualization, and trauma analysis. Each dog was identified based on their sex, age-at-death, fur coloration patterns, and through investigative information. The analysis conducted by forensic anthropologists in collaboration with a veterinary pathologist revealed evidence of perimortem blunt force trauma on all four skeletons. The distribution and severity of the injuries, including fractures concentrated mainly on the axial skeleton (i.e., skull, thorax, and vertebral column) and pelvis, are consistent with documented cases of non-accidental injury (NAI) reported in the literature. Healed rib fractures were also noted on one of the dogs, and likely occurred a few weeks prior to death, further supporting a diagnosis of NAI. The skeletal trauma findings were inconsistent with the dog owner's account of how each dog had died and were instrumental in resolving the investigation.

The rib is an unusual location for osteosarcoma and is reported in only 2% of all cases. The major histological variants of osteosarcoma are osteoblastic, chondroblastic, and fibroblastic, with a few rare variants including one epithelioid type. This report describes a 44-year-old male with an osteolytic mass in the right seventh rib. Histological examination revealed osteosarcoma with unique features of epithelioid appearance and rosette structures. To the best of our knowledge, this is the first reported case of a rosette-forming osteosarcoma of the rib that showed epithelioid morphology. Despite successful surgery, the patient’s prognosis was poor because this malignancy had an unusual location within the axial skeleton and was a rare histological variant.

Axial spondyloarthritis is an inflammatory disease of the axial skeleton. Its pathogenesis is only partly understood. At the beginning, there are inflammatory changes in the sacroiliac joints which are followed by inflammation in vertebral bodies and in facet joints. Low back pain occurring in the morning hours is the dominant clinical symptom. In the early phase, inflammatory changes are detectably by MRI. Inflammation promotes a process of joint remodelling in the sacroiliac joints which leads to erosions, sclerosis and bony bridging, i. e. ankylosis, which are detectable by X-ray. In the spine, vertical osteophytes developing at sites of previous inflammation connect vertebral bodies as syndesmophytes. Additional ossification of longitudinal ligaments contributes to the so-called bamboo spine. Ossification of the spine promotes fixation of a severe kyphosis of the thoracic spine which strongly impairs spine mobility and quality of life. High disease activity seems a prominent risk factor for development of structural damage. However, although NSAIDs improve clinical symptoms, they do not reduce new bone formation. In contrast, TNFα and IL-17 inhibitors seem to retard new bone formation apart from their clinical efficacy. Research work of the last years identified immunological pathways of inflammation. However, the trigger and cellular components of the immune reaction in the bone marrow are still poorly defined. Osteoclasts are involved in the destruction of the subchondral bone, while osteoblasts facilitate new bone formation and cartilage ossification. This review gives an overview about diagnostics and therapy of axSpA and about risk factors for the development of structural damage. Concepts about the immune pathogenesis and joint remodeling in AS are given under recognition of genetic and histopathological studies.

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease that manifests primarily in the axial skeleton, initially mostly in the sacroiliac joints (SIJ), usually later spreading to the spine. The disease is characterised by inflammation and new bone formation which are mainly assessed by conventional radiography (CR) and magnetic resonance imaging (MRI). Tumour necrosis factor inhibitors (TNFi) and interleukin-17 antagonists have been shown to be efficacious and efficient in patients with axSpA. This treatment seems to also inhibit structural damage, for example, retard radiographic progression. Indeed, a reduction of new bone formation in the spine, as assessed by CR, has been reported to occur after at least 2 years of therapy with TNFi. Recently, a reduction of erosions and ankylosis in the SIJ has also been observed in axSpA patients treated with etanercept and filgotinib. In this narrative review, we discuss the limited significance of such findings.

Vertebral column is made of 33 vertebrae named as cervical, thoracic, lumbar, sacral and coccygeal vertebrae. Axial skeleton comprises of skull and vertebral column. 12 pairs of cranial nerves and 31 pairs of spinal nerves exit from the central nervous system which control the entire body. Malformations or fusion of vertebrae could be one of the etiologies of nerve compression syndromes. Vital structures emerge out through intervertebral foramina extending from cervical to coccygeal vertebrae. Occipitalisation of atlas, the first cervical vertebra is one of the emergencies leading to wide spectrum of presentations like chronic neck pain or foramen magnum syndrome or unconscious state due to compression of medulla oblongata. During routine examination of skull bones while teaching, one skull was found to exhibit assimilation of atlas. Photographs were captured and compared with normal skull. Thorough examination revealed incomplete occipitalisation of atlas. The anterior arch was completely fused but the posterior arch was bifid showing a split. The styloid process on right side seemed to be long and very close leading to compression of structures of styloid apparatus in addition. On observation, it was found to be a male skull. Fusion of vertebrae may be a congenital anomaly due to maldevelopment of somites in forming vertebrae. Skeletal element of caudal 4th occipital somite forms the occipital bone and when it is fused with the proximal 1st cervical somite leads to occipitalisation of atlas. Acquired conditions like atlantoaxial subluxation, chiari malformations or cervical vertebral fusion or foramen magnum abnormalities have been associated with assimilation of atlas. The present study reports occipitalisation of atlas which is incomplete with a bifid posterior arch. Prevalence of such anomalies may form the differential diagnosis of chronic headache or myelopathies.

Calcium pyrophosphate deposition disease (CPPD) is characterized by polymorphism of clinical manifestations: from asymptomatic course to severe chronic arthropathy with destruction of bone structures. It is believed that calcium pyrophosphate crystals are more often found in the knee and so-called root joints (hip and shoulder), as well as in the triangular fibro-cartilaginous complex. However, CPPD can also affect the axial skeleton. A pathological process localized in the spine is more common in older people and is rare at a young age. The article presents a case of chondrocalcinosis of the cervical spine in a 62-year-old female patient who did not have risk factors.

The axial skeleton of orange rumped agouti, Dasyprocta leporina, was studied for better understanding of its locomotor behaviour. The bones from eight adult agoutis of both sexes were observed for their anatomical features and functional significance. The vertebral formula was found to be C7 T12 L7 S5 Cy5-6 . The well-developed occipital crest, caudally oriented prominent axis spine and well-developed transverse processes from C3 -C7 indicated a highly flexible neck with greater sagittal mobility. Articular facets were horizontal in anterior series while oblique in the posterior series, which enabled them to perform both lateral and sagittal movements during locomotion. The caudally directed thoracic spines, T12 as anticlinal vertebra and prominent mamillary process in the posterior series were suggestive of strong dorso-ventral flexion/extension and rotation. The robust lumbar vertebrae, well-developed transverse processes with cranio-ventral extension, were the feature for powerful sagittal/dorsoventral movement. The presence of spinous processes and well-developed transverse processes in all caudal vertebrae was an indication of a highly movable tail. The ribs were 13 pairs with first seven as sternal and six as asternal. They were laterally compressed in the anterior series as a cursorial adaptation. A strong muscular attachment to vertebrae provides this rodent speed, agility, dexterity and strength suitable for survival in food chain.

Gorham's disease is a rare condition characterized by progressive osteolysis of bone ultimately resulting in the total disappearance of bone. The etiology is unknown and the disease predominantly affects the pelvis, humerus, and axial skeleton. Because of its unusual, ambiguous presentation and rare occurrence, the disorder goes unrecognized and is often masqueraded by other disorders. The diagnosis of this disorder is by exclusion. About 50 cases of Gorham's disease involving the maxillofacial region are reported to date and most of them involve the mandible. Exclusive involvement of maxilla is documented in only 4 cases. We report an exceptional case of Gorham's disease of the maxilla in a 68-year-old male patient presenting with chronic pain and masquerading as an odontogenic infection.

A critical stage in the development of all vertebrate embryos is the generation of the body plan and its subsequent patterning and regionalisation along the main anterior-posterior axis. This includes the formation of the vertebral axial skeleton. Its organisation begins during early embryonic development with the periodic formation of paired blocks of mesoderm tissue called somites. Here, we review axial patterning of somites, with a focus on studies using amniote model systems – avian and mouse. We summarise the molecular and cellular mechanisms that generate paraxial mesoderm and review how the different anatomical regions of the vertebral column acquire their specific identity and thus shape the body plan. We also discuss the generation of organoids and embryo-like structures from embryonic stem cells, which provide insights regarding axis formation and promise to be useful for disease modelling.

The bony pelvis is an irregular but complete bony ring made up of the right and left hip bones anterolaterally and the sacrococcygeal part of the vertebral column posteriorly. The two hip bones are firmly united anteriorly at the pubic symphysis, and together constitute the pelvic girdle. The pelvic girdle articulates with the femoral heads and thereby connects the vertebral column (axial skeleton) to the two femora (appendicular skeleton). The main functions of the pelvic girdle are to transmit weight from the upper body to the lower limbs during locomotion and while standing, and to support the weight of the upper body when seated or stationary. Another important function of the bony pelvis is to provide attachment for the powerful muscles (e.g. gluteal muscles) that act on the lower limb and those muscles that support the abdominal wall. The bony pelvis also provides ample protection to the many delicate viscera, vessels and nerves that lie within the pelvic cavity. Successful orthopaedic management of disruptions of the bony pelvis and management of associated injuries to intrapelvic viscera require a sound appreciation of the anatomy of the pelvic ring and pelvic cavity.

Extreme body elongation has occurred repeatedly in the evolutionary history of ray-finned fishes. Lengthening of the anterior-posterior body axis relative to depth and width can involve changes in the cranial skeleton and vertebral column, but to what extent is anatomical evolution determined by selective factors and intrinsic constraints that are shared broadly among closely related lineages? In this study, we fit adaptive (Ornstein-Uhlenbeck) evolutionary models to body shape and its anatomical determinants and identified two instances of extreme elongation by divergent anatomical peak shifts in the Blenniiformes, a radiation of small-bodied substrate-associated marine teleost fishes. Species in the genus Xiphasia (hairtail blennies) evolved toward a peak defined by a highly elongated caudal vertebral region but ancestral cranial and precaudal vertebral morphology. In contrast, a clade that includes the genera Chaenopsis and Lucayablennius (pike and arrow blennies) evolved toward a peak with a long slender skull but ancestral axial skeletal anatomy. Neither set of anatomical peak shifts aligns closely with the major axis of anatomical diversification in other blenniiform fishes. These results provide little evidence that ancestral constraints have affected body shape transformation, and instead suggest that extreme elongation arose with distinct shifts in selective factors and development.

Some studies report neurological lesions in patients with genetic skeletal disorders (GSDs). However, none of them describe the frequency of neurological lesions in a large sample of patients or investigate the associations between clinical and/or radiological central nervous system (CNS) injury and clinical, anthropometric and imaging parameters. The project was approved by the institution’s ethics committee (CAAE 49433215.5.0000.0022). In this cross-sectional observational analysis study, 272 patients aged four or more years with clinically and radiologically confirmed GSDs were prospectively included. Genetic testing confirmed the diagnosis in the FGFR3 chondrodysplasias group. All patients underwent blinded and independent clinical, anthropometric and neuroaxis imaging evaluations. Information on the presence of headache, neuropsychomotor development (NPMD), low back pain, joint deformity, ligament laxity and lower limb discrepancy was collected. Imaging abnormalities of the axial skeleton and CNS were investigated by whole spine digital radiography, craniocervical junction CT and brain and spine MRI. The diagnostic criteria for CNS injury were abnormal clinical and/or radiographic examination of the CNS. Brain injury included malacia, encephalopathies and malformation. Spinal cord injury included malacia, hydrosyringomyelia and spinal cord injury without radiographic abnormalities. CNS injury was diagnosed in more than 25% of GSD patients. Spinal cord injury was found in 21.7% of patients, and brain injury was found in 5.9%. The presence of low back pain, os odontoideum and abnormal NPMD remained independently associated with CNS injury in the multivariable analysis. Early identification of these abnormalities may have some role in preventing compressive CNS injury, which is a priority in GSD patients.

Mammaliamorpha comprises the last common ancestor of Tritylodontidae and Mammalia plus all its descendants1. Tritylodontids are nonmammaliaform herbivorous cynodonts that originated in the Late Triassic epoch, diversified in the Jurassic period2–5 and survived into the Early Cretaceous epoch6,7. Eutriconodontans have generally been considered to be an extinct mammalian group, although different views exist8. Here we report a newly discovered tritylodontid and eutriconodontan from the Early Cretaceous Jehol Biota of China. Eutriconodontans are common in this biota9, but it was not previously known to contain tritylodontids. The two distantly related species show convergent features that are adapted for fossorial life, and are the first ‘scratch-diggers’ known from this biota. Both species also show an increased number of presacral vertebrae, relative to the ancestral state in synapsids or mammals10,11, that display meristic and homeotic changes. These fossils shed light on the evolutionary development of the axial skeleton in mammaliamorphs, which has been the focus of numerous studies in vertebrate evolution12–17 and developmental biology18–28. The phenotypes recorded by these fossils indicate that developmental plasticity in somitogenesis and HOX gene expression in the axial skeleton—similar to that observed in extant mammals—was already in place in stem mammaliamorphs. The interaction of these developmental mechanisms with natural selection may have underpinned the diverse phenotypes of body plan that evolved independently in various clades of mammaliamorph. Fossiomanus sinensis and Jueconodon cheni, a newly described Early Cretaceous tritylodontid and eutriconodotan, respectively, show convergence on a fossorial body plan and provide insights into the evolution of the axial skeleton in mammaliamorphs.

To date, 40 cases of placental teratoma and 21 cases of umbilical cord teratoma have been reported in the literature. Such entities are purportedly described as originating from ectopically derived totipotential germ cells forming 1 or more of 3 germ layers, similar to teratomas arising in other sites. These entities have been described as distinct from acardiac twins based on the absence of both an axial skeleton and/or separate umbilical cord attachment. We present a case that would be compatible with placental teratoma according to these criteria. However, DNA genotyping analysis of the "teratoma" and its corresponding normal placental tissue revealed an identical genetic profile at all microsatellite polymorphic loci with exception of one locus demonstrating loss of heterozygosity involving 1 of 2 "teratoma" samples tested. Our finding established that the "teratoma" in fact represented a monozygotic acardiac (amorphous) twin with aberrant division of embryogenesis as a continuum of the monozygotic twinning phenomenon. In summary, this is the first case study of so-called placental teratoma by DNA genotyping investigation. We conclude that the diagnostic term "placental teratoma" should be discouraged unless evidence of monozygotic twining can be ruled out by molecular genotyping.

The postcranial axial skeleton of actinopterygian fishes is typically divided into three regions: (1) an anterior abdominal region, (2) a posterior caudal region and (3) those vertebrae supporting the caudal fin. However, in some actinopterygians, the axial skeleton is more finely subdivided, with up to six morphologically distinctsub-regions recognized. Phylogenetic continuity and homology of structures across these sub-regions have not been investigated in detail, either between or among groups. We examine variation in axial regionalization in saurichthyid fishes, a clade of extinct non-teleostean actinopterygians with highly variable axial skeletal morphology but an otherwise conservative body plan, and compare these findings to other non-teleostean actinopterygians to assess conservation of a regionalized axial skeleton within bony fishes. We document up to eight distinct regions in the vertebral column of Triassic Saurichthys: (1) a postoccipital region, (2) an anterior and (3) a posterior abdominal region, (4) a transitional region spanning the abdominal– caudal boundary, (5) an anterior and (6) a posterior caudal region and (7) preural and (8) ural regions. Based on taphonomical and morphological evidence, the transitional region appears to function in axial stiffening in the area of the median fins, whereas the abdominal region is highly flexible. The degree to which these axial regions are osteologically differentiated is highly variable across Saurichthyidae, implying iterative evolution of differentiation and de-differentiation over relatively short geological timescales. Such variably expressed regionalization was also identified in the outgroup non-teleostean actinopterygians Birgeria and Australosomus. Despite variation in morphological disparity, the regions identified in saurichthyids correlate well with those documented in some teleosts and Paleozoic actinopterygians, suggesting potential deep patterning homology but independent evolution of specific regionalized axial morphologies in response to changing functional demands.

Ankylosing spondylitis (AS) is a rare inflammatory disorder that affects the axial skeleton. It is characterized by inflammation of the joints of the spine with subsequent bridging of the spinal segments resulting in a reduced mobility of the spine and subsequent stiffness of the spine. It can be a severely limiting condition adversely affecting the quality of life of affected individuals. It has been found to be commoner in Caucasians and Asians but rare in blacks in the Americas with few cases reported amongst the African Black population. It is associated with the occurrence of the major histocompatibility complex (MHC) class 1 allele HLA-B27. We present the case of a 44-year-old Nigerian man presenting with a 21-year history of progressively worsening back pain and stiffness associated with hip pain and difficulty in extending his neck. He had no extraspinal manifestations. He was diagnosed with Ankylosing Spondylitis using the modified New York criteria. He was commenced on selective COX2 inhibitors and a physical therapy program aimed at improving the flexibility of the spine and reducing pain. He had a significant improvement in his pain and improved flexibility of his spine in all planes. Ankylosing spondylitis affects the axial skeleton primarily but there may be some extra spinal manifestations such as anterior uveitis, psoriasis and inflammatory bowel disease. Various modalities are employed in its treatment ranging from physical therapy, drugs e.g. Nonsteroidal anti-inflammatory drugs, tumour necrosis factor inbibitors and surgery where complications arise. These have proven effective in improving the symptoms of the disease and quality of life.

Background The process of calcium carbonate biomineralization has arisen multiple times during metazoan evolution. In the phylum Cnidaria, biomineralization has mostly been studied in the subclass Hexacorallia (i.e. stony corals) in comparison to the subclass Octocorallia (i.e. red corals); the two diverged approximately 600 million years ago. The precious Mediterranean red coral, Corallium rubrum, is an octocorallian species, which produces two distinct high-magnesium calcite biominerals, the axial skeleton and the sclerites. In order to gain insight into the red coral biomineralization process and cnidarian biomineralization evolution, we studied the protein repertoire forming the organic matrix (OM) of its two biominerals. Results We combined High-Resolution Mass Spectrometry and transcriptome analysis to study the OM composition of the axial skeleton and the sclerites. We identified a total of 102 OM proteins, 52 are found in the two red coral biominerals with scleritin being the most abundant protein in each fraction. Contrary to reef building corals, the red coral organic matrix possesses a large number of collagen-like proteins. Agrin-like glycoproteins and proteins with sugar-binding domains are also predominant. Twenty-seven and 23 proteins were uniquely assigned to the axial skeleton and the sclerites, respectively. The inferred regulatory function of these OM proteins suggests that the difference between the two biominerals is due to the modeling of the matrix network, rather than the presence of specific structural components. At least one OM component could have been horizontally transferred from prokaryotes early during Octocorallia evolution. Conclusion Our results suggest that calcification of the red coral axial skeleton likely represents a secondary calcification of an ancestral gorgonian horny axis. In addition, the comparison with stony coral skeletomes highlighted the low proportion of similar proteins between the biomineral OMs of hexacorallian and octocorallian corals, suggesting an independent acquisition of calcification in anthozoans.

Somitogenesis is the process by means of which a tissue known as presomitic mesoderm (PSM) is segmented in blocks of cells, called somites, along the anterior-posterior axis of the developing embryo in segmented animals. In vertebrates, somites give rise to axial skeleton, cartilage, tendons, skeletal muscle, and dermis. Somite formation occurs periodically, and this periodicity is driven by a genetic oscillator that operates within PSM cells and is known as the segmentation clock. The correct synchronization of the segmentation clock among PSM cells is essential for somitogenesis to develop normally. When synchronization is disrupted, somites form irregularly and, in consequence, the tissues that originate from them show clear malformations. In this work, based in a model for zebrafish segmentation clock, we investigate by means of a mathematical modeling approach, how PSM-cell synchronization is affected by factors like: the size of PSM-cell networks, the amount of cell-to-cell interactions per PSM cell, the strength of these interactions, and the inherent variability among PSM cells. Interestingly we found that very small PSM-cell networks are unable to synchronize. Moreover, the effect of decreasing the strength of interactions among PSM cells is corrected by increasing the network connectivity-level, and a moderated level of variability among cells can have a positive effect on synchronization, specially in large networks.

Background Long-term stabilization of the cervical spine after extensive multilevel tumor resection is difficult to achieve. The current standard approach of instrumentation combined with allograft or nonvascularized autograft is limited in settings of increased risk of nonunion or delayed union (i.e., prior radiation therapy or poorly vascularized wound beds). Case Description We report the first time to our knowledge that a vascularized fibular free flap has been used to reconstruct the cervical column across 5 vertebral levels, from the craniocervical junction to the lower cervical spine. We describe a transoral approach to the area and compare this method with other reconstructive options. Conclusions Vascularized bone grafting is a viable alternative to achieve lasting stability because of hastened fusion time, limited reliance on osseous remodeling, and incorporation into the axial skeleton with strut strength.

Purpose The prevalence of childhood obesity has increased over past decades with a concomitant increase in metabolic and bariatric surgery (MBS). While MBS in adults is associated with bone loss, only a few studies have examined the effect of MBS on the growing skeleton in adolescents. Methods This mini-review summarizes available data on the effects of the most commonly performed MBS (sleeve gastrectomy and gastric bypass) on bone in adolescents. A literature review was performed using PubMed for English-language articles. Results Dual-energy x-ray absorptiometry (DXA) measures of areal bone mineral density (aBMD) and BMD Z scores decreased following all MBS. Volumetric BMD (vBMD) by quantitative computed tomography (QCT) decreased at the lumbar spine while cortical vBMD of the distal radius and tibia increased over a year following sleeve gastrectomy (total vBMD did not change). Reductions in narrow neck and intertrochanteric cross-sectional area and cortical thickness were observed over this duration, and hip strength estimates were deleteriously impacted. Marrow adipose tissue (MAT) of the lumbar spine increased while MAT of the peripheral skeleton decreased a year following sleeve gastrectomy. The amount of weight loss and reductions in lean and fat mass correlated with bone loss at all sites, and with changes in bone microarchitecture at peripheral sites. Conclusion MBS in adolescents is associated with aBMD reductions, and increases in MAT of the axial skeleton, while sleeve gastrectomy is associated with an increase in cortical vBMD and decrease in MAT of the peripheral skeleton. No reductions have been reported in peripheral strength estimates.

Axial skeletal injury is observed in 25–70% of patients with psoriatic arthritis (PsA). Spondylitis frequently occurs subclinically, which leads to serious structural and functional disorders over time. An update shows that axial skeleton involvement in PsA is characterized by a more severe clinical course: these patients are observed to have a greater severity of peripheral arthritis, enthesitis, and dactylitis, skin and nail psoriasis, a higher CRP level, and worse functional status. In addition, the disease is more severe according to the patients' subjective assessment, as evidenced by questionnaires. Synthetic disease-modifying antirheumatic drugs used to treat peripheral PsA are not recommended for axial injury. When nonsteroidal anti-inflammatory drugs are ineffective, biological drugs (tumor necrosis factor-α inhibitors or interleukin-17A (IL-17A) inhibitors) should be prescribed immediately to patients with psoriatic spondylitis. The paper describes two clinical cases demonstrating the successful use of the IL-17A inhibitor secukinumab (SEC) in patients with axial PsA (axPsA). Given the positive experience with SEC in real clinical practice, it seems reasonable to prescribe it to patients at earlier stages of axPsA.

Gorham’s disease, or vanishing bone disease, is a rare condition of unknown etiology characterized by bone absorption.The disease can affect any part of the skeleton, however the pelvis, humerus, axial skeleton and the mandible are morefrequently involved. The mechanism of bone resorption is unclear, but localized endothelial proliferation of lymphatic vesselsis shown in osteolytic lesions The diagnosis is based on clinical, radiological and histological features after excludingother infectious, inflammatory, endocrine and neoplastic etiological factors. Medical treatment for Gorham’s diseaseincludes anti-osteoclastic medications (bisphosphonates), and alpha-2b interferon, radiation therapy induced sclerosis ofthe proliferating vascular tissue within the bone. Also surgical treatment options are available including resection of thelesion and reconstruction with bone grafts and/or prostheses. We present a case of Gorham’s disease of the right maxillain a 67 years old female affecting the alveolar process, zygoma and the floor of the orbit. The initial clinical manifestationat the onset of the disease was the mobility of the upper right molars, mimicking periodontal disease followed by theworsening of a preexisting diplopia with undefined origin. The patient received a medical treatment with zoledronic acid,vitamin D and calcium carbonate for 12 months which proved to be effective in controlling the progression of the disease.

El género Spalacopus incluye una sola especie, S. cyanus, endémica de la región central del Chile, siendo una de las especies mejor adaptada a la vida subterránea de la familia Octodontidae. Miembro del linaje que consiste en Octodontomys como hermano de Octodon y el clado representado por Spalacopus y Aconaemys. Si bien la morfología externa y cráneo-dentarias en S. cyanus han sido bien estudiadas, su morfología postcraneal es pobremente conocida. Por las peculiaridades de su estilo de vida y locomoción entre los miembros de la familia, es interesante caracterizar detalles de la morfología del esqueleto postcraneal de esta especie e inferir sus aspectos funcionales de la morfología. Se revisaron 29 ejemplares con material de postcráneo disponibles en dos colecciones sistemáticas: Museo de La Plata (MLP), La Plata, Buenos Aires, Argentina y Colección de Mamíferos del Instituto de Ciencias Ambientales y Evolutivas (UACH), Universidad Austral de Chile, Valdivia, Chile. Para la descripción detallada de la morfología de los elementos óseos se dividió al esqueleto en las siguientes regiones: esqueleto axial, cintura escapular y miembros anteriores, y cintura pélvica y miembros posteriores. Las estructuras incluidas en el esqueleto axial fueron descriptas principalmente en sentido cráneo-caudal y en los miembros en sentido próximo-distal. La observación de las estructuras se realizó con las lupas estereoscópicas Leica Wild M3Z y Nikon SMZ 745T, incluyendo fotografías para ilustrar las descripciones. En la morfología postcraneal de S. cyanus se observan características que se consideran altamente conservadas entre los miembros de la familia Octodontidae, pero algunos caracteres son exclusivos de la especie. El esqueleto axial está compuesto por siete vértebras cervicales, 12 ó 13 torácicas, seis o siete lumbares, cuatro sacras, entre 16 y 18 caudales, 12 ó 13 pares de costillas y un esternón compuesto por cinco esternebras. Los elementos óseos de las cinturas pectoral y pélvica como de los miembros anterior y posterior se describen en detalle, excepto los carpos y tarsos debido al mal estado de preservación o ausencia de los mismos. El patrón morfológico que presenta el postcráneo de S. cyanus se ajusta a un plan anatómico típico de especies terrestres y en algunos elementos óseos (húmero y ulna principalmente) se observan características típicamente asociadas con la habilidad excavadora. Los datos generados permitirán a futuro una mejor interpretación de los atributos postcraneales funcionalmente relacionados con los diferentes estilos de vida, evaluar sus estrategias locomotoras, así como también comprender la evolución de estos rasgos en un contexto filogenético. The genus Spalacopus includes only one species, S. cyanus, endemic to central Chile and one of the species best adapted to a subterranean lifetyle in the family Octodontidae. It is a member of the lineage consisting in Octodontomys as a sister clade containing Octodon and of a clade represented by Spalacopus and Aconaemys. Although the external and cranio-dental morphology have been well studied, little is known of the postcranial morphology of S. cyanus. Because of the peculiarities of its lifestyle and locomotion among the members of the family, it is interesting to characterize details of the morphology of the postcranial skeleton of this species and to infer their functional aspects of the morphology. Twenty-nine specimens with postcranial material stored in two collections were studied: Museo de La Plata (MLP), La Plata, Buenos Aires, Argentina and Colección de Mamíferos del Instituto de Ciencias Ambientales y Evolutivas (UACH), Universidad Austral de Chile, Valdivia, Chile. To describe in detail the morphology of the bone elements, the skeleton was divided in the following regions: axial skeleton, scapular girdle and forelimb, and pelvis girdle and hindlimb. The structures included in the axial skeleton were mainly described in cranial-caudal orientation and the limbs in proximal-distal orientation. All structures were observed with stereoscopic microscopes Leica Wild M3Z and Nikon SMZ 745T including pictures to illustrate the descriptions. Highly conservative characteristics among members of the family Octodontidae were observed in the postcranial morphology of S. cyanus, although some characters are exclusive to this species. The axial skeleton has seven cervical vertebrae, 12 or 13 thoracic, six or seven lumbar, four sacral, 16 to 18 caudal vertebrae, 12 or 13 ribs and a sternum with five sternebrae. The elements of the scapular and pelvic girdles as well as forelimbs and hindlimbs are described in detail, except the carpus and tarsus due to their poor state of conservation, or because they not available. The morphological pattern observed in the postcranial skeleton of S. cyanus conforms to a typical anatomical plan for terrestrial species, and some bones (mainly humerus and ulna) present characteristics associated with digging. The information obtained provided will allow a better interpretation of the postcranial attributes, functionally related with different lifestyle, in a future, as well as the evolution of the traits in a phylogenetic context. Fil: Pérez, María Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Conservación de los Murciélagos de Argentina; Argentina Fil: Díaz, María Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Conservación de los Murciélagos de Argentina; Argentina. Fundación Miguel Lillo; Argentina

Juvenile spondyloarthropathy is an umbrella term for a group of childhood rheumatic diseases that can cause chronic arthritis extending to the axial skeleton before the age of 16. Although ankylosing spondylitis has aortic involvement as one of its most important effects, this relationship has not been extensively studied in children with juvenile spondyloarthropathy. Here, a cross-sectional study of the elastic properties of the aorta of 43 patients with juvenile spondyloarthropathy and 19 healthy controls is reported. Aortic stiffness assessed by echocardiography was used to predict the presence of aortitis, supplemented by pulsed-wave tissue Doppler indices. The right ventricular fractional area change was found to be significantly lower in the patients with juvenile spondyloarthropathy than in the healthy controls; aortic strain and distensibility were also significantly lower, and aortic stiffness index β was significantly higher; and the aortic root diameter change was significantly lower. According to HLA-B27 positivity, there was no difference in the stiffness parameters between the two groups. There was a significant correlation between juvenile Ankylosing Spondylitis Disease Activity Index and aortic diameter change, between juvenile Ankylosing Spondylitis Disease Activity Index and aortic stiffness. Thus, juvenile spondyloarthropathy is linked to high aortic stiffness parameters.

Plasmacytoma is a tumor arising from plasma cell, which mainly grows within soft tissue or within axial skeleton, when it is present as a discreet solitary mass it is called as solitary plasmacytoma & it is rare, we report a 46 years male, presented to us with the complaints of painless swelling in the left frontoparietal region which is about 8.6x6.5cm in diameter, Magnetic resonance imaging revealed an extra axial mass in fronto parietal region with overlying bone destruction mimicking meningioma with bony erosion, we did frontoparietal craniectomy and complete resection of tumor with bony margin subsequently cranioplasty was also done, histopathology of which revealed plasmacytoma,after that we did urinary bence jones protein which was negative. Bang. J Neurosurgery 2020; 10(1): 106-110

A new species Melanostigma lazarevi sp. n. is described from the D’Urville Sea (Southern Ocean). This species differs from the other species of the genus Melanostigma in an original combination of the characters, particular, in the structure of the lateral line system on the head (interruption in supratemporal commissure with the loss of medial segments, absence of pores and the presence of two (instead one) segments in the temporal canal), coloration and some meristic characters of the axial skeleton.

A tenosynovial giant cell tumor is a benign proliferative disease, mostly arising from the synovial membrane of tendon sheaths, bursae, and joints. Axial skeleton involvement is very rare, but it is often found in the cervical spine. Spinal tenosynovial giant cell tumors often arise at the facet joints; a completely extra-articular spinal tenosynovial giant cell tumor is rare. We report an extremely rare case of tenosynovial giant cell tumor in the upper cervical spine that extended from the posterior atlanto-occipital membrane rather than the facet joint. Herein, the clinical and radiological findings will be reviewed to better our understanding of the characteristics of spinal tenosynovial giant cell tumors, and to help improve their diagnosis despite their non-typical locations of origin.

Introduction: Chordoma is a rare sarcoma of the axial skeleton. The incidence of this tumor is different between races. To understand the epidemiologic characteristic and due to rarity of this pathology, large number of cases should be evaluated through national data registries. Materials and Methods: All pathologically confirmed cases of chordoma were derived from the Iran National Cancer Registry. Descriptive analysis was performed to extract age-standardized and age-specific incidence rates. Data regarding tumor location and chordoma subtypes were derived and analyzed. Results: One hundred twenty-two cases of chordoma including 80 male and 42 female were identified. One hundred seven cases of nonotherwise specified chordoma, 14 chondroid chordoma, and one dedifferentiated chordoma were detected. The age-standardized incidence rate (ASIR) of chordoma was 0.28. Chordoma of the sacrum composed 67.2% of cases. The mean survival time was 4.5 years. Conclusion: Epidemiology characteristic of chordoma in Iran is similar to other studies; however, the total ASIR was lower and the incidence in sacrum is nearly twice respect to the mobile spine. While men affected by sacral chordoma in relatively older age, the female patients had higher mean age in case of mobile spine involvement. The survival rate of chordoma is significantly lower in comparison with other studies.

Background Xanthomas are benign lipomatous deposits that can be found systemically in various tissues including bones. Their presence in the skull remains a rare entity. Despite their benign characteristics, imaging modalities are often unable to distinguish them from malignant lesions. This leads to a diagnostic dilemma in patients with underlying malignancy. This case report highlights such a case where clinical history of prostate cancer and image findings were concordant with that of metastatic deposit in the parietal skull region. Case Description This 65-year-old gentleman was diagnosed with prostatic adenocarcinoma. During systemic workup for his tumor, he was found to have a right parietal skull lesion. Magnetic resonance imaging of the brain, as well as a bone scan, were consistent with that of a metastatic deposit. As treatment would be drastically affected by the diagnosis, an excision biopsy was performed. The histology was consistent with that of a bone xanthoma. Conclusions Xanthomas are benign lesions that can be seen deposited in appendicular and axial skeleton. Skull lesions are rare with most case descriptions focusing on their presence in the frontoorbital regions and mandible and temporal bone. They usually have a benign course but may present with symptoms due to localized mass effect. Surgical intervention and histologic diagnosis may still be required in these lesions due to their lack of imaging characteristics that confirm their diagnosis through noninvasive methods.

Background Solitary plasmacytoma of bone has a predilection for the axial skeleton, most commonly affecting the thoracic spine. We report the case of a patient who presented with acute on chronic back pain and developed severe neurologic deficits within several hours of admission secondary to a pathologic fracture of L1. Methods The patient underwent an urgent magnetic resonance imaging scan followed by T12 to L2 posterior decompression and T11 to L3 posterior instrumented stabilization. Subsequent histopathologic examination of specimens taken at the time of surgery found this to be secondary to a plasmacytoma affecting the lumbar spine. Results At follow-up, recovery has been rapid and extensive, with the patient remaining under hematologic review because of the risk for developing multiple myeloma. Conclusions The unique features of this case relate to the location of the plasmacytoma and the neurologic signs; to our knowledge this is the first reported case in the literature of paraplegia secondary to a lumbar spine plasmacytoma.

Fetiform teratoma is a rare highly developed mature teratoma with organoid differentiation although it is not as developed as fetus in fetus which is the only differential diagnosis of this entity. It should be distinguished from the fetus in fetu by absence of the axial skeleton. A 6-month-old baby girl with a lumbar lump underwent ultrasonography, CT-scan and surgery. On imaging, a sac-like structure was noted in the lumbar region containing bowel segments, mesentery-like structure and few lymph nodes. The patient underwent surgery. The entire sac with its content were completely excised. Very few cases of fetiform teratoma have been reported in English literature however to the best of our knowledge lumbar fetiform teratoma has not been reported up to now. Highly developed teratoma is a diagnostic dilemma as it resembles fetus in fetu. The absence of a spinal axis differentiates this entity from the fetus in fetu.

BACKGROUND This study aimed to evaluate the long-term clinical and radiologic follow-up results of eosinophilic granulomas (EGs) of the axial and appendicular skeleton managed with biopsy alone. METHODS Fifty-five patients with unifocal osseous EGs of the axial and appendicular skeleton were followed after biopsy. Patients were divided into 2 groups on the basis of localization of the lesions. In group 1, there were 32 (58.2%) children with extremity long bone involvement: femur, tibia, humerus, ulna, and radius. Group 2 included 23 (41.8%) patients with lesions located in other appendicular and axial skeleton bones: pelvis, scapula, clavicle, lumbar, and thoracic vertebrae. After confirming the diagnosis by a closed biopsy, no further surgical intervention was performed. Clinical recovery included regression of the localized symptoms, mainly pain resolution. Functional improvement was assessed by Musculoskeletal Tumor Society (MSTS) scoring. Radiologic healing was defined as ossification of the entire lesion with cortical thickening in long and flat bones, and restoration of vertebral body height in the spine. Complications, including local recurrence, were determined. RESULTS The patients comprised 28 boys and 27 girls with an average age of 9.2 years (range, 3 to 16 y). The average follow-up was 76 months (range, 28 to 132 mo). The median time from biopsy to clinical recovery was 17 days [95% confidence interval (CI), 13.3-20.6] and 36 days (95% Cl, 32.8-39.1) in group 1 and group 2, respectively. MSTS scores increased progressively till the end of 12 months in both groups. The median time from biopsy to radiologic healing was 16 months (95% CI, 11.5-20.4) and 42 months (95% Cl, 39.3-44.6) in group 1 and group 2, respectively. Both clinical recovery (P=0.021) and radiologic healing (P=0.009) were significantly faster in group 1 compared with group 2. No major complication was seen after biopsy. All lesions regressed without a local recurrence. CONCLUSIONS Unifocal osseous EGs have spontaneous healing potential and confirming the diagnosis by biopsy is enough to obtain good clinical and radiologic results without any additional surgical intervention. TYPE OF STUDY This was a therapeutic study. LEVEL OF EVIDENCE Level IV.

The age-related carcass-morphology and composition changes and the growth and development patterns of the axial and peripheral skeleton systems and the bones composing them in the Simmental and crossbred young beef bulls have been studied. In order to carry out the survey, the young bulls were divided into three groups of 15 animals each. The first (control) group included the purebred Simmental young bulls. The second (experimental) group was formed of the halfbred and crossbred young stock produced by crossbreeding between the Simmental cows and the Simmental beef bulls of German selection. The third (experimental) group was composed of the crosses of Simmental cows with Charolais bulls. The Charolais crosses had more energy for growth. Thus, their liveweights comprised 431.9, 523.4, and 620.6 kg at the ages of 12, 15, and 18 months, respectively, which were 7.8, 7.5, and 10.2% more than that in their peers of the maternal breed. The crossbred young stock in both groups was distinct for carcass morphology and composition, reaching a more advanced level of the carcass flesh-coverage mass in all the age intervals when compared that to the purebred Simmentals. The age-related changes in the absolute and relative masses of the young-bull carcass bones are caused by different intensities specific to bone growth in the axial and peripheral skeleton systems. For instance, the intensity of bone growth in the axial skeleton system tended to increase in the postnatal period, while the bone growth rates of the peripheral skeleton system decreased. Irregularity in developing the indicated skeleton systems is caused by different intensities specific to growth of certain bones and their complexes. The highest growth rate is usually typical for ribs and the vertebral column, while the slowest growth rate is most common for extremitas thoracica and extremas pelvina. The bone growth rates for the limb proximal structures generally exceed that for the distal bone structures. The age-related differences in the growth rates of certain skeleton structures can cause some changes in ratios between the linear body measurements of the young bulls.

The larval development of Chirolophis japonicus and Ch. saitone from the yolk-sac stage to the settlement on the bottom is described from waters of Peter the Great Bay, Sea of Japan. The pattern of distribution of melanin pigmentation over the body of larvae in these Chirolophis species is formalized for the first time. It consists of six rows, the aggregation on the top of head, and several single melanophores. Despite the similarity between the species, each of them has its specific features that are manifested mainly as a different number of axial skeleton elements (total number of vertebrae and number of rays in the dorsal and anal fins). A conclusion is made that a reliable diagnostic character to identify larvae of Ch. japonicus and Ch. saitone within the period of their development from hatching to settlement can be the number of melanophores at the base of the anal fin rays.

Spondyloarthritis (SpA) is a chronic inflammatory condition that can have a predominately peripheral or axial presentation. Axial SpA (axSpA) affects the axial skeleton with either radiographic (r-axSpA) or nonradiographic (nr-axSpA) changes. Radiographic changes are a late disease feature and earlier disease stages can be identified by incorporating other imaging methods. The diagnosis of axSpA is a clinical diagnosis and classification criteria are not aimed to be diagnostic tools. The split between r-axSpA and nr-axSpA is artificial and we should move toward the unifying concept of axSpA. Our understanding of genetics, biomarkers, and immunopathophenotypes will drive further refinement of classification criteria.

Aneurysmal bone cyst (ABC) and telangiectatic osteosarcoma (TOS) share several clinical and imaging features, including young presentation, long bone involvement, lytic appearance on radiography and fluid-fluid levels on MRI. Therefore, they may be difficult to differentiate. The aim of this study is to identify clinical, radiological and MRI features which aid differentiation of the two lesions. Retrospective review of all histologically confirmed ABC and TOS over an 11-year period. Data recorded include age at presentation, sex, skeletal location and various radiographic and MRI features. This retrospective study included 183 patients, 92 males and 91 females. Mean age at presentation of 18.4 years (range 1–70 years); 152 cases of ABC and 31 TOS. No significant difference between age and sex. TOS was significantly less likely to involve the axial skeleton; no difference related to location within the bone. Radiographic findings significantly favouring ABC included a less aggressive pattern of bone destruction, a purely lytic appearance, an expanded but intact cortex, no periosteal response and no soft tissue mass. MRI features significantly favouring ABC included smaller tumour size (maximum mean dimension 46 mm compared to 95 mm for TOS), absence of soft tissue mass, > 2/3 of the lesion filled with fluid levels and thin septal enhancement following contrast. Several radiographic and MRI features aid in the differentiation between ABC and TOS. Lesions with a geographic Type 1A or IB pattern of bone destruction which are completely filled with FFLs on MRI can confidently be diagnosed as ABC.