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The International Journal of... 2021The axial skeleton of the has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have... (Review)
Review
The axial skeleton of the has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have emerged as a highly specialized anatomical adaptation to its locomotor jumping pattern. The development programs that direct the vertebral morphogenesis of the anurans are poorly described and the molecular bases that have caused their pattern to differ from other tetrapods are completely unknown. In this work, we review the ontogeny of the spinal column of the anurans and explore the genetic mechanisms that could explain the morphological difference and the maintenance of the body plan during evolution. Here, we propose that the absence of caudal osseous elements, as a consequence of the inability of sclerotomes to form cartilaginous condensations in frogs, could be due to changes in both pattern and expression levels of , , and genes along the anteroposterior axis. The anteriorised expression of the genes together with the reduction in the expression levels of , and in the posterior somites could explain, at least partly, the loss of caudal vertebrae in the anurans during evolution.
Topics: Animals; Anura; Bone and Bones; Gene Expression Regulation, Developmental; Genes, Homeobox; Skeleton; Somites
PubMed: 32930370
DOI: 10.1387/ijdb.200230ss -
Current Topics in Developmental Biology 2019Development of the axial skeleton is a complex, stepwise process that relies on intricate signaling and coordinated cellular differentiation. Disruptions to this process... (Review)
Review
Development of the axial skeleton is a complex, stepwise process that relies on intricate signaling and coordinated cellular differentiation. Disruptions to this process can result in a myriad of skeletal malformations that range in severity. The notochord and the sclerotome are embryonic tissues that give rise to the major components of the intervertebral discs and the vertebral bodies of the spinal column. Through a number of mouse models and characterization of congenital abnormalities in human patients, various growth factors, transcription factors, and other signaling proteins have been demonstrated to have critical roles in the development of the axial skeleton. Balance between opposing growth factors as well as other environmental cues allows for cell fate specification and divergence of tissue types during development. Furthermore, characterization of progenitor cells for specific cell lineages has furthered the understanding of specific spatiotemporal cues that cells need in order to initiate and complete development of distinct tissues. Identifying specific marker genes that can distinguish between the various embryonic and mature cell types is also of importance. Clinically, understanding developmental clues can aid in the generation of therapeutics for musculoskeletal disease through the process of developmental engineering. Studies into potential stem cell therapies are based on knowledge of the normal processes that occur in the embryo, which can then be applied to stepwise tissue engineering strategies.
Topics: Animals; Bone and Bones; Humans; Intervertebral Disc; Nucleus Pulposus; Signal Transduction; Somites
PubMed: 30902259
DOI: 10.1016/bs.ctdb.2018.11.018 -
Seminars in Cell & Developmental Biology Jul 2022A 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... (Review)
Review
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.
Topics: Animals; Body Patterning; Embryonic Development; Gene Expression Regulation, Developmental; Mesoderm; Mice; Somites; Spine; Vertebrates
PubMed: 34690064
DOI: 10.1016/j.semcdb.2021.10.003 -
Seminars in Musculoskeletal Radiology Feb 2023Magnetic resonance imaging (MRI) of the axial skeleton, spine, and sacroiliac (SI) joints is critical for the early detection and follow-up of inflammatory rheumatologic...
Magnetic resonance imaging (MRI) of the axial skeleton, spine, and sacroiliac (SI) joints is critical for the early detection and follow-up of inflammatory rheumatologic disorders such as axial spondyloarthritis, rheumatoid arthritis, and SAPHO/CRMO (synovitis, acne, pustulosis, hyperostosis, and osteitis/chronic recurrent multifocal osteomyelitis). To offer a valuable report to the referring physician, disease-specific knowledge is essential. Certain MRI parameters can help the radiologist provide an early diagnosis and lead to effective treatment. Awareness of these hallmarks may help avoid misdiagnosis and unnecessary biopsies. A bone marrow edema-like signal plays an important role in reports but is not disease specific. Age, sex, and history should be considered in interpreting MRI to prevent overdiagnosis of rheumatologic disease. Differential diagnoses-degenerative disk disease, infection, and crystal arthropathy-are addressed here. Whole-body MRI may be helpful in diagnosing SAPHO/CRMO.
Topics: Humans; Bone Marrow; Osteomyelitis; Arthritis, Rheumatoid; Spine
PubMed: 36868247
DOI: 10.1055/s-0043-1761496 -
Proceedings of the National Academy of... Apr 2024The axial columns of the earliest limbed vertebrates show distinct patterns of regionalization as compared to early tetrapodomorphs. Included among their novel features...
The axial columns of the earliest limbed vertebrates show distinct patterns of regionalization as compared to early tetrapodomorphs. Included among their novel features are sacral ribs, which provide linkage between the vertebral column and pelvis, contributing to body support and propulsion by the hindlimb. Data on the axial skeletons of the closest relatives of limbed vertebrates are sparce, with key features of specimens potentially covered by matrix. Therefore, it is unclear in what sequence and under what functional context specializations in the axial skeletons of tetrapods arose. Here, we describe the axial skeleton of the elpistostegalian and show that transformations to the axial column for head mobility, body support, and pelvic fin buttressing evolved in finned vertebrates prior to the origin of limbs. No atlas-axis complex is observed; however, an independent basioccipital-exoccipital complex suggests increased mobility at the occipital vertebral junction. While the construction of vertebrae in is similar to early tetrapodomorphs, its ribs possess a specialized sacral domain. Sacral ribs are expanded and ventrally curved, indicating likely attachment to the expanded iliac blade of the pelvis by ligamentous connection. Thus, the origin of novel rib types preceded major alterations to trunk vertebrae, and linkage between pelvic fins and axial column preceded the origin of limbs. These data reveal an unexpected combination of post-cranial skeletal characters, informing hypotheses of body posture and movement in the closest relatives of limbed vertebrates.
Topics: Animals; Biological Evolution; Fossils; Vertebrates; Bone and Bones; Lower Extremity
PubMed: 38564638
DOI: 10.1073/pnas.2316106121 -
Annals of the Royal College of Surgeons... May 2016A chordoma is a slow growing malignant tumour of notochordal origin. A tumour with histological features that are identical to those of a chordoma may arise outside the...
INTRODUCTION
A chordoma is a slow growing malignant tumour of notochordal origin. A tumour with histological features that are identical to those of a chordoma may arise outside the axial skeleton. To date, there is little in the literature documenting their clinical course.
METHODS
Our large orthopaedic oncology database was used to document the clinical course of extra-axial chordoma.
RESULTS
Over a 30-year period, 131 patients diagnosed with a chordoma were treated at our unit. Only three (2.3%) of these cases were extra-axial chordomas: one in the femur, one in the ulna and one in the proximal fibula. All underwent surgical resection.
CONCLUSIONS
In view of the rarity of this tumour and the difficulty in confirming its diagnosis, we suggest that any suspected case is discussed with a specialist sarcoma multidisciplinary team so that the correct diagnosis can be achieved and treatment tailored accordingly.
Topics: Adult; Aged; Bone Neoplasms; Chordoma; Fibula; Humans; Male; Middle Aged; Radiography; Ulna
PubMed: 27087325
DOI: 10.1308/rcsann.2016.0138 -
Developmental Dynamics : An Official... Sep 2007The axial skeleton in all vertebrates is composed of similar components that extend from anterior to posterior along the body axis: the occipital skull bones and... (Review)
Review
The axial skeleton in all vertebrates is composed of similar components that extend from anterior to posterior along the body axis: the occipital skull bones and cervical, thoracic, lumbar, sacral, and caudal vertebrae. Despite significant changes in the number and size of these elements during evolution, the basic character of these anatomical elements, as well as the order in which they appear in vertebrate skeletons, have remained remarkably similar. Through extensive expression analyses, classic morphological perturbation experiments in chicken and targeted loss-of-function analyses in mice, Hox genes have proven to be critical regulators in the establishment of axial skeleton morphology. The convergence of these studies to date allows an emerging understanding of Hox gene function in patterning the vertebrate axial skeleton. This review summarizes genetic and embryologic findings regarding the role of Hox genes in establishing axial morphology and how these combined results impact our current understanding of the vertebrate Hox code.
Topics: Animals; Body Patterning; Bone Development; Bone and Bones; Cell Lineage; Developmental Biology; Drosophila; Genetics; Homeodomain Proteins; Humans; Mesoderm; Mice; Models, Biological; Somites; Vertebrates
PubMed: 17685480
DOI: 10.1002/dvdy.21286 -
Radiographics : a Review Publication of... 2020The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial... (Review)
Review
The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.
Topics: Acromioclavicular Joint; Biomechanical Phenomena; Humans; Joint Diseases
PubMed: 32762593
DOI: 10.1148/rg.2020200039 -
The Israel Medical Association Journal... Nov 2017Axial spondyloarthritis (axSpA) covers the stage of non-radiographic axial spondyloarthritis (nr-axSpA) and classic ankylosing spondylitis. The pathognomonic findings of... (Review)
Review
Axial spondyloarthritis (axSpA) covers the stage of non-radiographic axial spondyloarthritis (nr-axSpA) and classic ankylosing spondylitis. The pathognomonic findings of axSpA are mainly inflammatory and osteoproliferative changes in the sacroiliac joints (SIJ) and the spine. Various imaging techniques are being used in daily practice for assessment of disease-specific changes, such as periarticular bone marrow edema, erosions, sclerosis, fat metaplasia and ankylosis in the SIJ or spondylitis, spondylodiscitis, facet joint involvement, or syndesmophytes in the spine of patients with axSpA. Conventional radiographs are still considered the gold standard for assessment of structural changes, while the method of for detection of inflammatory changes is magnetic resonance imaging (MRI). A result for an MRI in the SIJ is considered positive for axSpA when more than one lesion is present on one MRI slice, If there is one lesion only, this should be present on at least two consecutive slices. For the spine, inflammatory lesions should preferably be located in the corner of the vertebral bodies, while occurrence of spondylitis in three or more vertebral corners is considered highly suggestive of axSpA. This review gives a detailed overview about the benefits and limitations of all available imaging techniques in patients with axSpA, explains the usage of imaging techniques in the context of diagnosis and differential diagnosis of the disease, and reports on the potential future trends in the area of imaging of the axial skeleton in patients who are suspicious for this diagnosis.
Topics: Diagnosis, Differential; Humans; Magnetic Resonance Imaging; Radiography; Reproducibility of Results; Sacroiliac Joint; Spine; Spondylarthritis
PubMed: 29185288
DOI: No ID Found -
PeerJ 2023is an abelisaurid theropod from the Anacleto Formation (lower Campanian, Upper Cretaceous) of Patagonia, Argentina. The holotype of includes cranial material, axial...
is an abelisaurid theropod from the Anacleto Formation (lower Campanian, Upper Cretaceous) of Patagonia, Argentina. The holotype of includes cranial material, axial elements, and almost complete fore- and hind limbs. Here we present a detailed description of the axial skeleton of this taxon, along with some paleobiological and phylogenetic inferences. The presacral elements are somewhat fragmentary, although these show features shared with other abelisaurids. The caudal series, to date the most complete among brachyrostran abelisaurids, shows several autapomorphic features including the presence of pneumatic recesses on the dorsal surface of the anterior caudal neural arches, a tubercle lateral to the prezygapophysis of mid caudal vertebrae, a marked protuberance on the lateral rim of the transverse process of the caudal vertebrae, and the presence of a small ligamentous scar near the anterior edge of the dorsal surface in the anteriormost caudal transverse process. The detailed study of the axial skeleton of has also allowed us to identify characters that could be useful for future studies attempting to resolve the internal phylogenetic relationships of Abelisauridae. Computed tomography scans of some caudal vertebrae show pneumatic traits in neural arches and centra, and thus the first reported case for an abelisaurid taxon. Moreover, some osteological correlates of soft tissues present in and other abelisaurids, especially derived brachyrostrans, underscore a previously proposed increase in axial rigidity within Abelisauridae.
Topics: Animals; Phylogeny; Osteology; Dinosaurs; Skull; Tooth
PubMed: 38025666
DOI: 10.7717/peerj.16236