Search results for "Cervical atlas"
showing 10 items of 13 documents
Krapina atlases suggest a high prevalence of anatomical variations in the first cervical vertebra of Neanderthals
2020
The first cervical vertebra, atlas, and its anatomical variants have been widely studied in Homo sapiens. However, in Neanderthals, the presence of anatomical variants of the atlas has been very little studied until very recently. Only the Neanderthal group from the El Sidrón site (Spain) has been analysed with regard to the anatomical variants of the atlas. A high prevalence of anatomical variants has been described in this sample, which points to low genetic diversity in this Neanderthal group. Even so, the high prevalence of anatomical variations detected in El Sidrón Neanderthal atlases needs to be confirmed by analysing more Neanderthal remains. In this context, we analysed the possibl…
Double Retrotransverse Foramen of Atlas (C1)
2018
Background The retrotransverse foramen is a nonmetric variant of C1 that consists of an abnormal accessory foramen on the posterior root of the transverse process. Case Description During a study on the prevalence of the retrotransverse foramen in 150 dry C1 vertebrae, we observed an exceptional C1 (0.67%) with a right double retrotransverse foramen of the 14 C1 vertebrae (9.3%). This has not been reported previously in the literature. No osteogenic reaction and no degenerative signs were observed in this C1 with the double retrotransverse foramen. Conclusions Neurosurgeons should be aware of the possible presence of the “conventional” retrotransverse foramen and the “exceptional” double re…
Craniovertebral Junction Transanasal and Transoral Approaches: Reconstruct the Surgical Pathways with Soft or Hard Tissue Endocopic Lines? This Is th…
2017
A variety of pathological conditions may affect the clivus and the craniovertebral junction (CVJ). These include congenital disorders, chronic inflammation, neoplasms, infections, and posttraumatic conditions that could all result in CVJ compression and myelopathy Endoscopic-assisted procedures have been further developed for CVJ decompression and they have now become conventional approaches. The aims of the present study were: (1) to compare “radiological” and “surgical” nasoaxial lines (NAxLs); (2) to introduce an analogous radiological line as a predictor of the superior extension of the transoral approach (palatine inferior dental arch line (PIA); (3) to compare the “radiological” nasop…
The Decreasing Prevalence of the Arcuate Foramen
2018
[Background]: The arcuate foramen (AF), or ponticulus posticus, is an anatomic variant of the first cervical vertebra that consists of a complete or partial osseous bridge over the groove for the vertebral artery and extends from the posterior aspect of the superior articular facet to the superior lateral border of the posterior arch. The AF has been associated with clinical symptoms, such as headache, migraine, neck pain, shoulder pain, arm pain, and vertebral artery dissection. We aimed to test whether the prevalence of the AF has decreased in the modern human population over the past centuries as a result of reduction in inbreeding and endogamy.
Shape change in the atlas with congenital midline non-union of its posterior arch: a morphometric geometric study.
2017
Background Context The congenital midline non-union of the posterior arch of the atlas is a developmental variant present at a frequency ranging from 0.7% to 3.9%. Most of the reported cases correspond to incidental findings during routine medical examination. In cases of posterior non-union, hypertrophy of the anterior arch and cortical bone thickening of the posterior arches have been observed and interpreted as adaptive responses of the atlas to increased mechanical stress. Purpose We sought to determine if the congenital non-union of the posterior arch results in a change in the shape of the atlas. Study Design/Setting This study is an analysis of the first cervical vertebrae from osteo…
The Retrotransverse Foramen of the Atlas Is not a Modern Anatomic Variation
2019
Background The retrotransverse foramen (RTF) is a nonmetric variant of the atlas vertebra that consists of an abnormal accessory foramen located on the posterior root of the transverse process and it extends from the posterior root of the transverse process to the root of the posterior arch. Its presence has been related to regional variations of the venous circulation. It is currently unknown whether the RTF is a modern or an ancient anatomic variation. Case Description We analyzed the skeletal remains from the late-ancient Roman necropolis (II-VI centuries ad ) of La Boatella (Valencia, Spain) and we found a well-preserved individual skeleton that presented with a left retrotransverse for…
Prevalence of anatomic variations of the atlas vertebra
2018
Abstract BACKGROUND CONTEXT The retrotransverse foramen (RTF), arcuate foramen (AF), unclosed transverse foramen (UTF) and posterior atlas arch defects (PAAD) are anatomic variations of the atlas vertebra that surgeons must be aware of before spine surgery is performed. PURPOSE To analyze the prevalence of the AF, RTF, UTF, and PAAD. STUDY DESIGN Ex-vivo anatomical study. PATIENT SAMPLE Two hundred eighteen atlas vertebrae obtained from 100 Caucasian subjects and 118 sub-Saharan African subjects (48 Sotho subjects, 35 Xhosa subjects and 35 Zulu subjects). METHODS We studied 218 atlas vertebrae from skeletons of the Raymond A. Dart Collection in order to analyze the prevalence of AF, RTF, UT…
Atlases with Arcuate Foramen Present Cortical Bone Thickening That May Contribute to Lower Fracture Risk.
2018
To date, no information about the cortical bone microstructural properties in atlas vertebrae with arcuate foramen has been reported. As a result, we aimed to test in an experimental model if there is a cortical bone thickening in an atlas vertebra which has an arcuate foramen that may play a protective role against bone fracture.We analyzed by means of micro-computed tomography the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry atlas vertebrae with arcuate foramen and without arcuate foramen. We also reviewed a case series of 31 posterior atlas arch fractures to correlate the possible presence in t…
Cortical bone thickening in Type A posterior atlas arch defects: experimental report.
2017
Abstract Background Context To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. Purpose To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. Study Design Micro-computed tomography (CT) study on cadaveric atlas vertebrae. Methods We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. Results The micro-CT study revealed significant differences in cortica…
Difficulties in distinguishing between an atlas fracture and a congenital posterior atlas arch defect in postmortem analysis.
2013
We found one atlas from a sample of 148 skeletons (0.67%) that presented different anatomical variations which made it difficult to determine whether the vertebra had an atlas fracture, an unusual Type B posterior atlas arch defect, or a combination of both. We carried out a stereomicroscopy, radiographic, and computerized tomography scan study that revealed that the dry atlas we found presented a very uncommon congenital Type B posterior atlas arch defect, simulating a fracture. In short, the present paper has revealed that differentiating Type B posterior atlas arch defects from fractures in post-mortem dry vertebrae is more difficult than expected. Thus we believe that it can be easier t…