Differentiation and classification of thoracolumbar transitional vertebrae

The literature states that transitional vertebrae at any junction are characterized by features retained from two adjacent regions in the vertebral column. Currently, there is no published literature available that describes the prevalence or morphology of thoracolumbar transitional vertebrae (TLTV). The aim of this study was to identify the qualitative characteristics of transitional vertebrae at the thoracolumbar junction and establish a technique to differentiate the various subtypes that may be found. A selection of vertebral columns from skeletal remains (n = 35) were evaluated in this study. Vertebrae were taken based on features that are atypical for vertebrae in each relative region. The transitional vertebrae were qualitatively identified based on overlapping thoracic and lumbar features of vertebrae at the thoracolumbar junction. The following general overlapping characteristics were observed: aplasia or hypoplasia of the transverse process, irregular orientation on the superior articular process and atypical mammillary bodies. The results show that the most frequent location of the transitional vertebrae was in the thoracic region (f = 23). The second most frequent location was in the lumbar region (f = 10). In two specimens of the selection (f = 2), an additional 13th thoracic vertebra was present which functioned as a transitional vertebra. This study concluded that one can accurately identify the characteristics of transitional vertebrae at the thoracolumbar junction. In addition, the various subtypes can be differentiated according to the region in the vertebral column the vertebra is located in and the relative number of vertebral segments in the adjacent regions of the vertebral column. This provides a qualitative tool for researchers to differentiate the transitional vertebrae from distinctly different typical thoracic or lumbar vertebrae at the thoracolumbar junction.     

The musculature of the mouse tail is characterized by metameric arrangements of bicipital muscles

This is the first report, to our knowledge, of the full characterization of the musculature of the mouse tail. Bicipital muscles form a major part of the tail musculature. The tail tendons originate with fusiform muscle from the dorsal and ventral lumbo-sacro-coxal regions and are inserted into the coccygeal vertebrae (extrinsic muscles of the tail). Each coccygeal vertebra has short muscles that terminate on the adjacent vertebrae (intrinsic muscles of the tail). The short muscle and its corresponding tail tendon are joined, thereby forming a bicipital muscle that is inserted into the coccygeal process. A geographical correspondence is strictly maintained between the origin of the tendon in the lumbo-sacro-coxal region and the insertion of the bicipital muscle in the coccygeal vertebrae. In other words, the organization of the tail musculature is based upon repetitions of fusion between the extrinsic and intrinsic muscles at each coccygeal vertebral level. This design is referred to as the metameric arrangement of the bicipital muscles. The organization, arrangement and function of muscles in the tail have features in common with those muscles in the digits of the human extremities.     

Reinterpretation of tuberculate cervical vertebrae of Eocene birds as an exceptional anti-predator adaptation against the mammalian craniocervical killing bite

We report avian cervical vertebrae from the Quercy fissure fillings in France, which are densely covered with villi-like tubercles. Two of these vertebrae stem from a late Eocene site, another lacks exact stratigraphic data. Similar cervical vertebrae occur in avian species from Eocene fossils sites in Germany and the United Kingdom, but the new fossils are the only three-dimensionally preserved vertebrae with pronounced surface sculpturing. So far, the evolutionary significance of this highly bizarre morphology, which is unknown from extant birds, remained elusive, and even a pathological origin was considered. We note the occurrence of similar structures on the skull of the extant African rodent Lophiomys and detail that the tubercles represent true osteological features and characterize a distinctive clade of Eocene birds (Perplexicervicidae). Micro-computed tomography (μCT) shows the tubercles to be associated with osteosclerosis of the cervical vertebrae, which have a very thick cortex and much fewer trabecles and pneumatic spaces than the cervicals of most extant birds aside from some specialized divers. This unusual morphology is likely to have served for strengthening the vertebral spine in the neck region, and we hypothesize that it represents an anti-predator adaptation against the craniocervical killing bite (“neck bite”) that evolved in some groups of mammalian predators. Tuberculate vertebrae are only known from the Eocene of Central Europe, which featured a low predation pressure on birds during that geological epoch, as is evidenced by high numbers of flightless avian species. Strengthening of the cranialmost neck vertebrae would have mitigated attacks by smaller predators with weak bite forces, and we interpret these vertebral specializations as the first evidence of “internal bony armor” in birds.     

Malformed vertebrae: a new mutant with the "wirbel-rippen syndrom" in the mouse.

A new skeletal mutant in the house mouse, "malformed vertebrae" (MV), is described. It is semidominant. The skeletal malformations can be traced back to disturbed somite formation.     

The metamorphic fate of supernumerary caudal vertebrae in South Asian litter frogs (Anura: Megophryidae)

Tadpoles of the Megophryidae, a South Asian family of litter frogs, are unique among anurans by virtue of their expanded caudal skeletons, which include supernumerary vertebral centra. The number of these vertebrae varies widely within the family, with tadpoles of Leptobrachella having as many as 30 and Leptolalax only five. Vertebral morphology is also quite variable, ranging from complete, perichordal centra to fragmentary ossifications. This variation in the caudal osteology of larval megophryids, however, is not manifested in the adult morphology. Post-metamorphic litter frogs have a typical anuran axial skeleton, invariably comprising eight presacral vertebrae, a single sacral vertebra and, postsacrally, the urostyle. To resolve this incongruity between life phases and to determine the precise metamorphic fate of supernumerary caudal vertebrae in megophryids, we examined metamorphic specimens from the genera Leptobrachella, Leptolalax, Ophryophryne and Megophrys. In all four, the caudal larval skeleton undergoes massive reduction, leaving only the coccyx and hypochord untouched. Caudal centra are apparently degraded by osteoclasts, which have not previously been implicated in vertebral remodelling during anuran metamorphosis. In Megophrys and Ophryophryne metamorphs, presacral centra also undergo resorption, consistent with an epichordal mode of centrum formation. The conservation of megophryid adult axial osteology in the face of extensive larval skeletal diversity reveals the role of metamorphosis in constraining anuran morphology.     

起床过程中腰椎应力动力学响应

目的揭示起床过程中腰椎间盘的应力响应特征。方法根据实验数据,建立并验证考虑材料非线性和各向异性属性的全腰椎有限元模型,在此基础上模拟并计算人体从仰卧、起身、左转到坐在床沿完整过程中腰椎主要结构的应力分布和动态变化情况。结果起床过程中腰椎间盘纤维环、髓核及终板的应力大小和分布不断变化,各节段的应力集中在背侧,L4~5上最大,应力峰值出现在当躯干从仰卧起转过35°~62°之时,分别是坐稳时的3倍、仰卧时的17倍。结论 L4~5椎间盘后侧是损伤和退变高发区,在日常活动中实际承受的应力可能要比以往按静态测算的应力更高,影响范围也更大。动力学模拟能更全面深入地了解腰椎间盘的负载特点,为防治相关腰椎疾病提供科学依据。     

胎儿标本胸12椎体水平椎管发育的CT影像研究

目的 CT影像测量胎儿标本胸12椎体(T₁₂)水平正常椎管的形态、大小,并分析其随胎龄增长的发育趋势。方法 利用64排螺旋CT对30例23～40孕周脊柱发育正常的胎儿标本进行扫描,并以T₁₂椎体中份水平为中心进行3D重建,在T₁₂椎体中份水平横断面图像上观察T₁₂椎管的正常形态,使用Image J软件测量椎管的前后径、左右径和面积,计算出各胎龄所测径线的平均值,并对所测数据和胎龄作回归分析,分析其随胎龄增长的发育趋势。结果 T₁₂水平椎管可以清晰显示,呈类圆形,并随胎龄逐渐增大,其前后径、左右径及面积均随胎龄呈线性增长,线性回归方程分别为:＾Y_{椎管前后径}(mm)=0.126+0.26×X_胎龄(周),R²=0.857, P<0.01 ;＾Y_{椎管左右径}(mm)=-0.411+0.274×X_胎龄(周),R²=0.822,P<0.01;＾Y_椎管面积(mm²)=-52.09+3.43×X_胎龄(周),R²=0.911,P<0.01。结论 CT可清晰显示胎儿T₁₂椎体水平椎管形态;T₁₂水平椎管各径线的大小与胎龄有良好的相关性,可以用来评估胎儿脊柱发育。     

Validation of the relative 3D orientation of vertebrae reconstructed by bi-planar radiography

The three dimensional (3D) reconstruction of the spine can be obtained by stereoradiographic techniques. To be safely used on a routine clinics basis, stereoradiography must provide both accurate vertebral shape and coherent position. Although the accuracy of the reconstructed morphology of the vertebrae is well documented, only few authors studied the accuracy of the vertebral orientation. Therefore, this paper focuses on the evaluation of the orientation accuracy of the reconstructed vertebrae (obtained by non-stereo corresponding point technique) considering either a 178 point vertebral model or a 6 point vertebral model (previously proposed in the literature). Five dried vertebrae were fixed on holders containing four markers each. The 3D reconstruction of both vertebrae and markers were obtained by stereoradiographic techniques. Using least square method matching from one position to another, the relative orientation was computed for the vertebral models (6 or 178 points) and the four markers. These vertebral and holder orientations were compared (considering the holder's one as reference). The repeatability of these relative orientations (vertebrae and holders) was also evaluated. The mean (RMS) orientation error of 178 point vertebral model was 0.6 degrees (0.8 degrees ), for lateral rotation, 0.7 degrees (1.0 degrees ) for sagittal rotation and 1.4 degrees (1.9 degrees ) for axial rotation. The intra-observer repeatability was 0.5 degrees (0.7 degrees ) for lateral rotation, 0.7 degrees (0.8 degrees ) for sagittal rotation and 0.9 degrees (1.2 degrees ) for axial rotation. The orientation was found more accurate and precise when using the 178 point vertebral model than when using the basic 6 point vertebral model. The relative orientation (in post-operative follow-up with respect to the pre-operative examination) of the vertebrae of one scoliotic patient was performed as an example of clinical application. The stereoradiographic method is a reliable 3D quantitative tool to assess the spine deformity, that can be used in clinics for the follow-up of scoliotic patients.     

Mechanical evaluation by patient-specific finite element analyses demonstrates therapeutic effects for osteoporotic vertebrae

Osteoporosis can lead to bone compressive fractures in the lower lumbar vertebrae. In order to assess the recovery of vertebral strength during drug treatment for osteoporosis, it is necessary not only to measure the bone mass but also to perform patient-specific mechanical analyses, since the strength of osteoporotic vertebrae is strongly dependent on patient-specific factors, such as bone shape and bone density distribution in cancellous bone, which are related to stress distribution in the vertebrae. In the present study, patient-specific general (not voxel) finite element analyses of osteoporotic vertebrae during drug treatment were performed over time. We compared changes in bone density and compressive principal strain distribution in a relative manner using models for the first lumbar vertebra based on computer tomography images of four patients at three time points (before therapy, and after 6 and 12 months of therapy). The patient-specific mechanical analyses indicated that increases in bone density and decreases in compressive principal strain were significant in some osteoporotic vertebrae. The data suggested that the vertebrae were strengthened structurally and the drug treatment was effective in preventing compression fractures. The effectiveness of patient-specific mechanical analyses for providing useful and important information for the prognosis of osteoporosis is demonstrated.     

Substructure in rod photoreceptor membranes.

Frog retinae, fixed only in buffered glutaraldehyde, were embedded for sectioning in glutaraldehyde polymerized with urea. In suitably thin sections globular substructures were seen in negative contrast after ionic staining with uranyl acetate and lead citrate, or after staining with neutralized phosphotungstic acid. Efforts to extract at least some of the lipid from sections before ionic staining enhanced the visualization of the "globules". Exposure to KMnO4 solution, used as an oxidative section stain, also outlined globular substructure in negative contrast, but with the additional feature that positively stained surface "leaflets" associated with the aqueous compartment were well defined. Staining sections with OSO4 vapor resulted in positively stained membranes, but without any evident substructure. However, when sections which previously had been exposed to OSO4 vapor were secondarily stained with uranyl acetate and/or lead citrate, positively stained globular substructures then were revealed. The globular substructures always were centered in the hydrophobic core region of the disc membranes, and symmetrically spanned the full thickness of this layer. The diameter of individual particles approximated 50-55 A. Reasons are presented for the supposition that the evident globules incorporate at least hydrophobic components of rhodopsin molecules. Findings are discussed in relation to various models of disc membrane organization that have been proposed in recent years.     

腰骶移行椎与骶骨之间椎间盘的MRI影像特点及其临床意义

目的探讨腰骶移行椎与骶骨之间椎间盘的MRI影像特点。方法对52例腰骶移行椎患者的MRI及X线片影像学进行分析。结果Ⅰ型23.1%(12例)、Ⅱ型17.3%(9例)、Ⅲ型48.1%(25例)、Ⅳ型11.5%(6例)。Ⅰ型腰骶移行椎与骶骨间椎间盘的形态与正常腰椎的L5/S1椎间盘相同;Ⅱ型与正常相近,但有发育不良现象;Ⅲ型和Ⅳ型则明显发育不良。结论Ⅰ型的椎间盘具备与正常L5/S1椎间盘相同的功能;Ⅱ型其椎间盘接近正常L5/S1椎间盘;Ⅲ型和Ⅳ型则为残存椎间盘,几乎不具备椎间盘功能,无退变发生。     

不同运动状态下模拟人体腰椎结构特征变化的有限元分析

目的比较不同运动状态下正常与退变腰椎节段三维有限元模型的应力变化特点及量效关系,分析中医推拿手法对退变腰椎节段力学调衡作用机制。方法建立完整、真实人体脊柱退变腰椎节段(L4~5)三维有限元模型,模拟腰椎节段前屈与后伸的生理活动。在加载外力即中医推拿手法作用下,分析退变腰椎节段的应力变化特点以及外加载荷逐渐递增过程中退变腰椎节段的应力变化,并与正常腰椎节段在不同运动状态下的应力、应变改变趋势进行对比。结果在不同运动状态下,人体腰椎节段椎间盘内应力分布、髓核、纤维环等结构的弹性模量随着腰椎退变程度的增加呈逐渐增大的趋势。中医推拿手法作用后能改变椎间盘内的应力分布,一定程度地增大椎管内的空间,使神经根所受的应力减小,椎体、小关节应力、椎弓根应力后伸位大于前屈位;椎间盘内部应力前屈位大于后伸位;且均由上至下呈逐渐增大的趋势。结论中医推拿手法对人体退变腰椎节段力学环境的调衡起到改善和治疗腰椎间盘病变的目的。同时,与人体正常腰椎节段三维有限元模型对比,从生物力学环境与特性改变角度研究腰椎退变的过程,能够为中医推拿手法在临床中预防和治疗脊柱退行性疾病的推广应用提供科学依据,也为中医推拿手法有效地预防和治疗脊柱腰椎节段病损的生物力学机制的研究提供新研究思路。     

椎体成形中病椎内骨水泥弥散与骨折时间的关系

背景：椎体成形骨水泥注射治疗骨质疏松椎体压缩性骨折具有肯定的临床疗效,但在手术最佳时机方面还存在着较大的争议。 目的：分析骨折时间对椎体成形病椎内骨水泥弥散的影响。 方法：纳入骨质疏松椎体压缩性骨折老年患者160例,均采用高黏度骨水泥进行椎体成形治疗,按骨折至手术时间分为新鲜组(<3周)、亚急性组(3-6周)和陈旧组(>6周)3组,术后即刻采用CT三维立体图像及X射线分析病椎内骨水泥的分布特点、弥散及渗漏情况。 结果与结论：骨水泥弥散体积比较为新鲜组>亚急性组>陈旧组,组间两两比较差异有显著性意义(P < 0.05);各组骨水泥弥散特征均以均匀分布为主,骨水泥形状以实习团块状为主,绝大多数骨水泥均能够较大程度地弥散到超过椎体中线、达到上下椎板;各组患者病椎内骨水泥弥散系数为新鲜组>亚急性组>陈旧组,组间两两比较差异有显著性意义(P < 0.05);新鲜组骨水泥渗漏率明显低于亚急性组和陈旧组(P < 0.05)。表明选择骨折3周内进行椎体成形治疗可获得较好的病椎内骨水泥弥散效果。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程      

Participation of ventral and dorsal tail muscles in bending movements of rat tail

The rat controls the form of its tail, from straight to curved, by contraction and relaxation of its four tail muscles. The tendons of these muscles insert on any of the cranial articular, transverse, and hemal processes of each of 24 coccygeal vertebrae (Co5–Co28). In this study, we isolated for the four coccygeal muscles each muscular fascicle segment inserting on any process of the coccygeal vertebrae. We measured the length and weight of all muscular fascicles and tendons, and then divided all muscular fascicles into four groups based on their insertion: Co5–Co10, Co11–Co16, Co17–Co22, and Co23–Co28. Moreover, we used soft X-ray imaging to investigate the geometrical relationship between neighboring coccygeal vertebrae. Additionally we carried out serial sectioning at the sacral and caudal portions, and traced the course of the tendons of coccygeal muscles from their origin to the Co4 level. We discuss which muscles and tendons play important roles when coccygeal vertebrae bend along and rotate around the longitudinal axis.     

保留椎弓连续性的有限椎管次环状减压术式的研究

目的为减少传统的椎管次全环状减压术所造成的脊椎结构破坏过多、导致脊柱不稳的发生,探索一种保留椎弓连续性的有限椎管次环状减压新术式。方法首先对T11～L3脊椎骨(脊柱骨折的好发部位)标本进行测量。得到可靠数据后,再进行临床操作。结果发现该段脊柱椎板与椎弓根的位置关系,完全不在同一平面上,且椎板有足够宽度,只需将椎板的上缘部分切除,即可显露椎弓根结构,经椎弓根达到椎体后缘的显露,再解除椎管前方的碎骨块压迫。结论椎管次环状减压术,无须按传统的方法破坏过多的脊柱后部的结构,使椎弓的环状完整性有效保留。保留椎弓连续性的椎管次环状减压术存在可行性,该术式既保留脊椎的稳定性,又达到了椎管减压彻底的目的。     

Paget sarcoma of the cervical vertebrae: An autopsy case report and review of the literature

A 69 year old Japanese woman was hospitalized for emergency treatment of sudden onset of tetraplegia and somnolence. The patient had a long history of occipital pain without definite diagnosis. After admission, the patient progressively developed generalized palsy including respiratory paralysis, and died of bronchopneumonia. Autopsy revealed osteosarcoma of the cervical vertebrae with the features of Paget's disease involving the skull and the cervical vertebrae. Paget sarcoma is rare in Japan, where Paget's disease of the bone is an uncommon condition. A review of the world literature failed to reveal any reports describing Paget sarcoma of the cervical vertebrae. The present report indicates that the development of Paget sarcoma in the upper cervical vertebrae may cause life-threatening neurologic complications.     

骨水泥注射体积与骨质疏松压缩性骨折椎体及邻近椎体应力的关系

背景：椎体成形及椎体后凸成形可有效修复骨质疏松性椎体压缩性骨折,但术后可引起骨折椎体及邻近椎体应力改变易导致新发骨折。 目的：应用三维有限元法分析椎体成形不同体积骨水泥注射后骨折椎体及邻近椎体的应力变化。 方法：选取1例有代表性的健康成年男性志愿者行腰椎CT扫描,将图像处理后导出应用Mimics进行三维重建,应用Geomagic对三维模型进行光滑、打磨、去噪,Ansys Workbench下装配实体模型,赋值后建立L2-L4段骨质疏松椎体压缩性骨折模型。设定在L3椎体注入分别1 mL、2 mL、4 mL、6 mL骨水泥,骨水泥在椎体中央呈球形分布。在L2上表面施加500 N预载荷,附加弯矩为50 N•m,约束L4下表面自由度。模拟L2-L4前屈、后伸、右屈及右侧轴向旋转4种运动状态,比较不同体积骨水泥注射前后骨折椎体及上下邻近椎体的应力变化。 结果与结论：骨折椎体及邻近椎体应力骨水泥注射后均较注射前明显增加,并随骨水泥注入量的增加骨折椎体及邻近椎体承受的应力也随之增大,其可能是导致邻近椎体骨折的因素之一。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程      

Morphological variability is greater at developing than mature mouse neuromuscular junctions

The neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, thereby enabling the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, how synaptic morphology changes during development, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31−32) timepoints. The inter-muscular variability was greater in mature post-synaptic AChR morphology than that of the pre-synaptic motor neuron terminal. Moreover, the developing NMJ showed greater differences across muscles than the mature synapse, perhaps due to the observed distinctions in synaptic growth between muscles. Nevertheless, the amount of nerve to muscle contact was consistent, suggesting that pathological denervation can be reliably compared across different muscles in mouse models of neurodegeneration. Additionally, mature post-synaptic endplate diameters correlated with fibre type, independently of muscle fibre diameter. Altogether, this work provides detailed information on healthy pre- and post-synaptic NMJ morphology from five anatomically and functionally distinct mouse muscles, delivering useful reference data for future comparison with neuromuscular disease models.     

Morphometric analysis of vertebrae and intervertebral discs as a basis of disc replacement

In this study measurements were obtained from 359 vertebrae and 215 intervertebral discs in an attempt to classify discs by their size. At the cervical and thoracic levels, this attempt was unproductive because of extensive variations. In the lumbar spine, discs were allocated to six size-matched groups. The breadth of marginal rims were also measured with a view to provide surgeons operating on the spine with precise data on disc morphology to facilitate dise replacement.     

A modeler's view on the spatial structure of intrinsic horizontal connectivity in the neocortex

Most current computational models of neocortical networks assume a homogeneous and isotropic arrangement of local synaptic couplings between neurons. Sparse, recurrent connectivity is typically implemented with simple statistical wiring rules. For spatially extended networks, however, such random graph models are inadequate because they ignore the traits of neuron geometry, most notably various distance dependent features of horizontal connectivity. It is to be expected that such non-random structural attributes have a great impact, both on the spatio-temporal activity dynamics and on the biological function of neocortical networks. Here we review the neuroanatomical literature describing long-range horizontal connectivity in the neocortex over distances of up to eight millimeters, in various cortical areas and mammalian species. We extract the main common features from these data to allow for improved models of large-scale cortical networks. Such models include, next to short-range neighborhood coupling, also long-range patchy connections.