Investigation of connective tissue attachments to the cervical spinal dura mater

The connective tissue attachments to the cervical spinal dura mater originating from the ligamentum nuchae (LN) and rectus capitis posterior minor (RCPM) muscle were evaluated in 30 cadaveric spines. Magnetic resonance images (MRIs) were correlated with the attachments in four cadaveric specimens. Attachments from the LN to the RCPM were also identified. The LN and the RCPM to dura attachments were found in all 30 specimens. Our results indicate that: 1) the attachments between the LN and RCPM and the dura occur between vertebrae C1-C2 and the occipital bone and C1, respectively, and that they are substantial normal anatomic attachments, 2) attachments between the LN and RCPM are usually present, and 3) the attachments between the LN and dura mater can be identified on MRI. These latter attachments may play a role in neck pain, making their MRI appearance clinically important.     

下颈椎血供的解剖研究及其临床意义

目的为颈椎前路减压手术中减少出血量,改善显露和减少手术并发症的发生提供解剖学基础。方法在15具成人尸体标本上,解剖观测C3～7椎体前后部血供的起源、走行、分支及吻合。结果椎体前部血供来自颈升动脉脊支、甲状腺下动脉和颈深动脉脊支,C4～7椎前动脉在椎体上的分支相互吻合,在颈长肌的内侧缘处常吻合成一纵行动脉链;椎体后部血供来自椎间动脉发出的椎后动脉,其分支在颈椎体后部吻合形成节段性弧形动脉吻合链。结论阻断术椎的椎前动脉及其与相邻椎前动脉的纵行动脉吻合,并在颈椎后部减压时注意对硬膜囊外侧缘及椎体中部处的椎后动脉及其分支的处理,可减少颈椎前路减压手术的术野出血,改善手术显露。     

“椎动脉-硬膜动脉导管韧带”的解剖学及临床意义

目的　探讨椎动脉第3段（V3段）的垂直段（V3v段）与硬膜囊前壁和周围骨性结构间的连接及其临床意义。 方法　头颈标本16具（32侧）,在C3~4节段,将V3段周围的软组织及其相关联的连接结构分离,探寻“椎动脉-硬膜动脉导管韧带”,观察其解剖学特点。取该韧带与椎动脉壁相连部,石蜡切片、HE染色,光镜观察、摄片。 结果　所有标本在寰枕关节后内侧V3v段发现“椎动脉-硬膜动脉导管韧带”共11条（43.7%）,长度9.25~4.76 mm,平均（7.39±1.33）mm,直径为（1.16±0.15）mm。该韧带出现于硬膜外层,自V3v段发出,末端分叉或呈分枝状穿入枕骨或连于硬膜。组织学特点为空心管状,管腔与椎动脉相通。 结论　“椎动脉-硬膜导管韧带”是椎动脉连于硬膜和骨之间的空心圆索状结构,可能是椎动脉的脑膜后动脉闭锁形成,是有孔型椎动脉畸形的形态学基础,其对椎动脉的固定及头活动时颅内压的形成有一定作用。枕颈部显露椎动脉时此结构断裂可能是造成椎动脉大出血的原因。     

近节指骨滑车损伤对近指间关节侧方稳定性影响的应用解剖学研究

目的　通过近节指骨滑车损伤实验，探究其对近指间关节侧方稳定性影响，为治疗提供解剖依据。 方法　解剖6具成人双上肢手标本，选择示指、中指、环指共36只手指进行研究。分别测量0 °屈曲位时近指间关节近节指骨滑车未损伤及桡侧损伤10%、20%、30%、40%、50%的桡偏角度。 结果　未损伤时近节指骨滑车两端长度平均为（10.25±1.12）mm，桡偏角度为（0.14±0.10）°，损伤10%时桡偏角度为（5.06±0.53）°，损伤20%时桡偏角度为（8.47±0.42）°，损伤30%时桡偏角度为（12.28±0.71）°，损伤40%时桡偏角度为（16.33±0.76）°，损伤50%时桡偏角度为（20.03±0.75）°。近节指骨滑车损伤程度越重，近指间关节桡偏角度越大，关节稳定性越差（P<0.0001，Wilcoxon检验）。 结论　近节指骨滑车缺损对近指间关节侧方稳定性具有显著影响，损伤达10%时即可发生侧方不稳定。     

The human lumbar anterior epidural space: morphological comparison in adult and fetal specimens

To increase our understanding of the clinical anatomy of the epidural space, the human lumbar anterior epidural space was studied morphologically and developmentally. Histological transverse sections of human lumbar spines were taken at the level of the intervertebral disc and the vertebral body in adult specimens and in fetuses aged 13, 15, 21, 32 and 39 weeks (menstrual age). At 13 weeks, connective tissue filled the epidural space. The dura mater was attached anteriorly to the posterior longitudinal ligament (PLL). The PLL was attached to the vertebral body beside the midline, whereas it adhered to the posterior edge of intervertebral disc. The anterior internal vertebral venous plexus was located anterolaterally and anteromedially. The vertebral canal was lined with connective tissue that differentiated in a periosteum in contact with the ossification centers. At 15 weeks, the PLL was composed of deep and superficial layers. At 21 weeks, the attachment between the dura mater and PLL was ligament-like at the level of the vertebral body. At 32 weeks, the dura mater was adherent to the superficial layer of PLL. At 39 weeks, groups of adipocytes were identified, and the dura mater was attached to the PLL by some ligaments. There were many more similarities between the adult and the 39-week fetus. In conclusion, some differences in the anatomy of the epidural space exist at each fetal stage studied. The structures of the epidural space are already formed in the fetus of 13 weeks, but they differentiate progressively within the connective tissue.     

椎动脉和第1颈神经穿经硬膜处的形态学特点及其与高血压颈枕痛的关系

目的　观察椎动脉和第1颈神经穿经硬膜处的形态特点及毗邻结构,探讨高血压合并枕颈部疼痛的发生机制。 方法　头颈部标本18具,解剖剥离法暴露,观察椎动脉穿经硬膜处部位及毗邻结构、椎动脉与第1颈神经（C1）的位置关系。 结果　椎动脉在寰枕外侧关节内后侧穿经硬膜,穿经处形成边缘光滑的圆孔,直径6.5~9.0 mm,硬膜与椎动脉外膜由纤维结缔组织连结。C1神经前后根自脊髓发出向外侧走行于椎动脉内侧并在其下方相伴共同穿经硬膜孔（100%）,其中与动脉壁相贴者66.7%（12例）;神经嵌入动脉壁者22.2%（4例）;隔有硬膜组织者11.1%（2例）。C1神经根出孔后走行于椎动脉与椎动脉沟之间。 结论　椎动脉穿经硬膜孔处位置固定,孔边缘致密,限制椎动脉扩张,利于颈椎活动时维持椎动脉供血,当全身血压波动时椎动脉管径不会产生明显变化,以维持后循环血液动力学稳定,但血压升高有可能将C1颈神经根卡压在硬膜边缘,椎动脉搏动刺激C1颈神经根导致椎枕肌痉挛,出现枕颈部疼痛。这可能是高血压合并枕颈部症状的形态学基础。     

颈椎硬脊膜后方膜椎韧带的解剖学研究

目的　研究颈椎硬脊膜后方膜椎韧带的解剖学特征,探讨其临床意义。 方法　内窥镜下观测13具成人防腐标本颈椎硬脊膜后方膜椎韧带的形态学特点,随后打开椎管,肉眼及手术显微镜下对膜椎韧带进行观测,记录其起止点、走行方向。用游标卡尺测量膜椎韧带的长度、宽度、厚度或直径。对膜椎韧带进行HE染色、Masson三色法染色,观察其组织形态结构特点。 结果　13例颈椎标本中硬脊膜后方均有膜椎韧带出现,膜椎韧带将硬脊膜向后连于椎板或黄韧带。膜椎韧带与黄韧带连接较紧密且数量居多,占72.4%。膜椎韧带在C1/2、C4/5黄韧带出现率为100%,C1/2黄韧带处膜椎韧带厚度最大,为（1.04±0.61）cm(0.3~2.01 cm)。膜椎韧带多呈前上后下走行。根据形态特点可将膜椎韧带分4型：条带型、条索型、网格型、薄片型。光镜下观察膜椎韧带由大量密集排列的胶原纤维构成。 结论　颈椎硬脊膜背部膜椎韧带是将硬脊膜连于椎管后壁的正常结构,其两端分别与硬脊膜背侧及椎管后壁尤其是黄韧带连接紧密,膜椎韧带可牵拉固定硬脊膜,从而维持脊髓在椎管中的相对位置。另外膜椎韧带可能是颈椎后路手术中硬脊膜撕裂及硬脊膜外出血的解剖学因素,建议相关手术中先予辨认并切断。     

Histological investigations on the dura mater vascular system of mice

The human dura mater encephali is a well innervated and vascularized membrane. Its vascular system plays a crucial role in disorders and pathological cases like dural hematoma, meningitis, and different headache types. To investigate these diseases mouse models are increasingly being used. However, the literature on the vascular system of the mouse dura mater is sparse and explicit studies concerned exclusively with its vasculature are lacking. Here we present a detailed light and scanning electron microscopic investigation of the supratentorial dura mater of the mouse species, with a focus on the largest part of it, the parietal dura mater. By utilizing different immunohistochemical and classical staining methods, a “cartography” of the vascular system was achieved. Additionally, the different blood vessel types with their mural cells were characterized. In contrast to humans, no arteries were found in the mouse parietal dura mater. Its supply is assured through frontolateral and occipital localized arteriolar branches. These arteriolar vessels exhibit in some specimens arteriolar anastomoses with one another. The venous blood is drained to the superior sagittal and transverse sinus through satellite venules accompanying the arterioles or through solitary venules. In all samples, large ruptured venules were identified in the frontolateral dural area. Scanning electron microscopy revealed that these vessels were ruptured on the dorsal side (skull bones-oriented side) of the dura. Our results contribute to the anatomical data on the mouse species and may set up a basis for fundamental investigation of disorders, for which the role of dural blood vessels is not yet clarified.     

Analysis of dural sac thickness in the human cervical spine

The thickness of the dura mater in the human cervical spine can vary between individuals and by vertebral level; these differences can result in various clinical outcomes. The purpose was to measure and analyze cervical dura mater thickness. Microscopic measurements were made of tissue from human cadavers. The subjects were nine human cadavers with no previous history of spinal deformity or surgery. Fourteen segments of both anterior and posterior dura mater from the C1 to C7 cervical vertebrae were obtained. Dura mater thickness was measured using an infrared laser-based confocal microscope. Statistical analyses were performed to examine the relationships of cervical dura mater thickness with vertebral level, age, and sex. The overall average cervical dura mater thickness was 379.3 × 10^?3 mm. Statistically significant differences in thickness were found between the anterior and posterior segments (P < 0.0001). Moreover, the thickness at each vertebral level was significantly different from the thicknesses at the other levels (P < 0.05). The posterior dura mater thickness was highest at C1 and lowest at C5/6. Posterior dura mater thickness was significantly different at the axial, sub-axial, and lower cervical levels, whereas anterior dura mater thickness was relatively constant among levels. A significant correlation was found between thickness and age (P < 0.05); however, the average dura mater thickness was not significantly different between males and females. This study shows anatomical differences in cervical dura mater thickness with respect to vertebral level and age. These results provide anatomical information that will inform basic research and clinical approaches.     

脊柱颈段椎间盘平面椎管内前部结构的解剖学研究

目的　探讨经脊柱颈段椎间盘入路椎管内减压的相关解剖。 方法　取18具正常成人颈段脊柱防腐标本,通过不同断层,观察硬脊膜、后纵韧带与硬膜外前隙的毗邻关系和结构特点;测量椎间盘平面的硬脊膜厚度、后纵韧带宽度、椎体矢状径长度。 结果　颈段后纵韧带分为深、浅层,两层在中线两侧4～5 mm处分开,浅层与硬脊膜形成潜在的硬膜外前隙,该隙内有Hofmann's韧带连于硬脊膜与后纵韧带之间。深、浅层在硬脊膜前外侧形成一梭形腔隙－后纵韧带间隙; 椎体后面矢状正中线到两侧后纵韧带间隙外侧角的距离约为10 mm。 结论　根据后纵韧带的宽度和毗邻关系,颈椎前路手术经椎间盘达后纵韧带,逐渐由外进入后纵韧带间隙减压,可减少硬膜囊、脊髓或神经根的损伤。     

Biological rhythms of tissue basophils in various sites of rat dura mater

Changes in the components of biorhythms of functionally active basophils were studied in the frontal, parietal, and occipital areas of the dura mater of adult rats in the circadian and ultradian ranges. Spectral analysis revealed differences in rhythm parameters in each area of the dura mater, synchronized for 24-h period. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 1, pp. 96–99, January, 2000     

The obliquus capitis inferior myodural bridge

This study was designed to examine the obliquus capitis inferior (OCI) muscle from a gross anatomical perspective. The objective was to isolate and identify the OCI myodural bridge, while examining its course and contributing elements. An earlier study of the posterior cervical spine briefly reported a connection between the OCI and the cervical dura mater. To the best of our knowledge, a study has not yet been conducted specifically on this muscle and its relation to the dura mater. In this study, the suboccipital regions of nine embalmed cadavers were dissected. A total of 14 OCI muscles were isolated for examination. All findings were documented via photograph. Of the 14 OCI muscles isolated, all emitted fibrous tissue bands from the anterolateral portion of the muscular belly. These fibers attached to the posterolateral cervical dura mater by route of the atlantoaxial interspace. The OCI myodural bridge appeared to coalesce with the rectus capitis posterior major myodural bridge, giving the appearance of a single atlantoaxial structure that links these two muscles to the dura mater. In conclusion, the OCI was attached to the dura mater in all of the 14 muscle specimens. We hypothesize that the OCI myodural bridge may play a physiological role in monitoring dural tension and preventing dural infolding. It may also contribute to certain clinical symptoms manifesting from alterations in dural tone. Clin. Anat. 2013. © 2012 Wiley Periodicals, Inc.     

Variants in the structure and topography of the superior margin of the epidural space of the human spinal cord

Variants in the structure of the upper margin of theepidural space at sites of transition from the dura mater of the spinal cord to the dura mater of the brain were studied. Stereoepidurographic (88 observations) and corrosion studies (49 observations) identified four levels for the position of the upper margin of the anterior section (intracranially located, lower edge of the occipital bone, bodies of C₁ and C₂) along with five levels for the posterior section (occipital bone, occipital bone-arch of C₁, C₁, C₁–C₂, C₂) of the epidural space. Variants on the shape of the upper margin of the anterior (falciform, oval, and dentate in the frontal plane; pointed, flexed spurs, pointed slits, and olive-shaped in the sagittal plane) and posterior (collar-shaped, oval, and bidentate forks with prongs of equal length and forks with prongs of unequal lengths) sections of the epidural space arose as a result of asymmetry in the attachment of the upper sections of the sac of the dura mater of the spinal cord to the walls of the vertebral canal. Weak areas of the upper wall of the epidural space (sites of transition from the dura mater of the spinal cord to the dura mater of the brain, paravasal capsule of the vertebral artery, the area of the first intervertebral foramen) were seen. __________ Translated from Morfologiya, Vol. 132, No. 5, pp. 38–42, September–October, 2007.     

枢椎4层皮质骨椎弓根螺钉的影像学测量及置钉策略

目的　探讨枢椎经椎管4层皮质骨椎弓根螺钉置钉策略的可行性及技术方法。 方法　利用PACS系统调阅92例正常成人枢椎椎弓根水平横断面MRI图像,测量椎弓根内侧壁切线（tangent of pedicle medial wall,TPMW）与脊髓切线（tangent of spinal cord,TSC）、硬膜切线(tangent of dura mater,TDM)间距离及椎管内侧壁切线 (tangent of spinal canal medial wall,TSCMW)与TSC、TDM间距离,以及脊髓和椎管横径、矢状径等参数。 结果　同性别双侧参数差异无统计学意义。男性枢椎TPMW与TSC的距离为9.05 mm,女性为8.57 mm;男性TPMW与TDM的距离为5.04 mm,女性为4.76 mm。男性TSCMW与TSC的距离为7.14 mm,女性为6.70 mm;男性及女性TSCMW与TDM的距离均为3.28 mm。 结论　在枢椎椎弓根水平,经椎管行枢椎4层皮质骨椎弓根螺钉理论上可行,但需根据具体情况采用个性化的策略。     

Morphological characteristics of the cranial root of the accessory nerve

There has been the controversy surrounding the cranial root (CR) of the accessory nerve. This study was performed to clarify the morphological characteristics of the CR in the cranial cavity. Fifty sides of 25 adult cadaver heads were used. The accessory nerve was easily distinguished from the vagus nerve by the dura mater in the jugular foramen in 80% of 50 specimens. The trunk of the accessory nerve from the spinal cord penetrated the dura mater at various distances before entering the jugular foramen. In 20% of the specimens there was no dural boundary. In these cases, the uppermost cranial rootlet of the accessory nerve could be identified by removing the dura mater around the jugular foramen where it joined to the trunk of the accessory nerve at the superior vagal ganglion. The cranial rootlet was formed by union of two to four short filaments emerging from the medulla oblongata (66%) and emerged single, without filament (34%), and usually joined the trunk of the accessory nerve directly before the jugular foramen. The mean number of rootlets of the CR was 4.9 (range 2–9) above the cervicomedullary junction. The CR of the accessory nerve was composed of two to nine rootlets, which were formed by the union of two to four short filaments and joined the spinal root of the accessory nerve. The CR is morphologically distinct from the vagus nerve, confirming its existence. Clin. Anat. 27:1167–1173, 2014. © 2014 Wiley Periodicals, Inc.     

The development of the anterior falcate and lacrimal arteries in the human

Summary Certain arteries of the head were studied in injected human fetuses from 143 to 290 mm C.-R., as well as in the organg-utan and gorilla, and in microscopical sections from 29 to 162 mm C.-R., as well as in an adult. It was found that, during human ontogenesis, an anterior falcate artery supplies the dura mater of the medial part of the frontal bone. It appears at 40 mm and reaches its full development by 115 mm. Normally it becomes reduced and is transformed into the anterior meningeal artery postnatally. It communicates with the meningeal branches of the lacrimal artery. Under pathological conditions that affect the dura mater, the falcate artery may appear postnatally in angiograms.This work was supported in part by research programme grant No. HD-08658, Institute of Child Health and Human Development, National Institutes of Health, USA.     

Continuation of the ascending cervical artery as the occipital artery in man

We report an elderly male cadaver with unilateral anomalous continuation of the ascending cervical artery as the occipital artery. The ascending cervical artery was enlarged from its origin and supplied segmental branches through the intervertebral foramina. At the upper cervical spine, the ascending cervical artery continued as the occipital artery providing the branches normally seen stemming from this artery. No other vascular anomalies were noted in this specimen. This anatomical curiosity should be kept in mind by the clinician or academic who may manipulate this anatomical area.     

Hypoplastic occipital condyle and third occipital condyle: Review of their dysembryology

Disruption or embryologic derailment of the normal bony architecture of the craniovertebral junction (CVJ) may result in symptoms. As studies of the embryology and pathology of hypoplasia of the occipital condyles and third occipital condyles are lacking in the literature, the present review was performed. Standard search engines were accessed and queried for publications regarding hypoplastic occipital condyles and third occipital condyles. The literature supports the notion that occipital condyle hypoplasia and a third occipital condyle are due to malformation or persistence of the proatlas, respectively. The Pax‐1 gene is most likely involved in this process. Clinically, condylar hypoplasia may narrow the foramen magnum and lead to lateral medullary compression. Additionally, this maldevelopment can result in transient vertebral artery compression secondary to posterior subluxation of the occiput. Third occipital condyles have been associated with cervical canal stenosis, hypoplasia of the dens, transverse ligament laxity, and atlanto‐axial instability causing acute and chronic spinal cord compression. Treatment goals are focused on craniovertebral stability. A better understanding of the embryology and pathology related to CVJ anomalies is useful to the clinician treating patients presenting with these entities. Clin. Anat. 26:928–932, 2013. © 2013 Wiley Periodicals, Inc.     

“安全减压间隙”在前路椎体次全切除治疗颈椎后纵韧带骨化症中的应用

目的 探讨后纵韧带与硬脊膜间“安全减压间隙”在前路椎体次全切除术治疗颈椎后纵韧带骨化症(OPLL)中的应用价值。方法 回顾性分析2010年1月—2014年1月第二军医大学附属长征医院脊柱外科行颈椎前路椎体次全切除治疗的134例颈椎OPPL患者临床资料,其中男88例,女46例;年龄35～71岁,平均(50.5±16.7)岁。术前CT矢状面显示节段型105例,连续型12例,混合型17例,骨化均不超过3个椎体。术中以韧带未骨化处为突破口,使用后纵韧带钩钩起骨化物,形成后纵韧带与硬脊膜间“安全减压间隙”,锐利神经剥离子仔细分离,超薄型枪钳逐步咬除骨化的韧带。术中观察有无硬脊膜粘连及破损而导致脑脊液漏以及脊髓损伤,采用JOA评分评估患者术前、术后神经功能改善程度。结果 CT横断面上椎管狭窄率＜30%者58例,利用“安全减压间隙”行骨化物切除术,无硬膜破损;30%～60%之间者62例,1例硬脊膜破损导致脑脊液漏;＞60%者14例,4例脑脊液漏。术中发现硬脊膜粘连97例,在“安全减压间隙”下用锐利神经剥离子成功分离92例。患者均未出现脊髓损伤,术后JOA评分(14.9±2.7)分,较术前(9.3±1.9)分有显著改善,差异有统计学意义(t=2.210, P﹤0.05)。结论 利用后纵韧带钩钩起骨化后纵韧带创造 “安全减压间隙”,可有效地分离后纵韧带与硬脊膜的粘连,避免骚扰脊髓,减少硬脊膜破损及脊髓损伤。     

Role of the C2 articular branches in occipital headache: an anatomical study

One of the most important structures involved in the pathogenesis of occipital headache is the lateral atlanto-axial joint. Previous studies demonstrated that injection of this joint with local anesthetic can alleviate occipital headache, while injection of contrast medium exacerbates it. The aim of our study is to improve the understanding of the nerve supply to the lateral atlanto-axial joint by the C2 nerve elements, in order to determine the optimal target for an anesthetic block of this area. Ten C2 spinal nerves and roots were dissected in five embalmed cadavers with the aid of a 40X microscope and the lateral atlanto-axial joint was shown to be extensively supplied by articular branches of C2 nerve elements (dorsal ganglion, spinal nerve, and ventral ramus). Following our observations on their distribution, we propose a target for local anesthetic injection of the C2 articular branches that is based on reliable landmarks and is easily identifiable at fluoroscopy. We suggest that local anesthetic injection at this target point could be of benefit in the relief of occipital pain due to cervical trauma or degenerative disease involving the lateral atlanto-axial joint.