Anatomical relationship and positions of the lumbar and sacral segments of the spinal cord according to the vertebral bodies and the spinal roots

Segments of the spinal cord generally do not correspond to the respective vertebral level and there are many anatomical variations in terms of the segment and the level of vertebra. The aim of this study is to investigate the variations and levels of lumbar and sacral spinal cord segments with reference to the axilla of the T11, T12, and L1 spinal nerve roots and adjacent vertebrae. Morphometric measurements were made on 16 formalin fixed adult cadaveric spinal cords. We observed termination of the spinal cord between the axilla of the L1 and L2 spinal nerve roots in 15 specimens (93.8%). In all cadavers the emergence of the T11, T12, and the L1 spinal nerve roots was at the level of the lower one‐third of the same vertebral body. In 15 specimens (93.8%), the beginning of the lumbar spinal cord segment was found to be above the T11 spinal nerve root axilla and corresponded to the upper one‐third of the T11 vertebral body. The beginning of the sacral spinal cord segment occurred above the L1 spinal nerve root axilla and corresponded to the upper one‐third of the L1 vertebral body. The results of this study showed that when the conus medullaris is located at the L1–L2 level, the beginning of the lumbar spinal cord segment always corresponds to the body of T11 vertebra. This study provides detailed information about the correspondence of the spinal cord segments with reference to the axilla of the spinal nerve roots. Clin. Anat. 27:227–233, 2014. © 2013 Wiley Periodicals, Inc.     

Anatomical studies on the ovine spinal cord

The root attachment lengths were consistently greater in the cranial cervical (C3), midthoracic (T7), caudal lumbar (L5) and cranial sacral (S1) cord segment levels than the corresponding caudal cervical, caudal thoracic, cranial lumbar and caudal sacral levels respectively. As to the root emergence length the greatest values were obtained bilaterally at C3, T1, L4 and S1 cord segment levels respectively. The interroot intervals were maximum at C3, T13, L1 and S1 cord levels in the respective regions. The longest cord segments were located at C2, T13, L3 and S1 levels; the shortest were at C8, T1, L6, and S4 cord levels. The greatest diameter and cross-sectional area were confined to the last cervical, first 2 thoracic, last lumbar and first sacral cord segment levels. The spinal cord segments C2, T13, L4 and S1 were most voluminous in the respective regions. The topography of cord segments and the level of termination of the spinal cord have been studied and recorded.     

Spread of the dorsal root potentials in lower lumbar,sacral and upper caudal spinal cord

Spread of the dorsal root potentials (DRPs) along lower lumbar, sacral, and upper caudal segments of the cord has been studied in spinal cats. Ipsilateral DRPs produced by stimulation of L5 dorsal root with single volleys and recorded in consecutively more and more caudal segments gradually decrease and after passing 6 segments attain 47% of amplitude observed in L6 dorsal root. DRPs spreading cranially from Ca2 dorsal root along 6 segments decrease virtually to zero. Depolarizations spreading caudally show greater conduction velocity, are maintained during repetitive stimulation in larger number of segments and display larger occlusion than DRPs spreading cranially. These findings show the preponderance of depolarization spreading from lower lumbar cord to sacral and caudal segments over that produced in caudal parts of the cord and spreading cranially. The extent of cranial spread of DRPs, appearance of sudden increases in latency of DRPs and changes in effectiveness of stimulation in maintaining prolonged depolarization show correlations with neuronal arrangement of the substantia gelatinosa. This suggests that substantia gelatinosa subserves the spread of DRPs along the spinal cord.     

与胸12,腰1椎骨对应的腰骶神经根的应用解剖

在２０具（男１６，女４）成人尸体上，对胸１２、腰１椎骨对应的蛛网膜下隙内脊髓节、脊神经前、后根进行了应用解剖学研究。结果胸１２椎骨多与腰２￣５脊髓节、胸１２￣腰５神经根对应；腰１椎骨与骶１￣尾脊髓节、腰１￣尾脊神经根对应，据此，损伤时利于定位诊断。腰１￣３脊神经根远侧段与腰４￣骶３的近侧段之间常有一定长度的重叠，重叠的长度供神经缝接参考。文内还对神经根排列位置，前、后根的数目、长度和外径等进行了观     

The intersegmental anastomoses between spinal nerve roots

Frequency and morphological characteristics of the intersegmental anastomoses between the spinal roots were investigated in 100 adult spinal cords from the cervical to lumbar segments. The frequencies of dorsal root anastomoses were 61, 7, and 22% of the cervical, thoracic, and lumbar cords, respectively. On the other hand, the incidence of anastomosis between the ventral roots was significantly low in both the cervical (10%) and lumbar (5%) cords as compared with that between the dorsal roots in these regions (P less than .01). No anastomotic connections were found in the thoracic ventral roots. The anastomoses were classified into four types: types A and B; the borders between the spinal segments were cranially and caudally shifted, respectively; type C, anastomosis attached to the spinal cord at the border between the segments; and type D, anastomosis bridged between the adjacent rootlets and coursing parallel to the cord. The proportions of the four types at each spinal level disclosed that type A was most commonly observed compared with the other three types in the dorsal roots (P less than .01). In the lumbar cord, the proportion of type C anastomosis between the dorsal roots increases noticeably toward the sacral level, while a complementary decrease occurred in type A. In the cervical ventral roots, types C and D predominated over the other two types (P less than .01). The lumbar ventral roots contained types B and/or C. Type D anastomosis occurred exclusively in the cervical segments.     

Shortlasting Increase in the Synthesis and Utilization of Noradrenaline due to Axotomy-Induced Irritation

The synthesis and the utilization of noradrenaline in the caudal and cranial part of intact and sectioned rat spinal cords were determined at 20 h or for 30 min - 2 h after an operation. The synthesis and the utilization of noradrenaline in the caudal pari of spinal cords transected 20 h previously were retarded as compared to those in the cranial part of sectioned cords or in the caudal part of intact cords. The synthesis of noradrenaline was stimulated in the caudal and cranial part of the spinal cord when measured for 30 min after a transection. The utilization of noradrenaline in the spinal cord caudal to a transection was not decelerated during 2 h after an operation. Local application of lidocaine to the cord prior lo the cut changed the synthesis and the utilization of noradrenaline in both parts of the spinal cord to values similar to those obtained 20 h after the operation. Transection of the spinal cord might stimulate the synthesis and the utilization of noradrenaline by a shortlasting mechanical irritation of neurons cut by the lesion.     

Spinal arachnoid calcifications

Arachnoid calcifications have been imaged on axial-CT and MRI. These often clinically asymptomatic deposits have been attributed to trauma, myelography (particularly with the use of oil-based contrast), subarachnoid hemorrhage, and spinal anesthesia. This report describes calcified arachnoid plaques in an 86-year-old male cadaver located in the dorsal thoracic level. A laminectomy from C4 to the lumbo-sacral junction was performed and the dura mater was transected and pinned aside. Three plaques between T2-T3, 3 at T7, 2 at T9 were noted. Plaques were 1.0 mm in thickness and ranged from 0.5 cm to 1.0 cm in diameter. The spinal cord or nerve roots were not displaced. The plaques stained positively with Von Kossa and Alizarin Red S staining, confirming that the deposits included calcium phosphate and calcium. Arachnoid calcifications are an incidental finding in cadavers and typically do not compress the spinal cord or nerve roots. However such plaques may be precursors to spinal arachnoid ossificans, a more serious condition that may cause spinal cord or nerve root compression.     

Pathological changes of the spinal cord in centenarians

In order to study the changes that occur in the spinal cords of the aged, 19 centenarian spinal cords from two men and 17 women (age range, 100-116 years at death; mean, 103 years) were pathologically examined. Cross-sections at each segmental level of the 19 autopsied spinal cords were examined for histopathological changes. The cross-sectional area and flattening ratio at the level of the C7 segment were measured. The size of the cords had some negative correlation with age, but the individual variation was considerably large. Among the 19 centenarians, macroscopic anteroposterior flattening appeared in the lower cervical cords in six individuals. In these cases, various degrees of neuron loss were observed in the anterior horn. White matter degeneration appeared frequently, especially in the posterior column. In 12 cases, myelin loss in the fasciculus of Goll at the cervical level was observed. The degeneration of the fasciculus of Goll was considered to be upward wallerian degeneration secondary to posterior root damage at the lumbosacral level. These changes seemed to be produced by disorders in the spinal canal or surrounding tissue, such as cervical spondylosis, degeneration of the intervertebral disk and spinal canal stenosis. Argyrophilic structures such as neurofibrillary tangles and neuropil threads were observed in 16 cases; however, this incidence was less than in the brain. Medial thickening of the anterior spinal artery was found in four cords. Amyloidangiopathy was noted in only one cord. Necrosis and hemorrhage due to vascular disturbance were not found.     

Specific innervation of guinea-pig superior cervical ganglion cells by preganglionic fibres arising from different levels of the spinal cord.

1. The synaptic contribution of preganglionic nerve fibres arising from the last cervical (C8) and the first seven thoracic spinal cord segments (T1-T7) to neurones of the guinea-pig superior cervical ganglion has been studied by means of intracellular recording during ventral root stimulation in vitro. 2. The majority of neurones received innervation from the middle segments (T2 and T3) of the length of spinal cord from which preganglionic fibres derive; an intermediate number of ganglion cells were innervated by fibres from the segments adjacent to these (T1, T4, and T5), and relatively few neurones by fibres from the most rostral and caudal segments supplying innervation to the ganglion (C8, T6 and T7). 3. Each neurone received preganglionic terminals from multiple thoracic segments (range 1-7, mean = 4-0). The estimated minimum number of preganglionic fibres contacting each neurone was 10, on average. 4. As a rule, the spinal segments innervating a neurone were contiguous. Thus we rarely encountered neurones innervated by segments located both rostrally and caudally to a segment which failed to provide innervation. 5. Neurones tended to be innervated predominantly by axons arising from a single spinal segment, with adjacent segments contributing a synaptic influence that diminished as a function of their distance from the dominant segment. All segments provided dominant innervation to at least some neurones. 6. Stimulating the ventral roots of C8-T7 in vivo showed that the axons arising from each segment produced a characteristic pattern of peripheral effects. Thus different populations of neurones in the superior cervical ganglion of the guinea-pig are innervated by preganglionic axons from different levels of the spinal cord, as originally suggested by Langley (1892) for the cat, dog, and rabbit. 7. On the basis of our in vitro studies we conclude that underlying the specificity of innervation of neurones of the superior cervical ganglion that can be inferred from in vivo experiments is a tendency for individual neurones to be innervated in a systematically graded fashion by a contiguous subset of the eight spinal segments which provide innervation to the ganglion.     

Neurons of origin of the internal ramus of the rabbit accessory nerve: localization in the dorsal nucleus of the vagus nerve and the nucleus retroambigualis

The neurons of origin of the internal ramus of the rabbit accessory nerve were identified in the dorsal nucleus of the vagus nerve, using bilateral injections of horseradish peroxidase into the inferior vagal ganglion, soft palate, and pharynx, which were preceded by different combinations of the unilateral intracranial severings of the rootlets of the vagus and glossopharyngeal nerves, those of the cranial root of the accessory nerve, and the trunk of its spinal root. The neurons of origin occupied the caudal four-fifths of the dorsal vagal nucleus extending from about 1.0 mm rostral to the obex as far caudally as the second cervical spinal segment, with their number being about half the total number of neurons of the nucleus. Although considerably fewer, they were also located in the nucleus retroambigualis of the caudal half of the first cervical spinal segment and the second segment. Axons of most internal ramus neurons traversed the rootlets of the cranial accessory root. Axons of the few neurons located more caudally than about 1.0 mm caudal to the obex emerged from the upper cervical spinal cord to run along the trunk of the spinal accessory root before finally joining the internal ramus; caudal to the midlevel of the first cervical segment, the dorsal vagal nucleus and the nucleus retroambigualis contained neurons whose axons followed only that course.     

Anomaly with no right ventral root at the seventh cervical segment in humans: Gross anatomical and neuroanatomical study

The cadaver of an 89-year-old woman who had died of cerebral apoplexy and which was dedicated to anatomy practice for medical students at Kumamoto University, was found to have complete lack of the right ventral root of the seventh cervical segment (C7). Observation of the peripheral spinal nerve indicated that the branch, which appeared to be a descending collateral of the ventral root of C6, became confluent with the dorsal root of C7 at the point just distal to the dorsal root ganglion. Following this confluence, new fiber elements ran out of the intervertebral foramen as the seventh cervical nerve. More peripherally, this fiber bundle joined the brachial plexus, its outward appearance was normal in the manner of ramification and each nerve's supply to muscles. Additionally, the inside view of the spinal cord of C6, C7 and C8 was examined neuroanatomically. Nissl staining of transverse sections at C7 (block 2) showed that motor neurons existed in the right anterior horn and their histological features were normal. Subsequently, horizontal sections were made from the two blocks, each of which contained C6/C7 (block 1) or C7/C8 (block 3), and were treated dually with Nissl and myelin staining. These sections also had a normal picture of cells and myelinated fibers on the right side as compared with those on the left side. The results suggested that motor neurons of the right C7 had a normal supply to the targets, although the trajectory of their axons in the spinal cord was obscure.     

胎儿脊髓脊柱发育的观察

用１９３例正常胎儿尸体观察测量了脊髓的全长、重量，体积，颈膨大，腰骶膨大及终丝等方面出生前的逐月发育值及的变化。在４个月时脊髓已脱离了骶管；出生时脊髓下端位于腰２￣腰３椎体间高度；硬脊膜囊下界位于骶１￣骶２椎体间高度；外终丝止点基本在尾１￣尾２椎体间；脊髓长与身长之比逐月下降，至出生前约为１／３；脊髓重与体重之比始终保持在０．１％左右，脊髓发的性别差异不明显。上述结果可为教学及临床提供基本的参考数     

Microsurgical anatomy of the denticulate ligaments and their relationship with the axilla of the spinal nerve roots

The denticulate ligaments (DL), 20 or 21 pairs of meningeal extensions, spread from the lateral aspect of the spinal cord to the internal aspect of the spinal dura mater. The aim of this study is to define the specific relationship of the DL with adjacent axilla of the spinal nerve roots and to investigate the anatomical features of the DLs and their variations. The topographical anatomy of the DLs and their relationships with the adjacent axilla of the spinal nerve roots was examined on 16 formalin‐fixed adult cadaveric spinal cords. The distances from the dural attachment of the DL to the axilla of the superior and inferior spinal nerve roots were measured bilaterally at every spinal level. Also the distances from the dural attachment of the DL to the lateral aspect of the spinal cord were measured bilaterally. Cervical DLs showed a triangular shape, while in the thoracic segment the ligament changes the shape to “Y.” Also the most caudal DL was identified to be at the L1–2 level. Our study revealed that the distances from the dural attachment of the DL to the superior and inferior spinal nerve root axilla were different at the cervical, upper thoracic and the lower thoracic segments. Both distances to the superior and inferior spinal nerve root axilla were shown to increase from cervical to lower thoracic segments. This study provides a detailed anatomy of the DLs and their relationship with the adjacent spinal nerve root axilla. Clin. Anat. 27:733–737, 2014. © 2013 Wiley Periodicals, Inc.     

Role of Neurotrophin 3 in spinal neuroplasticity in rats subjected to cord transection

That neuroplasticity occurs in mammalian spinal cord is well known, though the underlying mechanism still awaits elucidation. This study evaluated the role of endogenous Neurotrophin-3 (NT-3) in the spinal neuroplasticity. Following cord transection at the junction between T9 and T10, the hindlimb locomotor functions of rats showed gradual but significant improvement from 7 to 28 days post-operation. Corresponding to this was a significant increase in the level of NT-3 in the cord segments caudal to injury site. Significantly, after NT-3-antibody administration, the spinal transected rats displayed poor hindlimb locomotor functions and a decrease in the number of neurons in spinal laminae VIII–IX. Whether NT-3-antibody was administered, corticospinal tract regeneration and somatosensory evoked potentials could not be detected. Our findings suggested that endogenous NT-3 could play an important role in spinal plasticity in adult spinal cords subjected to transection, possibly through a regulation of neuronal activity in the local circuitry.     

Microsurgical Anatomy of Lumbosacral Nerve Rootlets for Highly Selective Rhizotomy in Chronic Spinal Cord Injury

It is known that selective sacral roots rhizotomy is effective for relieving the neurogenic bladder associated with spinal cord injury. The goal of this study is to review the surgical anatomy of the lumbosacral nerve rootlets and to provide some morphological bases for highly selective sacral roots rhizotomy. Spinal cord dissections were performed on five cadavers under surgical microscope. At each spinal cord segment, we recorded the number, diameter and length of the rootlets, subbundles and bundles from the L1 to S2 spinal segments, and the length of the dorsal/ventral root entry zone. Peripheral nervous system myelin was examined by immunohistochemistry. We found: (1) the ventral or the dorsal root of the lumbosacral segment of the spinal cord was divided into one to three nerve bundles and each bundle was subdivided into one to three subbundles. Each subbundle further gave out two to three rootlets connected with the spinal cord; (2) there were no significant differences in the number of rootlets within the L1 to S2 segments, but the size of rootlets and the length of nerve roots varied (P < 0.05); and (3) the more myelinated fibers a rootlet contained, the larger transection area it had. The area of peripheral nervous system myelin positive cells and the total area of rootlets were correlated (P < 0.001). Thus, during highly selective sacral roots rhizotomy, the ventral and dorsal roots can be divided into several bundles of rootlets, and we could initially distinct the rootlets by their diameters. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

大鼠脊髓半横断损伤后硫酸软骨素蛋白多糖Versican的变化

目的观察大鼠脊髓半横断损伤(hSCI)位点头尾段硫酸软骨素蛋白多糖Versican的表达变化,探讨其与脊髓损伤修复的关系。方法20只成年健康SD大鼠随机分为假手术对照组和脊髓半横断损伤3d、7d和14d组。建立成年SD大鼠脊髓半横断(T9～T10)模型。取损伤位点头尾段T9、T10节段制作冰冻切片,运用Versican抗血清进行免疫组化ABC法染色。分别观察并计数各组前角中Versican阳性细胞数,采用计算机图像分析技术测量免疫阳性产物的平均光密度(A)值。结果Versican阳性产物主要分布于细胞外基质中,前角神经元和胶质细胞的胞浆中也有分布;损伤后前角中Versican阳性神经元和胶质细胞数较对照组明显减少(P<0.05),免疫阳性产物平均A值较对照组明显增加(P<0.05)。结论脊髓半横断损伤后,表达增加的Versican很可能参与损伤后轴突生长被抑制的过程。     

Identification of neuroanatomic circuits from spinal cord to stomach in mouse: retrograde transneuronal viral tracing study

To determine the spinal innervation and neuronal connections is important for studying gastric carbohydrate metabolism and motor responses. Neurons involved in the efferent control of the stomach were identified following visualization of pseudorabies virus (PRV)-614 retrograde tracing. PRV-614 was injected into the ventral stomach wall in 13 adult C57BL/6J strain male mice. On the fifth day postinjection, animals were humanely sacrificed, and spinal cords were removed and sectioned, and processed for PRV visualization. The virus injected into the ventral stomach wall was specifically transported to the thoracic spinal cord. At 5 d after injection of the PRV-614, stomach enlargement and tissue edema were found, and PRV-614 positive cells were found in the intermediolateral cell column, the intercalates nucleus or the central autonomic nucleus of spinal cord segments T3 to L1, and major PRV-614 labeled cells were focused in the T6-10 segment. Our results revealed neuroanatomical circuits between stomach and the spinal intermediolateral cell column neurons.     

嗅鞘细胞移植对大鼠脊髓半横断损伤后轴突再生及后肢功能恢复的作用

为了对嗅鞘细胞移植治疗大鼠脊髓损伤(spinal cord injury, SCI)后轴突再生及后肢功能恢复进行综合性的评价,本实验采用22只雌性成年SD大鼠,并随机分成A、B、C、D 4组。其中A、B、D组行左侧T11 ～T12节段脊髓半横断手术,然后A组移植嗅鞘细胞(olfactory ensheathing cells,OECs)悬液;B组移植DMEM/F12培养液;D组移植核荧光试剂(Hoechst33342)标记的嗅鞘细胞,用于鉴定嗅鞘细胞在体内的存活情况;C组作为正常对照组。术后6周内,对大鼠进行BBB评分、IP斜板试验并观察皮质体感诱发电位(cortical somatosensory evoked potential, CSEP)、运动诱发电位(motor evoked potential, MEP)的潜伏期。将辣根过氧化物酶(HRP)注射到横断面尾段脊髓,逆行追踪观察横断面头段脊髓及对侧中脑红核内HRP逆标细胞数,并观察左侧后肢小腿三头肌肌细胞横截面积及直径的变化。结果显示:(1)移植后的OECs数量未见明显减少,细胞核形态较好,细胞未向头、尾侧迁移;(2)移植3周后BBB评分及IP斜板,试验A、B组较C组明显低(P<0.05),但A组明显高于B组(P<0.05);(3)A、B组的CSEP及MEP潜伏期较C组明显延长(P<0.05),但A组要比B组明显缩短(P<0.05);(4)HRP逆行追踪观察到对侧中脑红核大细胞区及脊髓T9 ～T11节段逆标细胞的数量,A组明显多于B组,但A、B组均少于C组;(5)左侧后肢小腿三头肌肌细胞的横截面积及直径,A、B组均较C组减少,但A组减小的幅度明显小于B组。以上结果表明OECs移植能促进半横断脊髓轴突的再生及后肢功能的恢复。     

牛脊髓前角匀浆皮下注射损伤豚鼠脊髓运动神经元

目的探讨牛脊髓前角匀浆对豚鼠脊髓、前根及坐骨神经的影响。方法采用新鲜牛脊髓前角匀浆免疫豚鼠。观察脊髓、前根、坐骨神经光镜及超微结构的变化。结果豚鼠体重在第4次免疫后明显下降。脊髓前角运动神经元变性和丢失,有卫星、噬节及墓穴现象形成。电镜下最主要的表现是线粒体异常;其次神经元核周质内异常神经丝聚集,形成包涵体;轴突内异常神经丝聚集形成轴索球。前根及坐骨神经的变化,表现为轴索变性及继发的髓鞘改变。结论牛脊髓前角匀浆可以作为抗原引起豚鼠脊髓、前根及坐骨神经免疫所介导的损伤,为进一步研究运动神经元病的发病机制提供了可靠的方法。     

脊神经前根吻合重建脊髓损伤大鼠的股四头肌功能

背景：如何重建脊髓损伤肢体运动功能对截瘫患者具有重要的意义。 目的：探索利用脊髓损伤平面以上健存的脊神经前根与支配股四头肌的腰神经建立神经通路,恢复脊髓损伤后股四头肌的神经支配和肌收缩功能。 方法：对清洁级SD大鼠L₁神经根的前根与L3神经根的前根进行显微吻合。经一段时间(6个月)的轴突再生后,期望建立新的肌肉收缩功能。神经缝合后6个月,在破坏L₂ 脊髓节段前后,分别进行神经电生理检测,观察股四头肌神经支配情况。 结果与结论：在同侧L₂半切脊髓前后,电刺激移植神经干时可记录到股四头肌的收缩肌电图。在同侧L₂半切脊髓前后,电刺激L₁感觉根时可同样在股四头肌记录到肌电图。说明利用脊髓损伤平面以上健存的L₁神经根前根与L₃神经前根移植吻合能重建新的股四头肌神经支配反射通路,并使股四头肌低级反射中枢上移。