正常成人近段坐骨神经的弥散张量成像**

背景：弥散张量成像及神经纤维束示踪的出现为外周神经细微结构的显示及定量分析提供了新的方法。 目的：前瞻性分析健康成人大腿近段坐骨神经纤维束示踪、弥散张量成像的可行性及最佳成像参数。 方法：采用单次激发自旋回波-平面回波技术对28名健康志愿者双侧坐骨神经进行弥散张量成像及神经纤维束示踪,b值分别为1 200,1 400,1 600 s/mm2。 结果与结论：弥散张量成像及神经纤维束示踪成功者26名,成功率93%,神经纤维束示踪图上能清晰显示近段坐骨神经,与T1WI上解剖图像融合较好。两侧坐骨神经具有相同的弥散特征：随着b 值增加,信噪比逐渐减少,b值为1 200 s/mm2,信噪比值最大为142.72±32.25,神经纤维束长度最长,所占体素最大,但不同b值的弥散张量参数无差异(P > 0.05),且两侧坐骨神经弥散张量参数无差异。说明正常成人大腿近段坐骨神经的弥散张量成像及经纤维束示踪是可行的,可清晰显示坐骨神经走行及弥散特征;最佳b值为1 200 s/mm2。 关键词：弥散张量成像;坐骨神经;磁共振成像;神经纤维束示踪术;成年人 doi:10.3969/j.issn.1673-8225.2012.09.030     

The subparaneurial compartment: A new concept in the clinicoanatomic classification of peripheral nerve lesions

Based on our experience in treating peripheral non‐neural sheath derived pathology, we have identified a novel pattern of lesion progression along the anatomic course of nerves. This report highlights the existence of a subparaneurial compartment around peripheral nerves. We first applied an anatomic framework to review MR images and intraoperative photographs of patients treated by the senior author in the last 10 years. After identifying a pattern that was consistent with subparaneurial lesion progression, we searched for other examples of cases that might exhibit this pattern. Four examples of subparaneurial pathology were identified, a hemangioma of the ulnar nerve, a ganglion cyst of the common fibular nerve, a lymphoma of the sciatic nerve and a lipoma of the ulnar nerve. All four patients were operated on and had intraoperative photographs; three had high resolution MR imaging. This report highlights the existence of pathology contained within a subparaneurial compartment, outside of the epineurium, that follows the course of the nerve and surrounds it circumferentially. The subparaneurial localization of peripheral nerve lesions has hitherto received little attention. Identification of this new pattern on preoperative MRI may have implications for surgical management. Clin. Anat. 28:925–930, 2015. © 2015 Wiley Periodicals, Inc.     

Restoration of motor function of the deep fibular (peroneal) nerve by direct nerve transfer of branches from the tibial nerve: an anatomical study

Traction injuries of the common fibular (peroneal) nerve frequently result in significant morbidity due to tibialis anterior muscle paralysis and the associated loss of ankle dorsiflexion. Because current treatment options are often unsuccessful or unsatisfactory, other treatment approaches need to be explored. In this investigation, the anatomical feasibility of an alternative option, consisting of nerve transfer of motor branches from the tibial nerve to the deep fibular nerve, was studied. In ten cadaveric limbs, the branching pattern, length, and diameter of motor branches of the tibial nerve in the proximal leg were characterized; nerve transfer of each of these motor branches was then simulated to the proximal deep fibular nerve. A consistent, reproducible pattern of tibial nerve innervation was seen with minor variability. Branches to the flexor hallucis longus and flexor digitorum longus muscles were determined to be adequate, based on their branch point, branch pattern, and length, for direct nerve transfer in all specimens. Other branches, including those to the tibialis posterior, popliteus, gastrocnemius, and soleus muscles were not consistently adequate for direct nerve transfer for injuries extending to the bifurcation of the common fibular nerve or distal to it. For neuromas of the common fibular nerve that do not extend as far distally, branches to the soleus and lateral head of the gastrocnemius may be adequate for direct transfer if the intramuscular portions of these nerves are dissected. This study confirms the anatomical feasibility of direct nerve transfer using nerves to toe-flexor muscles as a treatment option to restore ankle dorsiflexion in cases of common fibular nerve injury.     

Injection of the sciatic nerve with TMEV: a new model for peripheral nerve demyelination

Demyelination of the human peripheral nervous system (PNS) can be caused by diverse mechanisms including viral infection. Despite association of several viruses with the development of peripheral demyelination, animal models of the condition have been limited to disease that is either autoimmune or genetic in origin. We describe here a model of PNS demyelination based on direct injection of sciatic nerves of mice with the cardiovirus, Theiler's murine encephalomyelitis virus (TMEV). Sciatic nerves of FVB mice develop inflammatory cell infiltration following TMEV injection. Schwann cells and macrophages are infected with TMEV. Viral replication is observed initially in the sciatic nerves and subsequently the spinal cord. Sciatic nerves are demyelinated by day 5 post-inoculation (p.i.). Injecting sciatic nerves of scid mice resulted in increased levels of virus recovered from the sciatic nerve and spinal cord relative to FVB mice. Demyelination also occurred in scid mice and by 12 days p.i., hindlimbs were paralyzed. This new model of virus-induced peripheral demyelination may be used to dissect processes involved in protection of the PNS from viral insult and to study the early phases of lesion development.     

Extracting structural features of rat sciatic nerve using polarization-sensitive spectral domain optical coherence tomography

We present spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) imaging of peripheral nerves. Structural and polarization-sensitive OCT imaging of uninjured rat sciatic nerves was evaluated both qualitatively and quantitatively. OCT and its functional extension, PS-OCT, were used to image sciatic nerve structure with clear delineation of the nerve boundaries to muscle and adipose tissues. A long-known optical effect, bands of Fontana, was also observed. Postprocessing analysis of these images provided significant quantitative information, such as epineurium thickness, estimates of extinction coefficient and birefringence of nerve and muscle tissue, frequency of bands of Fontana at different stretch levels of nerve, and change in average birefringence of nerve under stretched condition. We demonstrate that PS-OCT combined with regular-intensity OCT (compared with OCT alone) allows for a clearer determination of the inner and outer boundaries of the epineurium and distinction of nerve and muscle based on their birefringence pattern. PS-OCT measurements on normal nerves show that the technique is promising for studies on peripheral nerve injury.     

Anatomical relation between sciatic nerve and piriformis muscle and its bifurcation level during fetal period in human

Purpose

The aim of this study is to determine the morphometric development, location and variant formations of the sciatic nerve using anatomic dissection method during the fetal period.

Methods

Sciatic nerves of 200 human fetuses (103 males and 97 females) aged between 9 and 40 weeks of gestation were studied bilaterally. The bifurcation level of the sciatic nerve to its terminal branches was evaluated with respect to popliteal fossa. Then the length of the sciatic nerve, starting from where it leaves the piriformis muscle till the bifurcation point of the nerve, and its width at the point where it leaves infrapiriforme foramen and its width at the bifurcation level were measured. We also measured the distance of the sciatic nerve to the ischial tuberosity, the greater trochanter and the intergluteal sulcus. Mean values and standard deviations of all parameters according to trimesters were calculated.

Results

We found that all parameters increase with age during the fetal period (P < 0.05). Parameters do not show any significant differences between sexes (P > 0.05). In our analysis, we observed that in 98 % of the cases (on the right and the left side) the sciatic nerve leaves the pelvis below the piriformis muscle. The remaining cases (2 %) are variant formations.

Conclusion

We believe that our study will be useful for better understanding of sciatic nerve development and it may contribute to future studies in obstetrics, orthopedics and fetal pathology. Knowledge of variant formations of the sciatic nerve, its bifurcation level and its relation with neighboring structures may be important for blockade of the nerve in newborn surgeries.     

坐骨神经鞘膜的形态学观察

目的 明确成人盆部坐骨神经筋膜鞘存在与否及其完整性,为临床坐骨神经阻滞提供形态学依据。方法 选用14具盆腔至腘窝段完整的成人坐骨神经标本,采用局部乳胶注射解剖（10例）,矢状位、水平位断层解剖（2例）,组织学切片（2例）和磁共振（MRI）（20例）等方法来观察坐骨神经盆腔段的形态学特点。
结果 盆部乳胶未沿神经根走行扩散;断层和组织学资料显示,骶丛神经根无完整鞘膜包裹,骶丛神经和闭孔神经之间无筋膜分割;MRI结果与断层结果相符。结论 坐骨神经根在成人盆腔段无完整筋膜鞘包裹,骶旁阻滞可以阻滞到闭孔神经。     

Normal values of F wave in lower extremities of 73 healthy individuals in Iran

F wave latency has been shown to be a simple and valuable method in evaluation of proximal part of peripheral nerves. According to our previous study of F wave of upper extremity nerves (1), maximum normal F wave latency for the median nerve was 28 ms with stimulation at wrist and 25 ms with stimulation at elbow. These values for the ulnar nerve were 29 ms and 25 ms respectively. Maximum normal difference between right and left F wave latency with wrist stimulation was 2 ms for median nerve and 2.5 ms for ulnar nerve. Maximum normal difference between median and ulnar nerve F latency was 3.5 ms with stimulation at wrist. In this study we measured F wave of lower extremity nerves in 73 healthy individuals in Shiraz. Maximum normal F wave latency for tibial nerve was 55 ms with stimulation at ankle and 46 ms with stimulation at popliteal area. Maximum normal F wave latency for the peroneal nerve was 54 ms with stimulation at ankle and 47 ms with stimulation at fibular head. Mean F ratio for both nerves was 1.29 with stimulation at knee. Maximum normal difference in F wave latency between right and left lower extremities was 3.5 ms with stimulation at ankle and 3 ms with stimulation at knee for the peroneal nerve. These values were 3 ms and 2.5 ms for the tibial nerve respectively. Maximum normal difference in F wave latency between tibial and peroneal nerve was 4 ms with stimulation at ankle and 3 ms with stimulation at knee.     

Peripheral nerve explants grafted into the vitreous body of the eye promote the regeneration of retinal ganglion cell axons severed in the optic nerve

Summary We have conducted experiments in the adult rat visual system to assess the relative importance of an absence of trophic factors versus the presence of putative growth inhibitory molecules for the failure of regeneration of CNS axons after injury. The experiments comprised three groups of animals in which all optic nerves were crushed intra-orbitally: an optic nerve crush group had a sham implant-operation on the eye; the other two groups had peripheral nerve tissue introduced into the vitreous body; in an acellular peripheral nerve group, a frozen/thawed teased sciatic nerve segment was grafted, and in a cellular peripheral nerve group, a predegenerate teased segment of sciatic nerve was implanted. The rats were left for 20 days and their optic nerves and retinae prepared for immunohistochemical examination of both the reaction to injury of axons and glia in the nerve and also the viability of Schwann cells in the grafts. Anterograde axon tracing with rhodamine-B provided unequivocal qualitative evidence of regeneration in each group, and retrograde HRP tracing gave a measure of the numbers of axons growing across the lesion by counting HRP filled retinal ganglion cells in retinal whole mounts after HRP injection into the optic nerve distal to the lesion. No fibres crossed the lesion in the optic nerve crush group and dense scar tissue was formed in the wound site. GAP-43-positive and rhodamine-B filled axons in the acellular peripheral nerve and cellular peripheral nerve groups traversed the lesion and grew distally. There were greater numbers of regenerating fibres in the cellular peripheral nerve compared to the acellular peripheral nerve group. In the former, 0.6–10% of the retinal ganglion cell population regenerated axons at least 3–4 mm into the distal segment. In both the acellular peripheral nerve and cellular peripheral nerve groups, no basal lamina was deposited in the wound. Thus, although astrocyte processes were stacked around the lesion edge, a glia limitans was not formed. These observations suggest that regenerating fibres may interfere with scarring. Viable Schwann cells were found in the vitreal grafts in the cellular peripheral nerve group only, supporting the proposition that Schwann cell derived trophic molecules secreted into the vitreous stimulated retinal ganglion cell axon growth in the severed optic nerve. The regenerative response of acellular peripheral nerve-transplanted animals was probably promoted by residual amounts of these molecules present in the transplants after freezing and thawing. In the optic nerves of all groups the astrocyte, microglia and macrophage reactions were similar. Moreover, oligodendrocytes and myelin debris were also uniformly distributed throughout all nerves. Our results suggest either that none of the above elements inhibit CNS regeneration after perineuronal neurotrophin delivery, or that the latter, in addition to mobilising and maintaining regeneration, also down regulates the expression of axonal growth cone-located receptors, which normally mediate growth arrest by engaging putative growth inhibitory molecules of the CNS neuropil.     

Anatomical variations of the sural nerve

An anatomical study of the formation of the sural nerve (SN) was carried out on 76 Thai cadavers. The results revealed that 67.1% of the SNs were formed by the union of the medial sural cutaneous nerve (MSCN) and the lateral sural cutaneous nerve (LSCN); the MSCN and LSCN are branches of the tibial and the common fibular (peroneal) nerves, respectively. The site of union was variable: 5.9% in the popliteal fossa, 1.9% in the middle third of the leg, 66.7% in the lower third of the leg, and 25.5% at or just below the ankle. One SN (0.7%) was formed by the union of the MSCN and a different branch of the common fibular nerve, running parallel and medial to but not connecting with the LSCN, which joined the MSCN in the lower third of the leg. The remaining 32.2% of the SNs were a direct continuation of the MSCN. The SNs ranged from 6-30 cm (mean = 14.41 cm) in length with a range in diameter of 3.5-3.8 mm (mean = 3.61 mm), and were easily located 1-1.5 cm posterior to the posterior border of the lateral malleolus. The LSCNs were 15-32 cm long (mean = 22.48 cm) with a diameter between 2.7-3.4 mm (mean = 3.22 mm); the MSCNs were 17-31 cm long (mean = 20.42 cm) with a diameter between 2.3-2.5 mm (mean = 2.41 mm). Clinically, the SN is widely used for both diagnostic (biopsy and nerve conduction velocity studies) and therapeutic purposes (nerve grafting) and the LSCN is used for a sensate free flap; thus, a detailed knowledge of the anatomy of the SN and its contributing nerves are important in carrying out these and other procedures.     

The significance of tibial and common peroneal nerves in nerve blocks

Purpose

The aim of this study was to elucidate the anatomical location of tibial nerve (TN) and common peroneal nerve (CPN) in the popliteal crease for specific nerve block.

Methods

Fifty fresh specimens from 27 adult Korean cadavers (16 males and 11 females, age 35–87 years) were investigated. Five of the 27 cadavers were used to determine the depths of nerves in cross-section.

Results

Tibial nerve was located 50 % from the most lateral point of the popliteal crease and 1.4-cm deep to the surface. In 20 % of the 50 specimens, the medial sural cutaneous nerve branched out below or at the popliteal crease, whereas the CPN was located at 26 % from the most lateral point of the popliteal crease and 0.7-cm deep from the surface. Furthermore, in 6 % of specimens the lateral sural cutaneous nerve branched out below or at the popliteal crease.

Conclusion

The results concerning the location of the TN and CPN at the popliteal crease offer a good guide to optimal nerve block.     

带腓肠外侧皮神经及其营养血管筋膜皮瓣的应用解剖

目的 为带腓肠外侧皮神经及其营养血管筋膜皮瓣的临床应用提供解剖学基础.方法 在32例成人下肢标本上,对腓肠外侧皮神经及其营养血管进行解剖观测.结果 腓肠外侧皮神经在腓骨头平面上方 7.1±2.4cm处起于腓总神经,分布于小腿后外侧上半或上2/3的皮肤.其营养动脉主要为:腓肠外侧皮动脉:起自腘动脉,在腓骨头平面上方5.0±1.5cm处浅出,外径为0.9±0.3mm;肌间隔筋膜皮支:起自胫后动脉和腓动脉,分别在腓骨头平面下方9.2±3.8cm和15.8±3.8cm处浅出,外径为0.7±0.3mm和0.9±0.4mm.该营养动脉除在腓肠外侧皮神经周围或其内呈链式吻合外,还发出筋膜皮支与邻位的皮动脉连接.静脉血可沿伴行静脉或小隐静脉及其属支回流至深静脉.结论 以腓肠外侧皮神经及其营养血管为蒂,可设计成顺行或逆行转位筋膜皮瓣,修复邻近部位的软组织缺损.     

腓总神经与腓骨颈的关系及其小腿各肌支的解剖学研究

目的明确腓总神经与腓骨颈的关系以及小腿各肌支的解剖学特征。方法取成人下肢标本40例,在肉眼及放大镜下解剖,观察腓总神经与腓骨颈的关系以及腓总神经各肌支的数目及走行,以腓骨头最突出点为测量起点,测量腓总神经绕腓骨颈处至腓骨头最突出点的距离;测量各肌支的发出点、入肌点的高度,并作统计学分析。结果腓总神经绕腓骨颈处至腓骨头最突出点的距离,左、右侧分别为(1.64±0.36)cm和(1.58±0.34)cm。各肌支的数目不等,其中胫骨前肌支数目最多,腓骨短肌支和跗长伸肌支的数目较少。40例标本中,腓总神经均穿行于腓骨颈部骨一筋膜管。结论腓总神经在绕腓骨颈处均穿行于骨一筋膜管。提示:这可能是导致腓总神经卡压综合征的主要原因之一;不同肌肉的神经肌支数目差别较大,与其所支配肌肉的结构、功能有关。     

High and low lateral approaches to the popliteal artery

Using a series of 20 dissections and two anatomic transverse sections of a lower limb, the authors investigated the lateral approaches to the popliteal artery. The high lateral approach (above the knee) is not very aggressive and gives access to the retro-genicular part of the popliteal artery. After cutaneous and fascial incision, a simple gap between the vastus lateralis and biceps femoris mm. allows easy exposure of the popliteal vessels after backward retraction of the sciatic nerve. The low lateral approach to the artery (below the knee) is very aggressive for the vessels, nerves, and ligaments of the area. It involves the resection of the upper fourth of the fibula and the isolation and protection of the common peroneal nerve Nevertheless, these lateral approaches must be known and used when classic approaches (medial and posterior) are impossible.     

The promotion of peripheral nerve regeneration by chitooligosaccharides in the rat nerve crush injury model

Chitooligosaccharides (COSs), the biodegradation product of chitosan, have shown many biological functions. In this study, we examined the possible benefits of treatment with COSs (M.W. 800) on regeneration of rat crushed sciatic nerves. The rats with sciatic nerve crush injury were administered intraperitoneally daily with 3 or 6 mg/kg body weight of COSs over a 3-week period. During and at the end of COSs treatment, a series of functional and histological examinations, including the measurement of withdrawal reflex latency (WRL) values, walking track analysis, electrophysiological assessments, morphometric analysis of gastrocnemius muscle, as well as immunohistochemistry and electromicroscopy to regenerated sciatic nerves, were performed to evaluate the therapeutic outcomes of COSs. The experimental data demonstrated that COSs promoted peripheral nerve regeneration with the desired functional recovery in the rat sciatic nerve crush injury model. This study raises a possibility of developing COSs as a potential neuroprotective agent for peripheral nerve repair applications.     

Similarities and dissimilarities of the blood supplies of the human sciatic,tibial, and common peroneal nerves

The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty‐six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. Fetal age ranged from 12 to 28 weeks of gestation. Microdissection of the fetal lower extremities was done under ×5 magnifying lenses. The sciatic nerves of 10 lower extremities were dissected and excised and radiographs taken. The extraneural arterial chain of the sciatic nerve was composed of 2–6 arterial branches of the inferior gluteal artery, the medial circumflex femoral artery, the perforating arteries, and the popliteal artery. The extraneural arterial chain of tibial nerve was composed of 2–5 arteries, which were branches of the popliteal, the peroneal, and the posterior tibial arteries. Radiographs showed the presence of complete intraneural arterial chains in the sciatic and tibial nerves, formed from anastomosing vessels. Dissection showed that, in 97.2% of the specimens, the common peroneal nerve was supplied only by one popliteal artery branch, the presence of which was confirmed radiologically. The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression. Clin. Anat. 26:875–882, 2013. © 2012 Wiley Periodicals, Inc.     

人股二头肌肌内神经分布和神经入肌点定位

目的查清人股二头肌长头和短头的肌内神经分布和神经入肌点定位,为其肌移植提供形态学依据。方法(1)观察20具尸体股二头肌长头和短头的神经分支数量,拟将坐骨结节与股骨外上髁连线分4等份,观测神经入肌点水平。(2)用3具童尸股二头肌做Sihler's肌神经染色,观察肌内神经分布。结果(1)长头神经来自坐骨神经胫侧,神经肌支一支型占22.5%,两支型72.5%,三支型5.0%,入肌点位于1/4区占22.1%,2/4区57.1%,3/4区20.8%。短头神经来自坐骨神经腓侧,一支型占95.0%,两支型5.0%,入肌点在肌的近部浅面。(2)长、短头肌内神经分支各形成一条神经支配带,横过各肌束中段。结论股二头肌长头和短头有单独神经支配。长头神经支配多见于两支型,神经入肌点多见于2/4区。     

兔坐骨神经急性损伤的高频超声影像学观察

目的用高频超声观察兔坐骨神经急性损伤的超声图像表现,评价其临床诊断价值。方法16只健康家兔随机分为4组,建立兔坐骨神经急性损伤模型,分别在损伤后第1、2、4、8周,应用高频超声在同部位上观察双侧坐骨神经的声像图变化。结果坐骨神经损伤后,在不同阶段,高频超声均可观察到相应变化图像改变与神经损伤后退变、再生及肢体功能在动态变化上相一致。结论高频超声可实时准确反映神经退变和再生的过程,为诊断外周神经损伤提供新方法,对临床判断和预后提供客观依据。