Peculiarities of the sural nerve complex morphologic types in human fetuses

The sural nerve is the most frequently used sensory nerve in nerve transplantation. It can be transplanted alone or together with the other elements of the neurovascular stalk within the superficial sural flap. The aim of this study was to define the morphologic types of the sural nerve complex, as well as to describe their specific characteristics. Microdissection was performed on 100 human fetuses (200 calves) after 10% formalin fixation. Five morphologic types of sural nerve complex with different incidence were defined. Two morphologic types dominated: type I (58.5%) in which the sural nerve was formed by merging of a fibular communicating branch and the medial sural cutaneous nerve, and type III (26%) in which the medial sural cutaneous nerve took over the function of the sural nerve. Other morphologic variations were less common.     

Origin and make up of the human sural nerve

Abstract The dissection of 37 cadavers has shown that in only a third of cases, the sural nerve comes from the communication between the medial cutaneous nerve, derived from the tibial nerve, and the communicating branch of the lateral cutaneous nerve of the leg which comes from the lateral popliteal nerve. The communication is most often at the junction between the proximal two-thirds and distal third of the leg, on average 2 mm below the transverse crease of the popliteal fossa. The medial cutaneous nerve was absent in only one case. On the other hand, in 11 cases the lateral cutaneous nerve or its communicating branch was missing. In 12 cases without any anastomoses, the route of the sural nerve was followed by the medial cutaneous nerve of the leg in 9 cases and by the lateral cutaneous nerve in 3 cases. The majority of branches to the proximal half of the calf came from the lateral cutaneous nerve. In the lower part of the leg, the sural nerve and/or the medial cutaneous nerve gave numerous branches to the Achilles’ tendon and to the integuments of the lateral aspect of the heel and lateral malleolus.     

Formation and location of the sural nerve in the newborn

In this study, the location and formation of the sural nerve were examined in 40 legs of new-born cadavers. The sural nerve was formed by the peroneal communicating branch from the common peroneal nerve joining the medial sural cutaneous nerve in 27 of 40 legs (67.5%). It was formed by the peroneal communicating branch from the lateral sural cutaneous nerve joining the medial sural cutaneous nerve in 4 (10%). It was formed by the peroneal communicating branch from the common peroneal nerve and fibers from the posterior femoral cutaneous nerve joining the medial sural cutaneous nerve in 2 (5%). In 5 of 40 legs (12.5%), the medial sural cutaneous nerve was in the place of the sural nerve without joining any other nerve. In one case (5%), the sural nerve was not formed bilaterally.     

腓肠神经临床应用解剖及其临床意义的研究进展

目的 探讨腓肠神经的应用解剖及其在相关手术入路中的损伤风险。方法 以“腓肠神经”“解剖”“手术入路”和“sural nerve”“anatomy”“surgical approaches”为中英文关键词,在中国知网、万方数据、SinoMed、PubMed等中英文数据库检索2000年1月-2019年7月间有关腓肠神经临床应用解剖的文献,检索到文献999篇,剔除内容不符合、无法获取原文、重复性研究或存在设计缺陷的文献,最终纳入34篇。总结腓肠神经应用解剖研究成果,重点阐述踝关节骨折的后外侧入路和跟骨骨折的L型入路、跗骨窦入路,以及第五跖骨基底部骨折入路等4种手术入路与腓肠神经的解剖学关系。结果 研究显示,腓肠神经在解剖学上变异类型众多,其走行区域与踝关节骨折的后外侧入路、跟骨骨折的L型入路和跗骨窦入路、第五跖骨基底部骨折入路4种手术入路的关系十分密切。结论术前正确掌握腓肠神经的解剖特点,对足踝骨折手术入路选择以及减少手术中腓肠神经损伤风险至关重要。     

Anatomical and histological basis of surgery to the radial nerve

Summary A study of the anatomical relationships of the radial nerve centered on those areas of greatest clinical interest, that is to say the spiral groove of the humerus and the radial canal of the elbow. The microscopical study based on serial histological sections from 7 specimens showed an immense variation in topography and in the number and diameter of nerve bundles in the different specimens. No particular endoneural fascicular organization was apparent to us from the studies. Emphasis is placed on the high percentage of connective tissue in relation to nervous tissue. All these factors together makes alignment of a sectioned nerve exceedingly difficult for the surgeon. Among other clinical applications of the study, the authors draw attention to the relationship of the radial nerve to disorders of the epicondyle.

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Bases anatomiques et histologiques dans la chirurgie du nerf radial

Résumé L'étude des rapports du nerf radial est centrée sur les régions d'intérêt clinique dans la gouttiére de torsion de l'humérus et dans le canal radial au coude. L'etude microsocipique par coupes histologiques sériées sur 7 spécimens fait apparaître une trés grande variabilité dans la topographie, le nombre et le diamétre de fascicules chez les différents spécimens. Aucune systématisation fasciculaire endoneurale ne nous est aaparue possible dans notre série. L'accent est mis sur le grand pourcentage du tissu conjonctif par rapport au tissu nerveux. Tous ces éleéments rendent difficile la réparation nerveuse aprés section. Parmi les applications cliniques, les auteurs insistent sur les relations entre le nerf radial et les épicondylalgies.

     

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 relative contributions of the medial sural and peroneal communicating nerves to the sural nerve

The medial sural cutaneous nerve (MSCN) and peroneal communicating nerve (PCN) conjoin in the calf area to form the sural nerve (SN). In previous anatomic studies, there was unresolved debate as to the main contributor to the sural nerve, and the relative contributions of MSCN and PCN had not been studied. The purpose of this study is to determine their relative neurophysiologic contributions to the SN by nerve conduction study (NCS). A total of 47 healthy subjects (25 males and 22 females, mean age 29.6 +/- 10.4 yrs, range 20-59 yrs) participated in the study. This study employed the orthodromic nerve conduction technique: stimulation at the ankle and recording at the mid calf (SN); specifically, we preformed stimulation at the mid calf (MSCN, PCN) and recording at 14 cm proximal to the middle of the popliteal fossa (MSCN) and fibular head (PCN). The onset and peak latencies (ms) were SN 2.3 +/- 0.2 and 3.0 +/- 0.2; MSCN 2.1 +/- 0.2 and 2.8 +/- 0.2; and PCN 2.1 +/- 0.2 and 2.8 +/- 0.2. The peak-to-peak amplitudes (microV) and areas (nVsec) of the SN, MSCN, and PCN were 9.7 +/- 3.9, 7.0 +/- 4.7, and 5.0 +/- 3.2; and 7.2 +/- 2.9, 5.7 +/- 3.4, and 4.0 +/- 2.4, respectively. The side-to-side difference was not statistically significant. The main contributor to the SN was found to be the MSCN. The relative contribution ratio of the MSCN to the PCN was 1.37:1 by amplitude and 1.42:1 by area. However, in 32.9% of the subjects, the contribution of the PCN was greater than that of the MSCN.     

Techniques for digital histological morphometry of the pineal gland

IntroductionThe pineal gland is a small photo-neuro-endocrine organ. This study used human post-mortem pineal glands to microscopically assess immunohistochemical marker intensity and percentage of positivity using known and novel digital techniques.Materials and methodsAn experimental non-inferiority study has been performed on 72 pineal glands harvested from post-mortem examinations. The glands have been stained with glial fibrillary acidic protein (GFAP), synaptophysin (SYN), neuron-specific enolase (NSE), and neurofilament (NF). Slides were digitally scanned. Morphometric data were obtained using optical analysis, CaseViewer, ImageJ, and MorphoRGBResultsStrong and statistically significant correlations were found and plotted using Bland-Altman diagrams between the two image analysis software in the case of mean percentage and intensity of GFAP, NSE, NF, and SYN.DiscussionsSoftware such as SlideViewer and ImageJ, with our novel software MorphoRGB were used to perform histological morphometry of the pineal gland. Digital morphometry of a small organ such as the pineal gland is easy to do by using whole slide imaging (WSI) and digital image analysis software, with potential use in clinical settings. MorphoRGB provides slightly more accurate data than ImageJ and is more user-friendly regarding measurements of parenchyma percentage stained by immunohistochemistry. The results show that MorphoRGB is not inferior in functionality.ConclusionsThe described morphometric techniques have potential value in current practice, experimental small animal models and human pineal glands, or other small endocrine organs that can be fully included in a whole slide image. The software we used has applications in quantifying immunohistochemical stains.     

腓肠神经营养血管蒂岛状皮瓣的应用解剖

目的 :为带腓肠神经营养血管蒂岛状皮瓣的临床应用提供解剖学依据。方法 :在 3 8侧经动脉灌注红色乳胶成人下肢标本上解剖观测腓肠神经及营养血管的起始、走行、分支分布、吻合及外径 ,2侧成人新鲜下肢标本墨汁灌注观察营养血管的墨染范围。结果 :腓肠神经由腓肠内侧皮神经与腓神经交通支汇合而成 ,其汇合点在外踝上 12 .7± 3 .7cm ,腓肠神经沿窝中点至外踝与跟腱中点连线下行 ,外踝上 12 .6± 3 .4cm处穿出深筋膜。其营养血管主要来源于窝中间皮动脉和腓动脉肌间隔穿支 ,上段起始部外径 0 .6± 0 .1mm ,下段距外踝上 6.7± 1.6cm处与腓动脉穿支恒定吻合 ,吻合支外径 0 .6± 0 .1mm ,沿途发出众多筋膜皮支营养小腿后部皮肤。结论 :以腓肠神经及其营养血管为蒂可设计切取顺行或逆行岛状皮瓣。     

直肠癌手术相关腹膜后自主神经的筋膜解剖学观察

目的　从临床解剖学和组织学角度进一步阐明盆自主神经的筋膜层次。 方法　选取7具尸体标本和52例接受腹腔镜直肠癌切除手术的病人,观察其自主神经与肾前筋膜-骶前筋膜的关系。切取尸体降乙结肠系膜与主髂动脉之间、直肠系膜与骶骨骨膜之间的腹膜后组织做组织学检查。 结果　解剖学观察显示,腹主动脉丛、上腹下丛、腹下神经、下腹下丛位于肾前筋膜-骶前筋膜后外侧。组织学检查显示：神经纤维位于筋膜后,部分较细的纤维位于筋膜内。 结论　自主神经位于肾前筋膜-骶前筋膜后外侧。保持这一筋膜的完整性,是直肠癌手术中保护自主神经的解剖学基础和基本方法。     

Anatomical basis of neurotisation of the median nerve in the hand by the radial nerve

Summary The sensory sequelae after lesions of the median nerve cause difficulties in treatment since few sensory transfers are available. Neurotisation of the median by sensory branches of the radial nerve have aroused little interest although they have already been used by some authors after anastomosis at the wrist or through the first or second interosseous spaces. Based on what was originally a purely anatomic study, our interest was directed to the possibilities of performing more distal neurotisation for the treatment of sensory disorders of limited extent. The chief object was to obtain faster sensory reinnervation. 30 hands were dissected and a radial branch was defined as suitable for neurotisation whose diameter approximated that of its palmar digital homolog. Only those findings constantly observed in analysis of the hands studied were taken into account. It is therefore possible to reliably define the type and site of the routes of approach as well as the sensory branches suitable for neurotisation.

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Bases anatomiques de la neurotisation du nerf médian à la main par le nerf radial

Résumé Les séquelles sensitives après lésion du nerf médian posent un problème thérapeutique car peu de transferts sensitifs sont disponibles. La neurotisation du médian par les branches sensitives du radial suscite peu d'intérêt bien que déjà utilisée par quelques auteurs après anastomose au poignet ou à travers le ler ou 2ème espace inter-osseux. A partir d'un travail uniquement anatomique, notre intérêt s'est porté sur les possibilités effectives de neurotisations plus distales pour le traitement de troubles sensitifs limités dans leur topographie. L'intéret étant surtout d'obtenir une réinnervation sensitive plus rapide. 30 mains ont ainsi été disséquées. Nous avons défini comme neurotisable un rameau radial dont le diamètre était voisin de son homologue digital palmaire. Seules ont été prises en compte les données constantes retrouvées après l'analyse des mains étudiées. Il est ainsi possible de définir de manière fiable le type et le siège des voies d'abord ainsi que les rameaux sensitifs utilisables pour la neurotisation.

     

Anatomical variations of the human sural nerve and its role in clinical and surgical procedures

The sural nerve is the most commonly nerve used in nerve transplantation, and so the aim of this study was to determine the variations of the sural nerve in the back of the leg, its relations to the calcaneal tendon and lateral malleolus, and determine the patterns of its distribution on the dorsum of the foot. Twenty‐four Egyptian legs and feet were dissected. The results showed that the sural communicating nerve connected with the sural nerve in 87.5%. The predominant site of union between these two nerves was in the lower one‐third of the leg and ankle region (62%). There was only one right leg that the sural nerve passed through the gastrocnemius. The small saphenous vein passed along the medial side of the sural nerve in 100%. The sural nerve crossed the lateral border of the calcaneal tendon in 50%. The distance between the sural nerve and insertion of calcaneal tendon was 16 + 7 mm in 91.7%. There were four types of pattern of innervation of the toes by the sural nerve. The predominant pattern was type I (45.8%), where the lateral side of the little toe was supplied by the sural nerve alone. The second pattern was type IV (29.2%), where the lateral 2 ½ toes were supplied by the sural nerve alone. These findings are important for sural nerve biopsy and grafts, surgical repair of the calcaneal tendon, and regional anesthesia of the foot. Clin. Anat. 24:237–245, 2010. © 2010 Wiley‐Liss, Inc.     

Differences between steady-state and transient post-synaptic potentials elicited by stimulation of the sural nerve

Summary In cat medial gastrocnemius motoneurons, single stimuli to the cutaneous sural nerve evoke a post-synaptic potential with a mixture of depolarization and hyperpolarization, depolarization being dominant in type F cells and hyperpolarization in type S cells. This pattern is consistent with previous reports showing that activation of the sural nerve can sometimes reverse the normal order of motor unit recruitment by inhibiting S motor units while simultaneously exciting F motor units. However, during repetitive stimulation for 1–2 s, we found that the hyperpolarizing component of the sural input to medial gastrocnemius motoneurons was not persistent, but instead gave way to depolarization after the first 30 ms. The net steady-state response after 0.5–1.0 s of stimulation was depolarization in all cells, regardless of motor unit type. This suggests that tonic sural input may be incapable of producing prolonged recruitment reversals.     

The marginal mandibular branch of the facial nerve

The peripheral, extraparotid course and localisation of the marginal mandibular branch of the facial n. is described, with variations, based on the dissection of 40 cadaver half heads. Its anatomical relationships with the ramus of mandible and facial a. are studied and morphometric features are reported. Knowledge of the accurate course and relationship of the marginal mandibular branch should help to protect this nerve from surgical injury.     

The marginal mandibular branch of the facial nerve

Summary The peripheral, extraparotid course and localisation of the marginal mandibular branch of the facial n. is described, with variations, based on the dissection of 40 cadaver half heads. Its anatomical relationships with the ramus of mandible and facial a. are studied and morphometric features are reported. Knowledge of the accurate course and relationship of the marginal mandibular branch should help to protect this nerve from surgical injury.

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Étude anatomique du rameau marginal de la mandibule du nerf facial

Réumé Sur la base de la dissection de 40 hémi-têtes, le trajet distal extra-parotidien et la situation du rameau marginal de la mandibule du nerf facial sont décrits. Les rapports anatomiques entre ce rameau et l'artère faciale sont étudiés et les aspects morphologiques décrits. La connaissance du trajet précis et des rapports du rameau marginal de la mandibule est utile pour la protection de ce nerf au cours des interventions chirurgicales.

     

Anatomical bases of tibial neurotomy for treatment of spastic foot

Spastic pes equines, possibly associated with varus posture or spastic claw of the toes, can require neurosurgical treatment. In these cases, a selective fascicular neurotomy can be proposed, which consists of a partial section of some motor collateral branches of the tibial nerve. In order to avoid sensory and trophic complications after surgery due to an excessive manipulation of the nerve, accurate anatomical data must be collected. Therefore, biometric, histological and ultrastructural studies were carried out. A total of 50 dorsal compartments of the leg were dissected. The distance between the emergence of each muscular branch of the tibial nerve and anatomical landmarks were measured. Complementary histological study was processed on three specimens with slices stained by Masson's trichromatic method. Eventually, electronic microscopy observation was processed on two other specimens. In 16 cases (32%), we found a common muscular branch for all the muscles of the dorsal leg compartment, which emerged from the nerve trunk near the tendinous arch of the soleus (67 +/- 29 mm from the femorotibial articular line). In the other cases, muscular branches of the nerve emerged from its ventral lateral aspect, with variable origins (inferior nerve for the soleus: 82 +/- 31 mm from the femorotibial articular line, nerve for flexor digitorum longus: 116 +/- 41 mm, nerve for tibialis posterior: 106 +/- 51 mm, with a second nerve in 9/50 cases, nerve for flexor hallucis longus: 129 +/- 48 mm, with a second nerve in 6 cases). Histological and ultrastructural analysis confirmed the presence of the motor nervous fibers in the ventral lateral part of the nerve trunk. These new anatomical findings allow a more precise dissection during operative procedure, in order to avoid sensory or trophic complications.     

腓肠神经的交感成分及其对腓肠神经营养血管皮瓣血流动力学影响的探查

目的　探讨腓肠神经是否有发出交感纤维支配其伴行血管及腓肠神经切段后近端蒂腓肠神经营养血管皮瓣的血流动力学会出现何种相应变化。 方法　在探明兔下肢腓肠神经及其伴行血管相应解剖后,取17只白兔,其中2只白兔直接处死,取腓肠神经血管束。其余15只（30侧后肢）随机等分入神经保留组与神经切断组。神经保留组白兔在行皮瓣切取术后,不对腓肠神经进行处理;神经切断组则在皮瓣掀起后将腓肠神经在其起点处切断。在相应时间点处死两组动物,取腓肠神经营养血管束行乙醛酸染色。利用红外热像仪对上述两组皮瓣术后24 h皮瓣的平均温度进行测量。 结果　神经切断组术后3、5及7 d 3个时间点腓肠神经内荧光点及其伴行动脉外膜荧光出现高度一致性的下降,组间荧光评分具有显著性差异(F=13.563, P=0.004)。神经保留组在术后整个过程中荧光强度未出现明显改变。术后2 h起,神经保留组皮瓣平均温度低于神经切断组,两者差异具有统计学意义（P＜0.05）。 结论　腓肠神经有发出交感纤维至其伴行血管,调节其伴行血管张力。腓肠神经切段后,近端蒂腓肠神经营养血管皮瓣的微循环会出现相应改善,皮瓣存活率有可能增加。