Characteristics of the electrophysiological activity of muscles attached to the transverse carpal ligament in carpal tunnel syndrome

The main cause of carpal tunnel syndrome (CTS) remains unknown. Stiffness of the subcutaneous area of the volar aspect of the carpal tunnel is present in many patients and suggests that the stiffness of muscles attached to the transverse carpal ligament is increased. We performed an electrophysiological study to investigate muscle activities and to clarify whether the stiffness of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS. The subjects of this study included 16 patients with early CTS showing no motor dysfunction. Both thenar muscles (opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis) and hypothenar muscles (opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis) were investigated. Surface electrodes were placed on each muscle, and maximum voluntary contractions with the thumb and little finger in opposition were maintained for 3 seconds in all patients and in 7 control subjects. Electromyographs were subjected to fast Fourier transform analysis, and the root mean square (RMS) and the mean power frequency (MPF) were determined for each muscle. The RMS of the opponens pollicis was significantly less in hands affected by CTS (292.8 μV) than in healthy hands (405.9 μV). The RMS did not differ between affected hands and healthy hands for the other 2 thenar muscles but did differ significantly for the hypothenar muscles. The MPF did not differ between affected hands and healthy hands for any muscle. The results show that electrophysiological differences are present among muscles innervated by the median nerve and that hypothenar muscles originally unrelated to median nerve dysfunction are also affected in early CTS. These results suggest that modulation of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS.     

人鱼际肌的肌内神经分支分布和肌梭密度研究

目的探索鱼际肌肌肌内神经分支和肌梭密度的分布。方法采用改良Sihler’s肌内神经染色法和HE染色法进行解剖学研究。结果鱼际肌的神经常从肌起端深面入肌,神经入肌后在拇短展肌、拇对掌肌、拇收肌横头内与肌长轴垂直走向,拇收肌斜头和拇短屈肌内沿肌长轴平行走形。80%～82.5%的拇短屈肌和拇指对掌肌接受正中神经和尺神经的双重支配。拇短屈肌浅头和深头、拇收肌横头和斜头有独立的神经支配,可分出神经肌肉亚部。4块肌内神经分支分布密集区多在肌的中部与近端,可见"Y"、"O"、"H"或"U"型等不同的神经吻合形式。鱼际肌肌梭密度高达16.19～27.14个/g,高低顺序为拇指对掌肌拇短屈肌拇短展肌拇收肌。结论鱼际肌肌内神经吻合丰富,肌梭密度高,除拇对掌肌外,其余肌块可作整肌或半肌移植的供体。     

Biometry of thenar muscle origins on the flexor retinaculum

The transverse carpal ligament (TCL), the main part of the flexor retinaculum, serves as an anchor for the thenar muscles: abductor pollicis brevis (APB), superficial head of the flexor pollicis brevis (sFPB), and opponens pollicis (OPP). Biomechanically, the thenar muscles rely on their TCL anchoring to transmit muscle contractions distally for thumb force and motion production, and reciprocally, muscle contraction interacts with the TCL at the proximal end through the origins. However, scarce knowledge exists regarding the distribution pattern of the thenar muscle origins. The purpose of this study was to understand the anatomical interface between the thenar muscles and TCL by examining the origin distributions of the individual muscles. Ten cadaveric specimens were dissected for digitization of the muscle origins and TCL volar surface. Digitized data were used for mesh reconstruction and calculation of surface areas and centroids. The origin areas for APB, sFPB, and OPP were 105.8 ± 30.3, 64.6 ± 15.2, and 245.9 ± 70.7 mm², respectively. The surface area of the TCL was 386.2 ± 86.9 mm². The origin areas of APB and OPP on the TCL were comparable, 18.4 ± 4.8% and 17.3 ± 9.6% of the TCL area, respectively. The origin locations for APB, sFPB, and OPP were in proximal-radial quadrant of the TCL, on distal aponeurosis outside the TCL, and around the ridge of trapezium, respectively. The knowledge of the anatomical interface provides a foundation for the understanding of biomechanical interactions between the muscles and ligaments and pathomechanical implications.     

Case of an abductor pollicis longus muscle: variation or differentiation?

A variation of the abductor pollicis longus muscle in a 65 year old cadaver was encountered during routine dissection in our department. The muscle was found to split into two bellies and give off two tendons, one of which inserted to the abductor pollicis brevis, opponens pollicis and flexor pollicis brevis muscles. The other tendon inserted to the first metacarpal bone which is considered a normal insertion site for the abductor pollicis longus muscle.     

正中和尺掌-腕混合神经潜伏期差在腕管综合征诊断中的应用

目的:评估正中和尺掌-腕混合神经潜伏期差在腕管综合征(CTS)诊断中的应用价值。方法:选取2019年1月至2019年12月在常熟市中医院门诊诊断为CTS的患者47例(77只手掌)作为研究组,同时收集同时段在体检中心健康检查的志愿者46名(69只手掌)作为对照组,分别记录正中神经腕-拇短展肌的远端运动潜伏期(DML)、腕-中指的感觉神经传导速度(SCV)、感觉神经动作电位(SNAP)波幅及正中和尺掌-腕混合神经潜伏期差(ΔDSL)。结果:研究组与对照组比较,腕-拇短展肌DML延长[(4.49±0.97)ms比(3.16±0.42)ms],腕-中指SCV减慢[(42.62±7.35)m/s比(60.65±6.70)m/s],SNAP波幅下降[(11.89±8.05)μV比(22.07±7.22)μV],正中和尺掌-腕混合神经ΔDSL延长[(0.84±0.34)ms比(0.23±0.10)ms],差异均具有统计学意义(P<0.05)。腕-拇短展肌DML、腕-中指SCV、正中和尺掌-腕混合神经ΔDSL诊断特异度分别为97.1%、100%、98.6%(P>0.05),诊断敏感度分别为66.2%、59.2%、90.1%(P<0.05)。结论:正中和尺掌-腕混合神经ΔDSL用于诊断CTS是比较敏感的,尤其可以提高早期CTS的阳性检出率。     

The thenar muscles

Examination of the thenar muscles in 30 anatomical preparations of the hand have shown that the abductor pollicis brevis, the opponens pollicis, and the adductor pollicis muscles are made up of several muscle bellies. The number and insertions of these bellies are varied. Both heads of flexor pollicis brevis do not originate from any particular muscle belly. The superficial head of this muscle always inserted into the head of the thumb metacarpal, either completely, or, some of the fibres of the dorsal aponeurosis of the thumb were attached to the base of the proximal phalanx. Furthermore the anatomy of the abductor pollicis brevis muscle was related to the presence of a tendinous slip from abductor pollicis longus. These variations could have an influence on proprioception in the thumb ray.     

CT examination of the manipulation system in the giant panda (Ailuropoda melanoleuca)

The manipulation mechanism of the giant panda ( Ailuropida melanoleuca ) was examined by means of CT (computed tomography) and 3-dimensional (3-D) Volume Rendering techniques. In the 3-D images of the giant panda hand, not only the bones but also the muscular system was visualised. Sections of the articulated skeleton were obtained. It was demonstrated that the hand of the panda is equipped with separately moulded manipulation units as follows: (1) the radial sesamoid (RS), the radial carpal, and the first metacarpal (R–R–M) complex; and (2) the accessory carpal (AC) and the ulnar (A–U) complex. When the giant panda grasps anything, the R–R–M complex strongly flexes at the wrist joint, the RS becomes parallel with the AC, and the phalanges bend and hold the object. It is shown that the well-developed opponens pollicis and abductor pollicis brevis muscles envelop and fix the objects between the R–R–M complex and the phalanges during grasping.     

47例腕管综合征患者的临床及神经电生理改变特征

目的：分析腕管综合征（CTS）患者临床及神经电生理改变特征,以提高临床诊断准确性。方法：对47例临床症状、体征均符合CTS患者的正中神经和尺神经各55条分别进行运动神经传导速度（MCV）和感觉神经传导速度（SCV）测定,其结果与正常参考值作比较;对拇短展肌和某些病例的掌长肌作针极肌电图（EMG）,观察失神经电位以作鉴别诊断。结果：本组正中神经肘-腕MCV有6条未引出动作电位,41条正常,8条减慢,平均MCV较正常参考值减慢,差异有显著意义（P％0．05）;正中神经远端潜伏期（DML）异常率为96％,平均DML较正常参考值延长,经比较差异有显著意义（P〈0．05）;尺神经肘-腕MCV均在正常范围,其DML异常率为2％,与正常参考值比较差异无统计学意义;正中神经SCV异常率为98％;尺神经SCV异常率为2％;47例共55块拇短展肌EMG有49％见失神经电位。结论：结合临床及神经电生理改变特点,可对CTS作出明确诊断,为治疗提供依据。     

用于显露前臂骨间膜的桡骨背侧入路应用解剖

目的 找出显露前臂骨间膜的最佳入路.方法 用卡尺测量了30例成人上肢,测量项目如下:桡骨头至旋后肌腱弓处骨间背神经的长度(LHA);桡骨头到旋后肌管下口之间骨间背神经的长度(LHS);骨间背神经从旋后肌管下口至桡骨外缘的距离(DSR);骨间背神经从旋后肌管下口至尺骨内缘的距离(DSU);骨间背神经最外侧分支穿拇长展肌处至桡骨外缘的距离(DSP).结果 LHA、LHS、DSR、DSU和DSP的测量结果分别为19.3±4.4mm(11mm～29mm)、53.4±5.2mm(45mm～62mm)、9.7±3.1mm(4mm～15mm)、22.8±3.5mm(20mm～28mm)和7.5±1.6mm(5mm～9mm).牵开拇长展肌、拇短伸肌和拇长伸肌,于桡侧腕短伸肌与指伸肌之间显露前臂骨间膜中1/3和远1/3段.结论 桡骨背侧入路可较少剥离肌肉和软组织,能方便、安全显露前臂骨间膜中1/3和远1/3段.     

Bilateral abductor pollicis longus muscle variation. Case report and review of the literature

An abnormal abductor pollicis longus muscle was encountered bilaterally during the dissection of the upper limb of a 26-year-old male cadaver. In the left side, the abductor pollicis longus had seven tendon slips. The medial two inserted into the abductor pollicis brevis, the other five inserted into the base of the first metacarpal bone. In the right side of the case, the abductor pollicis longus was consisted of three bellies. The lateral belly's tendon was the main abductor pollicis longus tendon and inserted into the base of the first metacarpal bone. The medial belly inserted into the abductor pollicis brevis. Between these muscle bellies, there was an intermediate belly. Its tendon was split into two thin slips and inserted into both the abductor pollicis brevis and the opponens pollicis muscles. The number of such accessory tendons has a functional significance in the development of de Quervain's stenosing tendovaginitis and possibly also has a practical significance. This paper is the first to describe seven tendons of the abductor pollicis longus and extensor pollicis brevis in the same compartment.     

Radial sesamoid bone as a part of the manipulation system in the lesser panda (Ailurus fulgens).

The well-developed radial sesamoid bone presented a rod-like shape in the lesser panda. It could be separated into two components: (1) an ulnar cartilaginous, (2) a radial osseous part. The radial sesamoid bone was connected with four elements as follows: (1) the tendon of the M. abductor pollicis longus, (2) M. abductor pollicis brevis and M. opponens pollicis, (3) Aponeurosis palmaris, and (4) Flexor retinaculum. The bone made no articulation with the first metacarpal. The movement of the radial sesamoid bone may be controlled by the connecting muscles and muscle-related structures. It is suggested that the bone acts as a supporting ridge in the gripping action in the lesser panda. However, we suggest that the grasping mechanism is obviously different from that of the giant panda, in which the radial sesamoid bone is connected strongly with the first metacarpal.     

正中神经返支卡压及易损伤部位的解剖学基础

目的：探讨腕管综合征术后大鱼际功能恢复不良的原因与返支易损伤部位。方法：对20侧成人新鲜上肢标本进行显微解剖，观测正中神经返支走行中存在的卡压因素以及易损伤部位。结果：(1)拇短屈肌浅头尺侧存在腱弓及腱纤维束结构，对正中神经返支形成卡压；(2)住屈肌支持带远侧返支与掌腱膜关系密切，在此部位掌腱膜可对返支形成卡压或术中易误伤返支；(3)走行中返支与拇长屈肌腱和示指屈肌腱存在交叉走行关系。结论：(1)返支走行中存在易卡压因素，治疗腕管综合征时应常规探查松解返支；(2)涉及拇长屈肌腱，示指屈肌腱和掌腱膜手术时，应注意防止损伤返支。     

小鱼际肌肌内神经和肌梭密度分布

目的揭示小鱼际肌肌内神经和肌梭密度的分布规律。方法对成年20具尸体(40例)小鱼际标本用改良Sihler肌内神经染色法和苏木精-伊红(HE)染色法。结果小鱼际肌肌外神经干长0.49～1.64 cm,从肌起端深面入肌。小指展肌内尺侧和桡侧有独立的神经支配,可分为两个神经肌亚部;小指短屈肌的肌内神经干斜行穿越肌实质中央;小指对掌肌内神经吻合形式多样,"U"型吻合更明显。3块肌的桡侧部神经分支分布密集。小指对掌肌肌梭密度最高为(19.33±2.72)个/g;小指短屈肌其次,有(15.79±1.33)个/g;小指展肌最少,为(12.86±1.69)个/g。结论三块肌桡侧部更多地参与精细调节;肌块越小,肌梭密度越高。     

拇短展肌对拇指指骨间关节背伸作用的解剖学研究

目的　为解决胸小肌移植重建拇对掌功能术后出现拇指指骨间关节屈曲畸形提供解剖学依据并寻找解决办法。 方法　在15具尸体手标本上,使拇指处于对掌位时,测量拇指指骨间关节在拇短展肌未切断及切断两种情况下的自然屈曲角度;同时,通过外力作用使拇指指骨间关节分别屈曲处于45°及60°时,分析拇短展肌对拇指指骨间关节屈伸功能的影响。 结果　拇指处于对掌位时,拇短展肌在未切断及切断两种情况下,拇指指骨间关节自然屈曲角度分别为（13.30±2.13）°及（24.03±1.25）°;同时,使拇指指骨间关节屈曲处于45°时,所用外力分别约（0.50±0.08）N及（0.22±0.07）N,而使拇指指骨间关节屈曲处于60°时,所用外力分别约（1.48±0.09）N及（1.15±0.04）N。 结论　拇短展肌对拇指指骨间关节主要起背伸作用,因此胸小肌移植重建拇对掌功能时,应同时重建拇短展肌功能,才有可能纠正在拇对掌功能重建术后出现的拇指指骨间关节屈曲畸形。     

Electrophysiologic study of anomalous innervation of the intrinsic hand muscles

With electrophysiological methods the possible presence of anomalous innervation and/or of anastomosis between the median and ulnar nerve in the intrinsic hand muscles was studied in 34 limbs. The abductor pollicis brevis was supplied by the ulnar nerve in 12% to 38%, the first dorsal interosseus by the median nerve in 4.2% to 19.6%; the abductor digiti minimi was in no case supplied by the median nerve.     

足部相关肌肉、肌腱组织材料弹性模量的测定

背景：目前,几乎所有足部三维有限元模型的材料参数均来自国外研究,尚未见有关国人组织材料参数的测量与报道。 目的：对国人足部的相关肌肉、肌腱材料做测量,获得初步的参数数据。 方法：解剖成年女性左小腿足新鲜标本拇长屈肌及其肌腱、拇短屈肌内外侧头、拇长伸肌及其肌腱、拇收肌横头及斜头、拇展肌,分别测量和计算各试样的截面积和位于夹具之间的长度并记录数值,将标本加载载荷,1个测样反复测量4次,采集强度极限、最大载荷等数据,以及载荷-位移曲线。根据胡克定律,计算各标本的弹性模量。 结果与结论：共得到了包括拇长伸肌、拇长屈肌、拇收肌、拇展肌横头和斜头、拇短屈肌内外侧头、拇长屈肌腱、拇长伸肌腱9个样本的相关测量数据,主要包括长度、宽度、厚度、横截面积、最大载荷、强度极限和弹性模量。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;组织工程全文链接：     

重症腕管综合征的神经电生理诊断

目的：探讨重症腕管综合征（CTS）的神经电生理诊断价值。方法：回顾性分析了常规神经电生理检查正中神经运动和感觉传导均未诱发出电位即重症CTS者38例（44只手）,分别在正中神经和尺神经手腕处刺激,在第二蚓状肌和手掌骨间肌记录混合肌肉动作电位（CMAP）起始潜伏时差。结果：重症CTS44只手中,40只手（91％）在正中神经和尺神经刺激时,第二蚓状肌和手掌骨间肌记录CMAP起始潜伏时差延长,与正常对照组对比,其差异有统计学意义,4只手第二蚓状肌记录未引出波形;拇短展肌肌电图全部异常。结论：第二蚓状肌和手掌骨间肌记录CMAP起始潜伏时差测定是一项快速、简单而准确的诊断重症CTS的神经电生理检查方法。     

Neurovascular relationships of the approaches for arthroscopic total trapeziectomy with ligamentous stabilization

The aim of this study was to define the neurovascular relationships of the approaches used during arthroscopic total trapeziectomy with the Thompson "suspension-plasty." Fifteen fresh cadavers in which trapezio-metacarpal arthritis had been confirmed by preoperative radiographs were chosen. There were 12 women and 3 men (average age: 87 years), and small joint arthroscopy equipment was used. Two approaches for the trapezio-metacarpal joint were used: an ulnar approach situated at the ulnar border of the extensor pollicis brevis tendon and a radial approach placed at the middle of a line joining the tendons of the flexor carpi radialis and the abductor pollicis longus. A new transosseous approach at the base of the first metacarpal ("trans-M1" approach) is suggested and was used to do the ligamento-plasty. After the operation, a large skin flap was elevated in order to measure the distance between each surgical approach and the different neurovascular structures (radial artery, dividing branches of the superficial branch of the radial nerve and the end of the lateral cutaneous nerve of the forearm) and to verify the absence of neurovascular lesions. The different neurovascular structures at risk during this arthroscopic maneuver were the radial artery for the ulnar approach, the branches of the superficial branch of the radial nerve for all of the approaches and the ending of the lateral cutaneous nerve of the forearm for the radial and "trans-M1" approaches. The use of the approaches described allows arthroscopic trapeziectomy with the Thompson suspension-plasty without us having noted neurovascular lesion.