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。     

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.     

Single motor unit F-waves in the thenar muscles studied by the multichannel surface EMG

The thenar motor units (MUs) were studied by the multichannel surface electromyography (EMG) technique. The median nerve was stimulated at the wrist by repetitive submaximal stimulation. Three hundred consecutive evoked responses were recorded from the thenar muscles of 5 healthy volunteers with a 32 channel matrix-type multielectrode. Seven channel F-wave waveforms in a selected electrode array were classified using a template-matching method. The F-wave parameters, amplitudes, latencies and muscle fiber conduction velocities (MFCVs), were calculated to evaluate the properties of single MU F-wave. Most of the F-waves (93.3%) were composed of a single motor unit action potential (MUAP). The numbers of MU classified from single MU F-waves in 5 subjects were 11, 8, 13, 13 and 13, respectively. Many of them (84.5%) were originated from the abductor pollicis brevis (APB), and there were a few MUs originated from the flexor pollicis brevis (FPB). Significant correlations were found between F-wave amplitudes and latencies in 3 subjects.     

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.     

Needle electromyography in carpal tunnel syndrome

The role of needle electromyography (EMG) in the routine evaluation of carpal tunnel syndrome (CTS) is not clear. The aim of this study was to determine if needle EMG examination of the thenar muscles could provide useful information in addition to the nerve conduction (NC) studies. Electrophysiologic procedures performed on 84 patients (103 hands) consistent with CTS were reviewed. The median thenar motor NC data were matched with the needle EMG findings in the abductor pollicis brevis (APB) muscle. The severity of the needle EMG findings in the APB muscle correlated well with the severity of the motor NC data. As the thenar compound muscle action potential amplitude decreased and the degree of nerve conduction slowing and block across the wrist increased, there was a corresponding increase in the number of enlarged motor units and decrease in the recruitment pattern in the needle EMG findings. Needle EMG examination confined to the thenar muscles in CTS does not seem to provide any further information when the NC data had already established this diagnosis, and it should not be performed routinely.     

Fiber type composition of contiguous palmaris longus and abductor pollicis brevis muscles: Morphological evidence of a functional synergy

The palmaris longus (PL) tendon is used in surgical opponensplasty to restore functional hand movements in thenar paralysis. Although successful PL autologous tendon transfer has been attributed to an established synergistic relationship between the PL and abductor pollicis brevis (APB) muscles in vivo, this functional relationship may be dependent on the quality of their spatial relationship and properties of their constituent muscle fibers. The purpose was to compare the proportion of type I and type II muscle fibers in the APB based on its contiguous morphological relationship with the PL tendon for indirect insight into their functional synergy, contractile capacity, and digastric arrangement. Twenty-four contiguous PL and APB specimens were harvested from the upper limbs (12 right and 12 left) of twelve formalin-embalmed cadavers (mean age: 74 ± 10 years). The fiber type composition of these muscles was determined by labeling serial cross sections with myosin heavy chain (MyHC) type I and type II monoclonal antibodies. The PL consisted of a relatively heterogeneous fiber type composition irrespective of the presence of a discrete (type I: 41 ± 11%; type II: 55 ± 12%; hybrid: 4 ± 3%) or rudimentary (type I: 49 ± 10%; type II: 45 ± 9%; hybrid: 6 ± 4%) tendinous connection with the APB. The APB fascicles arranged contiguously with the PL through a discrete tendon had significantly greater proportions of type II fibers (41 ± 19%) compared to those with rudimentary PL connections (type II: 15 ± 8%). Therefore, the APB fascicles arranged in a digastric relationship with the PL may have the capacity to produce more powerful contractions than those with rudimentary PL tendons based on the known contractile properties of type II muscle fibers. Knowledge of the spatial relationship between the PL and thenar musculature prior to PL autologous tendon transfer may be a useful indicator of the quality of established synergy in vivo.     

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.     

Biomechanical alterations in the carpal arch and hand muscles after carpal tunnel release: A further approach toward understanding the function of the flexor retinaculum and the cause of postoperative grip weakness

The difference between maximal and minimal distance covered (the distance between the trapezium ridge and hamate hook; moment exerted on structures: I Nm) by an intact flexor retinaculum (FR; minimum, 3.3 ± 0.1 cm; maximum, 3.7 ± 0.2 cm) and the increase in the maximal distance on carpal tunnel release (CTR; increase, 1.6 ± 0.2 mm) were significant. Under an external supination moment, the distance between the attachments of the trapeziopisiform band increased after CTR. Under external pronation and ulnar abduction moments, the distance between the attachments of the scaphoideohamate band increased after CTR. The CTR resulted in an anatomic attachment loss for the following muscles: the superficial head of the flexor pollicis brevis (shortening by ∼25%, relative to rest length), the ulnar part of the abductor pollicis brevis (with opposition and adductory functions, ∼20%), the opponens pollicis (∼20%), the middle part of the abductor pollicis brevis (∼7%), and the opponens digiti minimi (∼10%). Preoperative and postoperative (2–7 weeks after surgery) measurements of the reaction force of the distal phalanx (under isometric thumb opposition and finger II–IV flexion with extended carpal joint) led to differentiation of three groups: (1) significant strength loss—the patients showed difficulties with grasping, lifting, twisting off lids and caps, screwing, pulling ropes, and pinching; (2) no significant change in force values; and (3) a significant increase in strength (patients who could grip more firmly). © 1996 Wiley-Liss, Inc.     

Quantitative analysis of the intrinsic muscles of the hand

As part of a study involving three-dimensional modeling of the hand, the intrinsic muscles of the hand were evaluated quantitatively to estimate the range of muscular forces crossing the fingers. The Brand method of dissection allowed determination of muscle volume, fiber length, and physiologic cross section to estimate the maximal force. The intrinsic muscles were grouped by components on the basis of their origins in the trilaminar scheme of Cunningham as (1) dorsal abductors from the central ray, exemplified by the bipennate dorsal interossei; (2) the intermediate layer consisting of inter-phalangeal joint extensors, exemplified by the unipennate palmar interossei with insertions into the extensor expansion; and (3) a superficial layer of adductors arising from the third metacarpal ridge, referred to as contrahentes. The fiber lengths of either component of the dorsal interossei averaged 1.3 cm. The intermediate layer of muscle, numbered as flexores breves (FB), included the palmar interossei FB_4,7,9; the superficial components of the dorsal interossei FB_3,5,6,8; and the accessory adductor pollicis FB₂. Fiber lengths averaged 1.7 cm. The superficial heads of the flexor pollicis brevis and abductor digiti quinti are possibly the border representations of the intermediate layer as FB₁ and FB₁₀. The thenar muscles made up 37%, dorsal interossei 24%, palmar interossei (flexores breves) of the fingers 16%, lumbricals 7%, and hypothenar muscles 16% of the total intrinsic muscle mass. The ratio of muscle mass to fiber length, the physiologic cross-sectional area, is useful in estimating available force. This quantitative analysis of the intrinsic musculature may find application in the understanding of hand function and biomechanics.     

Static dynamometer for the measurement of multidirectional forces exerted by the thumb

The functioning of a static dynamometer designed to measure simultaneous forces exerted by the thumb in the vertical and horizontal axes is described. The analysis of the output signals by a desktop computer program provides information regarding the forces generated in eight directions covering a plane transverse to the thumb by 45° increments. In 12 normal female subjects, the maximum voluntary torques exerted at the trapezo-metacarpal joint of the thumb were examined and the muscle activation patterns of the interosseus, flexor pollicis brevis and adductor pollicis brevis muscles were recorded in one subject. Torques and muscle activation patterns were depicted using polar plots. Dynamometric data indicate that strength varies with direction and that higher torques are obtained in directions that bring the thumb towards the palm, i.e. flexion, adduction, combined flexion-adduction and extension-adduction. Patterns of muscle activity vary according to the direction evaluated suggesting that strength depends on the number of activated muscles as well as the relative force contribution of each muscle.     

Excitability changes in human hand motor area induced by voluntary teeth clenching are dependent on muscle properties

To investigate whether the early effects of voluntary teeth clenching (VTC) among the first dorsal interosseous (FDI), abductor digiti minimi (ADM), and abductor pollicis brevis (APB) muscles are differently modulated depending on their muscle properties, we examined the responses of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation with selected current directions and by brainstem magnetic stimulation (BMS). Although MEP responses with anterior-medially current direction (preferentially elicited I1-waves) were facilitated in all three muscles, those responses with posterior-laterally current direction (preferentially elicited I3-waves) were different among FDI, ADM, and APB muscles. That is, MEP responses in FDI and APB muscles were significantly reduced, whereas those responses in ADM muscle were not significantly reduced. Further, inhibitory effects of VTC in FDI muscle were more potent than those in ADM or APB muscles. On the other hand, the responses to BMS were unchanged by VTC in all three muscles, suggesting that the modulations of MEP were attributed to the cortical origin. On the basis of our previous findings that the inhibitory connections in FDI muscle are more potent than those in ADM muscle (Takahashi et al. in Clin Neurophysiol 116:2757–2764, 2005), the cortical effects of VTC among three hand muscles are differently modulated, depending on muscle properties, presumably the extents of inhibitory connections to corticospinal tract neurons. Considering that the functional capacity in FDI muscle is higher than that in ADM or APB muscles, the cortical inhibitory effect of VTC might contribute to the sophisticated regulation of the motor outputs even during VTC.     

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。     

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：     

Effect of force development on contraction induced glucose transport in fast twitch rat muscle

A previous study has shown that in fast twitch frog sartorius muscle contraction stimulated glucose transport depends only on stimulation frequency and not on workload. In contrast, we have recently shown that in rat slow twitch muscle stimulated to contract at constant frequency, glucose transport varies directly with force development and, in turn, metabolism. The present study was carried out to clarify whether the discrepancy between the earlier studies reflected differences in physiological behaviour between fast and slow twitch muscle. We investigated the effect of force development on glucose transport in incubated fast twitch rat flexor digitorum brevis (rich in type 2a fibres) and epitrochlearis (rich in type 2b fibres) muscle. Muscles were electrically stimulated to perform repeated tetanic contractions at 1 Hz for 10 min. Resting length was adjusted to achieve either no force or maximum force. Glucose transport (2‐deoxyglucose uptake) increased when force was produced compared with when it was not (P < 0.05) in both flexor digitorum brevis (19 ± 7 (basal), 163 ± 14 (no force) and 242 ± 17 (max force) nmol × g^–1 × 5 min^–1) and epitrochlearis (60 ± 4 (basal), 100 ± 7 (no force) and 125 ± 6 (max force) nmol × g^–1 × 5 min^–1). In both muscles glucose transport increased in parallel with metabolic rate, as reflected by muscle lactate concentrations and 5′ AMP‐activated protein kinase activity, during contractions. In conclusion, as previously shown for rat soleus muscle, at a given stimulation frequency glucose transport varies directly with force development in rat flexor digitorum brevis and epitrochlearis muscle. Accordingly, force development enhances glucose transport in all mammalian muscle fibre types. The influence of force development probably reflects effects of enhanced 5′ AMP‐activated protein kinase activity resulting from reduced intra‐cellular energy status and pH.     

Bilateral small-hand-muscle motor evoked responses in a patient with congenital mirror movements

In a 56 year old patient with congenital mirror movements involving the muscles of the hands and forearms, transcranial electrical stimulation of either the left or right motor-cortex hand area induced bilateral surface electromyographic (EMG) responses in the abductor pollicis brevis (APB) muscles with normal latencies (21 msec). Slight volitional background contraction of the APB muscle contralateral to the stimulated motor cortex enhanced the motor evoked potential (MEP) and shortened the latency of the response by about 3 msec, while no definite facilitation was detected in the ipsilateral APB muscle. Volitional activation of the APB muscle ipsilateral to the stimulated motor cortex failed to enhance the response or shorten the latency of the response in either APB muscle. It is concluded that a fast conducting uncrossed or double crossed corticospinal system plays an important role in the execution of ipsilateral involuntary mirror movements and may be explained by aberrant reorganization of the pyramidal system.     

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.     

Covariation between human intrinsic hand muscles of the silent periods and compound muscle action potentials evoked by magnetic brain stimulation: evidence for common inhibitory connections

Transcranial magnetic stimuli at different stimulus intensities were applied in six healthy subjects to test the hypothesis that, in different intrinsic hand muscles, the duration of the resultant cortically evoked silent periods (C-SPs) from each stimulus would be positively correlated between muscles, indicating a common inhibitory mechanism. A figure-of-eight coil discharging through a Magstim 200 stimulator delivered 25 stimuli at each stimulus intensity at a minimum of five intensities ranging from 55% to 160% of the individual resting motor threshold. In each subject, simultaneous surface recordings from pairs of muscles were made from the first dorsal interosseous (FDI), opponents pollicis (OP), abductor pollicis brevis (APB) and abductor digiti minimi (ADM). The C-SP durations within all three muscle pairs tested were highly correlated (P<0.001). The amplitude of the preceding compound-muscle action potentials (CMAPs) was positively correlated between FDI and OP, but not between APB and ADM or FDI and ADM. C-SP duration was linearly related to stimulus intensity, but did not correlate with the latency or amplitude of the preceding CMAP. SPs elicited by peripheral nerve stimuli in pairs of hand muscles did not co-vary significantly. The results provide evidence that inhibitory influences of cortical origin are distributed widely to intrinsic hand muscles. In contrast, covariation of excitatory effects only appears between muscles synergistically involved in a motor task. Received: 16 February 1998 / Accepted: 20 May 1998