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。     

Long Abductor Digiti Minimi Muscle: Variation of the Hypothenar Muscles and Clinical Consequences

Variations in the hypothenar muscles influence the susceptibility of Guyon's canal and surgical procedures in this region. The hypothenar regions of both hands of 38 human donors were dissected and the single muscles identified. A semiquantitative evaluation included 19 donors. The opponens digiti minimi and the abductor digiti minimi were constantly present. The flexor digiti minimi showed various appearances: in 58% it formed one belly, in 21% two bellies, and in 21% it was missing. Rare unilateral supernumerary muscles (2.5% in this study) were associated to the abductor digiti minimi. The variation of the flexor digiti minimi and the possible appearance of additional muscles should be recognized for hypothenar region pathologies. Clin. Anat., 33:643–645, 2020. © 2019 Wiley Periodicals, Inc.     

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。     

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.     

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.     

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.     

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.     

Anomalous flexor digiti minimi brevis in Guyon's canal

In an adult male cadaver, the flexor digiti minimi brevis, a muscle of the hypothenar eminence, was found to arise from the superficial transverse septum (between the superficially placed flexor carpi ulnaris, palmaris longus, and flexor carpi radialis muscles, and the deeply placed flexor digitorum superficialis muscle) in the distal fourth of the flexor aspect of the left forearm. The muscle exhibited two strata of muscle fibers at its origin. The superficial stratum was a thin layer of transversely running fibers confined to the forearm, which has not been previously reported. The deep stratum, a thick layer of longitudinally running fibers, formed the bulk of the muscle. It traversed Guyon's canal superficial to the ulnar nerve and vessels to reach the hypothenar eminence. Its course through Guyon's canal could be a cause for ulnar tunnel syndrome. The ulnar nerve trunk innervated not only the anomalous flexor digiti minimi brevis muscle, but also abductor digiti minimi and palmaris brevis. This may be due to the common phylogeny of these three muscles from the same muscle mass.     

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.     

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。     

小指对掌肌腱弓的解剖学研究

目的探讨Guyon管以远尺神经深支卡压征的解剖学基础。方法对20例新鲜成人上肢标本腕部进行显微解剖，肉眼及镜下观测腕部尺神经分支与周围组织的关系。结果尺神经穿出Guyon管后进入小指对掌肌浅、深两头和钩骨钩之间的间隙，该间隙可分为顶、底和桡侧壁，有一个入口和一个出口，暂称其为小指对掌肌间隙。小指对掌肌浅头腱性起点的近侧缘锐利，呈腱弓样，存在率100％，暂称其为小指对掌肌腱弓。结论小指对掌肌腱弓可以卡压尺神经深支，引起除小鱼际肌以外的尺神经支配的所有手内在肌的功能障碍。     

足底内侧和外侧群肌的肌内神经整体分布模式及临床意义

目的 揭示足底内侧和外侧群肌的肌内神经整体分布模式,探讨其临床意义.方法 24具成年尸体,完整取下足底内侧和外侧群肌,采用改良Sihler染色显示肌内神经分布模式.结果 (足母)收肌的神经支从肌止端的深面入肌,而(足母)展肌、(足母)短屈肌、小趾展肌和小趾短屈肌的神经支常从肌起端的深面入肌.(足母)展肌中有1个半月形和...     

Variation in the hypothenar muscles and its impact on ulnar tunnel syndrome

Compression of the ulnar nerve at Guyon’s canal can be caused not only by tumor-like structures, a fibrotic arch, a ganglion, lipoma, aneurysm or thrombosis but also by anomalous hypothenar muscles which are reviewed here. For the search of relevant papers, PubMed and crucial anatomical textbooks were consulted. The abductor digiti minimi is the most variable hypothenar muscle. It can possess one to three muscle bellies. Additional heads can arise from the flexor retinaculum, the palmaris longus tendon, the pronator quadratus tendon or the deep fascia of the palmar side of the forearm. Our own case of an aberrant abductor digiti minimi appearing like connective tissue and originating in the antebrachial fascia is included here. Hematoxylin and eosin staining revealed that macroscopically non-muscle-like tissue contained skeletal muscle tissue. The muscle itself resembled other described cases. In addition, at the flexor digiti minimi accessory heads with origin from the flexor retinaculum, the antebrachial fascia or the long flexor muscles of the forearm can be detected. By contrast, the opponens digiti minimi mostly lacks variations and is sometimes missing. In our opinion, this is due to its hidden location. However, in few cases an additional head can arise from the lower arm aponeurosis. Furthermore, additional (fourth) hypothenar muscles might be expressed. These muscles are characterized by origins in the forearm and insertions on the head of the 5th metacarpal bone or on the 5th proximal phalanx. It must be noted that accessory hypothenar muscles might look like connective tissue at first glance. Often their origin extends to the antebrachial fascia. This can be explained by the phylogenetic fact that all intrinsic muscles of the hand are derived from muscle masses that originated in the forearm. In the opinion of several authors, ulnar nerve compression mostly is evoked by hyper trophied variant hypothenar muscles due to overuse as for example in carpenters. In some rare cases, an aberrant hypothenar muscle can also evoke median nerve compression.     

Undescribed variant muscle – “Deep abductor-flexor” of the little finger, in relation to ulnar nerve compression at the wrist

During routine anatomical dissection in the hypothenar region of the left hand of a 64-year-old female cadaver, a number of variant structures were observed. The most prominent finding in our case was a supernumerary muscle hitherto unknown in the anatomical literature. This variant muscle had a muscular body formed by the connection of two deeply situated muscular bellies--medial and lateral. The lateral belly originated from the flexor retinaculum, the medial one--from the hamate bone. The common muscular body inserted to the antero-lateral surface of the base of the fifth proximal phalanx. Due to its location and possible function, we named the variant muscle "deep abductor-flexor" of the little finger. The flexor digiti minimi brevis muscle showed two proximal tendons--the medial tendon was attached to the hamulus of the hamate bone while the aberrant lateral tendon originated from the lateral part of the flexor retinaculum. Both, the aberrant lateral tendon of the flexor digiti minimi brevis and the lateral belly of the "deep abductor-flexor", passed over the palmar branch of the ulnar nerve, which define their possible clinical significance in ulnar nerve compression. Therefore, the variations of the hypothenar muscles are reviewed and their relation to the compression of the ulnar nerve is discussed.     

Reinnervation of motor units in intrinsic muscles of a transplanted hand

Functional recovery of transplanted hand can be evaluated clinically but until now there has been no direct assessment of muscle control. In October 2000 we transplanted the right hand of a brain-dead man aged 43 onto a man aged 35 who had lost his right dominant hand 22 years before. Starting from day 205 after the transplant, multi-channel surface electromyographic (EMG) signals were recorded from intrinsic muscles of the transplanted hand in order to assess their degree of reinnervation. Eleven months post-operatively, the first motor unit action potential train was detected from the abductor digiti minimi. One month later, also the abductor pollicis brevis and the opponens pollicis muscles showed motor unit activity, while, after 15 and 24 months, the first dorsal interosseous and the first lumbricalis muscles, respectively, showed activation of their first motor units. An increase in the number of active motor units was observed after the first signs of reinnervation, although the process was rather slow. In sustained maximal contractions, the motor unit discharge rate decreased from (mean +/- S.D.) 34.0+/-6.7 pps to 23.4+/-5.1 pps in 60 s for the abductor digiti minimi, although the subject was verbally encouraged to maintain a maximal activation. Moreover, the subject was able to perform basic control tasks involving voluntary modulation of motor unit discharge rate. With a visual feedback, he could increase discharge rate of the abductor digiti minimi approximately linearly over time, from 13.4+/-6.7 pps to 32.5+/-11.2 pps in 60 s. In conclusion, we showed reinnervation of single motor units in a transplanted hand after 22 years of denervation. Moreover, voluntary modulation of discharge rates of these motor units could be performed since the first sign of reinnervation.     

An accessory belly of the abductor digiti minimi muscle: a case report and embryologic aspects

Accessory fasciculi of the hypothenar muscles have been involved in vascular and nerve compressions. During a routine dissection an accessory belly of the abductor digiti minimi muscle arising from the tendon of the palmaris longus muscle was found in the lower third of the forearm. The accessory fasciculus ran through Guyon’s canal enclosing the ulnar nerve and vessels. It was attached by means of two tendons where the fibres of the abductor digiti minimi muscle ended in a single pennate form. This anatomic variation was associated with a marked reduction of the caliber of the fourth tendon of the flexor digitorum superficialis muscle and a split of the median nerve. The nerve supply arose from the ulnar nerve. A fibrous band originating from this accessory muscular belly was found covering the median nerve. Based on the development of muscles and fibrous structures within the hand and forearm, as well as on our results, we consider the present anomalies as an unusual persistence of an undifferentiated group of mesenchymal cells. These belong to the superficial muscular anlagen layer of the hand, just between the flexor digitorum superficialis muscle blastema (which has the capacity of migration) and that for the abductor digiti minimi muscle.     

Doubled palmaris longus muscle (with accessorius ad flexorem minimi digiti)

An unusual combination of variations is described in a palmaris longus muscle. The muscle was completely doubled with a tendinous cross slip. Insertion was on the hypothenar and thenar fasciae, and carpal bones. One of the 2 tendons formed the origin of an accessorius ad flexorem minimi digiti muscle.     

Innervation of the abductor digiti minimi muscle of the human foot: anatomical basis of the entrapment of the abductor digiti minimi nerve

The origin, relationships and innervation of the abductor digiti minimi muscle were determined in 145 human feet, from formaldehyde-fixed cadavers. The muscle arises from both processes of the calcaneal tuberosity, from the plantar aponeurosis and from the septum which separates it from the flexor digitorum brevis muscle. The nerve to the abductor digiti minimi muscle arises next to the origin of the lateral plantar nerve, close to the abductor hallucis muscle, and descends becoming closely related to the medial face of the calcaneus and the deep face of the abductor hallucis muscle. Then, it passes inferiorly through the origin of the quadratus plantae muscle and later divides into two branches for the two heads of the muscle.     

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.