Anatomic bases for the compression and neurolysis of the deep branch of the radial nerve in the radial tunnel

The anatomy of the radial tunnel was studied on twenty-five elbow preparations. We noted five different elements that could affect the deep branch of the radial nerve in the radial tunnel and cause an entrapment syndrome: a capsule-tendon-aponeurotic complex on the anterior aspect of both the humeroradial joint and the radial head, the vascular arcade formed by the radial recurrent a. and its branches, the arcade formed by the medial edge of extensor carpi radialis brevis muscle, and the superior and inferior arcades of the superficial layer of the supinator muscle. These results are compared with recent anatomical and clinical data, and the relevance of a surgical approach between the extensor carpi radialis brevis and longus muscles is discussed.     

骨间后神经受压的解剖学基础

目的阐明骨间后神经(PIN)卡压的原因及其手术治疗提供解剖基础。方法30侧尸体上肢标本,将PIN分为3段(即桡管段、旋后肌管段和旋后肌管后段)观察其肌支的分支情况;用卡尺对桡管(RT)、旋后肌管(ST)和桡侧腕短伸肌腱弓(AECRM)的形态和大小进行了观测,并对ST入口和出口的体表投影定位。结果ST入口和出口的宽度分别为(14.1±2.1)mm和(6.2±1.7)mm,长度为(35.0±6.9)mm。PIN从桡骨头至旋后肌腱弓(AF)和PIN从旋后肌穿出处的长度分别为(19.3±4.4)mm和(53.4±5.2)mm。AF的53.3%由肌性加腱性组织构成,23.3%由腱性组织构成,23.3%由肌组织构成。70%旋后肌远侧缘由腱性组织构成,所有AECRM均是腱性。桡骨背侧桡骨头下方1示指宽和3示指宽分别为ST的入口和出口的体表投影。结论本文提供的RT、ST和AECRM详细形态资料,对于PIN卡压的诊断和手术治疗具有指导意义。     

骨间后神经穿桡管远端处的解剖特点及其临床意义

目的：了解骨间后神经穿旋后肌后可能的卡压位置及临床意义,方法：在2倍放大镜下解剖骨间后神经穿旋后肌后的行程,分支,可能卡压位置以及前臂活动对其影响。结果：骨间后神经穿旋后肌后恒定地分尺仙支和桡侧支;旋后肌远侧缘和拇短伸肌,拇长展肌浅面的腱性肌纤维结构可能是致卡压的解剖结构,前臂伸肌群的活动可 诱发上述结构卡压骨间后神经,结论：在桡管远端同样存在卡坟骨间后神经的解剖结构,必要时应手术探查,松解。     

The course and branching pattern of the deep branch of the radial nerve in relation to the supinator muscle in fetus elbow

We aimed to make first demonstration of the course and branching pattern of deep branch of the radial nerve (DBRN) in relation to the supinator muscle in the forearms of fetuses and make morphological measurements in both fetuses and adults. We carried out dissection on 80 radial nerves from 20 adult cadavers (16 males and 4 females), ranging from 30 to 56 years old and 20 formalin-fixed, spontaneously aborted fetuses (10 males and 10 females) without detectable malformations, ranging from 20 to 37 weeks of gestation. There were three different branching patterns of the DBRN in fetuses. It divided its terminal branches at entrance of the supinator in 2 (5%), after entry of the supinator in 4 (10%) and after the supinator in 34 (85%) forearms. The course was bilaterally same in fetuses. Dividing pattern at the entrance of the supinator was not seen in adults. Only 4 (10%) were seen at after entering to the supinator and 36 (90%) were seen at after the supinator. We saw in fetuses neither fibrous band deep from the extensor carpi radialis longus nor upper border of the supinator. We assume that these fibrous structures appear after birth, perhaps favored by physical exercise, such as repeated pronation–supination movements. We think that it is one of the reasons why DBRN compression has never been reported in children. This is the first fetal study about the course and branching pattern of the DBRN and there is a constant ratio (mean 4.3) between the measurements of the fetuses and adults.     

Extensor carpi radialis brevis origin,nerve supply and its role in lateral epicondylitis

Lateral epicondylitis (LE) or tennis elbow has been the subject of concern during the last 60 years, but the pathogenesis of the LE remains unclear. The LE can be due to the tendinogenic, articular or neurogenic reasons. Numerous theories have been put fourth in the recent past, out of which one of the most popular theories is that the condition results from repeated contraction of the wrist extensor muscles, especially the extensor carpi radialis brevis (ECRB) which may compress the posterior branch of the radial nerve (PBRN) at the elbow during pronation. We studied 72 upper limbs (36 formalin-fixed cadaver) for the origin, nerve supply and the course of PBRN in relation to the ECRB as one of the goal for the present study. The possible presence of an arch of the ECRB around the PBRN was also observed and recorded. The nerve to ECRB was a branch from the radial nerve in 11 cases (15.2%); from the PBRN in 36 cases (50%) and from the superficial branch of the radial nerve in 25 cases (34.7%), respectively. The ECRB had a tendinous arch in 21 cases (29.1%); a muscular arch in 8 (11.1%) cases and the arch was absent in 43 cases (59.7%). When the ECRB had a tendinous or muscular arch around the PBRN, it may compress the same and this condition may worsen during the repeated supination and pronation as observed in tennis and cricket players. The presence of such tendinous or muscular arch should be considered by orthopedicians and neurosurgeons, while releasing the PBRN during LE surgery.     

桡神经深支卡压综合征的解剖学研究

根据５４侧成人尸体肘部桡管，旋后肌管及桡神经深支在肘部行程的解剖学研究，特别观察到桡侧腕短伸肌纤维桥有９０．６％为全腱性，其中有８８．９％与旋后肌弓外侧半重叠直接紧邻桡神经深支，认为该纤维桥是桡神经深支在肘部卡压的主要因素。并注意到桡神经深支与桡骨头部位的关节囊等关系密切，提示临床医生注意。     

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。     

肘部及前臂上段正中神经卡压综合征的临床解剖学研究

目的 探讨肘部正中神经卡压综合征的解剖学基础。方法 解剖观察５０侧上肢标本,结果 肱二头肌腱膜与正中神经的关系有非覆盖４０例（８０％）,部分覆盖型６侧（１２％）和完全覆盖型４侧（８％）。旋前圆肌纤维桥斜过正中神经前方３２侧（６４％）。旋前圆肌肱骨头肌内有腱束８例（成人,占１８．６％）,尺骨头汪岙较厚筋膜４７侧（９４％）。指浅屈肌起始结构有联合腱弓型４４侧（８８％）,纤维情怀２侧型（４％）和腱束型（     

Anatomic basis of the physiopathology of the epicondylalgias: a study of the deep branch of the radial nerve

Summary Compression of the deep branch of the radial n. during its passage through Fröhse's arcade in the supinator m. is one of the classical explanations advanced for epicondylalgia. The object of this study was to define the anatomy of the deep branch of the radial n. from its origin up to the origin of the branches to the lateral epicondylar mm. 34 upper limbs were dissected and three segments of the deep branch of the radial n. were distinguished: segment I, from its origin to its entry into the supinator m; segment II, corresponding to its passage through the supinator m.; and segment III, extending from its exit from the supinator m. to the origin of the nn. to the lateral epicondylar mm. The lengths of these three segments were defined, as well as the level of division of the radial n. in relation to the joint-line, the thickness of the arcade of the supinator m., and the number of nerve branches to the supinator m. It was found that segment III is closely related to the radial head, around which it winds in supination and extension. The three nerve segments thus defined were studied separately microscopically for evidence of lesions. The results were as follows. Segment I: absence of any marked histologic lesions; segment II: marked fibrous thickening of the perineurium and the interstitial connective tissue, replacing certain nerve fibers; segment III: persistence of moderate interstitial fibrosis. These findings appeared constant in all the specimens examined. These results indicate that the deep branch of the radial n. is most affected during its passage through the supinator m. It therefore remains advisable to treat certain epicondylagias by a procedure at this site, dividing not only Fröhse's arcade but also, and this is less often stated, the supinator m. throughout its length, in view of the lesions observed in segment II.

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Bases anatomiques de la physiopathologie des épicondylalgies : étude de la branche profonde du nerf radial

Résumé La compression de la branche profonde du nerf radial au cours de la traversée du muscle supinateur par l'arcade de Fröhse est une des explications classiquement donnée à l'épicondylalgie. L'objet de ce travail est de préciser l'anatomie de la branche profonde du nerf radial depuis sa naissance jusqu'à l'origine des branches nerveuses destinées aux muscles épicondyliens latéraux. 34 membres supérieurs ont été disséqués permettant d'individualiser trois segments sur la branche profonde du nerf radial : le segment I va de sa naissance à sa pénétration dans le muscle supinateur, le segment II correspond à la traversée du muscle supinateur, et le segment III s'étend de la sortie du muscle supinateur jusqu'à la naissance des nerfs des muscles épicondyliens latéraux. Les longueurs de ces trois segments ont été précisées, ainsi que le niveau de division du nerf radial par rapport à l'interligne, l'épaisseur de l'arcade du muscle supinateur, le nombre de branches nerveuses destinées au muscle supinateur. Nous avons constaté que le segment III est en rapport très étroit avec la tête du radius autour de laquelle il s'enroule en supination et en extension. Les trois segments nerveux ainsi définis ont été observés séparément au microscope à la recherche de signes d'altération. Les résultats sont les suivants : Segment I : absence d'altération histologique notable. Segment II : importante majoration fibreuse du périnèvre et du tissu conjonctif interstitiel, remplaçant certaines fibres nerveuses. Segment III : persistance d'une discrète fibrose de l'interstitium. Ces constatations apparaissent constantes sur toutes les pièces examinées. A l'issue de ce travail, il apparait que c'est bien essentiellement au niveau de la traversée du muscle supinateur que la branche profonde du nerf radial est la plus altérée. Il reste donc toujours conseillé d'agir à ce niveau pour traiter certaines épicondylalgies, en sectionnant non seulement l'arcade de Fröhse mais aussi, ce qui est moins décrit, le muscle supinateur sur toute sa longueur, compte tenu des lésions observées dans le segment II.

     

Anatomic and morphometric study of the arcade of Frohse in cadavers

The most superior part of the superficial layer of the supinator muscle is named as the arcade of Frohse (AF). The deep branch of the radial nerve runs under this arch. The AF is reported to be the most common structure causing entrapment neuropathy of the deep branch of the radial nerve. The aim of our study was to reveal the anatomical properties and especially morphometric measurements of the AF in cadavers. This study was performed on 55 cadaver upper extremities. The AF was classified macroscopically as either tendinous or membranous. The width, length and thickness of the AF were measured as the dimensions of the AF. The distance AF between the lateral epicondyle of the humerus and the AF was measured. The forearm length between the lateral epicondyle of the humerus and the styloid process of the radius was measured. The distance AF was divided by the forearm length to find the ratio AF. In 87% of the extremities the AF was tendinous, and in 13% it was membranous. The mean width, length and thickness of the AF were 10.13, 8.60 and 0.77 mm, respectively. The mean distance AF and forearm length were 46.23 and 233.17 mm, respectively. The mean ratio AF was 0.199 (approximately 1/5). These measurements of the dimensions of the AF may contribute to the anatomy of the AF. The surgeon may find the predicted distance AF of any upper extremity by dividing its forearm length by 5.     

Neuromuscular partitioning in the extensor carpi radialis longus and brevis based on intramuscular nerve distribution patterns: A three-dimensional modeling study

Differential activation of specific regions within a skeletal muscle has been linked to the presence of neuromuscular compartments. However, few studies have investigated the extra- or intramuscular innervation throughout the muscle volume of extensor carpi radialis longus (ECRL) and brevis (ECRB). The aim of this study was to determine the presence of neuromuscular partitions in ECRL and ECRB based on the extra- and intramuscular innervation using three-dimensional modeling. The extra- and intramuscular nerve distribution was digitized and reconstructed in 3D in all the muscle volumes using Autodesk Maya in seven formalin embalmed cadaveric specimens (mean age, 75.7 ± 15.2 years). The intramuscular nerve distribution was modeled in all the muscle volumes. ECRL was found to have two neuromuscular compartments, superficial and deep. One branch from the radial nerve proper was found to innervate ECRL. This branch was divided into anterior and posterior branches to the superficial and deep compartments, respectively. Five innervation patterns were identified in ECRB with partitioning of the muscle belly into two, three, or four compartments, in a proximal to distal direction depending on the number of nerve branches entering the muscle belly. The ECRL and ECRB both demonstrated neuromuscular compartmentalization based on intramuscular innervation. According to the partitioning hypothesis, a muscle may be differentially activated depending on the required function of the muscle, thus allowing multifunctional muscles to contribute to a variety of movements. Therefore, the increased number of neuromuscular partitions in ECRB when compared with ECRL could be due to the need for more differential recruitment in the ECRB depending on force requirements.     

The innervation of deep muscles of the human forearm extensors]

The innervation of four deep muscles of the human forearm extensors (the abductor pollicis longus, the extensor pollicis brevis, the extensor pollicis longus, and the extensor indicis muscles) were investigated in 24 bodies (48 sides) from those used in the 1989 and 1990 student courses in gross anatomy dissection at the Iwate Medical University School of Medicine. The forearm extensor muscles and the deep branch of the radial nerve were dissected intensively in the student courses in gross anatomy and were removed afterwards. The four deep muscles of the human forearm extensors and the nerves innervating the muscles were observed while they were immersed in the water and with use of a stereomicroscope--with the assistance of which they were drawn. In six sides the intramuscular nerve supply was also examined carefully and drawn. The results were as follows. 1. The nerves to the four deep muscles of the forearm extensors arose usually from the deep branch of the radial nerve after emerging the supinator muscle and sending branches to superficial forearm extensors. In some cases a nerve or nerves to the superficial forearm extensors were observed arising from the deep branch of the radial nerve after sending one or more branches to the deep forearm extensor muscles, or from the branches to the deep muscles themselves. However they were split easily from the deep branch of the radial nerve and from the branches to the four deep forearm extensors proximally near to the emerging of the deep branch from the supinator muscle. Therefore, it was considered to be constant that the nerves to the four deep forearm extensors arose from the deep branch of the radial nerve after branching to the superficial forearm extensors. 2. The radial group of the deep forearm extensors (the abductor pollicis longus and the extensor pollicis brevis muscles) was innervated usually by one branch that arose from the deep branch of the radial nerve just after emerging from the supinator and giving off branches to the superficial forearm extensors. This branch ran on the dorsal (extensor) surface of the abductor pollicis longus muscle distally, sending many twigs to this muscle, and entered into the muscle at various distances from the origin (Figs. 1-6). The abductor pollicis brevis muscle was innervated by some twigs that ran usually inside but occasionally outside of the abductor pollicis longus muscle (Figs. 7-10).(ABSTRACT TRUNCATED AT 400 WORDS)     

The variable anatomy of the nerve to the extensor carpi radialis brevis

The origin and course of the nerve to the extensor carpi radialis brevis are closely related to the lateral aspect of the elbow joint and proximal portion of the radius—both of which are frequent sites of pathology and surgical treatment. The specific origin of the nerve supply to the extensor carpi radialis brevis muscle has been attributed variably by diverse anatomic and clinical texts to be the radial nerve, its deep branch or its superficial branch. This study was undertaken to determine the most common source of the nerve to the extensor carpi radialis brevis, as well as the most predictable topographic site of its origin. A total of 111 limbs were dissected, with the most common origin (56.7%) found to be the deep radial nerve, followed by the superficial branch of the radial nerve (31.5%), and least frequently from the bifurcation of the radial nerve into its superficial and deep branches (11.7%). This nerve branch was found to arise in most individuals within one centimeter of the distal edge of the humeroradial joint and to pass distally about 3.5 centimeters before entrance into the extensor carpi radialis brevis muscle. © 1993 Wiley-Liss, Inc.     

The abductor pollicis longus: relation between innervation, muscle bellies and number of tendinous slips

The aim of this study was to assess the relation between the insertions of the distal tendinous slips, the muscle bellies and the innervation pattern of the abductor pollicis longus (APL) muscle and of the extensor pollicis brevis (EPB). The upper extremities of 31 frozen cadavers were dissected under magnifying lenses to describe the distribution of the posterior interosseous nerve (PION). The number and the distribution of distal tendinous slip insertions of the APL muscle were variable. Two superficial and deep distal tendon groups were noted. The separation into superficial and deep muscular parts of the APL was frequent (87%). The EPB muscle was generally constituted by one muscle belly and one tendinous slip (93.5%). The innervation by the PION to the APL and EPB muscles was classified into five types. The specific innervation between superficial and deep muscular parts of the APL muscle, the specific innervation of the deep muscle bellies and the independence of the superficial and deep distal tendon groups of the APL muscle are arguments in favor of a complex functional role of the APL motor unit in thumb mechanics. However, no independence of the tendinous slips in the two distal tendon groups and no correlation between the number of tendinous slips and muscle bellies or innervation were observed. These limit the functional role of the two independent superficial and deep musculotendinous APL motor units. The use of the APL tendon for interposition arthroplasty, for tendon transfer or tendon translocation seems logical, particularly if using one of the two distal tendon groups.     

前臂近中段Thompson入路中桡神经深支医源性损伤的解剖学因素及对策

目的　探讨前臂近中段Thompson入路中容易发生桡神经深支损伤的解剖学因素并提出对策。 方法　教学用成人尸体标本48具,按照Thompson入路显露,观察前臂伸肌与桡神经深支及其肌支的位置关系;测量桡神经深支穿出旋后肌的位置距离桡侧腕短伸肌的横向距离;观察指伸肌和桡侧腕短伸肌在前臂近段的愈着情况,测量二者在肱桡关节线以远的愈着长度。 结果　指伸肌和桡侧腕短伸肌在前臂近段相愈着,愈着长度在肱桡关节以远(7.1±2.1)cm;桡神经深支在旋后肌下缘的穿出点与桡侧腕短伸肌尺侧缘的水平距离为(1.3±0.3) cm,与肱桡关节线距离为(6.1±1.8) cm。 结论　前臂近中段Thompson入路中容易发生桡神经深支损伤存在着解剖学因素,了解桡神经深支的解剖特点及其与前臂伸肌的位置关系可以避免桡神经深支损伤。     

Variant of the coracobrachialis muscle with a tunnel for the median nerve and brachial artery

This case report documents a variation in the insertion of the coracobrachialis muscle of the right arm of an adult male cadaver of unknown age. In addition to the normal insertion of the coracobrachialis muscle into the middle of the medial border of the humerus, an additional slender tendon passed inferiorly, crossing anterior to the median nerve and brachial artery before attaching to the medial epicondyle of the humerus. Most of the proximal part of the tendon gave rise to an aponeurotic expansion that inserted into the distal medial border of the humerus. The tendinous insertion and aponeurotic expansion may represent a variant of the coracobrachialis longus (Wood's) muscle and the internal brachial ligament, respectively. The median nerve and brachial artery traversed a tunnel bounded by the additional tendon and aponeurotic expansion as well as the usual humeral insertion of the coracobrachialis muscle. The clinical implication of this variation is that it may be a cause of median nerve entrapment and brachial artery compression.     

肱三头肌长头重建肩外展功能的应用解剖

目的研究肱三头肌长头血管神经蒂特点为以其重建肩外展功能提供解剖学基础。方法对44侧固定尸体的肱三头肌长头肌肉起点及血管神经蒂进行解剖与测量。结果肱三头肌长头起点背侧为肌性,腹侧为腱性,腱性起点长度(9.9±1.5)cm,宽度(2.4±0.4)cm。神经支配来自桡神经的分支,可分离长度(6.8±2.7)cm,直径(2.0±0.4)mm。血供来自①肱动脉肱三头肌支,长度(3.4±1.4)cm,外径(2.0±0.3)mm;②肱深动脉的分支,长度(2.5±0.9)cm,外径为(1.6±0.5)mm,分离至肱动脉长度为(3.9±1.3)cm。血管神经蒂以多级分支为主。结论依据肱三头肌长头及其血管神经蒂的特点,可作为肩外展功能重建术中的动力肌。     

Central sensitization does not identify patients with carpal tunnel syndrome who are likely to achieve short-term success with physical therapy

The aim of the current study was to identify whether hyperexcitability of the central nervous system is a prognostic factor for individuals with carpal tunnel syndrome (CTS) likely to experience rapid and clinical self-reported improvement following a physical therapy program including soft tissue mobilization and nerve slider neurodynamic interventions. Women presenting with clinical and electrophysiological findings of CTS were involved in a prospective single-arm trial. Participants underwent a standardized examination and then a physical therapy session. The physical therapy sessions included both soft tissue mobilization directed at the anatomical sites of potential median nerve entrapment and a passive nerve slider neurodynamic technique targeted to the median nerve. Pressure pain thresholds (PPT) over the median, radial and ulnar nerves, C5-C6 zygapophyseal joint, carpal tunnel and tibialis anterior muscle were assessed bilaterally. Additionally, thermal detection and pain thresholds were measured over the carpal tunnel and thenar eminence bilaterally to evaluate central nervous system excitability. Subjects were classified as responders (having achieved a successful outcome) or non-responders based on self-perceived recovery. Variables were entered into a stepwise logistic regression model to determine the most accurate variables for determining prognosis. Data from 72 women were included in the analysis, of which 35 experienced a successful outcome (48.6%). Three variables including PPT over the C5-C6 joint affected side <137 kPa, HPT carpal tunnel affected side <39.6o and general health >66 points were identified. If 2 out of 3 variables were present (LR + 14.8), the likelihood of success increased from 48.6 to 93.3%. We identified 3 factors that may be associated with a rapid clinical response to both soft tissue mobilization and nerve slider neurodynamic techniques targeted to the median nerve in women presenting with CTS. Our results support that widespread central sensitization may not be present in women with CTS who are likely to achieve a successful outcome with physical therapy. Future studies are now necessary to validate these findings.     

Identification of two accessory muscle bundles with anomalous insertions in the flexor side of the right forearm

During dissection practice held at Kyorin University School of Medicine in 2004, two anomalous muscles were observed on the Rt-forearm-flexor-side of an 83-year-old man. The results of this investigation are reported. One accessory muscle originated from the tendinous insertion of the biceps brachii and medial epicondyle. After passing through the deep layer of the pronator teres, it became tendinous, passing towards the trapezium and second metacarpal base. Its two origins fused superficial to the ulnar artery distal to the cubital fossa, and it merged with the deep region of the pronator teres. More distally, the accessory muscle formed a belly before again becoming tendinous and bifurcated, one branch attaching to the trapezium and the other fusing with the belly of the second accessory muscle. These findings suggested that this accessory muscle was similar to Gantzer's muscle. The other accessory muscle arose distal to the origin of the flexor pollicis longus and inserted onto the second metacarpal base. In addition, from the distal side of its origin, a small muscle bundle was formed and became tendinous. It fused with the insertion tendon of the first accessory muscle to the trapezium. The second accessory muscle was thought to be deep radial carpal flexor.