Multiple variations in the region of Mm. extensores carpi radialis longus and brevis.

While dissecting the body of an 80-year-old female we observed multiple variations in the right region of Mm. extensores carpi radialis longus and brevis. The M. extensor carpi radialis longus gave origin to an accessory head. The tendon of this accessory head passed through a separate tunnel in the extensor retinaculum and inserted in the middle of the first metacarpal bone. Concerning its function, this accessory head of the M. extensor carpi radialis longus could be regarded as an additional abductor pollicis. The M. extensor carpi radialis brevis had an accessory tendon lying underneath the main tendon of this muscle. The accessory tendon joined with the main tendon just when undercrossing Mm. abductor pollicis longus and extensor pollicis brevis. Afterwards the tendon lay in the second tunnel of the extensor retinaculum and inserted in the base of the third metacarpal. In her lifetime the individual's tabatière probably must have been conspicuously pronounced at its radial margin.     

An additional radial wrist extensor and its clinical significance

The knowledge of anatomical variations in the antebrachial and dorsal regions of the arm and hand are useful in hand surgery. The extensor carpi radialis intermedius and extensor carpi radialis accessorius are two classic variants described for the radial wrist extensors, in the antebrachial region. We report an additional extensor carpi radialis muscle taking origin from the common extensor origin, between the extensor carpi radialis longus and extensor digitorum communis. The tendon of the variant muscle divides below the abductor pollicis longus and becomes attached to the base of the second and third metacarpal bone. Due to its considerable size and independent origin from the lateral epicondyle, we suggest the present variation should be named extensor carpi radialis tertius. The clinical significance of the present variation is discussed.     

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.     

Anatomical study on the extensor digitorum profundus muscle in the Japanese

An anatomical study on the extensor digitorum profundus muscle was made using 832 upper limbs from 416 Japanese adults. The separate muscles derived from the extensor digitorum profundus consist of 10 kinds: namely, the extensor pollicis longus, extensor pollicis et indicis accessorius, extensor indicis radialis, extensor indicis proprius, extensor indicis ulnaris, extensor indicis et medii accessorius, extensor medii proprius, extensor annularis proprius, extensor carpi profundus and extensor digiti brevis. The configuration of the muscles (except for the extensor digiti brevis) in the upper limb was classified into 13 types according to their arrangement and insertion. The most frequent type involved coexistence of the extensor pollicis longus and the extensor indicis proprius: it was observed in 664 limbs (79.8%). The next type involved coexistence of the extensor pollicis longus, extensor indicis proprius and the extensor medii proprius: it was observed in 67 limbs (8.1%). It appears that the extensor digiti brevis of man is derived from the most ulnar part of the extensor digitorum profundus which does not migrate proximally.     

A variation in the organization of abductor pollicis longus

The abductor pollicis longus (APL) muscle has been studied bilaterally in 50 cadavers. A variation in the organization of the muscle was found bilaterally in 15 of the 50 specimens. The novel muscular arrangement gives the appearance of being an additional muscle belly arising from the lateral aspect of the distal portion of the typical abductor pollicis longus muscle belly. This variation in the arrangement also creates a retinacular-like tunnel which encases the tendons of the extensor carpi radialis longus and the extensor carpi radialis brevis muscles. To the authors' knowledge, this arrangement has not been cited in the recent medical literature. An understanding of this unusual finding may be clinically relevant in describing the dorso-lateral compartment of the distal forearm. © 1996 Wiley-Liss, Inc.     

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.     

微创治疗桡骨远端骨折安全进针区域的解剖学研究

目的　测量桡骨茎突在腕关节不同角度时与周围肌腱、血管的距离,探讨手法复位经皮闭合穿针内固定术微创治疗桡骨骨折经桡骨茎突的相对安全进针区域。 方法　20侧成人前臂标本,以腕部外固定支架固定腕部,分别在腕关节掌屈0°、20°、40°、60°和尺偏0°、30°等8个位置,测量桡骨茎突最高点与桡侧腕长伸肌腱、拇短伸肌腱的最短距离,桡骨茎突最高点与桡侧腕长伸肌腱、拇长伸肌腱、拇短伸肌腱、桡动脉各交点的距离。 结果　腕关节掌屈、尺偏运动引起桡骨茎突周围肌腱相对位置规律性地变化,腕关节在尺偏30°掌屈0°~20°范围内时,桡骨茎突的相对安全进针区域最大。 结论　以桡骨茎突最高点为体表标志,当腕关节在尺偏30°掌屈0°~20°范围内,桡骨茎突最高点周围一定距离范围内,经皮克氏针固定桡骨骨折,能最大限度降低对肌腱及血管的损伤率。     

Extensor pollicis et indicis communis or extensor indicis radialis muscle

Anatomical variations of the fingers extensor tendons are not uncommon and have been described by several authors. Participation of intertendinous band of fascia in this kind of variation can change muscle functionality. However, this element is scarcely described in the literature. In this case report, we describe the finding of an accessory tendon located between the extensor digitorum communis muscle tendon, destined for the index finger, and the extensor pollicis longus tendon. In an anatomical analysis, we observed a connection between the radial portion of the accessory tendon and the ulnar portion of the extensor pollicis longus tendon by intertendinous fascia. This finding corresponds anatomically to the supernumerary muscle denominated extensor indicis radialis, but due to the fascial connections observed with the extensor pollicis longus, this muscle would behave functionally as a supernumerary muscle denominated extensor pollicis et indicis communis. This report suggests that participation of fascia in muscular variation in this anatomical segment is essential to establish the correct morpho-functional denomination of muscular variants.     

Anatomical variation of radial wrist extensor muscles: a study in cadavers

OBJECTIVE: The tendons of the extensor carpi radialis longus and brevis muscles are quite useful in tendon transfer, such as in correction of finger clawing and restoration of thumb opposition. Knowledge of additional radial wrist extensor muscle bellies with independent tendons is useful in the above-mentioned surgical procedures. METHODS: The skin, subcutaneous tissue, and antebrachial fascia of 48 (24 on the right side and 24 on left side) male upper limb forearms were dissected. The following aspects were then analyzed: (a) the presence of additional muscle bellies of radial wrist extensors, (b) the origin and insertion of the additional muscle, and (c) measurements of the muscle bellies and their tendons. RESULTS: Five out of 48 upper limbs (10.41%) had additional radial wrist extensors; this occurred in 3 out of 24 left upper limbs (12.5%) and 2 out of 24 right upper limbs (8.3%). In one of the right upper limbs, two additional muscles were found. The length and width of each additional muscle belly and its tendon ranged between 2 - 15 cm by 0.35 - 6.4 cm and 2.8 - 20.8 cm by 0.2 0.5 cm, respectively. The additional radial wrist extensor tendons in our study basically originated either from the extensor carpi radialis longus or brevis muscles and were inserted at the base of the 2nd or 3rd metacarpal bone. CONCLUSION: The present study will inform surgeons about the different varieties of additional radial wrist extensors and the frequency of their occurrence.     

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：     

Anatomical variations of the extensor pollicis brevis tendon and abductor pollicis longus tendon--relation to tenosynovectomy

Sufficient improvement in De Quervain disease, is not always archieved even by tenosynovectomy, and the reason for this appears to be anatomical variation in the first extensor compartment of the hand. In this study we examined the first extensor compartment of 159 hands of 80 human cadavers. Hiranuma and colleagues documented four anatomical types of first compartment, and in this study type A was observed in 76 (47.8%) of the 159 hands, type B in 49 (30.8%), and type C in 21 (13.2%). No type D compartments in which the extensor pollicis brevis tendon is absent, were observed. There were 13 hands that did not fit any of Hiranuma's categories, and we classified them into three new types: E, F, and G. The numbers of extensor pollicis brevis tendons in the first compartment varied from one to three, and the number of abductor pollicis longus tendons varied from one to seven. Successful tenosynovectomy in the treatment of De Quervain disease requires to pay close attention to accessory tendons of the extensor pollicis brevis tendon and abductor pollicis longus tendon, branching of the tendons, and the presence of an atypical septum in the first compartment.     

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.     

Unusual variant of the extensor carpi radialis brevis muscle: a case report

A variation of the extensor carpi radialis brevis muscle (ECRB) origin was discovered during a cadaveric dissection. The identified ECRB originated from the fascia/tendon of the extensor digitorum communis (EDC), without any of its origin at the usual location on the lateral epicondyle. The ECRB tendon inserted onto the third metacarpal base. A branch of the posterior interosseous nerve innervated the ERCB. This is the first report of an ECRB originating from the EDC fascia/tendon. This unique variation of the ECRB origin may be of clinical interest, especially in the treatment of lateral epicondylitis (tennis elbow).     

Anomalous interconnection between flexor and extensor carpi radialis brevis tendons

A rare case of a short radiocarpal flexor (M. flexor carpi radialis brevis vel profundus of Wood) was found on the right forearm of a 47-year-old Japanese male corpse. The muscle arose from the anterior surface of the radius, ran distally in the deep layer of the flexor region to enter deeply into the carpal tunnel, and then interconnected with the subtendon of the extensor carpi radialis brevis at the gap between the bases of the second and third metacarpal bones. This muscle was supplied by a branch of the anterior interosseous nerve.     

Analysis of the gross anatomical variations found in four cases of trisomy 13.

The variations and defects observed during detailed gross anatomical dissections of four cases of trisomy 13 are described. Emphasis is on the muscular system where previously undocumented variations, absences, and supernumerary elements were observed. A muscle phenotype which includes absence of palmaris longus, palmaris brevis, plantaris, and peroneus tertius, the presence of pectorodorsalis muscles and muscles from the central tendon of the diaphragm to the pericardium near the pulmonary veins, and variations in the extensor indicis, extensor carpi radialis longus and brevis, biceps, and suprahyoid muscles is discussed. The brain defects which include absent olfactory bulbs and tracts and hypoplastic commissures are compared to those defects seen in cases of alobar holoprosencephaly wherein severe defects of the ethmoid bone are concomitants. Previously well-documented defects of the viscera are included.     

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.     

Analysis of the gross anatomical variations found in four cases of trisomy 13

The variations and defects observed during detailed gross anatomical dissections of four cases of trisomy 13 are described. Emphasis is on the muscular system where previously undocumented variations, absences, and supernumerary elements were observed. A muscle phenotype which includes absence of palmaris longus, palmaris brevis, plantaris, and peroneus tertius, the presence of pectorodorsalis muscles and muscles from the central tendon of the diaphragm to the pericardium near the pulmonary veins, and variations in the extensor indicis, extensor carpi radialis longus and brevis, biceps, and suprahyoid muscles is discussed. The brain defects which include absent olfactory bulbs and tracts and hypoplastic commissures are compared to those defects seen in cases of alobar holoprosencephaly wherein severe defects of the ethmoid bone are concomitants. Previously well-documented defects of the viscera are included.     

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.     

人腕关节动力肌腱的力臂值及意义探讨

目的：测量人腕关节主要动力肌腱在腕运动过程中的力臂的大小。方法：运用７只新鲜成人尸体上肢标本,将运动腕关节的肌腱和旋转电压计相连,在腕关节分别从屈曲至伸直,桡偏至尺偏过程中,用计算机同时记录腕动力肌腱滑动距离和腕运动角度,根据腱滑动距离和腕运动角度计算出肌腱平均力臂和力臂变化。结果：桡侧腕长伸肌腱的腕桡偏力臂最大,桡侧腕短伸肌腱的伸腕力臂最大,尺侧腕伸肌腱和腕尺偏力臂最大,而伸腕力臂很小,桡侧、尺     

Kongenitale oder erworbene Anlage des separaten Faches für die Sehne des M. extensor pollicis brevis bei der Tendovaginitis stenosans de Quervain? Makroanatomische und fetal-plastinationshistologische Untersuchungen zum 1. Strecksehnenfach

Our macroanatomical studies with cadaver specimens and clinical findings in the operative treatment of tendovaginitis stenosans de Quervain confirm the high number of anatomical variations in the first dorsal compartment of the wrist. With the help of thick transparent transversal-sections in one of 14 fetal wrists manufactured by plastination histology we found the first compartment with two tendons of the abductor pollicis longus and dorsal of this compartment a connective tissue formation and a separate compartment for the extensor pollicis brevis tendon, proved as a primary anatomical disposition. Macroscopically the septation is always located distal and dorsal-ulnar to the first compartment and is evidentally more common as an intraoperative than an cadaver dissection finding and probably should be considered as a pathological condition. The secondary formation of an incomplete until complete separate septum may depend on the multiple abductor pollicis longus tendons and on chronical inflammatory reaction of the synovialis of the constricted extensor pollicis brevis tendon.