正中神经返支"握拳三点法"体表定位

目的:研究正中神经返支简单实用的体表定位方法。方法:对20侧成人新鲜上肢标本的正中神经返支进行解剖,观测返支的走行,测量起点,最高点,入肌点,根据解剖学观测制定体表定位。结果:⑴返支起点变化较大,多起源于腕管外,正中神经返支最高点,距远侧腕横纹距离为(36.80±2.82)mm(33.98～39.62mm),距屈肌支持带远侧缘(5.35±2.25)mm(3.1～7.6mm),返支入肌点在拇短屈肌与拇短展肌肌间隙上距拇指基底桡侧缘(35.5±1.86)mm(33.64～37.36mm);⑵握拳三点定位法:①返支起点A点定位:握拳时中环指间线与拇指近节指骨基底尺侧,豌豆骨连线交点。②返支最高点B点定位法:握拳时中指指尖与拇指近节指骨基底尺侧,钩骨钩连线交点。③返支入肌点C点定位法:握拳时示中指间线与拇指近节基底桡侧,豌豆骨连线(此线为拇短屈肌与拇短展肌肌间隙的体表线)交点。结论:握拳定位法既可以给返支定位,又可以体现返支走行及常见变异。     

正中神经在肘部及前臂上段卡压综合征的解剖基础

目的：探讨正中神经在肘部及前臂上段卡压综合征的解剖学基础。方法；在50例上肢标本上解剖观察正中神经受压的解剖因素。结果：肱二头肌腱膜与正中神经的关系；非覆盖型80％（40侧），部分覆盖型12％（6侧）和全覆盖型4侧（8％）。64％（32侧）反转筋膜斜过正中神经前方。18．6％（8侧）旋前圆肌肱骨头肌内有明显腱束，94％（47侧）尺骨头浅面有增厚腱膜。指浅屈肌起始两头间的形态结构：88％（44侧）联合腱弓型，4％（2侧）纤维弓，8％（4侧）指浅屈肌腱束。结论：正中神经通过前臂上段及肘部时，肱二头肌腱膜，旋前圆肌肱骨头的反转筋膜和肌内腱束，尺骨头浅面的腱膜，指浅屈肌起始部的联合腱弓和纤维弓等可能是导致其受压的解剖学因素。     

桡掌肌一例

<正> 尸解一成年女尸时,发现右前臂屈肌多一块桡掌肌(或称副桡侧屈腕肌),现报告如下: 桡掌肌属长肌,以腱性起于旋前圆肌止点下方,桡骨下1/3上份外侧的骨膜上,肌纤维由外上稍斜向内下,在桡侧屈腕肌腱和拇长屈肌腱的深面,经腕管后成腱膜止于拇收肌斜头深面第二掌骨底。肌全长9.5cm,肌腹长6.8cm,最宽1.55cm,厚0.6cm,止端腱长2.7cm,宽3.0cm(见图)。     

副掌长肌变异一例

在一成年男性右上肢拇长屈肌与示指浅屈肌之间见1变异肌.该变异肌以腱膜形式起自旋前圆肌尺骨头肌腱的止点及上方的桡骨头,以粗腱和细腱的形式分别止于屈肌支持带和掌腱膜.从该变异肌的起点来看,其与拇长屈肌关系较为密切;但从止点判断,其收缩时具有紧张掌腱膜、屈肌支持带及屈腕的功能,其与掌长肌的功能相似,故命名为"副掌长肌".未见有此类肌的变异报道.     

腕部尺神经卡压的解剖学研究及其临床意义

目的：为腕部尺神经卡压的诊断和治疗提供解剖学依据。方法：对20例新鲜成人上肢标本的腕部进行解剖，观测尺神经行径中可能存在的卡压因素。结果：尺神经在腕尺管内分成浅、深两支，浅支于小鱼际肌腱弓浅面出腕尺管；深支在小鱼际肌腱弓深面穿出腕尺管后，走行于小指对掌肌浅、深两头腱性起点和钩骨钩之间的间隙，小指对掌肌浅头腱性起点近侧缘锐利成腱弓样，存在率100％。腕尺管内尺神经和尺动脉之间存在3种交叉伴行关系：尺动脉发出的小鱼际肌营养血管和尺神经深支交叉占10％，尺动脉深支和尺神经浅支交叉占20％，尺动脉深支和尺神经深、浅支分别交叉占70％。结论：尺神经在腕部的行程分为腕尺管段和小鱼际肌段，小指对掌肌腱弓可以卡压尺神经深支，尺动脉和尺神经之间的多种交叉伴行关系是尺动脉卡压尺神经的基础。     

肌电图在前臂正中神经卡压的诊断和鉴别诊断中的应用价值

目的:探讨肌电图检测在前臂正中神经卡压诊断和鉴别诊断中的应用价值.方法:回顾分析100例临床诊断并经手术证实的前臂正中神经的神经肌电图检查资料,分析其电生理阳性指标.其中腕管综合症(carpal tunnelsyndrome,CTS)75例,前骨间神经卡压综合征(anterior interosseous entrapment nerve syndrome,AINS) 12例,旋前园肌综合征(pronator teres syndrome,PTS)10例,正中神经返支卡压征(recurrent median nerve entrapment syndrome RMNES)3例.结果:肌电图检测发现CTS患者正中神经腕部潜伏期延长,腕部以下正中神经感觉神经动作电位异常;AINS患者正中神经感觉神经功能正常,拇短展肌EMG正常,前骨间神经支配肌有自发电位或潜伏期延长,波幅降低;PTS患者正中神经支配肘下肌有自发电位,前臂NCV减慢,波幅降低,正中神经干动作电位及感觉神经动作电位异常.正中神经返支卡压综合症仅拇短展肌有异常电位,掌部潜伏期延长,感觉神经功能正常.结论:肌电图技术在诊断和鉴别前臂正中神经卡压疾病中有重要价值.     

骨间掌侧神经受压综合征的解剖学研究

在32具成人尸体的64侧上肢中解剖了骨间掌侧神经及其发出的肌支共510支,对其分支平面,分支数目,长度及其走行过程中的受压因素进行了观察和测量,旋前圆肌尺骨头的纤维弓,指浅屈肌腱弓,拇长屈肌的异常肌束和骨间掌侧血管的分支血管束是造成骨间掌侧神经受压的主要因素.     

拇短屈肌形态特点及其神经支配

目的：进一步弄清拇短屈肌的神经支配，为临床有关神经损伤的诊治提供应用解剖学形态基础。方法：对３０只成人手标本拇短屈肌形态和神经支配进行了观测。结果：拇短屈肌浅头受正中神经返支支配，拇短屈肌深头受尺神经深支支配。尺神经深支的拇短屈肌深头肌支出现率占８６．７％，肌内平均支数为２．０±０．７支，有１０％的拇短屈肌深头肌支既支配拇短屈肌深头，又支配拇短屈肌浅头，并有一交通支与正中神经相连。结论：１０％的拇短屈肌具有双重性神经支配。因此，当正中神经损伤，部分病例的鱼际肌中个别肌肉可不出现瘫痪。     

掌长肌缺如伴发自尺动脉的正中动脉吻合成掌浅弓1例

掌长肌缺如和掌浅弓组成的形式变异分别均早有记载 ,但右侧掌长肌缺如伴发自尺动脉的正中动脉吻合成掌浅弓的变异少见 ,作者在解剖一例 10岁男童标本时遇见 1例 ,现报道如下。右侧掌长肌缺如 ,掌腱膜近端附着于桡侧腕屈肌腱尺侧缘上 (图 1) ,其远端和左侧掌长肌未见异常。右侧正中动脉 ,在距肱骨内、外上髁连线中点下方 3.5ｃｍ处发自尺动脉桡侧 ,外径 2ｍｍ(图 2 ) ,穿经指浅、深屈肌间下行 2ｃｍ(距肱骨内、外上髁连线中点下方 5 .5ｃｍ)处与正中神经伴行于桡侧腕屈肌与指浅屈肌之间的深面 ,然后经腕管入手掌 ,达掌腱膜深面 ,正中神经的指…     

枕大神经痛的解剖学基础

目的：探讨枕大神经痛发病的解剖学基础。方法：防腐固定10例(20侧)和新鲜标本5例(10侧)，以经骨性外耳门中点的水平线和后正中线为轴建立坐标系，定位枕大神经浅出点，观察枕大神经走行分布及其与枕动脉的毗邻关系。结果：(1)枕大神经皮下浅出点位于坐标原点旁开17～20mm；以浅出点为界，枕大神经可分为皮下段和肌内段。(2)皮下段与浅筋膜紧密附着，活动度小，为固定区；肌内段走行于半棘肌和斜方肌腱膜间，神经活动度大，为活动区。结论：颈部运动使活动区和固定区交界部位的神经处于“扭折”状态；浅出点腱膜组织对神经的固定作用造成了神经的“卡压”，此双重作用是构成枕大神经卡压的解剖学基础。     

Anomalous muscle belly to the index finger.

An unusual variation of flexor digitorum superficialis was observed during the cadaver dissection. The flexor digitorum superficialis (FDS) had a normal origin and insertion, except to the index finger, where a muscle belly replaced the tendon of FDS. The unusual muscle belly originated as a continuation of FDS tendon in the carpal tunnel and inserted normally into the middle phalanx. A branch of the median nerve innervated the anomalous muscle belly. The anomalous muscle belly described here should be considered in the aetiology of carpal tunnel syndrome.     

Palmaris profundus: One name,several subtypes,and a shared potential for nerve compression

The palmaris profundus is a rare, but known anatomic variation which may lead to compression of the median nerve and/or its branches. Two patients with carpal tunnel syndrome are presented in whom a palmaris profundus was discovered at operation. In these cases, median nerve compression at the wrist was attributed to the course of the extra tendon and its local mass effect on the nerve (i.e., the palmaris profundus and median nerve shared a common sheath); more commonly, the resultant decreased available space for the median nerve within the carpal tunnel due to the presence of an accessory (10th) flexor tendon is thought to be responsible. Postoperative 3 Tesla magnetic resonance imaging (MRI) was performed to demonstrate the full course of the variant muscle; despite variations in the size and longitudinal extent of the accessory musculotendinous unit, an important similarity was noted: the intimate relationship of the median nerve and the palmaris profundus. These two cases and our review of the literature highlight the fact that one name (i.e. palmaris profundus) reflects several anatomic subtypes. However, the close relationship of the palmaris profundus with the median nerve in the forearm and the palm is a common theme which emphasizes the potential pathoanatomic consequences of this relationship: nerve compression. Clin. Anat. 22:643–648, 2009. © 2009 Wiley‐Liss, Inc.     

Muscle variations and abnormal branching and course of the ulnar nerve in the forearm and hand

During dissection of the right forearm of a 27-year-old female cadaver, variations in the form and insertion of the palmaris longus muscle were observed. The tendon of the palmaris longus muscle, which demonstrated a centrally placed belly, split into two tendons: one inserted into the palmar aponeurosis and the other into the proximal part of the flexor retinaculum. Additionally, we found an accessory muscle extending between the flexor retinaculum and the tendon of the abductor digiti minimi muscle. This accessory muscle was located deep to the ulnar artery but superficial to the superficial and deep branches of the ulnar nerve at the wrist. Finally, an aberrant branch of the ulnar nerve was identified in the forearm; it traveled distally alongside the ulnar artery and in the palm demonstrated communications with common palmar digital nerves from the ulnar and the median nerves. No variations were observed in the contralateral upper limb.     

Relationships of the palmar cutaneous branch of the median nerve: a morphometric study

Treatment of carpal tunnel syndrome consists in decompression of the median nerve by section of the flexor retinaculum. Usually, this surgery improves the disease with disappearance of the symptoms. However, some painful sequelae may remain such as painful discharges, paresthesiae or permanent anesthesia of the base of the thumb or of the scar related to an injury of the palmar cutaneous branch of the median nerve (PCBm). This study was performed to define the accurate emergence and the anatomic characteristics of this nerve in relation to stable landmarks. Moreover, it assessed the importance of the visual identification of the branch during section of the flexor retinaculum. Thirty-five hands were dissected under macroscopic examination and under magnification of the thinnest branches. Measurements were performed with a caliper and the forearm in supination. Determination of the bistyloid line showed variability in the location of the distal wrist crease. Thus, it could not be used as a landmark to locate the PCBm. The palmar cutaneous branch is the distal collateral branch of the median nerve in the forearm. It emerges on its radial side, on average 44.3 mm before the bistyloid line. It courses in line with the third finger and perforates the antebrachial aponeurosis about 5.7 mm from the bistyloid line. This emergence can be located in the palm, where it can be injured if the incision is performed in line with the third finger. The PCBm usually ends in the palm by division into two or three branches. The lateral branch supplies the skin of the thenar eminence while the medial, usually shorter branch supplies the midline part of the palm. This study has shown the importance of performing the cutaneous incision in line with the fourth finger to avoid injury to the PCBm.     

Variations of Median Nerve in Carpal Tunnel and its Distribution in Hand

Aim of the study was to study the variations in the branching pattern of median nerve in the carpal tunnel and hand, which would form useful data for hand surgeons doing open/endoscopic carpal tunnel release. Median nerve and its branches were explored by dissection in fifty hands of twenty-five formalin fixed adult human cadavers over a period of three years. We found variations in 35 out of 50 hands. Based upon Lanz classification, frequency of variations in present series was variation in the course of thenar branch (58%), accessory branches at the distal portion of the carpal tunnel (34%), high divisions of the median nerve (8%) and accessory branches proximal to the carpal tunnel (nil). Rare variations including transligamentous median nerve and multiple thenar branches were also observed. Medial take off of thenar branch as observed in this series has special clinical significance in carpal tunnel release. Knowledge of the variable anatomy of median nerve would help to avoid incomplete decompression at operations for nerve entrapment and injury to thenar branch.     

早期腕管综合征的电生理指标比较

目的:分析诊断早期腕管综合征的电生理指标,比较其敏感性。方法:对临床诊断为早期腕管综合征、正中神经远端运动电位潜伏期(distal motor latency,DML)<4.5ms的患者50例60侧,测定正中神经、尺神经环指-腕的感觉神经动作电位(SNAP)潜伏期差值,正中神经、桡神经拇指-腕的SNAP潜伏期差值,以及正中神经节段检查两点间潜伏期差值,并对其结果进行比较分析。结果:正中神经、尺神经环指-腕的SNAP潜伏期差值异常(≥0.4ms)者58侧,达96.6%;正中神经、桡神经拇指-腕的SNAP潜伏期差值异常(≥0.4ms)者40侧,达80%;正中神经节段检查两点间潜伏期差值异常(≥0.4ms)者25侧,达41.6%。结论:正中神经、尺神经环指-腕的SNAP潜伏期差值异常是早期腕管综合征最敏感的指标。     

Anatomical work-up of an individual with multiple muscular variants on both forearms

Muscular variants of the forearm are common and frequently cause neurovascular compression syndromes, especially when interfering with the compact topography of the carpal tunnel or the Canalis ulnaris. Here, we report on a male body donor with multiple muscular normal variations on both forearms. The two main findings are (1) an accessory variant muscle (AVM) on the right forearm originating from the M. brachioradialis, the distal radius, and the M. flexor pollicis longus. It spanned the wrist beneath the Fascia antebrachia and inserted at the proximal phalanx of the digitus minimus. (2) Moreover, we found a three-headed palmaris longus variant on the left arm with proximal origin tendon and a distal, trifurcated muscle belly, with separated insertions at the palmar aponeurosis, the flexor retinaculum, and, in analogy to the accessory muscle on the contralateral arm, at the base of the proximal phalanx of the digitus minimus. We found a considerable thickening of the left-hand median nerve right before entering the carpal tunnel indicative of a possible chronic compression syndrome adding clinical relevance to this anatomical case. We also discuss the notion that both, the AVM and the contralateral three-headed palmaris variant are developmental descendants of the M. palmaris longus. Additionally, we found a previously not recorded variant of the M. palmaris brevis on the left hand.

     

A Case of the Bilateral Duplicate Palmaris Longus Muscles Coupled with the Palmaris Profundus Muscle

The palmaris longus muscle is one of the most variable muscles in human anatomy. During a routine anatomical dissection for medical students at Tottori University, we found duplicate palmaris longus muscles in the bilateral forearms together with the palmaris profundus muscle in the right forearm. The bilateral aberrant palmaris longus muscles were observed at the ulnar side of the palmaris longus muscle and their distal tendons were attached to the flexor retinaculum. The palmaris profundus muscle found in the right forearm was located at the radial side of the flexor digitorum superficialis muscle. The proximal tendon was originated from the anterior surface in the middle of the radius, while the distal tendon coursed radial to the median nerve through the carpal tunnel, finally inserting into the distal part of the flexor retinaculum. Both the palmaris longus and aberrant palmaris longus muscles were innervated by the median nerve. The palmaris profundus muscle was presumably supplied by the median nerve.     

Anatomic variations of the median nerve within the carpal tunnel

Two hundred seventy-five consecutive carpal tunnel releases were reviewed to identify anomalies of median nerve anatomy. High division of the median nerve was observed in nine cases; in two of these the nerve divided proximally and then rejoined distally as a “closed loop.” In 42 cases the motor branch passed through the flexor retinaculum. Multiple motor branches were present in 13 cases. The palmar cutaneous branch passed through the flexor retinaculum in seven cases. In three cases, the distal communicating sensory ramus between the medial and ulnar nerves arose proximal to the superficial arch. Median nerve anomalies within the region of the carpal tunnel are common. Knowledge of such anomalies is important to avoid iatrogenic injury.