Applied anatomy of the superficial branch of the radial nerve

The superficial branch of the radial nerve (SBRN) is highly vulnerable to trauma and iatrogenic injury. This study aimed to map the course of the SBRN in the context of surgical approaches and identify a safe area of incision for de Quervain's tenosynovitis. Twenty-five forearms were dissected. The SBRN emerged from under brachioradialis by a mean of 8.31 cm proximal to the radial styloid (RS), and remained radial to the dorsal tubercle of the radius by a mean of 1.49 cm. The nerve divided into a median of four branches. The first branch arose a mean of 4.92 cm proximal to the RS, traveling 0.49 cm radial to the first compartment of the extensor retinaculum, while the main nerve remained ulnar to it by 0.64 cm. All specimens had branches underlying the traditional transverse incision for de Quervain's release. A 2.5-cm longitudinal incision proximal from the RS avoided the SBRN in 17/25 cases (68%). In 20/25 specimens (80%), the SBRN underlay the cephalic vein. In 18/25 (72%), the radial artery was closely associated with a sensory nerve branch near the level of the RS (SBRN 12/25, lateral cutaneous nerve of the forearm (LCNF) 6/25.) A longitudinal incision in de Quervain's surgery may be preferable. Cannulation of the cephalic vein in the distal third of the forearm is best avoided. The close association between the radial artery and first branch of the SBRN or the LCNF may explain the pain often experienced during arterial puncture. Particular care should be taken during radial artery harvest to avoid nerve injury.     

Electrophysiological assessment in neurogenic thoracic outlet syndrome.

OBJECTIVES: To evaluate the value of different electrophysiological techniques in the diagnosis of neurogenic thoracic outlet syndrome (TOS). MATERIALS AND METHODS: Two females, aged 22 and 30 years, with progressive weakness and wasting of the right hand with slight sensory disturbances. Needle EMG, motor and sensory conduction along median and ulnar nerves, sensory conduction of medial (MACN) and lateral (LACN) antebrachial cutaneous nerves. RESULTS: Chronic neurogenic atrophy in small hand muscles, more severe in lateral part of thenar eminency, reduced compound muscle action potentials (CMAPs) more severe by median than ulnar stimulation, and reduced amplitude of the SNAPs of ulnar and MACN were the main findings consistent with neurogenic TOS. Both patients had right cervical rib in radiography. CONCLUSIONS: Electrophysiological study is useful in the diagnosis of neurogenic TOS. Reduced amplitude of MACN and ulnar nerve SNAPs, predominant denervation in thenar eminency, and reduced amplitude of CMAPs, more by median than by ulnar stimulation, are consistent with the diagnosis.     

Anatomic characteristics and clinical importance of the superficial branch of the radial nerve

The aim of this study was to demonstrate anatomic variations of the superficial branch of the radial nerve (SBRN) and to discuss the importance of this branch for surgical approaches. Upper extremities of 24 cadavers without any known history of disease or trauma were examined. the SBRN became subcutaneous at a mean of 9.20 cm and bifurcated at a mean of 4.90 cm proximal to the styloid process of the radius in 48 specimens. At the level of the extensor retinaculum, the mean distance of the closest branch to the first dorsal compartment was 0.54 cm, while its mean distance to the dorsal tubercle (Listers tubercle) was 1.58 cm. The relations of the three branches of the SBRN (SR1, SR2, SR3) to the anatomic snuffbox and lateral antebrachial cutaneous nerve (LABCN) were also examined. It was demonstrated that on eight wrists, SR2 went through the snuffbox (16.67%). On ten specimens, SR3 had connections with LABCN (20.83%). In four specimens, the SBRN did not have any bifurcation and was directly divided into SR1, SR2, and SR3. It should be very helpful to know the anatomic characteristics of the SBRN, especially for hand surgeons, to minimize the risk of injury of the SBRN during surgical approaches.     

Reliable techniques to avoid damaging the superficial radial nerve due to percutaneous Kirschner wire fixation of the distal radius fracture through the radial styloid process

Purpose

The use of percutaneous Kirschner wires for fixation of unstable fractures of the distal radius has been widely accepted as the least invasive procedure. However, the injury to the superficial branch of the radial nerve (SBRN) is common. Our purpose in this study was to develop a reliable technique to avoid damaging the SBRN.

Methods

Twenty cadaver forearms were dissected to identify the SBRN distribution, and 18 forearms were used to undergo placement of three Kirschner wires (KW-A, KW-B, and KW-C). The KW-A, KW-B, and KW-C were driven in the frontal plane into the distal radius, and KW-A and KW-C through the tip of radial styloid process at different angles. The SBRN distribution and its relationship with the KW insertion were identified. Fifty-three patients with unstable distal radius fractures were fixed with external fixator and augmented with 1–3 KW, and the injury rates of SBRN were evaluated.

Results

We found a blind region of the SBRN bound by its first bifurcations into radial and ulnar branches and the line crossing the tip of the styloid process. The mean distance of the three wires (KW-A, KW-C, and KW-B) to the closest nerve branch was 4.5, 4.4, and 3.4 mm, respectively. The injury of SBRN occurred in two of 53 patients.

Conclusion

The injury rate of the SBRN can be effectively reduced when the Kirschner wire is placed along the curve AB and as in proximity to the TRSP as possible under fluoroscopic guidance. Our pinning technique is therefore reliable and practical.     

桡,尺动脉肌,皮支的解剖学研究

目的:为手外科提供桡、尺动脉分出的肌、皮支.材料和方法:用福尔马林常规固定的成尸上肢69(男61,女8)侧,解剖观测桡、尺动脉分支的部位、支数及外径.主要结果:从尺、桡动脉壁两侧发出分支,大部分为不对称性分支间距不等,平均(3.0～15.0)mm.桡动脉平均分出15.8支,其中肌支10.3支,筋膜皮支5.5支.尺动脉平均分出12.4支,其中肌支7.6支,筋膜皮支4.8支.结论:桡、尺动脉分出肌、皮支,皮支为前臂筋膜瓣、皮瓣的血管蒂.     

Tendon and neurovascular injuries of the distal radius after pinning with Kirschner Wires: A meta‐analysis of cadaveric studies

Tendon and nerve structures are at risk when displaced fractures of the distal radius are pinned using K‐wires. The aim of this meta‐analysis (MA) is to examine the published evidence of such complications in cadavers. Eight studies met our inclusion criteria. The meta‐analytical results were as follows: (a) 2.87% and 30.5% tendon involvement at the radial styloid process (RSP) and the dorso‐radial area of the distal radius, respectively; (b) 3.5% and 1.1% tendon involvement when the percutaneous pinning (PP) and the limited open pinning (LOP) techniques were used, respectively; (c) 16.1% and 3.4% nerve involvement at the RSP and the dorso‐radial area of the distal radius, respectively; (d) in 35.7% the nerve was speared and in 64.3% it touched the K‐wire at the styloid area; (e) 61.3% cephalic vein involvement in the styloid area; (f) the second branch of the sensitive branch of the radial nerve (SBRN) was the closest to a wire inserted into the RSP; (g) the mean (±SD) distance between a branch of the SBRN and a styloid wire was 2.17 ± 0.82 mm. Our results for nerve and tendon injury frequencies in the RSP were close to those in clinical meta‐analytical studies, offering an excellent statistical model of evidence synthesis based on cadaveric studies to assess the frequency of such injuries in clinical practice. However, this cadaveric MA yielded more accurate data than the previously reported clinical MA in assessing the real risk of injury of such structures in the distal radius in terms of their proximity to the inserted K‐wires. Clin. Anat. 28:545–550, 2015. © 2015 Wiley Periodicals, Inc.     

肘关节前方入路切口“安全区域”的解剖学研究

目的 解剖学观察肱二头肌腱和前臂内、外侧皮神经之间的解剖位置关系,为肘关节前方入路手术切口设计提供理论依据。方法 解剖30例成人肘关节标本,均无外伤、畸形、肿瘤、骨折。其中新鲜冰冻标本8例(性别不详,左5例、右3例),经10%甲醛溶液浸泡的标本22例(男12例、女10例,左11例、右11例)。仔细观察肘关节前方的肱二头肌腱和前臂内、外侧皮神经,并测量前臂内、外侧皮神经穿出深筋膜的位置,及其与肱二头肌肌腱之间的解剖位置关系。结果 前臂外侧皮神经走行于肘关节的前方偏桡侧,与肱二头肌腱相毗邻,在肱骨外上髁平面下方(20.5±2.5)mm处穿出深筋膜,穿出点与肱二头肌腱桡侧缘之间的水平距离为(12.6±0.9)mm;前臂内侧皮神经沿肱动脉下行,在肱骨内上髁上方约5 cm处穿出深筋膜,在肱骨内上髁平面处,后支与肱二头肌腱尺侧缘之间的水平距离为(33.1±2.7)mm。两者之间的安全宽度约为40 mm。结论 距肱二头肌腱两侧缘之间约40 mm的宽度为肘关节前方入路的相对安全区域,以肱二头肌腱为参照设计切口,可以减少医源性前臂内、外侧皮神经损伤的发生。     

尺动脉腕背支升支皮瓣的应用解剖学研究

目的　为临床应用尺动脉腕背支升支皮瓣修复手部创面 ,提高治疗效果提供解剖学基础。方法　用新鲜成人男性上肢标本 1 6侧 ,采用显微解剖学技术 ,对尺动脉腕背支升支的起始、走行、分支及分布进行解剖学观察和测量。结果　尺动脉腕背支起始于尺动脉的尺侧 ,距豌豆骨上方 4 2 .6 0± 8.2 0mm ,起始处外径1 .4 6± 0 .32mm ,长 1 1 .4 6± 8.2 0mm。尺动脉腕背支与尺神经手背支伴行 ,穿过尺侧腕屈肌腱的深面 ,从掌侧向后内侧斜行 ,两者成锐角 ,平均 38.6 0± 8.2 0°,行至 1 1 .4 6mm处分为升支与降支。升支穿深筋膜进入皮下组织 ,沿前臂内侧缘上行 1 2 2 .4 0± 1 3.80mm处再分为细小分支 ,升支起始部的外径为 0 .6 2± 0 .2 8mm。结论　尺动脉腕背支升支皮瓣是以尺动脉腕背支升支为蒂 ,可在前臂尺侧设计大面积岛状皮瓣 ,通过转位修复腕部和手部创伤及挛缩瘢痕切除术后的创面 ,不牺牲前臂主要血管 ,手术操作易于掌握     

尺动脉腕上皮支下行支皮支链岛状皮瓣的应用解剖

目的　为尺动脉腕上皮支下行支皮支链岛状皮瓣修复前臂和手指缺损提供解剖学基础。方法　12侧肘关节以上部位截肢的上肢新鲜标本,10侧采用乳胶灌注肱动脉,2侧用乙酸乙酯和塑料灌注肱动脉制作铸型标本,解剖观测尺动脉腕上皮支下行支皮支的起始、走行、分布和吻合情况,并对其外径进行测量。  结果　以尺骨茎突尖端到手背尺侧第5掌指关节部位作为一个单位长度。尺动脉腕上皮支下行支发出的远段皮支2.3支,远段皮支血管聚集点约在第5掌骨颈部,到第5掌指关节的距离占总单位长度的(18.2±7.0)%; 近段皮支4.4支,近段皮支血管聚集点约在第5掌骨基底部,到第5掌指关节的距离占总单位长度的 (66.4±16.7)%。尺动脉腕上皮支下行支皮支在桡尺侧的分布无显著性差异。尺动脉腕上皮支下行支皮支在手背尺侧浅筋膜内相互吻合,形成与尺动脉腕上皮支下行支相平行的皮支链,并营养相应的皮肤。  结论　尺动脉腕上皮支下行支皮支链岛状皮瓣可用于修复手指或前臂较小的皮肤缺损,而且不损伤其主干血管。     

Anatomical survey of terminal branching patterns of superficial branch of radial nerve in fetuses

Background

Regional anesthesia plays a key role in elective as well as emergency orthopedic and other surgeries in children. However, peripheral nerve blocks are quite challenging in children due to lack of precise anatomical knowledge of the course and distribution of these nerves. The purpose of this study was to explore the terminal branches of the superficial branch of the radial nerve in fetuses. The relationship of the superficial branch of the radial nerve with cephalic vein and surrounding tendons was also observed.

Methods

A total of 60 upper extremities (42 males and 18 females) of 30 spontaneously aborted fetuses (32–40?weeks) were dissected to expose the superficial branch of the radial nerve in the distal forearm and hand.

Results

Three patterns of distribution based on the total area of the dorsum of the hand innervated were observed. Type 1 (66.7%): superficial branch of radial nerve (SBRN) innervated lateral two-and-a-half digits; Type 2 (23.3%): SBRN innervated lateral three digits; Type 3 (10%): SBRN innervated lateral three-and-a-half digits. The cephalic vein was seen to intersect the nerve more than twice along its course.

Conclusions

Detailed knowledge of the distribution patterns of terminal branches of superficial branch of radial nerve in hand will enhance the success rate of regional blocks or hand surgeries and minimize the postoperative complications due to injury to nerve or vascular structures.     

前臂桡侧头静脉-皮神经的营养血管的解剖学

目的：为前臂桡侧头静脉-皮神经营养血管远端蒂复合瓣设计提供解剖学基础。方法：动脉灌注红色乳胶成人上肢标本,解剖观测头静脉-前臂外侧皮神经下1/3段营养血管的来源、分支及其与桡骨膜血管的关系。结果：头静脉-前臂外侧皮神经下1/3段的营养血管来自：桡动脉皮支,掌浅支皮支,桡骨茎突返支皮支和桡动脉肌间隙骨皮支。上述诸支血管发皮支、筋膜支、骨膜支、神经-浅静脉营养血管,形成皮神经-头静脉血管链以及深、浅筋膜和骨膜血管网。结论：前臂桡侧缘头静脉-皮神经营养血管与肌、骨、皮营养血管同源,以桡骨茎突返支为蒂的远端蒂复合瓣,旋转轴点在腕关节平面,可用于手部远处组织缺损修复。     

正中神经返支和掌皮支血供的显微解剖

目的为修复正中神经返支提供带血管蒂神经桥接的有关数据和掌皮支血供的解剖学资料。方法用体视学方法研究了40侧灌注红色乳胶液的返支和掌皮支的营养血管。观察返支营养血管的来源、长度、外径和进入神经干的方式;观察掌皮支营养血管的来源和进入神经的方式。结果返支营养动脉主要发自掌浅弓凹侧筋膜支(称之来源动脉)。来源动脉起点至“零点”距离(11.62±2.30)mm,外径(0.95±0.10)mm,长度(10.12±1.30)mm。营养动脉主干长度(2.84±0.10)mm,外径(0.42±0.15)mm。营养动脉从返支主干近侧1/3段直入式进入神经者占86.5%;从返支中、远侧段伴入式进入神经者占14.5%;掌皮支营养动脉主要发自尺动脉(占52.5%)和桡动脉(占37.5%),以直式、伴入式和肌支式进入神经。结论返支营养动脉可作为血管蒂神经移植的受体血管。     

Can palmar creases serve as landmarks for the deeper neuro-vascular structures?

Purpose

The aim of this study was the examination of the superficial anatomy of palmar creases and their relation to deeper neuro-vascular structures.

Methods

Four creases: distal wrist flexion crease, thenar crease, proximal palmar crease and distal palmar crease were evaluated with reference to the following structures: palmar cutaneous branch of median nerve, palmar cutaneous branch of ulnar nerve, the nerve of Henle, transverse palmar branches from ulnar nerve, recurrent motor branch of median nerve, radial proper palmar digital nerve to the index and the ulnar proper palmar digital nerve to the thumb, Berrettini’s communicating branch, ulnar nerve and artery, superficial palmar arch. We performed dissections of 20 cadaveric upper limbs derived from a homogenous Caucasian group. In our study we measured the location of surgically important structures with reference to palmar skin creases.

Results

Among the other observations we noticed that the palmar cutaneous branches of the median and ulnar nerves were located at least 0.5 cm away from the thenar crease. The superficial palmar arch was found between the thenar and proximal palmar crease and never crossed the proximal or distal palmar creases.

Conclusions

These anatomical dissections will provide reference material for further ultrasound studies on the arrangements of neuro-vascular structures in reference to superficial palmar creases.     

The gross anatomy of the extrathoracic course of the intercostobrachial nerve

Recent reports emphasize the importance of preserving the intercostobrachial nerve (ICBN) during surgical procedures (i.e., mastectomy, axillary clearance). However, a limited number of scientific reports explore the surgical anatomy of this nerve. We dissected 100 adult human formalin-fixed cadavers (200 axillae). In all the cadavers the ICBN was present with variant contributions from intercostal nerves T1, T2, T3, and T4. The arrangements of the ICBN were typed as I through VIII. The components of Type I (45% or 90 of our specimens) included a branch to the posterior antebrachial cutaneous nerve, a branch to the anterior and lateral parts of the axilla, a branch to the medial side of the arm, and a branch to the medial antebrachial cutaneous nerve. Type II (25%) describes the ICBN arising from T2 and giving off a branch to the brachial plexus. In Type III (10%), lateral cutaneous branches of T2 and T3 fuse as a common trunk and then split immediately after exiting the intercostal space to form an ICBN. In type IV (5%), T2 and T3 join distally to form an ICBN that ends as its terminal branches. Type V (5%): T3 joins T2 from the same intercostal space proximally, with Type VI (3%) showing a very proximal branching of the sensory terminal nerves. Type VII (5%) displayed a contribution from T3 and a branch to the brachial plexus with multiple terminating branches. A contribution from T3 and T4 and a branch to the brachial plexus with multiple branches of termination comprised Type VIII (2%).     

Innervation of the elbow joint: Is total denervation possible? A cadaveric anatomic study

The aim of this anatomical study was to find out if total denervation of the elbow joint is technically feasible. The endbranches of the brachial plexus of eight fresh-frozen upper arm cadavers were dissected with optical loupe magnification. All major nerves of the upper limb (except the axillary and the medial brachial cutaneous nerve) give some terminal articular endbranches to the elbow. The articular endbranches arise from muscular endbranches, cutaneous endbranches, or arise straight from the main nerves of the brachial plexus. A topographic diagram was made of the different nerves innervating the elbow joint. The ulno-posterior part of the elbow is innervated by the ulnar nerve and some branches of medial antebrachial cutaneous nerve. The radial-posterior part of the elbow is innervated exclusively by the radial nerve. The ulno-anterior part of the elbow is innervated by the median nerve and the musculocutaneous nerve. The radio-anterior part of the elbow is innervated by the radial nerve and the musculocutaneous nerve. These elbow innervation findings are relevant to both anatomical and clinical field as they provide evidence that the total denervation of the elbow joint is impossible. Nevertheless, partial denervation, like denervation of the lateral epicondyle or the ulnar part of elbow, is technically possible.     

桡动脉掌浅支蒂腕横纹皮瓣的应用解剖

目的　为临床设计切取腕横纹皮瓣提供解剖学基础。 方法　选取6只新鲜手标本进行红色乳胶灌注,解剖观察桡动脉掌浅支的走行及皮支分布规律和特点。 结果　桡动脉掌浅支于桡骨茎突掌尺侧自桡动脉发出,起始处直径（1.26±0.36）mm,向鱼际肌走行。桡动脉掌浅支于舟骨结节近侧中间腕横纹处发出皮支,皮支发出处直径（0.23±0.06）mm,供养腕横纹皮肤。 结论　以桡动脉掌浅支腕横纹皮支供血,以腕横纹皮肤为供区切取游离皮瓣或带蒂转移可以修复手部皮肤软组织缺损,该术式具有血供可靠、不牺牲主干血管,切取安全等优点。     

带桡神经浅支及其营养血管筋膜皮瓣的应用解剖

目的:为带桡神经浅支及其营养血管筋膜皮瓣的临床应用提供形态学基础.方法:在32例成人上肢标本上,观测了桡神经浅支浅段及其营养血管、以及该血管与筋膜皮肤的供血关系.结果:桡神经浅交浅段的血供主要来自桡动脉的肌皮支或皮支,其中以桡动脉显露段的粗大皮支,鼻咽壶段的茎突返支及虎口区的皮动脉较为恒定,起点外径分别为0.8mm、0.7mm及0.6mm:穿出深筋膜前长分别为0.8cm、1.1cm及0.5cm.皮动脉的神经支在神经旁或神经干内相互沟通形成纵向链状血管网,并借吻合支与皮动脉筋膜皮支构成的皮下血管网、筋膜血管网等连接.结论:可设计成带桡神经浅支及其营养血管的顺行或逆行筋膜皮瓣,转位修复邻近部位的软组织缺损.     

Preserving the superficial branch of the radial nerve during carpometacarpal and metacarpophalangeal joint arthroscopy: an anatomical study

Background  

The superficial branch of the radial nerve (SBRN) is potentially at risk during thumb carpometacarpal (TCM) or thumb metacarpophalangeal (TMP) joint arthroscopy. The aim of this anatomical study was to describe the different branching patterns of the SBRN and to optimize positioning of portals during TCM and TMP arthroscopy.     

Anatomy of the lateral antebrachial cutaneous nerve in relation to the lateral epicondyle and cephalic vein

The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve supplying the lateral aspect of forearm. Because of its close proximity to the biceps brachii tendon (BBT), the lateral epicondyle (LE), and the cephalic vein (CV), surgery and venipuncture in the cubital fossa can injure the LACN. Measurement data regarding the relative anatomy of LACN are scarce. We, therefore, dissected 96 upper extremities from 26 males and 22 females to expose the LACN in the cubital fossa and forearm. The LACN consistently emerged from the lateral margin of BBT. It then pierced the deep fascia distal to the interepicondylar line (IEL) in 84.4% with mean distances of 1.8 ± 1.1 and 1.2 ± 0.9 cm (male and female, respectively). At the level of IEL, the LACN in all cases was medial to the LE (5.9 ± 1.1 cm male and 5.2 ± 0.9 cm female). Two types of branching were observed: single trunk (78.1%) and bifurcation (21.9%). Asymmetry in the branching pattern was observed in 6 males and 1 female. Concerning the relationship to the CV, the LACN ran medially within 1 cm at the level of IEL in 78.7%. Moreover, in 10 specimens, the LACN was directly beneath the CV. In the forearm, the LACN tends to course medial to the CV. Significant differences in the measurement data between genders but not sides were found in some parameters. These data are important for avoiding LACN injury and locating the LACN during relevant medical procedures.     

Ulnar nerve cutaneous distribution in the palm: Application to surgery of the hand

The ulnar nerve (UN) was classically described as supplying most of the intrinsic muscles of the hand, and the cutaneous innervation of the ulnar one and half digits, by dividing into superficial sensory and deep motor branches in Guyon's canal. Variations of this pattern have been reported in the literature. This study investigated the cutaneous distribution of the UN in the palm following the dissection of 144 cadaveric hands. The UN was examined and the distances from branching points of the superficial branch to the proximal edge of the pisiform were measured. The UN bifurcated (80.4%) into one deep trunk and one superficial trunk, which further divided distally into the proper digital (PDN) and common digital (CDN) nerves or trifurcated (19.6%) into one deep trunk, a PDN and a CDN in Guyon's canal. It received fibers from the median nerve in four cases and from the dorsal branch of the UN in six cases. A classification scheme based on the nerves contributing to the sensory innervation of the ulnar side of the palm was suggested. Understanding the cutaneous distribution of the UN in the palm and appreciating possible communicating branches can help clinicians to assess hand pathologies better and avoid injuries during surgical interventions. Clin. Anat. 28:1022–1028, 2015. © 2015 Wiley Periodicals, Inc.