The accessory brachioradialis muscle: prevalence of a rare variant with possible clinical implications.

PURPOSE: The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation. MATERIALS: Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained. RESULTS: The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply). CONCLUSIONS: In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy.

The brachioradialis longus: an unreported accessory form of the brachioradialis muscle.

The brachioradialis muscle (BR) belongs to the lateral forearm muscle. Typically, the radial nerve innervates it. BR morphological variability, such as split muscular belly, split tendon, or accessory BR (ABR), has been described in the current literature. A 68-year-old female donated cadaver was routinely dissected for research and educational purposes. A variant muscle was identified extending at the right arm's lateral and forearm compartments. It originated from the humerus lateral surface between the deltoid and the triceps brachii lateral head, joined the second muscular head from the brachialis muscle, and inserted into the radius styloid process. According to its origin, course, and insertion, the variant muscle probably corresponded to the BR accessory form. However, in the current literature, the ABR morphology corresponds to an accessory muscle originating adjacent to the typical BR and inserted into the radial tuberosity. At the same time, it was defined as "brachioradialis brevis." In the current case, the variant muscle differed significantly from the current literature due to the origin, insertion, length, and relationship with the typical BR; therefore, the term "brachioradialis longus" seemed adequate to describe this variant muscle.

A Fresh Cadaver Study on the Innervation of Brachioradialis and Extensor Carpi Radialis Longus Muscles.

PURPOSE: Distal nerve transfers have revolutionized peripheral nerve surgery by allowing the transfer of healthy motor nerves to paralyzed ones without causing additional morbidity. Radial nerve branches to the brachialis (Ba), brachioradialis (Br), and extensor carpi radialis longus (ECRL) muscles have not been investigated in fresh cadavers. METHODS: The radial nerve and its branches were dissected in 34 upper limbs from 17 fresh cadavers. Measurements were taken to determine the number, origin, length, and diameter of the branches. Myelinated fiber counts were obtained through histological analysis. RESULTS: The first branch of the radial nerve at the elbow was to the Ba muscle, followed by the branches to the Br and ECRL muscles. The Ba and Br muscles consistently received single innervation. The ECRL muscle showed varying innervation patterns, with one, two, or three branches. The branches to the Br muscles originated from the anterior side of the radial nerve, whereas the branches to the Ba and ECRL muscles originated from the posterior side. The average myelinated fiber counts favored the nerve to Br muscle over that to the ECRL muscle, with counts of 542 versus 350 and 568 versus 302 observed in hematoxylin and eosin and neurofilament staining, respectively. CONCLUSIONS: This study provides detailed anatomical insights into the motor branches of the radial nerve to the Ba, Br, and ECRL muscles. CLINICAL RELEVANCE: Understanding the anatomy of the radial nerve branches at the elbow is of utmost importance when devising a reconstructive strategy for upper limb paralysis. These findings can guide surgeons in selecting appropriate donor or recipient nerves for nerve transfer in cases of high tetraplegia and lower-type brachial plexus injuries.

Brachioradialis Involvement in Hirayama's Disease: An Atypical Presentation of a Rare Cervical Myelopathy.

Juvenile monomelic amyotrophy (JMA), also known as Hirayama's disease, is a rare cervical myelopathy that predominantly affects young Asian males. It is characterized by degeneration of anterior horn cells due to compression by the redundant dural sac. This study presents an atypical case of a 23-year-old Indian male who exhibited uncommon symptoms of JMA. The patient displayed progressive weakness and atrophy in the left forearm, including the usually spared brachioradialis muscle. Electrophysiological tests and MRI scans solidified the diagnosis of Hirayama's disease. After wearing a cervical collar for one year, the patient's condition stabilized, reinforcing the diagnosis. Unlike most JMA cases, this instance highlights the involvement of the brachioradialis muscle, underlining the variability in JMA presentations. A precise diagnosis is contingent upon clinical criteria, dynamic MRI, and electrophysiological findings. Recognizing these variations is crucial for early detection and appropriate management of the disease.

Experimental Analysis of the Efficiency and Usability of Tylke Versus Magill Forceps.

INTRODUCTION: The procedure of nasotracheal intubation (NI) has long been performed utilizing the Magill forceps as developed by Sir Ivan Magill in the 1920s. While used for nearly a century, several serious patient safety concerns remain including torn tube cuffs, vocal cord trauma, and inefficient tube placement. The Tylke forceps have been developed as a modification to the largely unchanged form of Magill forceps. METHODS: In the present investigation we compared the efficacy, number of clasps, and muscle activation involved in NI using the Tylke forceps versus the Magill forceps in previously untrained individuals. RESULTS: Tylke forceps showed faster successful NI over the standard Magill forceps at an average intubation time of 6.54s vs. 13.73s, respectively. Tylke forceps also had fewer clasps per intubation over the Magill. The trapezius, deltoid, and brachioradialis muscle activation was also compared in Tylke vs Magill forceps intubation trials. Tylke forceps required less lower muscle activation in the brachioradialis and trapezius over the Magill forceps with Tylke forceps resulting in higher deltoid muscle activation. CONCLUSION: Tylke forceps were more efficacious and reduced the number of clasps over the Magill forceps when used in successful NI with different muscle activation patterns.

Intraspecific anatomical variations of the extensor tendons of the carpus and digits with a reexamination of their insertion sites in the domestic dog (Canis lupus familiaris): a cadaveric study.

BACKGROUND: The aim of the current study was to investigate the frequency of variations of the extensor tendons of the carpus and digits in the domestic dog (Canis lupus familiaris) with a reexamination of their insertions as well as the morphometric measurements of the tendons and the brachioradialis muscle. In total, we investigated 68 paired thoracic limbs of the domestic dog (16 females and 18 males) which were fixed in a 10% formalin solution. RESULTS: The extensor carpi radialis (ECR) tendons showed striking variations in both splitting and insertion sites. In 4.4% of dissections, ECR had three tendons. Of these tendons, the extra tendon either attached independently on the fourth metacarpal bone (one right) or joined its counterpart tendon at the distal end (cross-connections) (one bilateral). It is worth mentioning that one of the ECR tendons split into two or three slips which inserted on the first, second, third, or fourth metacarpal bone in 11 (16.2%) of the specimens. In addition, we found a long tendinous slip originating from the ECR tendons to digit II or III in 7.4% of the distal limbs. The most common type of contribution to digit III was a third tendon of the extensor digiti I et II (ED III) joining the extensor digitorum lateralis (EDL III) with a frequency of 17.6%. In other types of variations, the contribution to digit III was incomplete. A part of the abductor pollicis longus (APL) deep to the superficial part of the flexor retinaculum seemed to continue up to the flexor digitorum superficialis (FDS) tendon. CONCLUSIONS: The rare intraspecific variations of the extensor tendons of the manus described in the current research are valuable from both clinical and phylogenetic perspectives. Nonetheless, their functional importance needs more studies.

Evaluation of the treatment of distal radial volar fracture by different methods sparing the pronator quadratus.

OBJECTIVE: The traditional volar approach requires the release of the pronator quadratus (PQ) muscle in the treatment of distal radius fractures. However, intraoperative repair of the PQ muscle often fails due to tissue injury and unstable muscle repair. This study compared the outcomes of different methods of sparing the PQ muscle combined with the volar plate in treating distal radius fractures. METHODS: A total of 95 patients with distal radius fractures sparing the PQ muscle were enrolled with the brachioradialis (BR) splitting approach (group A, 33 people), the volar plating insertion PQ muscle approach (group B, 35 people) and traditional Henry approach without sparing PQ muscle (group C, 27 people). Postoperative internal fixation, fracture healing and postoperative complications were observed in the three groups. The visual analog scale (VAS) of postoperative wrist pain was compared between three groups. The Dienst joint scale was used to evaluate the wrist function of patients, and imaging indexes were used to evaluate the surgical efficacy. RESULTS: A total of 95 patients with distal radius fractures were followed up for more than one year after surgery. All fractures obtained good union, with no vascular injury, nerve injury or wound infection. Outcomes at three days, one month and three months all showed no significant differences in postoperative imaging indexes among three groups and no significant differences in various indexes among three groups during the same period. The mean operative time in group C was significantly lower than that in groups A and B. There was significant difference in the mean operation time between group A and group B. The amount of mean operative blood loss or mean bone union time in groups A and B was significantly lower than those in group C. No significant difference was shown in mean operative blood loss or mean bone union time between group A and group B. No significant differences in limb function scores, VAS scores and the mean range of motion existed among three groups at the 12-month postoperative follow-up. However, outcomes assessed one week, one month and three months after surgery demonstrated significant differences in the VAS scores and the mean range of motion among three groups, and the group B had lower VAS score and greater the mean range of motion. According to Dienst score, the excellent rate in groups A, B and C was 91.0% (30/33), 94.2% (33/35) and 85.2% (23/27), respectively, at 12 months after surgery. Tendon irritation occurred in 2 cases and joint stiffness in 1 case in group A. In group B, there were 2 cases traumatic arthritis and 2 cases delayed carpal tunnel syndrome and 1 case tendon irritation. In group C, tendon irritation and delayed carpal tunnel syndrome occurred, respectively, in 3 cases. CONCLUSION: Our results demonstrated that these two different surgical approaches were effective ways to reserve PQ and had good clinical outcomes. The volar plating insertion PQ muscle approach could reduce early postoperative pain, promote early activity and return to normal life, while the BR splitting approach was more advantageous in intraoperative fracture exposure and could shorten the operative time. However, some defects also existed. At 12 months of follow-up, no significant advantage was seen in sparing the PQ muscle. Therefore, surgeons should be aware of their individual characteristics and choose patients carefully.

Duplicated superficial branch of the radial nerve and brachioradialis muscle belly: prevalence and significance.

BACKGROUND: The superficial branch of the radial nerve (SBRN) is a sensory nerve innervating the dorsoradial part of the hand. It originates in the cubital fossa, runs under the belly of the brachioradialis muscle (BM), emerges from underneath in the distal third of the forearm and continues in the subcutaneous tissue towards the hand. There exist several anatomical variations of its branching and course, including a rare variation of its duplication combined with a duplication of the brachioradialis muscle belly. The aim of this study was to find out the prevalence of this variation on a sample of cadaveric human bodies which has not been reported yet. MATERIALS AND METHODS: We have carefully dissected 208 cadaveric upper limbs (Central European population). All cases of limbs containing the variation of a double SBRN and/or a double BM belly were measured and documented. RESULTS: We have identified 2 cases of a double SBRN combined with a double BM belly (0.96%). Both were present in the right forearm of a male donor and in both cases the nerve was impinged by muscle bundles connecting the 2 muscle bellies together. Moreover, we have encountered 1 case of a double SBRN without a double BM belly (0.48%), i.e. the total prevalence of a double SBRN was 1.44%. CONCLUSIONS: The duplicated SBRN with the duplicated BM is a relatively rare anatomical variation that might cause complications while performing various surgical procedures in the forearm, moreover it might be a rare cause of Wartenberg's syndrome.

Rupture of the brachioradialis muscle following blunt trauma. A case report.

A 50-year old healthy male lost control over the pull string of a milling machine, which strangulated his right elbow and forearm with high velocity. Magnetic resonance imaging of the right upper extremity revealed a substantial tear in the muscle belly of the musculus brachioradialis with multiple small defects in the surrounding musculature of the forearm. The affected arm was immobilized for 1 week with an above the elbow cast. In the following months, guided training and strengthening exercises were performed. The patient could return to his physically demanding work after 10 months and regained full function of his hand and wrist after 18 months. This case report demonstrates that short immobilization followed by extensive and guided strength training has been observed to result in persisting weakness of elbow flexion but good functional outcome for the wrist and hand.

Brachioradialis to Extensor Carpi Ulnaris Transfer - An Additional Transfer to Prevent Radial Deviation Deformity of the Wrist following Tendon Transfers for Posterior Interosseous Nerve Palsy.

The usual recommendation in posterior interosseous nerve (PIN) palsy is to use the flexor carpi radialis instead of the flexor carpi ulnaris (FCU) for restoration of digital extension. The use of FCU takes away the only remaining ulnar deviator of the wrist. Although preserving the FCU prevents severe radial deviation deformity, we found that some patients still develop a radial deviation deformity, especially during wrist extension. We have used a brachioradialis (BR) to extensor carpi ulnaris (ECU) transfer to prevent the development of a radial deviation deformity and find that it restores the normal radio-ulnar balance of the wrist by providing a dynamic ulnar stabiliser. It is a simple addition to the standard two tendon transfers for PIN palsy with minimal donor morbidity. We have used this triple transfer for PIN palsy in seven patients with satisfactory results and no complications. Level of Evidence: Level V (Therapeutic).

Restoration of Hand Function in Isolated Lower Brachial Plexus Injury with Brachioradialis to Flexor Pollicis Longus and Biceps to Flexor Digitorum Profundus Transfer.

Background: Isolated lower (C8T1) brachial plexus injury (BPI) is uncommon and the aim of treatment is to achieve a satisfactory grasp enabling the use of the hand for daily activities. The aim of this study is to report the outcomes of the transfer of brachioradialis (BR) to flexor pollicis longus (FPL) and biceps to the flexor digitorum profundus (FDP) for an isolated lower BPI. Methods: This is a retrospective study of all patients with an isolated lower BPI who underwent a BR to FPL and biceps to FDP transfer for restoration of digital flexion over a 1-year period from May 2019 to June 2020. Patient demographic and injury data were collected at the presentation. Outcomes data included the ability to grasp and perform activities of daily living and DASH score. Results: The study included three patients (all men) with an average age of 30.3 years. All sustained an isolated lower BPI following a road traffic accident and tendon transfers were performed at a mean of 9.3 months after the initial injury. At a mean of 1-year follow-up, all three recovered grade M4 motor power of digital flexion, achieved good grasp function with pulp-to-palm distance of <1 cm. All are able to use the hand for independent as well as bimanual activities. The individual DASH scores were 36, 30 and 30. Conclusions: BR to FPL for thumb flexion and biceps to FDP using fascia lata graft to restore finger flexion is simple and effective surgeries in patients with isolated lower BPI. Level of Evidence: Level V (Therapeutic).

Technical note: Practical application of post-mortem mechanical stimulation of skeletal muscle, a field study.

BACKGROUND: Estimation of the post-mortem interval (PMI) is a crucial aspect in crime scene investigation. PMI is defined as the time between the moment of death and the moment of finding the dead body. A combination of methods for estimating the PMI in forensic casework is internationally mostly used. Supravital muscle reaction (SMR) is one of those methods. SMR is an idiomuscular contraction and can be provoked by mechanical stimulation. OBJECTIVES: A field study was carried out with the aim to investigate whether a reflex hammer can be used as tool for triggering an idiomuscular contraction and, furthermore, to determine if a learning period has to be taken into account by a forensic physician for appropriate application of a reflex hammer to trigger SMR. METHODS: From January 2017 to January 2022, four forensic physicians used this SMR by mechanically stimulating the musculus brachioradialis and musculus biceps brachii. In total, 332 cases were included with a PMI less than 24 h. The cases were divided in chronological clusters of 20 cases. The ratio of the number of positive SMR versus the total number stimulations per forensic physician was used as a measure of accuracy of a reflex hammer for triggering SMR. The distribution of the data was analyzed by comparing the clusters in chronological order to assess whether a learning curve applies. RESULTS: In 55.7%, a muscle reaction could be provoked by mechanical stimulation. Comparable outcome of SMR between the participating physicians was observed after 40 stimulations. CONCLUSION: A reflex hammer is usable for provoking SMR. A learning period has to be taken in to account during the first forty cases per forensic physician.

Shear wave elastography of the brachioradialis spastic muscle and its correlations with biceps brachialis and clinical scales.

BACKGROUND: Shear wave elastography technique estimates biological tissue shear elastic modulus (µ[kPa]), which can be used as an objective, muscle-specific indicator of stiffness increase caused by spasticity. We measured both the brachioradialis and biceps brachialis µ in hemiparetic post-stroke patients (n = 11). The spastic arm was compared with the supposedly non-affected contralateral limb and correlated with Fugl-Meyer Assessment and Modified Ashworth Scales. METHODS: Shear elastic modulus was estimated using an Aixplorer V.9 ultrasound device with the elbow at full extension. Average shear elastic modulus t-test, effect sizes, correlation matrix, spider plots and factor analysis were used to check for differences between spastic and nonspastic sides and explore relationships among the variables. FINDINGS: Spastic brachioradialis µ (22.54 ± 11.59 kPa) and biceps brachialis (26.86 ± 12.07 kPa) were significantly greater than the non-spastic counterparts (13.13 ± 2.81 kPa, p = 0.031, ηp2 = 0.3846 for brachioradialis and 15.25 ± 5.00 kPa, p = 0.007, ηp2 = 0.5345 for biceps brachialis). Significant correlations were observed between the spastic brachioradialis and biceps µ and Modified Ashworth Scales, but no correlation with Fugl-Meyer Assessment. INTERPRETATION: Elastography can provide muscle-specific shear elastic modulus estimations of spastic brachioradialis and biceps brachialis, which are distinct from the nonspastic side. In some patients, there was no clear correspondence of the Fugl-Meyer Assessment functional scale with Modified Ashworth Scales and µ, suggesting that spasticity is not the only determinant of arm function. Additionally, shear wave elastography of brachioradialis and biceps brachialis muscles may guide the spasticity treatment, for instance, selecting the preferable candidate for botulinum toxin therapy.

Acute Essex-Lopresti Syndrome: About a Case of Brachioradialis Tendon Transfer.

Background The classic treatment for acute Essex-Lopresti syndrome is closed reduction percutaneous pinning (CRPP) of the distal radioulnar joint (DRUJ). This work aimed to verify whether it was possible to add a transfer of the brachioradialis tendon to the pinning. Case Description The patient was a 39-year-old right-handed man, climbing instructor, who sustained the Mason II fracture and disjunction of the DRUJ. A transfer of the brachioradialis tendon severed from its muscle attach that was made through a bone tunnel passing through the radius and the neck of the ulna. The clinical and radiological result at the 6-month follow-up was satisfactory. Literature Review and Clinical Relevance Our results in a single case showed that the brachioradialis tendon transfer was useful in acute Essex-Lopresti syndrome.

VARIATIONS OF THE STRUCTURE, TOPOGRAPHY, BLOOD SUPPLY AND INNERVATION OF THE BRACHIORADIALIS IN HUMAN FETUS.

OBJECTIVE: The aim of the research was to establish the features of age-related and individual anatomical variability of the brachioradialis, its blood supply, and innervation options. PATIENTS AND METHODS: Materials and methods: The study of the variant anatomy of the brachioradialis and its vascular and nervous structures was carried out on 25 preparations of human fetuses of 4-7 months, 81.0-270.0 mm parietal-coccygeal length (PCL) using macromicroscopic preparation, injection vessels, and morphometry. RESULTS: Results: Spindle-like (56%) and round (24%) shapes of the brachioradialis were found in most of the studied fetuses; its elongated flat (12%) and triangular (8%) forms occur less often. In a fetus of 185.0 mm TKD, the right brachioradialis consisted of two separate parts: upper and lower, which were connected at the level of the middle of the forearm into a common short muscle belly. In another human fetus of 220.0 mm TKD, the right brachioradialis also consisted of two separate parts - upper and lower, triangular in shape, but separated by a pronounced horizontal gap. CONCLUSION: Conclusions: The features of the fetal anatomy of the brachioradialis are established: its variability and bilateral asymmetry of shape and size, variability of the places of origin and attachment, etc. In individual human fetuses, the brachioradialis consists of two separate parts that have special topographical relationships. The area of the greatest concentration of both extra- and intramuscular nerves and arteries is the upper and middle third of the brachioradialis. In the area of the forearm, the course of radial vascular-nerve formations is determined by the brachioradialis.

Brachioradialis Muscle Tendon Transposition in Extensor Pollicis Longus Reconstruction: Anatomical Study and a New Surgical Approach.

BACKGROUND: Complete extension of the thumb and activation of the extensor pollicis longus (EPL) tendon are fundamental to ensure maximum function. Many EPL repair techniques are described in the literature. METHODS: The authors present an alternative technique using the brachioradialis (BR) tendon. Thirty patients with injuries of the EPL tendon in zone 8 were studied. In all cases, neither direct suture repair nor traditional tendon transfer was possible. RESULTS: Thumb extension was restored in all patients with satisfactory extension recovery. All patients achieved excellent extension; good functional results were observed in 2 cases, and in 1 case satisfactory results were achieved using the Geldmacher assessment and the Kapandji assessment. The overall results were rated as excellent, good, fair, or poor according to the Quick Disabilities of the Arm, Shoulder, and Hand Scale. DISCUSSION: The BR tendon was suitable to treat all cases, in particular injuries occurring near Lister's tubercle, due to its appropriate length for tenorrhaphy albeit with a short distal head.

Nerve transfer in the spastic upper limb: anatomical feasibility study.

PURPOSE: Nerve transfers represent an innovative tool in the surgical treatment of upper limb paralysis. Well-documented for brachial plexus sequalae and under evaluation for tetraplegic patients, they have not yet been described for spastic upper limbs. The typical spastic deformity involves active and spastic flexor, adductor and pronator muscles, associated with paralysed extensor and supinator muscles. Experience with selective neurectomy has shown an effective decrease in spasticity together with preservation of muscle strength. We conceptualized a combination of neurectomy and nerve transfer, by performing a partial nerve transfer from a spastic elbow flexor muscle to a paralyzed wrist extensor muscle, hypothesizing that this would reduce the spasticity of the former and simultaneously activate the latter. METHODS: Ten cadaveric dissections were performed in order to establish the anatomic feasibility of transferring a motor branch of the brachioradialis (BR) onto the branch of the extensor carpi radialis longus (ECRL) or brevis (ECRB). We measured the emergence, length, muscle entry point and diameter of each branch, and attempted the transfer. RESULTS: We found 1-4 motor nerve for the BR muscle and 1-2 for the ECRL muscle. In all cases, the nerve transfer was achievable, allowing a satisfactory coaptation. The ECRB branch emerged too distally to be anastomosed to one of the BR branches. CONCLUSION: This study shows that nerve transfers from the BR to the ECRL are anatomically feasible. It may open the way to an additional therapeutic approach for spastic upper limbs.

Effect of muscle selection for botulinum neurotoxin treatment on spasticity in patients with post-stroke elbow flexor muscle over-activity: an observational prospective study.

PURPOSE/AIM: To investigate the effect of muscle selection for botulinum neurotoxin A (BoNT-A) treatment on spasticity in patients with post-stroke elbow flexor muscle over-activity. MATERIALS AND METHODS: Chronic stroke patients with a deforming spastic paresis in the upper limb (elbow flexion with forearm pronation) who were injected BoNT-A into at least one of elbow flexor muscles (brachialis, brachioradialis, and biceps brachii) were included in this prospective observational study. The main outcome measure was spasticity angle by Tardieu Scale recorded at pre-treatment and week 4 after treatment. RESULTS: Three muscle selection groups with sufficient sample size for statistical analysis were able to be created; brachialis (n = 14), biceps brachii (n = 21), and brachialis plus brachioradialis (n = 11). Although there was a significant improvement in spasticity angle within all groups over time (p < 0.05), the change in spasticity angle was not different between the groups (p > 0.05 for each pairwise comparison). However, the magnitude of the change in spasticity angle was larger in the groups in which brachialis was preferred. CONCLUSIONS: In stroke patients with a spontaneous spastic posture of elbow flexion and forearm pronation, targeting brachialis for BoNT-A injection seems more effective in reducing the severity of spasticity. CLINICAL TRIAL REGISTRATION NO: NCT04036981.

Electrode Size and Placement for Surface EMG Bipolar Detection from the Brachioradialis Muscle: A Scoping Review.

The brachioradialis muscle (BRD) is one of the main elbow flexors and is often assessed by surface electromyography (sEMG) in physiology, clinical, sports, ergonomics, and bioengineering applications. The reliability of the sEMG measurement strongly relies on the characteristics of the detection system used, because of possible crosstalk from the surrounding forearm muscles. We conducted a scoping review of the main databases to explore available guidelines of electrode placement on BRD and to map the electrode configurations used and authors' awareness on the issues of crosstalk. One hundred and thirty-four studies were included in the review. The crosstalk was mentioned in 29 studies, although two studies only were specifically designed to assess it. One hundred and six studies (79%) did not even address the issue by generically placing the sensors above BRD, usually choosing large disposable ECG electrodes. The analysis of the literature highlights a general lack of awareness on the issues of crosstalk and the need for adequate training in the sEMG field. Three guidelines were found, whose recommendations have been compared and summarized to promote reliability in further studies. In particular, it is crucial to use miniaturized electrodes placed on a specific area over the muscle, especially when BRD activity is recorded for clinical applications.