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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. [ABSTRACT FROM AUTHOR]

Abstract 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.

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. [ABSTRACT FROM AUTHOR]

Avulsion fracture of the brachioradialis muscle origin at the proximal two-thirds of the lateral supraepicondylar ridge of the humerus is an extremely rare fracture with only 4 reported cases in the literature so far. In this article, we describe the case of a 50-year-old male patient who had sustained a closed fracture of the latter after falling from a height of 1.5 m on a flexed elbow and pronated hand. The patient was managed with immobilization of the elbow and wrist with a posterior splint in neutral position for 3 weeks, followed by wrist and elbow therapeutic mobilization sessions for 3 months. At the final follow-up, the patient had painless active and passive full range of motion of the elbow along with good flexion strength. The unique mechanism by which this avulsion fracture occurred is explained on the basis of the mode of injury, position of the limb, and structure and function of the brachioradialis muscle.

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.

Objective: The brachioradialis muscle (BR) belongs to the radial forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABR) or brachioradialis "accessorius" represents an uncommon BR variant, not been enough studied. The present study investigates the incidence of the ABR variant, along with its origin, insertion, and innervation. Methods: Eighty-three (83) upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABR presence. When the variant muscle was identified, morphometric measurements were obtained. Results: The ABR was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BR, and its insertion was identified into the anterior surface of the radius. The radial nerve supplied the ABR, having a course posteriorly to it (in a deeper layer). Conclusion: In the current study, the variant muscle was observed in 2.4%, while the ABR reported incidence is recorded between 0.5-2.8%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABR could precipitate radial neuropathy. [ABSTRACT FROM AUTHOR]

The nerve for the brachioradialis muscle (BR) has been used in nerve transfers for recoveries in functions of the hand as a consequence of lesions affecting the brachial plexus. With the purpose of investigating the number and biometric location of the primary branches coming from the radial nerve and motor points with respect to a reference point located in the elbow region, thirty upper limbs of Brazilian adult individuals from the State University of Sciences of Saúde de Alagoas, Maceió, Brazil were used. The samples were fixed in 10 % formaldehyde solution, of which 15 were right and 15 left. As a reference point, a line was used that passed through the most prominent parts of the humeral epicondyls, bi-epicondilar line (BEL). With respect to the nervous origin for the BR muscle, all the branches originated from the radial nerve (RN). The average number of primary branches (PB) was 1.53 (SD 0.73). In 18 samples (60 %) only one PB was observed; in 8 cases (26.7 %) 2 PB were found, while in 4 cases (13.3 %) of the sample 3 PB were observed. Regarding the biometric location of the origins of PB, it is important to mention that all were located proximal to the BEL. On average, these were located at 38 mm (SD 0.9); 29 mm (DS 1.2) and 22 mm (DS 1.0) for the first, second and third PB, respectively. In relation to the motor points (MP), in 4 cases (13 %) 1 MP was observed as direct penetration of the PB, in 13 cases (43 %) there were 2 MP, in 8 cases (27 %) they found 3 MP and in 5 cases (17 %) 4 MP were observed. In three cases (10 %) the innervation towards the BR muscle emitted nerve fillets towards the extensor carpi radialis longus muscle. The results presented in this investigation are an important contribution to nerve blocks, electrical stimulations and nerve transfers. [ABSTRACT FROM AUTHOR]

The northern tamandua (Tamandua mexicana) is a xenarthran mammal with a distribution from Mexico to Peru. This species arrives to wildlife care centres due to illegal trafficking and attacks by domestic dogs, both of which are situations where the northern tamandua's thoracic limbs (forelimbs) can be affected. As such, it is necessary to have anatomical studies that allow us to perform better medical and surgical procedures. Among these, studies about the musculoskeletal system also aid in the muscular reconstructions of extinct species. The aim of this study was to characterize the craniolateral muscles of the forearm in Tamandua mexicana and compare them with other Xenarthrans to determine their gross adaptations. Six dead specimens were used, and none were sacrificed for the purpose of this investigation. In five specimens, arterial repletion was done. Four were fixed with 10% formaldehyde and 5% glycerin, and two were dissected in fresh. All were dissected in the Veterinary Anatomy Laboratory of the Universidad del Tolima. The weights of the muscles from seven forearms were taken and divided in three functional groups for comparison with non-parametric statistics. Two muscular groups were found: one superficial formed by the brachioradialis, brachioradialis accesorius, extensor carpi radialis, extensor digitorum communis, extensor digitorum lateralis and extensor carpi ulnaris; and one deep muscular group formed by the supinator, extensor digiti III et IV, abductor digiti I longus, and extensor digiti I et II. They were supplied by different branches of the cranial interosseous, transverse cubital and superficial brachial arteries, which had the shape of rete mirabile; and all muscles were innervated by the deep branch of the radial nerve. The presence of the brachioradialis accesorius muscle in this species allows its hand to remain in semi-supination when it is mobilized in a quadrupedal manner. It must also support elbow flexion together with the action of the brachioradialis and the extensor carpi radialis muscles. All the antebrachial digital muscles sent tendons for the digit III making it the most functional for different grip activities such as climbing trees and searching for its food, however, the most strength was directed to supination and carpal extension, and therefore also to the flexion of the elbow.

Arterial variations in the upper extremity occur in a high prevalence. The radial artery is a terminal branch of the brachial artery in the cubital fossa. This artery is used in some treatment interventions and it’s variation is important for clinicians. Here, we report a cadaver with a rare pattern of two radial arteries. In this cadaver, a hypoplastic radial artery in the cubital fossa was seen as a terminal branch of the brachial artery and high origin accessory radial artery in the arm separated from the brachial artery was also found.

Avulsion fracture of the brachioradialis origin at its proximal attachment on the lateral supracondylar ridge of the distal humerus is exceedingly rare, and only two cases have been reported in the literature so far. In this article, we present a 38 years old patient who sustained a closed avulsion fracture of the lateral supracondylar ridge of left humerus at the proximal attachment of brachioradialis following a fall backwards on outstretched hand after being struck by a lorry from behind while riding on a two-wheeler (motorcycle). He was managed with above elbow plaster for four weeks followed by elbow and wrist mobilization. At final followup, the patient had painless full range elbow motion with good elbow flexion strength. The unique mechanism by which this avulasion fracture occurred is explained on the basis of the mode of injury, position of the limb and structure and function of the brachioradialis muscle.

Objectives: The lateral intermuscular septum (LIS) is dense and opaque in gross cadaver dissection. It was suggested as source of pain in elbows with lateral epicondylalgia (LE). The study aimed to measure the length of LIS and to describe the fascia orientation and density of LIS in upper extremities of human cadavers. Methods: 19 upper extremities of 10 formalin preserved human cadavers were dissected using the fascia sparing approach. The LIS was measured from the level of the lateral epicondyle up to the upper arm. The LIS was harvested 5 cm above and below the lateral epicondyle and submitted to a laboratory for histological staining. Prepared slides containing stained LIS were observed under high power microscope. Results: In 17 out of the 19 upper extremities, the LIS attached from the brachioradialis to middle deltoid with a mean of 14.5 (13.8-15.1) cm. 68 out of the 72 fascia images of LIS were linearly oriented in relation to the lateral epicondyle. The LIS was dense on its distal (16/18) and loose (12/16) on its medial sides. Conclusion: The fibers of LIS were linearly arranged near the lateral epicondyle in the upper arm connecting the brachioradialis and the deltoid. The LIS was dense and loose on its distal and medial sides, respectively. Considering the arrangement, connection and density of LIS in the upper arm, the LIS contributes to the inherent tightness of the elbow that may be important in handgrip activities. The connection between brachioradialis and middle deltoid by LIS is important in considering the changes in shoulder movement associated with lateral elbow pain in LE. [ABSTRACT FROM AUTHOR]

Introduction: We sought to characterize the excitability properties of tibialis anterior (TA) and brachioradialis (BR) muscles at rest and during electrically induced muscle activation in normal subjects. Methods: Two centers recruited 10 subjects each. Multi-fiber velocity recovery cycles (VRCs) were recorded from TA (both centers) and BR (one center). VRCs were assessed at rest and during repetitive stimulation (intermittent 20 Hz for 6 min). Changes in latency and peak amplitude of the muscle action potential induced by a frequency ramp to 30 Hz were also characterized. Results: Excitability properties recorded from TA were very similar between centers. Repetitive stimulation generated marked excitability changes, which were similar between TA and BR. Conclusions: Standardized tests of muscle VRCs and responses to repetitive stimulation can provide consistent measures of membrane function and may encourage their wider use in clinical neurophysiology to investigate the pathophysiology of neuromuscular disorders. Muscle Nerve 46: 102-111, 2012 [ABSTRACT FROM AUTHOR]

This study clinically assessed the concept that both thumb flexion and forearm pronation can be restored by brachioradialis (BR)-to-flexor pollicis longus (FPL) tendon transfer if the BR is passed dorsal to the radius. Six patients [two women and four men, mean age 32.3 years (SD 4.9, range 23–56)] underwent BR-to-FPL transfer dorsal to the radius and through the interosseous membrane (IOM). Lateral key pinch strength and pronation range of motion (ROM) were measured 1 year after surgery. A group of six patients [two women and four men, mean age 31.2 years (SD 5.0, range 19–52)] who underwent traditional palmar BR-to-FPL was included for comparison. Postoperative active pronation was significantly greater in the dorsal transfer group compared to the palmar group [149 (SD 6) and 75 (SD 3), respectively] and pinch strength was similar in the two groups [1.28 (SD 0.16) kg and 1.20 (SD0.21) kg, respectively]. We conclude that it is feasible to reconstruct lateral key pinch and forearm pronation simultaneously using only the BR motor. [ABSTRACT FROM PUBLISHER]

Arterial variations in the upper extremity occur in a high prevalence. The radial artery is a terminal branch of the brachial artery in the cubital fossa. This artery is used in some treatment interventions and it's variation is important for clinicians. Here, we report a cadaver with a rare pattern of two radial arteries. In this cadaver, a hypoplastic radial artery in the cubital fossa was seen as a terminal branch of the brachial artery and high origin accessory radial artery in the arm separated from the brachial artery was also found. [ABSTRACT FROM AUTHOR]

The northern tamandua ( Tamandua mexicana ) is a xenarthran mammal with a distribution from Mexico to Peru. This species arrives to wildlife care centres due to illegal trafficking and attacks by domestic dogs, both of which are situations where the northern tamandua's thoracic limbs (forelimbs) can be affected. As such, it is necessary to have anatomical studies that allow us to perform better medical and surgical procedures. Among these, studies about the musculoskeletal system also aid in the muscular reconstructions of extinct species. The aim of this study was to characterize the craniolateral muscles of the forearm in Tamandua mexicana and compare them with other Xenarthrans to determine their gross adaptations. Six dead specimens were used, and none were sacrificed for the purpose of this investigation. In five specimens, arterial repletion was done. Four were fixed with 10% formaldehyde and 5% glycerin, and two were dissected in fresh. All were dissected in the Veterinary Anatomy Laboratory of the Universidad del Tolima. The weights of the muscles from seven forearms were taken and divided in three functional groups for comparison with non-parametric statistics. Two muscular groups were found: one superficial formed by the brachioradialis, brachioradialis accesorius, extensor carpi radialis, extensor digitorum communis, extensor digitorum lateralis and extensor carpi ulnaris; and one deep muscular group formed by the supinator, extensor digiti III et IV, abductor digiti I longus, and extensor digiti I et II. They were supplied by different branches of the cranial interosseous, transverse cubital and superficial brachial arteries, which had the shape of rete mirabile ; and all muscles were innervated by the deep branch of the radial nerve. The presence of the brachioradialis accesorius muscle in this species allows its hand to remain in semi-supination when it is mobilized in a quadrupedal manner. It must also support elbow flexion together with the action of the brachioradialis and the extensor carpi radialis muscles. All the antebrachial digital muscles sent tendons for the digit III making it the most functional for different grip activities such as climbing trees and searching for its food, however, the most strength was directed to supination and carpal extension, and therefore also to the flexion of the elbow.

The authors report a case of a male cadaver found to have two headed brachioradialis muscle tendon (BRMT) on both upper limb as revealed by routine dissection. The superficial branch of radial nerve (SBRN) descends in the forearm under the brachioradialis muscle (BRM) and then, pierced the deep forearm fascia between the BRMT and extensor carpi radialis longus tendon. In our case, we observed that BRMT was divided in two heads in both limbs and SBRN was passing between these two heads. Besides, on the right upper extremity, it was found that BRM with two heads. [ABSTRACT FROM AUTHOR]