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Concept: Brachioradialis

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BACKGROUND: Tendon transfers are essential for reconstruction of hand function in tetraplegic patients. To transfer the extensor carpi radialis longus (ECRL), the extensor carpi radialis brevis (ECRB) has to be sufficiently strong. However, there is currently no reliable clinical test to individually analyse both muscles. In order to develop a reliable preoperative clinical test, the anatomy of the muscle (innervation) areas of ECRB, ECRL and brachio-radialis (BR) was examined. METHODS: In 20 arms, the ECRB, ECRL and BR were dissected and localised. Subsequently, muscle-innervation points were mapped and categorised. A novel method, computer-assisted surgical anatomy mapping (CASAM), was used to visualise muscle areas and innervation points in a computed arm with average dimensions. RESULTS: For both ECRL and ECRB a 100% area could be identified, a specific area in the computed average arm in which the muscle was present for all 20 arms. For the ECRL, this area was situated at 16% of the distance between the lateral epicondyle and the deltoid muscle insertion. The ECRB 100% area was 5 times bigger than that of the ECRL and was located at 40% of the distance between the lateral epicondyle and the radial styloid process. The ECRL and BR showed one to three innervation points, the ECRB one to four. In 47% of the cases, there was a combined nerve branch innervating both the ECRL and the ECRB. CONCLUSIONS: It is feasible to develop a preoperative test; the 100% areas can be used for needle electromyography (EMG) or local anaesthetic muscle injections.

Concepts: Muscle, Electromyography, Nerve, Upper limb anatomy, Brachioradialis, Flexor carpi radialis muscle, Extensor carpi radialis brevis muscle, Extensor carpi radialis longus muscle

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This case report describes a 41-year-old female who presented with complaints of pain in the lower lateral one-third of the right radius extending into the first web space. Tinel’s sign reproducing the patient’s symptoms was elicited 8.2 cm above the radial styloid process. Physical diagnosis for superficial radial nerve entrapment was made based on a positive upper limb neural tension test 2a along with symptom reproduction during resisted isometrics to brachioradialis and wrist extensors. A potential first time successful conservative Kinesio tape (KT) management for entrapment of the superficial radial nerve is described in this report. An immediate improvement in grip strength and functional activities along with a reduction in pain and swelling was noted in this patient after the first treatment session, which was maintained at a 6 month follow-up. A model is proposed describing the mechanism by which KT application could be used to intervene for nerve entrapment interfaces.

Concepts: Upper limb anatomy, Forearm, Upper limb, Distal radius fracture, Brachioradialis, Radial nerve, Chauffeur's fracture, Radial collateral ligament

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Objective: The purpose of this study was to describe computed tomography (CT) features of the ununited anconeal process and relate them with the following elbow dysplasia signs: medial coronoid disease, medial humeral condyle changes, osteoarthritis (OA), and radioulnar incongruence. Methods: Computed tomographic images of dogs older than six months with an ununited anconeal process were evaluated (n = 13). Ununited anconeal process features were described as being complete or incomplete, and the degree of displacement, volume, and presence of cysts and sclerosis were also evaluated. Medial coronoid disease was defined as an irregular medial coronoid process shape, presence of sclerosis and fragmentation. Medial humeral condyle changes were defined as subchondral bone flattening, lucencies, and sclerosis. Osteoarthritis was graded depending on the osteophytes size. Radioulnar incongruence was measured on a sagittal view at the base of the medial coronoid process. Results: Eleven elbows had a complete and two had an incomplete ununited anconeal process. All ununited anconeal processes had cystic and sclerotic lesions. Seven ununited anconeal processes were displaced and six were non-displaced. Mean ununited anconeal process volume was 1.35 cm3 (0.61 cm³ - 2.08 cm³). Twelve elbows had signs of medial coronoid disease (4 of them with a fragmented medial coronoid process), and one elbow did not show any evidence of medial coronoid disease. Ten elbows had medial humeral condyle changes. One elbow had grade 1 OA, seven elbows had grade 2, and five elbows grade 3. All elbows had radioulnar incongruence: three elbows had a negative and 10 elbows had a positive radioulnar incongruence. Mean radioulnar incongruence was 1.49 mm (0.63 mm - 2.61 mm). Computed tomographic findings were similar in the majority of the elbows studied: complete ununited anconeal processes with signs of medial coronoid disease, positive radioulnar incongruence, high grade of OA, sclerotic medial humeral condyle changes, and large ununited anconeal process volumes. Clinical significance: Incomplete small ununited anconeal process volumes could be associated with a lower incidence of medial coronoid disease or medial humeral condyle changes. We recommend performing preoperative CT of elbows with an ununited anconeal process to evaluate concurrent lesions.

Concepts: Tomographic reconstruction, Humerus, Elbow, Tomography, Second grade, Brachialis muscle, Brachioradialis, Coronoid process of the ulna

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Background and purpose Humeral lengthening and deformity correction are now being done increasingly for various etiologies. Monolateral external fixators have advantages over traditional Ilizarov circular fixators; they are easy to apply, they are less bulky, and they are therefore more convenient for the patient. We assessed the effectiveness of hybrid monolateral lateral fixators in humeral lengthening and deformity correction. Methods We retrospectively reviewed 23 patients (40 humeri) with various pathologies who underwent lengthening-with or without deformity correction using monolateral external fixator-between 2003 and 2008. Mean age at the time of the surgery was 14 (10-22) years. The mean follow-up time was 3.4 (1-7) years. Results The average duration of external fixator use was 8.3 (6-19) months. The mean lengthening achieved was 8.8 (4-11) cm and percentage lengthening was 49% (19-73). The healing index was 28 (13-60) days/cm. The major complications were refracture in 3 humeri and varus angulation of 2 humeri. The minor complications were superficial pin tract infection (6 segments), transient radial nerve palsy (1 segment), and elbow flexion contracture (5 segments). All complications resolved. Interpretation Hybrid monolateral fixators can be used for humeral lengthening and deformity correction. The advantage over circular fixators is that they are less bulky and patients can perform their day-to-day activities with the fixator in situ.

Concepts: Patient, Varus deformity, Arithmetic mean, Extension, Ulnar nerve, Brachioradialis, External fixation, Radial neuropathy

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This study investigated the changes in muscular activity and tissue oxygenation while lifting and lowering a load of 20, 40, 60 or 80 % of one repetition maximum (1RM) with elbow flexor muscles until failure. The surface electromyogram (EMG) was recorded in biceps brachii (BB), brachioradialis (BRD) and triceps brachii (TB). For BB, a tissue oxygenation index (TOI) and a normalized total hemoglobin index (nTHI) were recorded by near-infrared spectroscopy. The number of repetitions decreased with the increase in load (P < 0.001), and the four loading conditions induced a decrease in MVC force immediately after failure (P < 0.001). The average of rectified EMG amplitude (aEMG) of elbow flexors increased for all loads during muscle shortening (SHO) and lengthening (LEN) phases of the movement (P < 0.05), except for the 80 % load during LEN phase. At failure, the aEMG was greater during the SHO than the LEN phase (P < 0.05), except for the 20 % load. TOI decreased for all loads and phases (P < 0.05) but less (P < 0.01) for the 20 % than 60 and 80 % loads (P < 0.01), and for LEN compared with SHO phase. At failure, TOI was negatively associated with aEMG during the SHO (r 2 = 0.99) and LEN (r 2 = 0.82) phases, while TOI and aEMG were positively associated with load magnitude (r 2 > 0.90) in both movement phases. This study emphasizes the influence of load magnitude and movement phase (SHO and LEN) on neuromuscular and oxydative adjustments during movements that involve lifting and lowering a load until failure.

Concepts: Muscle, Biceps brachii muscle, Elbow, Triceps brachii muscle, Flexion, Extension, Brachioradialis, Flexor muscle

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Radial head fractures can occur in isolation or in association with elbow and forearm injuries. Treatment options include nonoperative management, fragment or whole-head excision, open reduction and internal fixation (ORIF), and radial head arthroplasty. However, the evidence supporting ORIF for repairable radial head fractures is inconclusive.

Concepts: Implants, Orthopedic surgery, Brachioradialis, Internal fixator, Internal fixation

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Lateral epicondylalgia, pain at the lateral elbow, is commonly associated with extensor carpi radialis brevis tendinopathy. The radial head, which abuts the extensor tendons and is elliptical in shape, may affect the extensor tendons during pronation of the forearm. Cadaverous studies have shown that the radial head may act as a cam in pronation, to offer a mechanical advantage to the common extensor tendon and to mitigate load on the origin of the extensor carpi radialis brevis tendon.

Concepts: Forearm, Tendon, Brachioradialis, Tendinopathy, Flexor carpi radialis muscle, Extensor carpi radialis brevis muscle, Extensor carpi radialis longus muscle

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How do synergistic muscles interact, when their contraction aims at stabilizing and fine-tuning a movement, which is induced by the antagonistic muscle? The aim of the study was to analyze the interaction of biceps and brachioradialis during fine-tuning control tasks in comparison to load bearing ones. The surface electromyogram of biceps, brachioradialis and triceps were examined in 15 healthy subjects in dynamic flexion and extension movements with different combinations of contraction levels, joint angles and angular velocities. The measurements were conducted in two configurations, where the torque due to an external load opposes the rotational direction of the elbow flexion (load bearing tasks) or the elbow extension (fine-tuning tasks). Whereas during load bearing control tasks, similar muscular activation of biceps and brachioradialis was observed for all joint angles, angular velocities and external loads, during fine-tuning control tasks a significant difference of the muscular activation of both flexors was observed for 1kg, F(3.639,47.305)=2.864, p=0.037, and 5kg of external load, F(1.570,21.976)=6.834, p=0.008. The results confirm the synergistic muscular activation of both flexors during load bearing tasks, but suggest different control strategies for both flexors when they comprise a fine-tuning control task.

Concepts: Muscle, Biceps brachii muscle, Triceps brachii muscle, Knee, Flexion, Extension, Semitendinosus muscle, Brachioradialis

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Non-union of the humeral shaft is infrequently noticed after surgical fixation. Sixty eight patients whose osteosynthesis of humeral shaft had failed leading to non-union were identified over a duration of 10 years from (January 2006 to December 2015). Clinical and radiographical follow-up was available for 64 patients (4 patients were lost for follow-up), with a mean age of 58 years (range 25-78 years). All patients had aseptic atrophic non-union of either: proximal shaft (n=12), mid shaft (n=38), and lower shaft (n=14). All these patients had failure of primary fixation, with a minimum duration from 36 to 110 weeks. Non-unions were operated by excision of non-union, autogenous bone grafting and osteosynthesis by locking compression plating. Adequate fixation of non-union with bone grafting was achieved in all patients. All non-unions healed well at an average of 16 weeks (range 6-36 weeks). The mean length of follow-up was 120 weeks (range 60-250 weeks). The mean range of movements following healing of non-union was forward flexion of 140°, external rotation and internal rotation of 30° at shoulder and average fixed flexion deformity of 10° and flexion of 130° at elbow. Two patients had postoperative radial nerve palsy because of neuropraxia, which recovered in eight weeks. Three patient developed superficial infections at the iliac crest, which settled with antibiotics, dressings in 3 weeks time and two patients had some discomfort over the fibular graft harvest site. In all patients complete clinical and radiological union was achieved with satisfactory outcome in terms of relief of symptoms and functional improvement in the range of movements. The main points in surgical treatment were complete excision of non-union, correction of deformity, use of plenty of corticocancellous graft, furthermore the use of intramedullary fibula and osteosynthesis by long locking compression plating in different modes of fixation provided good to excellent results and clinical outcome.

Concepts: Surgery, Humerus, Elbow, Arithmetic mean, Shoulder, Excision, Brachioradialis, Radial neuropathy

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This study investigated the effect of supplementation with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the M-wave latency of biceps brachii and muscle damage after a single session of maximal elbow flexor eccentric contractions (ECC).

Concepts: Muscle, Omega-3 fatty acid, Biceps brachii muscle, Triceps brachii muscle, Eicosapentaenoic acid, Docosahexaenoic acid, Fish oil, Brachioradialis