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Concept: Upper limb anatomy

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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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We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The total pattern of all bones in the shoulder and arm reveals that Regourdou 1 was a right-hander. Confirmatory evidence comes from the mandibular incisors, which display a distinct pattern of right oblique scratches, typical of right-handed manipulations performed at the front of the mouth. Regourdou’s right handedness is consistent with the strong pattern of manual lateralization in Neandertals and further confirms a modern pattern of left brain dominance, presumably signally linguistic competence. These observations along with cultural, genetic and morphological evidence indicate language competence in Neandertals and their European precursors.

Concepts: Bone, Humerus, Ulna, Left-handedness, Upper limb anatomy, Upper limb, Handedness, Right-handedness

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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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Purpose: Snapping ulnar nerve syndrome (dislocation of the ulnar nerve over the medial epicondyle) is one of many causes of ulnar neuropathy at the elbow. This preliminary study was performed to search for sonographic signs suggesting the presence of this condition.Methods and Materials: We retrospectively investigated 11 patients with snapping ulnar nerve syndrome (SNAP) in comparison with an age-matched group of 20 patients with idiopathic cubital tunnel syndrome (SNU). Patients were grouped according to the presence of paretic or merely sensory deficits. Nerve cross section area (CSA) and thickness of outer epineurium (ET) was measured and correlated with neurological findings. Statistical differences were evaluated with the Mann-Whitney U-Test.Results: 5 SNAP (10 SNU) patients had sensory symptoms only, 6 SNAP (10 SNU) patients had paretic deficits. CSA in sensory SNU was 0.14 cm2, in paretic SNU 0.19 cm2, in sensory SNAP 0.15 cm2 and in paretic SNAP 0.14 cm2. ET in sensory SNU was 0.85 mm, 0.8 mm in paretic SNU, 1.05 mm in sensory SNAP and 1.1 in paretic SNAP. Differences in CSA were not significant depending on symptoms or group, differences in ET were not significant depending on symptoms but on group (SNAP versus SNU) at α = 0.05.Conclusion: A thickened, hyperechoic outer epineurium in a patient with ulnar neuropathy at the elbow might be a statistically significant differential feature of snapping ulnar nerve syndrome and should be involved in a further functional sonographic evaluation during flexion/extension of the elbow.

Concepts: Statistics, Statistical significance, Humerus, Upper limb anatomy, Ulnar nerve, Median nerve, Cubital tunnel, Ulnar nerve entrapment

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INTRODUCTION: Numerous static and dynamic techniques have been described for the management of acute acromioclavicular (AC) joint dislocation. To date, no standard technique has been established and several complications have been described for each of these techniques. The purpose of the present study was to evaluate the functional and radiographic outcomes of acute AC joint reconstruction after a mini-open technique using the double-button fixation system. PATIENTS AND METHODS: Twelve patients with acute AC joint dislocation treated with the double-button fixation system by one surgeon were retrospectively reviewed. Functional assessment was performed by an independent reviewer using the DASH, Constant and the VAS scores. The coracoclavicular (CC) distance of the affected shoulder was assessed on a standard radiograph and compared with the contralateral normal one. RESULTS: Eight patients were operated on for grade III AC joint dislocation and 4 for grade IV. The mean age of the patients at the time of surgery was 27.5 years. The mean follow-up was 18.25 months (range: 12-30 months). At the most recent follow-up, the mean Constant score was 94.8 (range: 84-100) showing a significant increase compared with the mean pre-operative value of 34.4 (range: 25-52) (p<0.001). The mean DASH score was significantly decreased from 19.6 (range: 14-28) preoperatively to 0.25 (range: 0-3) at the last follow-up (p<0.001). The mean VAS score showed a significant decrease from 5.75 (range: 4-7) to 0.2 (range: 0-2) (p<0.001). The mean CC distance on the operated shoulder was found to have no significant difference from the CC distance on the contralateral normal side (10.5 vs. 10mm) (p>0.05). There was no evidence of AC joint osteoarthrosis, CC calcification or osteolysis of the distal clavicle or the coracoid process. CONCLUSIONS: The proposed mini-open technique provides adequate exposure of the base of the coracoid with minimal damage to the soft tissues surrounding the CC ligaments while ensures an excellent cosmetic result. We recommend this fast and relatively simple technique for all type IV injuries and for type III injuries in heavy manual workers and high-demand upper extremities athletes.

Concepts: Synovial joint, Joints, Shoulder, Upper limb anatomy, Clavicle, Acromioclavicular joint, Acromion, Acromioclavicular ligament

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The wide-awake hand surgery (WAHS) technique involves injecting lidocaine with adrenaline for hand surgical procedures that are done without the use of tourniquets, sedation, regional or general anaesthetic. This is a retrospective review of the first 100 consecutive patients who underwent operations using this technique at our centre. The operations included carpal and cubital tunnel decompression, trapeziectomy, tendon transfer, and tenolysis. A questionnaire adapted from Lalonde’s previous work on wide-awake surgery was used to assess patients' experiences. Sixty-five percent of the patients responded to the postal questionnaire, the majority reporting a high satisfaction level. Ninety-one percent of responders reported that the operation was less painful or comparable with a procedure at the dentist; 86% would prefer to be wide-awake if they needed to have hand surgery again, and 90% stated they would recommend WAHS to a friend.

Concepts: Hospital, Surgery, Physician, Anesthesia, Dentistry, Upper limb anatomy, Ulnar nerve, Cubital tunnel

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In order to evaluate whether overuse has a significant role in rotator cuff tear (RCT) aetiology, we evaluated both shoulders of patients with old unilateral arm amputation expecting a higher rate of RC degeneration in the healthy side.

Concepts: Humerus, Amputation, Shoulder, Upper limb anatomy, Rotator cuff, Rotator cuff tear, Deltoid muscle

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PURPOSE: Objective of this study is to evaluate the diagnostic values of the Arm Squeeze Test. The test consists in squeezing the middle third of the upper arm. METHODS: 1,567 patients were included in this study. Diagnosis of cervical nerve root compression or shoulder disease was clinically formulated and confirmed with imaging before performing test. 350 healthy volunteers were recruited as controls. The test was positive when score on a VAS Scale was 3 points or higher on squeezing the middle third of the upper arm compared to acromioclavicular (AC) joint and anterolateral-subacromial area. RESULTS: Patients were subdivided as follows: 903 with rotator cuff tear, 155 with shoulder adhesive capsulitis, 101 with AC joint arthropathy, 55 with calcifying tendonitis, and 48 affected by glenohumeral arthritis. The study sample included 305 patients with cervical nerve root compression from C5 to T1 with shoulder radicular pain. The test was positive in 295/305 (96.7 %) of patients with cervical nerve root compression, compared to 35/903 (3.87 %), 3/155 (1.93 %), 0/101 (0 %), 1/55 (1.81 %) and 4/48 (8.33 %) of those with rotator cuff tear, adhesive capsulitis, AC arthropathy, calcifying tendonitis and glenohumeral arthritis, respectively. A positive result was obtained in 14/350 asymptomatic subjects (4 %). If patients with cervical nerve root compression were compared to controls and patients with shoulder diseases, the test had sensitivity of 0.96 and specificity from 0.91 to 1. CONCLUSIONS: The Arm Squeeze Test may be useful to distinguish cervical nerve root compression from shoulder disease in case of doubtful diagnosis. A positive result to this test may lead to cervical etiology of the shoulder pain.

Concepts: Diseases and disorders, Humerus, Shoulder, Upper limb anatomy, Rotator cuff, Adhesive capsulitis of shoulder, Glenohumeral joint, Soft tissue disorders

3

Increasing numbers of people are playing golf. Golf is a unique sport in that the ability to participate at a high level is not limited by age. In addition, participants tend to play more rather than less as they grow older. Injuries can occur at any point during the golf swing, from takeaway through follow-through. Upper extremity injuries can affect the hands, elbow, and shoulder and are usually a result of the golf swing at impact. Injuries are also common in the lower back as well as the lower extremities. Most injuries are the result of overuse and poor swing mechanics. When treating golfers, it is important to have a good understanding of the biomechanics and forces of the golf swing to diagnose and manage the vast spectrum of injuries incurred in this sport.

Concepts: Human anatomy, Upper limb anatomy, Play, Limb, Golf, Professional golfer, Golf stroke mechanics, Putter

3

Unilateral elbow pain results in sensori-motor dysfunction that is frequently bilateral, affects local and remote upper limb muscles and persists beyond resolution of local tendon symptoms. These characteristics suggest supraspinal involvement. Here we investigated i) the excitability and organisation of the M1 representation of the wrist extensor muscles and ii) the relationship between M1 changes and clinical outcomes in lateral epicondylalgia (LE; n=11) and healthy control subjects (n=11).

Concepts: Elbow, Thigh, Extensor digitorum muscle, Extension, Upper limb anatomy, Upper limb