The most common presentation of neuralgic amyotrophy (NA), also known as brachial plexus neuritis or Parsonage-Turner syndrome, is acute unbearable pain more severe at night involving the shoulder, upper arm and cervical region followed by patchy weakness in the C5-C6 innervated muscles and less prominent sensory symptoms.1 NA presentations may range from single nerve to widespread brachial and lumbosacral plexuses involvement, and include painless, bilateral and pure sensory phenotype.1 NA pathophysiology includes genetic predisposition, autoimmune triggers and mechanical vulnerability, but the mechanisms are not understood and the recovery may be incomplete.1 We report imaging findings in two cases of NA with selective brachialis muscle (BM) atrophy and fascicular involvement of the musculocutaneous nerve (MCN). Case 1 : A 46-year-old right-handed woman reported acute severe right upper limb pain after carrying a heavy load, followed by anterior arm muscles atrophy. Examination 4 months later showed BM atrophy (figure 1A) and elbow flexors weakness. Electrodiagnosis showed marked BM denervation. Nerve high-resolution ultrasound (HRUS) showed an enlarged MCN fascicle with thickened epineurium (figure 1B–C). MRI showed right BM degeneration (figure 1D–F). At 8-month follow-up there were no clinical/electrodiagnostic signs of reinnervation, while the recovery was nearly complete 4 years later. …

中文翻译：

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神经性肌萎缩症中肱肌的选择性萎缩：束状神经损伤的超声成像。

神经性肌萎缩症（NA）的最常见表现是臂丛神经炎或Parsonage-Turner综合征，是一种严重的急性无法忍受的疼痛，夜间伴有肩部，上臂和颈椎区域的疼痛更为严重，随后C5-C6神经支配的斑片性无力肌肉和较不明显的感觉症状。1NA表现可能从单神经到广泛的臂丛和腰神经丛受累，包括无痛，双侧和纯粹的感觉表型。1NA病理生理学包括遗传易感性，自身免疫触发和机械脆弱性，但机制1我们报道了2例NA患者的影像学表现，其中2例伴有选择性臂肱肌（BM）萎缩和肌皮神经（MCN）束状累及。情况1 ：一名46岁的惯用右手的妇女在举重后报告了急性严重的右上肢疼痛，随后是前臂肌肉萎缩。4个月后的检查显示BM萎缩（图1A）和肘屈肌无力。电诊断显示明显的BM失神经。神经高分辨率超声（HRUS）显示MCN束增大，而神经外膜增厚（图1B–C）。MRI显示右BM变性（图1D–F）。在8个月的随访中，没有再神经支配的临床/电诊断迹象，而4年后恢复已接近完成。… 神经高分辨率超声（HRUS）显示MCN束增大，而神经外膜增厚（图1B–C）。MRI显示右BM变性（图1D–F）。在8个月的随访中，没有再神经支配的临床/电诊断迹象，而4年后恢复几乎完成。… 神经高分辨率超声（HRUS）显示MCN束增大，而神经外膜增厚（图1B–C）。MRI显示右BM变性（图1D–F）。在8个月的随访中，没有再神经支配的临床/电诊断迹象，而4年后恢复几乎完成。…