摘要
平山症(Hirayama disease)好發於青少年男性病患，是一種因為下頸後部之脊硬膜不正常往前位移，導致頸椎脊神經壓迫的神經病變，雖然罕見，但通常可以觀察到典型疾病病程，患者發病時會以遠端上肢肌肉的無力或肌肉萎縮表現，並且有漸進式惡化，但幾年之後進入穩定期症狀也會停止惡化或改善，診斷此疾病除了典型病史，肌電圖檢查和脊椎影像學的檢查都有重要的角色，茲以本文報告一例平山症案例，及其典型影像學表現。
關鍵字
無資料參考文獻
Hirayama K, Toyokura Y, Tsubaki T. Juvenile muscular atrophy of unilateral upper extremity: a new clinical entity. Psychiatr Neurol Jpn 1959;61:2190-7."
Hirayama K. Juvenile non-progressive muscular atrophy localized in hand and forearm: ob-servation in 38 cases. Clin Neurol (Tokyo) 1972;12:313-24"
Hirayama K. Juvenile muscular atrophy of distal upper extremity (Hirayama disease). Intern Med 2000;39:283- 90."
Kuwabara S, Nakajima M, Hattori T, et al. Electrophysiology of juvenile muscular atrophy of unilateral upper limb (Hirayama's disease). Rinsho Shinkeigaku 1999;39:508-12."
Misra UK, Kalita J, Mishra VN, et al. Effect of neck flexion on F wave, somatosensory evoked potentials, and magnetic resonance imaging in Hirayama disease. J Neurol Neurosurg Psychiatry 2006;77:695-8."