my·as·the·nia /ˌmaɪəsˈθiniə/
  肌無力
  my·as·the·nia /ˌmaɪəsˈθɪnɪə/ 名詞
  myasthenia
       n 1: a chronic progressive disease characterized by chronic
            fatigue and muscular weakness (especially in the face
            and neck); caused by a deficiency of acetylcholine at
            the neuromuscular junctions [syn: myasthenia gravis]
       2: any muscular weakness