Methods.A 26-year-old man with Down syndrome suffered from retropharyngeal infection, after which his atlantoaxial subluxation was aggravated and myelopathy developed.

• 方法：一26岁男性唐氏综合症患者，在咽后部感染后，继发日益严重的寰枢椎半脱位，并发生脊髓病。