患者　女 ,2 4岁。于 3个月前无诱因自觉右膝关节疼痛并伴有右侧大腿隐痛 ,劳累、行走及蹲起后疼痛加重 ,无外伤和感染史。曾经外院对症治疗无效 ,近 1个月来该腿软弱无力 ,再次就医。体检 :右股四头肌肌萎缩 ,右股骨下端有轻度压痛 ,右膝关节轻度肿胀压痛 ,浮髌试验 ( -) ,体 Female patient, 24 years old. There was no cause to feel pain in the right knee joint and accompanied by pain in the right thigh 3 months ago. The pain was worse after fatigue, walking and paralysis, and there was no history of trauma or infection. The symptomatic treatment in the outer hospital was ineffective. In the past 1 month, the leg was weak and unable to seek medical treatment. Physical examination: Right quadriceps muscle atrophy, mild tenderness in the lower right femur, slight swelling tenderness in the right knee joint, impetigo test (-), body