英语语法分析

Extradural ectopic meningioma is a rare tumor.

硬膜外异位脑膜瘤是一种罕见的肿瘤。

Spinal and extradural combined anesthesia were used.

行脊麻与硬膜外联合阻滞麻醉。

There have been few reports on extradural rheumatoid nodules.

很少有关于硬膜外类风湿性结节的报道。