[名词解释] 扁平颅底

落日征 狭颅症 室间隔缺损合并急性感染性心内膜炎并血栓形成可引起() ["A．脑动脉栓塞","B．肾动脉栓塞","C．肺动脉栓塞","D．脾动脉栓塞","E．门静脉栓塞"] 脑膜膨出 脑积水()脊柱裂() ["A．唇裂","B．寰枢椎畸形","C．脊髓拴系综合征","D．第四脑室中孔和侧孔闭锁","E．颅内血肿"] 扁平颅底