运动神经元病的病因及发病机制是什么?
心冠状动脉粥样硬化最常受累的动脉分枝是（） ["右冠状动脉主干","左冠状动脉主干","右冠状动脉后降支","左冠状动脉回旋支","左冠状动脉前降支"]
脑动脉粥样硬化最常见的部位是() ["A．大脑中动脉","B．大脑前动脉","C．大脑后动脉","D．大脑中动脉及Willis环","E．基底动脉及大脑后动脉"]
主动脉粥样硬化的好发部位() ["A．升主动脉","B．主动脉弓","C．胸主动脉","D．腹主动脉","E．腹主动脉后壁和其分支开口处"]
颅内动脉瘤的最好发部位是() ["A．颈内动脉系统","B．大脑前动脉","C．椎—底动脉系统","D．大脑中动脉","E．海绵窦"]
脊髓亚急性联合变性的病因及发病机制是什么?
