基本解释腔静脉后同根派生 英汉例句Retrocaval ureter is a rare congenital venous anomaly.摘要腔静脉后输尿管是一个罕见的先天性静脉异常疾病。We report two cases of retrocaval ureter and review the relevant literature.在此，本文报导二例下腔静脉后输尿管并回顾相关的文献。