剑桥词典a three-sided area on the inner surface of the bladder (= the bag where urine collects ) （膀胱内壁的）三角区 Since most of these tumours involve the trigone, they are rarely operable . 这些肿瘤大部分发生在膀胱内壁三角区，因此极少能做手术。 返回 trigone