腿部下端肌肉收紧可发挥类似泵的作用。静脉壁能帮助血液回流到心脏。静脉中的微小瓣膜在血液流向心脏时打开，然后关闭以阻止血液倒流。如果这些瓣膜弱化或受损，血液可能倒流并在静脉中积聚，导致静脉拉伸或扭曲。 The precise explanation for a varicocele is not known. Just one contributing factor may be the malfunction of valves inside the veins that happen to be meant to maintain blood transferring... https://www.sgvascularctr.com/varicose-vein-treatment-in-singapore-everything-you-need-to-know/