Ƙasashen vena cava wata babbar jijiya ce a cikin jikin ɗan adam wadda ke ɗaukar jinin da ba shi da iskar oxygen daga ƙasan rabin jikin zuwa dama na zuciya. Ita ce jijiya mafi girma a jikin mutum kuma tana cikin bayan ciki, tana gudana tare da ginshiƙan kashin baya. Kalmar “ƙanana” a cikin sunanta tana nufin matsayinta dangane da mafi girma vena cava, wanda ke ɗauke da jini daga rabi na sama na jiki.