Few studies on the mechanism of dynamic circulation in intervertebral discs are reported. The purpose of this study is to clarify the dynamic mechanism of circulation in the lumber intervertebra discs with radioisotope clearance, experimentally and clinically. Rabbits were used as experimental animals and were divided jnto two groups, normal and artificially injured. I^131-sodium was injected into them and the clearance was followed. Injected I^131 - sodium was cleared in the order of