This invention locks inside the head (11) and the vertebra which are connected to the elastic stable or support system when it is transplanted, passes by the bow root and regards the bow root screw which consists of with the shaft which extends to the body. As for the shaft the stress relief territory (17) which is connected to the upper part shaft territory (19) and the upper part shaft territory which it adjoins to the head in the longitudinal direction length which was measured from the head, and it consists of, the stress relief territory has the flexural rigidity which is smaller than the upper part frame territory, as for the stress relief territory is placed in the territory of the shaft which is provided because it is placed inside the bone.本発明は、弾性安定若しくは支持システムに結合する頭部(11)と椎骨の内側に固定し、移植された場合、椎弓根を通り椎体へ伸びるシャフトとからなる椎弓根スクリューに関する。シャフトは頭部から測った長手方向長において、頭部に隣接する上方シャフト領域(19)と、上方シャフト領域に繋げられた応力緩和領域(17)とからなり、応力緩和領域は上方軸部領域より小さい曲げ剛性を有し、応力緩和領域は骨の内側に置かれるために設けられたシャフトの領域に置かれる。
