The present invention relates to a functional intramedullary fixation device capable of contracting and expanding. According to the present invention, a length corresponding to a subcostal space of a bone requiring surgery is contracted in the elastic region by the elastic deformation portions, inserted into the subclavian space, and expanded in the elastic region by the elastic deformation portions A fixing means for expanding radially toward the inner periphery of the medullary space； A bone infiltration preventing means installed in a structure inserted into the bone lumen space with the fixing means being embedded therein, the bone infiltration preventing means preventing the infiltration of the bone being contracted or expanded at the same time in accordance with the contraction or expansion of the fixing means, The elastic means are inserted into the central portion of the fixing means in the lengthwise direction to apply a load to constrict the cross sectional area of the fixing means and the bone penetration preventing means by the elastic deforming portions or to remove the fixing means and the bone penetration preventing means An intervening member for expanding the cross-sectional area； Thereby minimizing the burden on the physician and the patient by minimizing the cross-sectional area of the fixing means and the bone penetration preventing means when inserted into the bones of the human body, Not only can it speed up recovery, but it can also be easily removed at reoperation so that the difficulty of reoperation can be resolved.본 발명은 수축 및 팽창이 가능한 기능성 골수내 고정장치에 관한 것이다.이러한 본 발명에 의하면, 수술을 필요로 하는 뼈의 뼈속질공간에 대응하는 길이를 이루며, 탄성변형부들에 의해 탄성영역에서 수축되어 뼈속질공간에 삽입되고, 탄성변형부들에 의해 탄성영역에서 팽창되어 뼈속질공간의 내주연부를 향해 방사상으로 팽창되는 고정수단； 고정수단을 내재한 상태로 뼈속질공간에 삽입되는 구조로 설치되되, 고정수단의 수축 또는 팽창에 따라 동시에 수축되거나 팽창되어 재생되는 뼈의 침투를 방지하는 뼈 침투 방지수단； 고정수단의 중앙부에 길이 방향으로 삽입되어 하중을 가해 탄성변형부들에 의해 고정수단과 뼈 침투 방지수단의 단면적을 수축시키거나, 고정수단으로부터 제거되어 탄성변형부들에 의해 고정수단과 뼈 침투 방지수단의 단면적을 팽창시키는 중재부재； 를 포함하여 구성됨으로써, 인체의 뼈
