In one aspect of the disclosure, an intramedullary (IM) apparatus for treating a fractured bone of an animal includes an IM nail elongated along a longitudinal axis and having at least three locking holes equally distantly defined thereon along the longitudinal axis, and a positional reference member having a longitudinal vernier scale thereon. The IM nail is configured to be inserted to a medullary cavity of a bone fragment, such that the IM nail is fixable to the bone fragment by a locking member correspondingly inserted into one of the locking holes through the bone fragment. The positional reference member is configured to be detachably mounted to the IM nail by two positioning members inserted into two of the locking holes such that the longitudinal vernier scale is parallel to the longitudinal axis of the IM nail, and each of the locking holes is locatable by the longitudinal vernier scale.本發明涉及一種用於治療動物的骨折骨骼的髓內(IM)裝置，包括一種沿一縱軸延伸的髓內釘且其具有至少三個沿著該縱軸等距離設置的鎖固孔，以及一個具有縱向遊標尺的位置參考部件。該髓內釘被用於插入至該骨折骨骼之骨碎片的骨髓腔中，透過將一鎖固件貫穿該骨碎片對應插入至其中一個該鎖固孔中使該髓內釘固定於該骨碎片上。該位置參考部件透過將兩個定位件插入至其中兩個該鎖固孔中可拆卸式地安裝於該髓內釘上，使該縱向游標尺平行於該髓內釘的縱軸，並且各個鎖固孔透過該縱向遊標尺定位。
