A graduated guide pin for selecting a screw for connecting a fractured bone is formed by a pin-like main body 11 of a radiotransparent metal and ring-like members 12 of a radioopaque metal. The ring-like members are arranged on an outer surface of the main body such that successive members are separated from each other by a distance equal to that of the ring-like members. On an X-ray image, by counting the number of dark portions corresponding to the ring-like members, a length of the fractured bone is measured, and a screw 20 having a suitable length is selected.本發明係一種可獲得用以選定接合骨折部位用之最佳的螺釘長度的附刻度醫療用導銷前述。導銷(10)係以既定間隔劃分由放射線透射性金屬等所構成的基材(11),對這些劃分以每隔一個劃分區的區間中安裝有由放射線不透射性金屬所構成的周面固定材(12)。基材(11)由鈦或鈦合金等放射線容易透射的金屬所構成,周面固定材(12)由鉑、銥、鎢、鉭、金或這些金屬的合金等放射線難以透射的金屬所構成。在由透射X射線或X射線拍攝所獲得的X射線影像中,導銷(10)係以既定間隔交替地表示由周面固定材(12)形成的陰影較深的部分、與由基材(11)形成的陰影較淺的部分,因此,藉由對由骨頭(B)內的深淺所構成的刻度進行計數,可測定出包含骨折部位(A)在內的骨頭(B)的厚度。10‧‧‧附刻度醫療用導銷10a‧‧‧前端部11‧‧‧基材12‧‧‧周面固定材A‧‧‧骨折部位B‧‧‧骨頭C‧‧‧皮下組織D‧‧‧皮質骨E‧‧‧皮膚
