Figure 2
From: Anatomical evaluation of CT-MRI combined femoral model
Fixation of Balls. Balls were mounted using 2-stage bolt-nut system which was composed of two plastic bolts of 3.5 mm in diameter and one nut. (a) The 1st bolt was screwed into cortical bone. And a nut was glued on the head of the 1st bolt. (b) The 2nd bolt was connected by the 1st bolt. Finally the balls of 11.5 mm in diameter were mounted on the end of the 2nd bolt by screwing.