Fig. 9. Soft callus formation, which results in stabilization of the fracture site, is evident at day 14 after fracture by histologic but not radiographic or micro–computed tomography analysis. At day 14 after fracture, calcification of the callus around the fracture site has begun in female and male rats as shown in the radiographs (  A and  B ) and three-dimensional micro–computed tomography images (  C and  D ) of the mid-diaphysis.  Scale bar = 3.0 mm. Modified from Freeman KT  et al. , Anesthesiology 2008; 108:473–83.