Clavicle: The clavicle is the first bone to ossify (fifth week of gestation), and its medial epiphysis is the last ossification center to fuse between 20 and 25 years of age making the clavicle the last bone to complete the ossification process. When viewed from anterior, the clavicle is relatively straight; however, in the transverse plane, it resembles more of an “S” shape. 5 The medial portion of the clavicle is convex anterior, and the lateral side is convex posterior. The primary blood supply is periosteal.