Failure with compression: Bone that is loaded in compression can’t be “squished down” to a smaller size so it fails along “lines of shear” that are oriented about 45 degrees to the axis of load. This results in the “bursting” of fragments outward from the axis of the bone. Thus most “comminuted” fractures are from compression. The more energy that is imparted (violence) the more the comminution, so that highly comminuted fractures are often associated with severe soft tissue damage and a poor prognosis. For a thought experiment about energy and comminution, imagine tapping a brick barely hard enough to break it – you get two pieces eh? Now hit it as hard as you can, but stand back because you’re gonna get hurt by some of the many “bursting” pieces flying off of that “highly comminuted brick!