Transverse fractures are perpendicular to the long axis of a bone. Oblique fractures occur at an angle. Spiral fractures result from a rotatory mechanism; on x-rays, they are differentiated from oblique fractures by a component parallel to the long axis of bone in at least 1 view. Comminuted fractures have > 2 bone fragments. Comminuted fractures include segmental fractures (2 separate breaks in a bone). Avulsion fractures are caused by a tendon or ligament dislodging a bone fragment. In impacted fractures, bone fragments are driven into each other, shortening the bone; these fractures may be visible as a focal abnormal density in trabeculae or irregularities in bone cortex. Torus fractures (buckling of the bone cortex) and greenstick fractures (cracks in only 1 side of the cortex) are childhood fractures.