Fig. 4

Impact fractures and avulsion fractures. Longitudinal view (A) shows the impact fracture (white arrowhead) of the radial head (RH), but only by performing the transverse scan (B) the degree of rotation (white dotted arrow) of the bony fragment can be clearly observed. Likewise, cortical bone depression (yellow arrowhead) on the posterior surface of the humeral head (HH)—filled with fibrotic tissue (yellow asterisk)—can be observed in a patient with previous anterior subluxation of the shoulder (C). Unlike the post-acute injuries, in the acute phase of trauma (D) the misalignment of the cortical bone (green arrowhead) is usually coupled with the periosteal bulging (red arrowhead) and subperiosteal hematoma (white asterisk). Of note, avulsion fractures in the pediatric population (E) can show a simultaneous shifting of the cartilaginous epiphysis (yellow dotted line) and the epiphyseal ossification center (green arrowhead) located within the hyaline cartilage. LE lateral epicondyle, RC rotator cuff, AIIS anterior inferior iliac spine