RT Book, Section A1 Toth, Eric A1 Webley, James A2 Sherman, Scott C. SR Print(0) ID 1154632696 T1 Forearm T2 Simon's Emergency Orthopedics, 8e YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9781259860829 LK accessphysiotherapy.mhmedical.com/content.aspx?aid=1154632696 RD 2024/03/28 AB The radius and the ulna lie parallel to each other and are invested at their proximal ends with a relatively large muscle mass. Because of their close proximity, injury forces typically disrupt both bones and their ligamentous attachments. They can be thought of conceptually as two cones lying next to each other pointing in opposite directions (Fig. 13–1).