RT Book, Section A1 Webley, James A2 Sherman, Scott C. SR Print(0) ID 1103537795 T1 Forearm T2 Simon’s Emergency Orthopedics, 7e YR 2014 FD 2014 PB McGraw-Hill Education PP New York, NY SN 978-0-07-181965-7 LK accessemergencymedicine.mhmedical.com/content.aspx?aid=1103537795 RD 2024/04/25 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).