Nontraumatic First Rib Fracture and Empyema Presenting as Shoulder Pain.

Fracture of the first rib is rare because of the anatomic protection provided by surrounding structures. Osseous fatigue caused by repetitive motion and antagonistic muscular contraction is postulated to contribute to nontraumatic first rib fracture, which is most often described in adolescent athletes in sports that involve repetitive overhead motion of the arm. In this report, we describe a 49-year-old man with an occupation involving repetitive overhead motion at the shoulder who was found to have a nontraumatic first rib fracture.