Review Question - QID 8619

A 26-year-old weightlifter had increasing pain in his left shoulder for 4 months. Nonsurgical treatment consisting of anti-inflammatory medication, corticosteroid injections, and rest failed to alleviate his symptoms. He underwent an arthroscopic distal clavicle resection with excision of the distal 8 mm of clavicle (Mumford procedure). Three months after surgery, he reported popping by his clavicle and mild pain. His clavicle demonstrated mild posterior instability on examination without any obvious deformity on his radiographs. What structures were compromised during his excision?