Review Question - QID 220531

A 22-year-old male presents with recurrent right shoulder instability following a traumatic shoulder injury one year ago during a collegiate football game. You decide to perform an open labral repair and an inferior capsular shift. After the subscapularis is released from the inferior capsule while performing the inferior capsular shift, your assistant readjusts the medial retractor to provide countertraction on the subscapularis, but you realize afterward that the retractor was placing pressure on the inferomedial aspect of the subscapularis muscle belly. The procedure goes as planned, and postoperatively, the patient can perform elbow flexion and forearm supination; however, he is unable to abduct his shoulder. Which nerve and nerve roots are properly paired and responsible for this postoperative finding?