Review Question - QID 109874

A 68-year-old right hand-dominant man presents to the emergency room complaining of severe right arm pain after falling down a flight of stairs. He landed on his shoulder and developed immediate severe upper arm pain. Physical examination reveals a 2-cm laceration in the patient’s anterior right upper arm. Bone is visible through the laceration. An arm radiograph demonstrates a displaced comminuted fracture of the surgical neck of the humerus. Irrigation and debridement is performed immediately and the patient is scheduled to undergo definitive operative management of his fracture. In the operating room on the following day, the operation is more complicated than expected and the surgeon accidentally nicks a neurovascular structure piercing the coracobrachialis muscle. This patient would most likely develop a defect in which of the following?