Bones and joints of upper limbDownloads

A 16-year-old boy is brought to the emergency department after being tackled at a football game. Per his mom, he is the quarterback of his team and was head-butted in the left shoulder region by the opposing team. Shortly after, the mother noticed that his left arm was hanging by his torso and his hand was “bent backwards and facing the sky.” The patient denies head trauma, loss of consciousness, sensory changes, or gross bleeding. A physical examination demonstrates weakness in abduction, lateral rotation, flexion, and supination of the left arm and tenderness of the left shoulder region with moderate bruising. Radiograph of the left shoulder and arm is unremarkable. Which of the following is most likely damaged in this patient?

A 16-year-old boy presents to the emergency room with severe right shoulder pain following a painful overhead swing during a competitive volleyball match. On physical examination, the patient has limited active range of motion of the right shoulder and significant pain with passive motion. Suspecting a rotator cuff injury, the physician obtains an MRI, which indicates a minor tear in the tendon of the rotator cuff muscle that is innervated by the axillary nerve. Which of the following muscles was affected?