Cervical dermatomes and myotomesDownloads

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 53-year-old woman comes to the physician because of a 3-month history of intermittent severe left neck, shoulder, and arm pain and paresthesias of the left hand. The pain radiates to the radial aspect of her left forearm, thumb, and index finger. She first noticed her symptoms after helping a friend set up a canopy tent. There is no family history of serious illness. She appears healthy. Vital signs are within normal limits. When the patient extends and rotates her head to the left and downward pressure is applied, she reports paresthesias along the radial aspect of her left forearm and thumb. There is weakness when extending the left wrist against resistance. The brachioradialis reflex is 1+ on the left and 2+ on the right. The radial pulse is palpable bilaterally. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?