A 25 y/o male with a history of Type 1 Diabetes presents with acute right shoulder pain. The patient states he was playing ultimate Frisbee with his friends when he dived to make a catch. He landed on the ground has had immediate sharp pain in his right shoulder. Which of the following would be the most likely finding during your neuro exam of his arm (scroll down for answer)?

a) Decreased strength of biceps flexion 

b) Decreased sensation of the shoulder (at the deltoid)

c) Weak supination of the forearm

d) Decreased sensation of the back of the arm (at the triceps)

e) Decreased sensation along the 4th and 5th digits

Answer and Explanation: Correct answer is b) Decreased sensation of the shoulder (at the deltoid)

• Nerve injuries occur in 10-25% of acute dislocations with the axillary nerve as the most commonly affected nerve.
• The axillary nerve innervates the deltoid and the teres minor leading to weakness in external rotation and decreased sensation in the deltoid distribution.
• For a great view of shoulder dislocations, including reduction techniques, be sure to check out this CORE EM post