26th August 2024

A 78-year-old woman presents to your clinic with right arm pain. This extends from her neck

A 78-year-old woman presents to your clinic with right arm pain. This extends from her neck to her right shoulder and down into the upper part of her arm. She has also noted recently that her shoulder feels weaker. On examination of her upper limbs, there is 4/5 weakness of her right deltoid, but power is otherwise normal in the arm and normal on the left. Her supinator reflex is diminished, and she has abnormal sensation over her shoulder and lateral arm. What is the most likely cause of these symptoms?

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