74-year-old man presented...

74-year-old man presented  with involuntary and painful contractions in his right pectoralis muscles for the past 6 months. The muscle contractions persisted predominantly at rest, stopped during sleep, and could be relieved by active muscle forcing. Carbamazepine, gabapentin, clonazepam, levodopa, and topiramate therapy were ineffective for controlling symptoms. The patient denied a history of trauma, tumor, surgery, or prior exposure to any toxicant.

On admission, physical examination revealed rhythmic movements of his right pectoralis muscles. No other neurological signs were found....CAN YOU SPOT, WHAT IS THIS?   ....