Pneumothorax: a complication of needle electromyography of the supraspinatus muscle.

A patient developed sudden, severe pleuritic chest pain during needle electromyography (EMG) of the right supraspinatus muscle. Chest x-rays revealed a 10% right pneumothorax. The patient was treated conservatively and there was complete resolution one week later. A review of the pertinent anatomy indicates that the supraspinatus muscle overlies the pleural cavity. Indications for needle EMG of the supraspinatus muscle are reviewed. A new technique that minimizes the risk of pneumothorax when performing needle EMG of the supraspinatus muscle is presented.