Pneumomediastinum, pneumothorax and subcutaneous emphysema following the measurement of maximal expiratory pressure in a normal subject. Mediastinal and subcutaneous emphysema have been reported as a consequence of deliberate manipulations of the breathing pattern producing a Valsalva-like maneuver in healthy subjects. We present a case of pneumomediastinum, pneumothorax and subcutaneous emphysema occurring in a normal volunteer after repeated measurements of the PEmax. 