Subcutaneous emphysema may be found in the following conditions:

* Posterior tracheal wall laceration is responsible for emphysema after Percutaneous Tracheostomy. After perforation of the posterior trachea wall, the pleural space can be reached easily. This may result in a pneumothorax. * Trauma to chest including after a vigorous Hemilich maneuver can lead to subcutaneous emphysema.