This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous Questions, Subject name: Medicine
Subcutaneous emphysema may be found in the following conditions: 
Select and explain. 
A. Tracheostomy, B. Hemilich maneuver, C. Chest injury, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: * 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.