The term mediastinal and interstitial emphysema in our work is used to include not only the introduction of air into all the areolar tissues of the body, but also acute pneumothorax, acute pneumoperitoneum and air embolism. This condition has often been referred to as surgical emphysema because a good proportion of clinical cases develop after an injury which is usually treated by the surgeon.
The causes of interstitial emphysema as given by various authors may be summarized under the following groups:
1. Traumatic, namely, due to an injury of the lung produced by stab wound of the wall of the chest, a fractured rib or a needle during the induction of an artificial pneumothorax.
2. Sudden increase of the intrapulmonic air pressure resulting from physical strain such as coughing, childbirth or obstruction of the air passages by aspiration of foreign bodies.
3. Entrance of air into the fascial planes during