English: After the initial injury the elastic pulmonary recoil stabilizes the parenchyma in a condition of lowered tension both in pneumothorax and in emphysema.

           Pulmonary collapse in pneumothorax occurs in a centripetal direction with respect to the main injury (pleuro-alveolar laceration) favoring its obliteration. In the case of emphysema, on the other hand, the pulmonary collapse occurs in a centrifugal direction with respect to the injury, towards the thoracic wall and the mediastinum, which in this condition represent points of fixed support towards which the pulmonary parenchyma is attracted in its uneven collapse, thus widening the intrapulmonary air space.

The hatched polygon in red indicates the rearrangement of the thoracic wall elastic recoil to a condition of greater expansion due to the lesser inward traction on it by the decreased lung elastic recoil.