The anterior view showing the comparison between a pneumothorax and a tension pneumothorax behind the ribcage. A pneumothorax occurs when a lung or pleural membrane is ruptured and air escapes into the pleural cavity, causing air pressure to build up, and collapsing the affected lung. A tension pneumothorax occurs when a lung or pleural membrane is ruptured and air escapes into the pleural cavity, causing air pressure to build up. The affected lung collapses medially, pushing the heart and other mediastinal tissues in the opposite direction which causes the other lung to compress.
