Hemithorax is Symmetrical in Size
- Asymmetry of hemithorax can occur whenever the pleural pressures
equal on both sides.
- Size of hemithorax is determined by pleural negative pressure.
- Smaller hemithorax, when the pleural negative pressure is high
- Larger hemithorax, when the pleural negative pressure is lost
- Chest wall tends to spring out, while lung likes to recoil to resting
state, when not held by the negative pleural pressure.
- The balance of forces between chest wall and lung recoil determines the
position of hemithorax .
- The maximum is, total lung capacity position, as the ribs are anchored to
the sternum and vertebra.