Pneumothorax

• Presence of air in the pleural cavity
• Atelectasis proportional to the amount of air in the cavity always present
• Causes:
  • Spontaneous
    • Rare
  • Traumatic
    • In animals it is usually caused by traumatic rupture of the lung or perforation of the thoracic wall
    • Rarely following rupture of emphysematous lung or parasitic cysts
    • May be a complication of biopsy of the lung or resuscitation
• Air is easily absorbed if the cavity is closed again