Percussion

The character of the sound produced by percussion of the chest wall is important in the examination of the respiratory system.

For a right-handed examiner:

• the middle finger of the left hand is placed firmly on the chest wall of the patient
• the middle phalanx of the left middle finger is struck by the middle finger of the right hand
• the palm and other fingers are lifted clear of the chest to prevent any damping of the vibrations
• both sides of the chest should be percussed
• thought should given to the surface anatomy of the lungs
• the two sides of the chest are compared
• if an area of dullness is found then its limits are demarcated by percussing from a resonant to a dull area

Changes in resonance are seen in the following conditions:

• increased resonance:
  • emphysema
  • pneumothorax
    
    
• decreased resonance:
  • consolidation
  • collapse
  • abscess
  • neoplasm
  • fibrosis
    
    
• stony dull:
  • pleural effusion