Percussion is tapping on a surface to determine the underlying structure.

• Assess the thorax, for:
  • Pneumothorax
  • Emphysema
  • Other disease
  • Respiratory mobility of the thorax
• Assess the abdomen, for:
  • Organomegaly
  • Whether tissue is healthy or pathological

• The nonstriking finger (known as the pleximeter) is placed firmly on the body over tissue. When percussing bony areas (e.g. the clavicle), the pleximeter can be omitted, and the bone tapped directly
• Middle finger of the striking hand taps on the middle finger of the other hand, using a wrist action. Direct percussion uses only 1 or 2 fingers, and indirect uses the middle/flexor finger

• Note that can be heard:
  • Tympanitic, drum-like sounds, over air filled structures, in the abdominal exam
  • Hyper-resonant, which sounds similar to tapping puffed up cheeks
  • Resonant, which indicates hollow, air-containing structures, and sounds like percussing a normal chest
  • Impaired resonance, which is lower than normal percussion sounds. It indicates a mass, consolidation
  • Dull, which indicates consolidation, similar to tapping a mass (e.g. liver)
  • Stony dull, produced on tapping from the pleximeter, w/ no contribution from the underlying area
• Sensation in the pleximeter finger
• Can also indicate pain

• Percussion was first used to distinguish between empty and filled barrels of liquor

• Inspection
• Palpation
• Auscultation