VCP 411: Medicine Section

NOMENCLATURE OF PERCUSSION SOUNDS

Types of sound heard in the chest

• Resonant or Ringing sound
  • This usually indicates the presence of large volume of air or gas beneath the site of percussion. It is the normal sound produced during percussion over a normal large lung. The ringing sound is exaggerated when there is excessive quantity of air or gas present at the site of percussion. Such sound is induced in conditions like pulmonary emphysema, pneumothorax and gas filled viscous in diaphragmatic hernia.
• Dull of Flat sound
  • This sound will be heard when there is no air or gas beneath the part percussed. If dull sounds are heard over lung during percussion it indicates the existence of the disease. Dull sound will be heard only when there is solid airless part, which is sufficiently large i.e. about the size of a fist to produced the sound. Normally dull sound will be heard over the heart affected with pericarditis.
• Tympanic sound
  • This sound is distinguished from other sounds by its characteristic musical ring, which is like that produced by striking a kettle-drum. This type of sound is heard in pneumonia, pneumothorax and subcutaneous emphysema.
• Metallic ring
  • This tone is high-pitched one and resembles the response obtained on striking an empty meal jug. This occurs in diseases where there are small cavities of gas or air under pressure.
• Cracked pot sound
  • This sound stimulates that produced by striking a cracked pot. It arises when air escapes through a narrow opening. It will be produced in cases of emphysema and some times in pneumonia and pleurisy.

Types of sound heard in the abdomen and chest

• Tympanic sound
  • Drum like boom and very loud (over parts of digestive tract abnormally filled with gas, tympanic rumen in bloat, displaced abomassum or caecum etc.,)
• Subtympanic sound
  • Slightly booming and loud (on the dorsal part of the normally filled rumen, over loops of intestine containing gas, over emphysematous portions of lung etc).
• Full lung sound
  • Good resonance without booming (on the normal chest wall-lung tissue having normal air content).
• Relative or incomplete damping (dullness)
  • Sound weaker than the normal lung sound, because the structure percussed contains less air than the normal lung (a normal finding in the heart percussion field (or) over that portion of rumen containing solid food masses).
• Extensive but still incomplete damping (dullness)
  • Similar to the empty sound of the muscle but with weak resonane (in the ventral part of the abdomen – fore stomachs and intestine, where the ingesta is permeated by fine gas bubbles.
• Empty muscle sound (or) Absolute damping
  • Complete damping without resonance (in the region of large muscles and the liver percussion field, parenchymatous organs free from air and gas, over lung lesions larger than the size of a fist containing exudates (or) similar contents, over the heart affected with pericarditis, over an abomassum containing sand etc.)