Palpation and percussion of chest

Tactile Fremitus

  • Saying “ninety-nine” while palpating the chest wall
  • More prominent in men due to lower pitched voices.
  • ONLY ASYMMETRICAL FINDING IS SIGNIFICANT.

Percussion

3 types

  • Comparative
  • Topographical: used to delineate border of heart, liver and diaphragmatic excursions.
  • Auscultatory

Auscultatory percussion

  • Pleural effusion: stethoscope is placed below 12th rib. Percussion is done from posterior chest from apex to base. 
    – At some point, the dull sound will change to a clearer one as it approaches the stethoscope. If this happens above 12th rib, it indicates pleural effusion.
  • Another version is by listening over the back of chest while tapping over the manubrium. 
    – Clinician should hear identical sounds in two sides of chest. A decreased intensity indicates ipsilateral disease on that side

Percussion sounds

  1. Resonance
    – Special types of resonance: Skodaic’s, amphoric
  2. Dullness
  3. Tympanic

Skodaic resonance:

  • Resonance heard above the pleural effusion.
  • Why? Nobody knows

Amphoric resonance

  • Flicking the tense cheek while holding the mouth open mimics the sound
  • Indicates presence of cavities.

Grocco’s triangle

  • A small triangle of dullness at posterior chest contralateral to side of effusion

Kronig isthmus

  • Narrow area of resonance between the dullness of neck and shoulder muscles.
  • If this resonance is lost, it indicates apical lung diseases.

Pathogenesis

  • Topographic percussion theory
    – The characteristics of the underlying organs determine the type of the sounds heard.
  • Cage resonance theory (the chest wall is the cage, and how it resonates affects the percussion)
    – The type of sounds are also affected by the chest wall and the strength of the stroke.

Cage resonance theory maybe more accurate:

  • External pressure on the chest dampens the percussion notes.
  • Liver span is SMALLER when percussing with stronger stroke.
    – Stronger stroke produces more vibrations and therefore more resonance.
    – If according to topographic percussion theory (stronger strokes lead to deeper penetration), the liver span should have been larger.

Auscultatory percussion

  • Possibly sound transmission circumferentially in chest wall rather than through the lungs
  • Evidences:
    – Heart is not detected. If the sound is transmitted through the lung, some dullness should have been heard in left side of the chest
    – Sounds intensity changes during Valsava maneuver which tenses the chest wall.
    – Sound intensity recorded when the patient breathes room air and a mixture of oxygen and helium is the same (different gases should have different density and this affects the sound intensity).

So what’s good?

  • Only asymmetrical dullness/hyperresonance using comparative percussion maybe ok to detect pulmonary pathologies.
  • Auscultatory percussion is also very specific for detecting pleural effusion.

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Reference

Evidence Based Physical Diagnosis. Steven McGee.

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