Lung percussion is a physical examination technique that involves tapping on the chest wall. This method allows healthcare professionals to assess the underlying lung tissue and the pleural space, which is the area between the lungs and the chest wall. It provides a non-invasive way to gather information about the density of structures within the chest.
Purpose of Lung Percussion
Lung percussion evaluates lung tissue by listening to the sounds produced, which helps healthcare professionals determine if the tissue is filled with air, fluid, or is solid. Different sounds can indicate abnormal substances, such as excess fluid in the pleural space or trapped air within the lungs. This technique aids in identifying areas of increased tissue density, which could signal various conditions. Percussion is a component of a broader physical examination, offering insights without requiring invasive procedures.
Key Areas for Lung Percussion
Percussion of the lungs is systematically performed across various regions of the chest for a comprehensive assessment. On the anterior chest, areas above the clavicles (supraclavicular regions) are percussed. Moving downwards, the intercostal spaces between the ribs are examined, typically avoiding direct percussion over the sternum due to its solid nature. Percussion proceeds from the apices of the lungs down to the bases.
For the lateral chest, percussion is conducted along the axillary lines. On the posterior chest, percussion begins in the supraclavicular areas. The interscapular region is also percussed, often with the patient crossing their arms. Finally, the infrascapular areas and the bases of the lungs are percussed. Comparing sounds from symmetrical areas on both sides of the chest is important to detect differences.
Performing Lung Percussion
The most common method for lung percussion is mediate percussion, which involves using two fingers. One finger is placed firmly on the patient’s chest wall, acting as the “pleximeter.” Only the pad of this finger should make contact with the skin.
The “plexor” finger then delivers a quick, light tap to the distal joint of the pleximeter finger. The tapping motion should originate from the wrist, not the elbow or shoulder, to produce a consistent and controlled strike. After each tap, the plexor finger is lifted quickly to avoid dampening the sound. A quiet environment is important to allow the healthcare professional to clearly hear the resulting sounds and feel the vibrations.
Understanding Percussion Sounds
The sounds elicited during lung percussion provide valuable information about the underlying structures. A normal, air-filled lung produces a resonant sound, described as hollow and low-pitched. This sound indicates healthy, air-filled lung tissue.
When percussion produces a dull sound, it suggests denser tissue. This can indicate consolidation, such as in pneumonia, or fluid accumulation in the pleural space. Flatness is an even quieter and shorter sound than dullness, heard over very dense areas like bone or a large pleural effusion.
Hyper-resonance, a louder and lower-pitched sound than normal resonance, suggests an excess of air. This sound can be associated with conditions like emphysema or pneumothorax, where there is trapped air. Tympanitic sounds are high-pitched and drum-like. While normally heard over air-filled abdominal organs like the stomach, a tympanitic sound over the chest can indicate a large pneumothorax.