Bronchial Lung Sounds

  • This is the sound heard over large airways.
  • It has a "tubular" quality - it has been compared to the sound of air blowing through a cardboard tube.
  • This sound is abnormal when heard at a distance from large airways.

Bronchial or tracheal sounds are heard on the chest at sites which are close to large airways. In contrast to vesicular sounds they are relatively louder in expiration than inspiration. They have a tubular or blowing quality similar to air being blown through a tube. In the time amplitude plot an apparently random undulating pattern is again seen. It has greater amplitude in expiration than inspiration. This type of breath sound is heard best over the trachea.

Bronchial sounds are also heard on the back between the scapulae and at the lung apices especially on the right. They may also be heard in the axillae. When they are heard in locations at a distance from large airways they signify consolidation. This is believed to be due to better transmission of the centrally generated lung sound through the consolidated lung. This is more likely to occur during the expiratory phase because the expiratory phase has a more central origin than the inspiratory phase.