Table 1.

Normal breath sounds.

Breath sound	Location	Frequency range
Vesicular	Most of the lung	100 to 1,000 Hz, with energy drop at 200 Hz
Broncho vesicular	Between the scapula and center of the back	100 to 2,000 Hz, with energy drop at 600 Hz
Bronchial	The area between second and third intercostal spaces	100 to 4,000 Hz, with energy drop at 800 Hz
Tracheal	Over the trachea	100 to 4,000 Hz, with energy drop at 800 Hz
Mouth	In the mouth	200 to 2,000 Hz