Adventitious (Abnormal) Breath Sounds
Crackles in General:
Nonmusical, discontinuous popping sounds that occur during inspiration (while usually
heard on inspiration, they may also be heard on expiration); may or may not be cleared
by coughing
Etiology: Secondary to fluid in the airways or alveoli or to delayed opening of
collapsed alveoli during inspiration & associated with heart failure and pulmonary
fibrosis
Coarse Crackles:
Discontinuous popping sounds heard in early inspiration and throughout expiration;
harsh, moist sound originating in the large bronchi; can be heard over any lung region;
do not vary with body position
Etiology: Associated with obstructive pulmonary disease
Fine Crackles:
Soft, high-pitched, discontinuous popping sounds heard in mid to late inspiration; sounds
like hair rubbing together; originates in the alveoli, especially in dependent areas; may
vary with body position
Etiology: Associated with interstitial pneumonia, restrictive pulmonary disease
(e.g., fibrosis); fine crackles in early inspiration are associated with bronchitis or
pneumonia
Wheezes in General:
Continuous, musical, high-pitched, shrill sound usually heard on expiration but may be
heard on inspiration depending on the cause
Etiology: Associated with bronchial wall oscillation and narrowed airway diameter
or partially obstructed airway | Associated with chronic bronchitis or
bronchiectasis
Rhonchi:
Deep, lower-pitched rumbling sounds, snoring quality, heard primarily during expiration;
may clear with coughing
Etiology: Associated with secretions or tumor; variant of a wheeze; caused by air
moving through narrowed tracheobronchial passages
Pleural Friction Rub:
Discontinuous, low-pitched, rubbing or grating sound, like two pieces of leather being
rubbed together (sound imitated by rubbing thumb and finger together near the ear)
Heard during inspiration and expiration
May subside when patient holds breath; coughing will not clear sound | Best heard in
axillae and bases of lungs
Etiology: Secondary to inflammation and loss of lubricating pleural fluid between
the visceral and parietal pleurae
Stridor:
Continuous, high-pitched, musical sound, heard over the neck
Etiology: Narrowing of the upper respiratory tract; immediate intervention is
warranted