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Lung Sounds Explained: Crackles, Wheezes, Rhonchi, and Stridor

Assessment · Written by Professor Foxx, RN, MSN · Updated October 2026

Knowing what you hear, and what it means, is one of the most useful skills in a respiratory assessment.

Normal breath sounds

SoundWhere you hear itWhat it sounds like
VesicularMost of the lung fieldsSoft, low, longer on breathing in
BronchovesicularNear the sternum and between the shoulder bladesMedium, equal in and out
BronchialOver the tracheaLoud, high, harsh

Abnormal (adventitious) sounds

SoundWhat it sounds likeCommon causes
Fine cracklesShort popping, like hair rubbed by your ear, usually on breathing inFluid in the alveoli: heart failure, pneumonia
Coarse cracklesLower, louder bubblingSecretions: pneumonia, pulmonary edema
WheezesHigh-pitched whistling, often on breathing outNarrowed airways: asthma, COPD
RhonchiLow snoring or rattling that may clear with a coughMucus in the large airways: bronchitis
StridorLoud, high-pitched sound on breathing in, heard without a stethoscopeUpper airway blockage: swelling, foreign body. Emergency.
Pleural friction rubGrating, like leather rubbingInflamed pleura: pleurisy
Diminished or absentQuiet or no soundPneumothorax, collapsed lung, fluid around the lung

What to do

Practice this in Head-to-Toe

Put the stethoscope on and hear the difference for yourself.

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Quick answers

What is the difference between crackles and rhonchi?

Crackles are short popping sounds from fluid in the small airways and do not clear with coughing. Rhonchi are low rattling sounds from mucus in larger airways and may clear with a cough.

Is stridor an emergency?

Yes. Stridor means the upper airway is narrowed or blocked. Call for help right away.

Evidence & Clinical Sources
  • Jarvis, Physical Examination & Health Assessment, Elsevier
  • Hinkle & Cheever, Brunner & Suddarth's Textbook of Medical-Surgical Nursing, Wolters Kluwer

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