Adventitious Breath Sounds

This website offers free and paid lessons, auscultation guides and quizzes for adventitious breath sounds. On this page we provide a definition and then we examples of several types of adventitious breath sounds using audio recordings and text. Links to the free training courses are noted as well.

illustration for adventitious Breath Sounds

What Are Adventitious Breath Sounds?

Adventitious breath sounds are abnormal sounds that are heard over a patient's lungs and airways. These sounds include abnormal sounds such as fine and coarse crackles (crackles are also called rales), wheezes (sometimes called rhonchi), pleural rubs and stridor. Adventitious breath sounds are important clues used for diagnosing numerous cardiac and pulmonary conditions. These sounds and corresponding conditions are described in our breath sounds courses.

Crackles and Wheezes

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Crackles are discontinuous, brief, popping sounds. Similar to the sound of a hook and loop fastener being pulled apart.


Wheezes are continuous, musical sounds, high or low pitched. Usually more pronounced on expiration.

Pleural Rubs and Stridor

Pleural Rubs

Plural rubs are creaking or grating sounds that have been described as being similar to walking on fresh snow.


A loud, high-pitched sound heard during inspiration but may also occur throughout the respiratory cycle.

Breath Sounds Listening Tips

Our auscultation guide provides information and examples of adventitious breath sounds. The guide pages provide waveforms with a moving cursor that is synchronized to the audio recording. In addition, listening tips are available.
Breath Sounds Reference Guide

Adventitious Lung Sound Lesson

Our short courses cover many adventitious sounds.
Basics of Breath Sounds
Intermediate Breath Sounds