Adventitious Lung Sounds

This website offers lessons, reference guides and quizzes for adventitious lung sounds. On this page we provide a definition and then we examples of several types of adventitious lung sounds using audio recordings and text.

illustration for adventitious lung sounds

What Are Adventitious Lung Sounds?

Adventitious lung sounds are abnormal sounds that are heard when auscultating 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 lung sounds are important clues used for diagnosing numerous cardiac and pulmonary conditions. These sounds and corresponding conditions are described in our lung 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.

Adventitious Sounds Listening Tips

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

Lung Sounds Reference Guide

Adventitious Lung Sound Lesson

Our short courses on lung sounds cover many adventitious sounds.

Basics of Lung Sounds

Intermediate Lung Sounds