Adventitious sounds: crackles, wheezes, rhonchi, stridor and pleural rub !

Sign

Sounds that do not exist in healthy lungs; each type points to a different mechanism: fluid, narrow airways or inflamed pleura.

Updated 2026-11-01

See it in 3D: Pleura · Trachea · Segmental bronchi

What it is

Adventitious (added) sounds are heard on top of normal breath sounds. They are discontinuous (crackles) or continuous (wheezes, rhonchi and stridor); the pleural rub arises from the pleura. Recognizing them, placing them in the breathing cycle and checking whether they change with coughing guides the diagnosis.

The anatomy it tests

Crackles come from sudden opening of collapsed small airways or alveoli, or from air bubbling through secretions.
Wheezes come from vibration of narrowed bronchial walls, nearly touching, with fast airflow between them.
Stridor reflects narrowing of the upper extrathoracic airway (larynx, subglottis, cervical trachea), which collapses more on inspiration.
A rub arises when inflamed, roughened visceral and parietal pleura slide over each other.

How to elicit it

Listen with the diaphragm at symmetric points while the patient breathes through the mouth a little deeper than usual.
For any added sound, decide whether it is continuous (musical) or discontinuous (like bubbles or Velcro).
Place it in time: early or late inspiration, expiration or both phases.
Ask the patient to cough and listen again: sounds from secretions change or clear.
If a rub is suspected, ask the patient to hold the breath: a pleural rub stops; a pericardial rub continues.
If you hear a high-pitched inspiratory sound, listen over the neck: stridor is loudest over the larynx and trachea.
Record type, site, phase and change with coughing.

What a positive result means

Persistent fine bibasal crackles: interstitial lung disease or cardiogenic pulmonary edema.
Localized crackles with bronchial breathing and fever: pneumonia.
Diffuse expiratory wheezes: asthma or COPD; in infants, also bronchiolitis.
Stridor with fever and a barking cough in a child: croup; sudden stridor while eating or playing: foreign body.
Pleural rub with pain on breathing: pleuritis (pneumonia, pulmonary embolism, autoimmune disease); it may fade as fluid builds up.
No added sounds does not rule out disease: early or deep pneumonia may sound normal.

Usefulness and limits

Agreement between examiners is moderate for crackles and wheezes, and poor for less standard terms such as rhonchi.
Basal crackles that clear after several deep breaths may be atelectasis in people who have been lying down.
Chest radiograph, lung ultrasound and spirometry confirm what auscultation suggests.

Test yourself

Think of the answer, then tap the question to see it.

Which added sound suggests pulmonary fibrosis?

Fine, Velcro-like, late-inspiratory crackles, mainly at both bases.

How is a pleural rub told from a pericardial rub at the bedside?

Ask the patient to hold the breath: a pleural rub stops, a pericardial rub continues because it follows the heartbeat.

What does stridor mean and where is it loudest?

Upper airway obstruction (larynx or trachea); it is loudest over the neck and mainly inspiratory. It is an emergency.

What does a single, fixed, localized wheeze suggest?

Focal obstruction of one bronchus, for example by a tumour or a foreign body.

Which sounds change with coughing?

Those from secretions: coarse crackles and rhonchi. Fine crackles and a pleural rub do not change with coughing.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

← All of the clinical exam

Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: Breath sounds: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024); Asthma: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024).

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Representative model, for educational purposes only.