Encountered when auscultating over the lungs fields. The typical sound is low pitched with inspiration louder and longer than expiration.

Encountered when auscultating over the bronchi (such as at the 2nd/3rd intercostal spaces). The typical sound is between that of vesicular and tracheal (see below) breath sounds.

Encountered when auscultating over the trachea (such as at the neck). Typically harsher (due to turbulent airflow) and more high pitched than vesicular breath sounds. Both inspiration and expiration is audible. Has similarities to the hollow sound produced by breathing through a pipe.

Indicative of airway narrowing or partial obstruction. Can be classified into a sibilant wheeze (or just wheeze) which is characteristically a higher pitched whistle typically associated with constricted smaller airways (e.g. asthma or COPD exacerbation), or a sonorous wheeze (ronchi) which is a lower pitched snore or moan typically caused by constricted larger airways (e.g pneumonia, bronchitis or cystic fibrosis).

Harsh high pitched sound indicating upper airway obstruction (e.g. croup, laryngomalacia or epiglottitis).

Crackling, popping noises caused by small airways and alveoli snapping open or shut. Can be classified into fine crackles which are higher pitched and can be associated with interstitial lung disease, pleural oedema in heart failure and viral pneumonia, or coarse crackles which are lower pitched and can be associated with bronchiectasis and bronchopneumonia.

Noisy breathing which can be heard in individuals near death due to respiratory secretions (e.g. saliva) accumulating in the throat and upper airways.

Caused by rubbing of inflamed pleural linings. Typically a grating or squeaking sound. To distinguish from a pericardial rub, pleural rubs should cease when a patient holds their breath.

Characteristic inspiratory 'whoop' – a gasp for air – between coughs.

Characteristic stridor and seal-like barking cough.

Abnormal reflexive breathing pattern in response to hypoxia, usually in the context of cardiac arrest or stroke. Typically slow, noisy and laboured breathing with occasional gasps.

• Stridor #1: James Heilman and Natural Philo. CC BY-SA 3.0

• Coarse crackles #1: James Heilman. CC BY-SA 3.0

• Sibilant wheeze #2: James Heilman. CC BY-SA 3.0

• Whooping cough: US Center for Disease Control. Public Domain

• Fine crackles #1, ronchi #1, pleural rub #1, wheeze #1, combinations: María Dolores Mauricio et al. CC BY 3.0

• Pleural rub #3, coarse crackles #2, death rattle #2: theSimTech. Non-commercial licence

• Croup #1: Tbrunye. CC BY-SA 4.0

• Remaining sounds: RespWiki. CC BY-NC-SA 3.0