Normal breath sounds can also be identified by patterns of sound duration and the quality of the sound as described in the table below: NameĮxpiratory sound duration is equivalent to inspiratory soundĮxpiratory sound duration is longer than inspiratory soundĪnteriorly between the 1st and 2nd intercostal space Įxpiratory sound duration is about equivalent to inspiratory soundĮxpiratory sound duration is shorter than inspiratory soundĬommon types of abnormal breath sounds include the following: NameĬaused by narrowing of airways, such as in asthma, chronic obstructive pulmonary disease, foreign body. Normal breath sounds are classified as vesicular, bronchovesicular, bronchial or tracheal based on the anatomical location of auscultation. These include normal breath sounds and adventitious or 'added' sounds such as crackles, wheezes, pleural friction rubs, stertor, and stridor.ĭescription and classification of the sounds usually involve auscultation of the inspiratory and expiratory phases of the breath cycle, noting both the pitch (typically described as low (≤200 Hz), medium or high (≥400 Hz)) and intensity (soft, medium, loud or very loud) of the sounds heard. These may be easily audible or identified through auscultation of the respiratory system through the lung fields with a stethoscope as well as from the spectral characteristics of lung sounds. It is best heard in the lower anterior lungs and lateral chest, during both inspiration and expiration.Respiratory sounds, also known as lung sounds or breath sounds, refer to the specific sounds generated by the movement of air through the respiratory system. Potential causes include tuberculosis and pneumonia. The sound quality is considered a harsh grating or creaking. The pleural rub sound results from the movement of inflamed pleural surfaces against one another during chest wall movement. Fine crackles sound quality is like hair rubbing near the ear and may be heard in congestive heart failure and pulmonary fibrosis. Coarse crackles sound quality is low-pitched and moist it may be heard in pulmonary oedema and bronchitis.

Crackles can be further categorised as coarse or fine.

It is commonly heard in the bases of the lung lobes during inspiration. The cause of crackles can be from air passing through fluid, pus or mucus. The sound crackles create are fine, short, high-pitched, intermittently crackling sounds. It may be heard in asthma, emphysema and chronic bronchitis.Ĭrackles are also known as alveolar rales. It is commonly heard in the lungs during expiration. Alternately, what we often refer to as rhonchi is the sonorous wheeze, which refers to a deep, low-pitched rumbling or coarse sound, as air moves through tracheal/bronchial passages in the presence of mucus or respiratory secretions.

This refers to the high-pitched, whistle-like sound.

The classic wheeze may be referred to as a sibilant wheeze. This is caused by air passing through an obstructed, narrow airway. The sound of a wheeze is a high-pitched, continuous musical sound. It’s typically loudest over the anterior neck, as air moves turbulently over a partially-obstructed, upper airway. Stridor may be heard in conditions such as croup and foreign body obstruction. The cause of this sound is generally the partial obstruction of the larynx or trachea. Stridor is a continuous, high-pitched, crowing sound heard predominantly on inspiration.

Lung sounds wheezing