Respiratory sounds

Respiratory sounds
1) area for normal tracheal sound, 2) area for ascultation of upper lung fields, 3) area for normal bronchial sound. Blue marks ascultation area and red line marks heart.
Classification and external resources
ICD-10 R06
ICD-9-CM 786.7
MedlinePlus 007535
MeSH D012135

Respiratory sounds, breath sounds, or lung sounds refer to the specific sounds generated by the movement of air through the respiratory system. These may be easily audible or identified through auscultation of the respiratory system through the lung fields[1] with a stethoscope as well as from the spectral chacteristics of lung sounds.[2] These include normal breath sounds and adventitious or "added" sounds such as rales, wheezes, pleural friction rubs, stertor and stridor.

Description 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, medium or high) and intensity (soft, medium, loud or very loud) of the sounds heard.

Abnormal breath sounds

Common types of abnormal breath sounds include the following:[3]

Name Continuous/discontinuous Frequency/Pitch Inspiratory/expiratory Quality Associated conditions Example
Wheeze or rhonchi continuous high (wheeze) or lower (rhonchi) expiratory or inspiratory whistling/sibilant, musical Caused by narrowing of airways, such as in asthma, chronic obstructive pulmonary disease, foreign body.
The sound of wheezing as heard with a stethoscope.

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Stridor continuous high either, mostly inspiratory whistling/sibilant, musical epiglottitis, foreign body, laryngeal oedema, croup
Inspiratory and expiratory stridor in a 13-month child with croup.

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Inspiratory gasp continuous high inspiratory whoop pertussis (whooping cough) see New England Journal of Medicine, Classic Whooping Cough sound file, Supplement to the N Engl J Med 2004; 350:2023-2026
Crackles (aka crepitations or rales) discontinuous high (fine) or low (coarse), nonmusical inspiratory cracking/clicking/rattling pneumonia, pulmonar edema, tuberculosis, bronquitis
Crackles heard in the lungs of a person with pneumonia using a stethoscope.

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Pleural friction rub continuous low inspiratory and expiratory nonmusical, many repeated rhythmic sounds inflammation of lung linings, lung tumors not available
Hamman's sign (or Mediastinal crunch) discontinuous neither (heartbeat) crunching, rasping pneumomediastinum, pneumopericardium not available


Other tests of auscultation

Pectoriloquy, egophony and bronchophony are tests of auscultation. For example, in whispered pectoriloquy the person being examined whispers - typically a two syllable number as the clinician listens over the lung fields. The whisper is not normally heard over the lungs, but if heard may be indicative of pulmonary consolidation in that area. This is because sound travels differently through denser (fluid or solid) media than the air that should normally be predominant in lung tissue. In egophony, the person being examined continually speaks the English long-sound "E". The lungs are usually air filled, but if there is an abnormal solid component due to infection, fluid, or tumor, the higher frequencies of the "E" sound will be diminished. This changes the sound produced, from a long "E" sound to a long "A" sound.


  1. Respiratory sounds at the US National Library of Medicine Medical Subject Headings (MeSH)
  2. Sengupta, Nandini; Sahidullah, Md; Saha, Goutam (August 2016). "Lung sound classification using cepstral-based statistical features". Computers in Biology and Medicine. 75 (1): 118–129. doi:10.1016/j.compbiomed.2016.05.013.
  3. Bohadana, Abraham (February 20, 2014). "Fundamentals of Lung Auscultation". New England Journal of Medicine. 370: 744. doi:10.1056/NEJMra1302901. PMID 24552321. Retrieved February 28, 2015.
  4. "Breath sounds: Medline Plus". NIH. Retrieved 5 May 2015.
This article is issued from Wikipedia - version of the 10/16/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.