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Respiratory sounds

Field	Value
name	Respiratory sounds
synonyms	Breath sounds, lung sounds
image	Lungs diagram detailed.svg
field	Respirology

Respiratory sounds, also known as lung sounds or breath sounds, are 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 with a stethoscope as well as from the spectral characteristics of lung sounds. These include normal breath sounds and added sounds such as crackles, 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 (≤200 Hz), medium or high (≥400 Hz)) and intensity (soft, medium, loud or very loud) of the sounds heard.

Normal breath sounds

Normal breath sounds are classified as vesicular, bronchovesicular, bronchial or tracheal based on the anatomical location of auscultation. Normal breath sounds can also be identified by patterns of sound duration and the quality of the sound as described in the table below:

Name	Location where heard normally	Quality of sound	Sound duration
tracheal	over the trachea	very loud	expiratory sound duration is equivalent to inspiratory sound
bronchial	over the manubrium	loud, high pitched	expiratory sound duration is longer than inspiratory sound
bronchovesicular	anteriorly between the 1st and 2nd intercostal space;	intermediate	expiratory sound duration is about equivalent to inspiratory sound
vesicular	over most of both lungs	soft, low pitched	expiratory sound duration is shorter than inspiratory sound

Abnormal breath sounds

Common types of abnormal breath sounds include the following:

Name	Continuous/discontinuous	Frequency/pitch	Inspiratory/expiratory	Quality	Common Causes	Example
Wheeze or rhonchi	continuous	high (wheeze) or lower (rhonchi)	expiratory or inspiratory	whistling/sibilant	Caused by narrowing of airways, such as in asthma, chronic obstructive pulmonary disease, foreign body.	{{listen
Stridor	continuous	high	inspiratory, expiratory, or both	whistling/sibilant	epiglottitis, foreign body, laryngeal edema, croup	{{listen
Inspiratory gasp	continuous	high	inspiratory	whoop	pertussis (whooping cough)	see New England Journal of Medicine, [Classic Whooping Cough sound file](http://www.nejm.org/action/showMediaPlayer?doi=10.1056%2FNEJMp038243&aid=NEJMp038243_attach_1&area=), Supplement to the N Engl J Med 2004; 350:2023-2026
Crackles (rales)	continuous	high (fine) or low (coarse)	inspiratory	cracking/clicking/rattling	pneumonia, pulmonary edema, tuberculosis, bronchitis, heart failure	{{listen
Pleural friction rub	discontinuous	low	inspiratory and expiratory	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
Grunting	Continuous	low	expiratory	snoring	last1=McGann	first1=Kathleen A.	title=21 - Respiratory Tract Symptom Complexes	date=2018-01-01	url=https://www.sciencedirect.com/science/article/pii/B9780323401814000219	work=Principles and Practice of Pediatric Infectious Diseases (Fifth Edition)	pages=164–172.e2	editor-last=Long	editor-first=Sarah S.	publisher=Elsevier	language=en	isbn=978-0-323-40181-4	access-date=2022-05-06	last2=Long	first2=Sarah S.	editor2-last=Prober	editor2-first=Charles G.	editor3-last=Fischer	editor3-first=Marc}}

Continued

Rales: Small clicking, bubbling, or rattling sounds in the lungs. They are heard when a person inhales. They are believed to occur when air opens alveoli. Rales can also be described as moist, dry, fine, and coarse.
Rhonchi are coarse rattling respiratory sounds, usually caused by secretions in bronchial airways. The sounds resemble snoring. "Rhonchi" is the plural form of the singular word "rhonchus".
Stridor: Wheeze-like sound heard when a person breathes. Usually it is due to a blockage of airflow in the windpipe (trachea) or in the back of the throat.
Wheezing: High-pitched sounds produced by narrowed airways. They are most often heard when a person breathes out (exhales). Wheezing and other abnormal sounds can sometimes be heard without a stethoscope.

Other tests of auscultation

History

In 1957, Robertson and Coope proposed the two main categories of adventitious (added) lung sounds. Those categories were "Continuous" and "Interrupted" (or non-continuous). In 1976, the International Lung Sound Association simplified the sub-categories as follows: :Continuous

::Rhonchi ( :Discontinuous ::Fine crackles ::Coarse crackles Several sources will also refer to "medium" crackles, as a crackling sound that seems to fall between the coarse and fine crackles. Crackles are defined as discrete sounds that last less than 250 ms, while the continuous sounds (rhonchi and wheezes) last approximately 250 ms. Rhonchi are usually caused by a stricture or blockage in the upper airway. These are different from stridor. ## References ## References 1. ["Breath sounds: MedlinePlus Medical Encyclopedia"](https://medlineplus.gov/ency/article/007535.htm). 2. Sengupta, Nandini. (August 2016). "Lung sound classification using cepstral-based statistical features". *Computers in Biology and Medicine*. 3. Bickley, Lynn S. (2013). "Bates' Guide to Physical Examination and History-Taking". *Wolters Kluwer Health/Lippincott Williams & Wilkins*. 4. (2021). ["Lung Sounds"](https://www.ncbi.nlm.nih.gov/books/NBK537253/). *StatPearls Publishing*. 5. Bohadana, Abraham. (February 20, 2014). ["Fundamentals of Lung Auscultation"](https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1060&context=internalmedicine_facpub). *New England Journal of Medicine*. 6. (1999-11-15). ["Diagnosis of Stridor in Children"](https://www.aafp.org/afp/1999/1115/p2289.html). *American Family Physician*. 7. ["Breath sounds: MedlinePlus Medical Encyclopedia"](https://medlineplus.gov/ency/article/007535.htm). 8. (2018-01-01). ["21 - Respiratory Tract Symptom Complexes"](https://www.sciencedirect.com/science/article/pii/B9780323401814000219). *Elsevier*. 9. ["Breath sounds: MedlinePlus Medical Encyclopedia"](https://medlineplus.gov/ency/article/007535.htm). 10. ["Stridor: MedlinePlus Medical Encyclopedia"](https://medlineplus.gov/ency/article/003074.htm). 11. ["Breath sounds: Medline Plus"](https://www.medlineplus.gov/ency/article/007535.htm). *NIH*. 12. (1957). "Rales, rhonchi, and Laennec". *Lancet*. 13. (1977). "Updated nomenclature for membership reaction". *ATS News*. 14. (1984). "Lung Sounds". *Am Rev Respir Dis*. ::callout[type=info title="Wikipedia Source"] This article was imported from [Wikipedia](https://en.wikipedia.org/wiki/Respiratory_sounds) and is available under the [Creative Commons Attribution-ShareAlike 4.0 License](https://creativecommons.org/licenses/by-sa/4.0/). Content has been adapted to SurfDoc format. Original contributors can be found on the [article history page](https://en.wikipedia.org/wiki/Respiratory_sounds?action=history). ::

symptoms-and-signs:-respiratory-system pulmonology

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