Lung Sounds: Chest Auscultation

Authors:

Gunnar Gudmundsson, M.D.
Tryggvi ¡smundsson, M.D.
National University Hospital of Iceland
Reykjavik, Iceland

Peer Review Status: Internally Peer Reviewed
Creation Date: February 1999
Last Revision Date: January 2000

Icelandic Version

Table of Contents

This site's Awards, Comments and Reviews

• Normal Breath Sounds
• Abnormal Breath Sounds
• Normal Voice Sounds
• Abnormal Voice Sounds
• Adventious Sounds
• Table of Lung Sounds

Normal breath sounds

*R.A.L.E. Repository: Normal Breath Sounds
**Loyola University: Normal Breath Sounds

When listening to normal respiration, inspiration composes approximately one-third of the respiratory cycle and expiration the remaining two-thirds. It is easiest to hear breath sounds during inspiration and expiratory sounds are less well heard. The intensity of breath sounds depends on the location of auscultation and on the bodyshape. They are loudest where the large airways are closest to the body surface, and they are more distant in obese individuals than thin ones. They also tend to be louder in children than in adults.

Bronchovesicular breath sounds are also normal and are heard on both sides of the sternum in the first and second intercostal spaces, between the scapula and over the lung apices. At these locations expiratory sounds are also heard more clearly. The frequency of the sound is higher and it is more intense, and it resembles the sound created when blowing through a straw. Bronchovesicular sounds can be heard over all lung fields in very thin people and in children.

Abnormal breath sounds

Bronchial breath sounds

These sounds are louder than normal breath sounds. They are heard when there is consolidation of lung tissue with bronchi that open into the consolidation, such as occurs in pneumonia. The consolidation leads to better transmission of sound than when the lungs are filled with air.

Cavernous breath sounds

These are uncommon sounds that are characterized by a deep hollow sound, as heard when blowing over a bottle opening. Cavernous breath sounds are heard over large cavities in the lungs, or in the case of a large pneumothorax with an open bronchopleural fistula.

Decreased or absent breath sounds

Breath sounds can be diminished even though they are not abnormal. This can be secondary to increased filtration of sounds, such as with pleural effusion or pleural thickening. They can also be diminished when there is decreased air movement, as in the case of emphysema, severe asthma, pneumothorax, complete occlusion of large airways and where there is decreased movement of the chest. An example of this is when there is pain associated with breathing.

Normal voice sounds

Voice-generated sounds radiate through the airways and lungs out through the chest wall and are heard well through the stethoscope. They are best heard over the trachea and large airways but less well peripherally. It is hard to understand individual words with the stethoscope, and with whispering, nothing is usually heard.

Abnormal voice sounds

Bronchophony

This is a situation where the voice sounds are increased and clearer, even though one can not detect words. This is heard under similar circumstances as bronchial breath sounds, such as when there is consolidation of the lung but the airways leading into the consolidation are open.

Whispering pectoriloquy

When a normal person whispers it is poorly heard with a stethoscope. With whispered pectoriloquy one can hear words that are whispered with the stethoscope. This is usually heard under the same circumstances as bronchial breath sounds and broncophony has similar significance.

Egophony

When a normal individual says "E" it is heard under normal circumstances as an "E" with a stethoscope. With egophony this "E" becomes "A" when listening through a stethoscope. It is usually heard under the same conditions as bronchial breath sounds and bronchophony and has similar meanings. Egophony can also be heard if there are both consolidation of the lung and a pleural effusion.

Adventious sounds

Adventious sounds are never heard over normal lungs. They do not represent changes in normal breath sounds, rather these are sounds that are added to normal breath sounds. Adventious sounds can be heard from the lungs themselves, or from other parts of the chest, such as pleura or pericardium. They can be discontinous or continous.

Discontinous

Crackles

Fine crackles. These sounds resemble the sound that is created when a piece of hair is held close to the ear and rubbed between fingers or when the thumb and index finger moist with saliva are pulled slowly apart. They are heard at the end of inspiration and do not disappear with cough. Fine crackles are heard with pulmonary edema, pneumonia and pulmonary fibrosis.

Coarse crackles. They are heard at the beginning of expiration. They can disappear with cough.

Continous

Wheezes are loud sounds that originate in the small airways. These sounds have a longer duration than crackles and also have a musical quality. They are often detected more easily with forced expiration and are heard in patients with asthma or other obstructive diseases.

Other adventious sounds

Pleural rub
In normal individuals the visceral and parietal pleura rub together silently during breathing. When the pleura are inflamed, coarse rubbing sounds can be heard during breathing. One can imitate these sounds by pushing the palm of the hand close to the ear and rubbing lightly and slowly over the dorsum of the hand. Pleural rubs are close to the surface like they start at the end of the stethoscope. They occur during both inspiration and expiration, generally at the end of inspiration and the beginning of expiration.

*All .wav lung sounds appear courtesy of the R.A.L.E Repository. To find out more about these lung sounds, how they were recorded or information about lung sounds in general, please visit there

**The author would like to thank Dr. David Cugell, Northwestern University and the American College of Chest Physicians for providing these .au sounds.