Basic Lung Sounds

Vesicular Breathing – Normal

Vesicular breathing is the breathing in which the expiration is shorter than the inspiration period with no pause in between. The inspiration is 2 to 3 times longer than the expiration. During the expiration, the quality of sound fades rapidly. It has a lower pitch and is softer in nature. During the inspiration, the sound is of higher intensity and rustling in quality. It becomes softer during the expiration period. It is auscultated in all the areas of auscultation but mostly above the thorax. Vesicular breathing is considered normal breathing. It is the most commonly heard lung sound.

Crackles – Fine (Rales)

Fine crackles, also called pulmonary crackles or rales, are the rattling sounds perceived during the late inspiration period. They feel like the sound of hair rubbing together. Fine crackles arise in the smaller alveoli or the airways due to the collapse of these airways by some exudate or fluid. They are high pitched and soft in nature. They can be heard only by auscultating with a stethoscope. They are not normal and are heard in respiratory diseases like pulmonary fibrosis, congestive heart failure, interstitial pneumonia. They indicate extra fluid over the lungs, which might be due to aspiration, pneumonia, chronic bronchitis, etc.

Coarse crackles – (Rales)

Coarse crackles have a lower pitch than the fine crackles and are comparatively louder. They are heard during the early inspiration period. They sound moist or sturdy. They last for a longer period. They show the accumulation of extra fluid over the lungs resulted from the aspiration, pulmonary edema, bronchitis, etc. They are caused by the pathological processes taking place in the larger respiratory spaces or bronchioles. Mucous in the large bronchioles as in Chronic obstructive pulmonary disease (COPD) can result in coarse crackles or rales. Coarse crackles are also indicative of Adult respiratory distress syndrome (ARDS). Coughing can alter the quality of coarse crackles, but they do not disappear completely.

Wheeze

Wheeze is a kind of a whistling sound. It is caused by the narrowing and inflammation of the airways. It can be heard both during the inspiratory and expiratory phases. It is indicative of some kind of obstruction in the air spaces or narrowing of these spaces. It is a pathological sound. Wheezing is most commonly heard during serious respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD), requiring proper diagnosis and treatment. Wheezes have a musical or squeaky aspect to them. Wheezing feels like whistling when a person is breathing. The high-pitched wheezing is heard most commonly during expiration and some times during inspiration.

Ronchi – Low Pitched Wheezes

Ronchi( plural for ronchus) are also known as low pitched wheezes. They are coarse and rattling in nature. They are caused when some abnormal secretions in the bronchial airspaces cause blockage or obstruction. Ronchi resembles the sound of snoring. Ronchi are observed during respiratory disorders like chronic bronchitis, chronic obstructive pulmonary disease (COPD), pneumonia, bronchiectasis, or cystic fibrosis. When the obstruction or blockage occurs in intrathoracic airways, it’s known as expiratory ronchi. There are two types of ronchi. The high-pitched ronchi are referred to as sibilant ronchi, and the low-pitched ronchi are called sonorous ronchi. Coughing alters the nature of ronchi.

Bronchial Breath Sounds

Bronchial breath sounds are considered normal in respiration. They are commonly auscultated above the trachea. Although the bronchial breath sounds are normal, it is called consolidation when they are heard in some area away from their normal findings. Consolidation is found in pneumonia or lung compression. These conditions make the lung tissues dense. Sometimes the bronchial breath sounds are also heard in the peripheral areas where normally vesicular sounds should be heard. Bronchial breathing has a long expiratory phase, and the sounds are larger. In the condition of health, these sounds are heard only above the large air spaces like the trachea. Bronchial sounds consist of higher frequency components.

Pleural Rubs

Pleural rubs are abnormal lung sounds. These are heard when there is an inflammation of the lung’s pleural layer caused by the rubbing together of these layers. Pleural rubs are harsh and grating in nature. Pleural friction rubs can be heard during both inspiration and expiration. These have a low pitch. Pleural rubs are common in respiratory diseases like pneumonia, pulmonary embolism, malignant pleural disease, etc. There is a narrow fluid-filled space called the pleural cavity between the pleural layers of the lung. When this space becomes inflamed, or the lubrication between them is lost, pleural rubs are heard, and pain is observed.

Bronchovesicular Lung Sounds

Bronchovesicular lung sounds are tubular in nature. They are heard in the chest’s posterior portion, usually between the central part of the anterior chest and the scapulae. Compared to the bronchial lung sounds, bronchovesicular sounds are softer in nature. Bronchovesicular sounds have equal inspiratory and expiratory phases. The difference in the pitch of the sound is observed during the expiratory phase. They are considered normal breathing sounds. They can be auscultated throughout the lung area/field, especially near the trachea and the alveoli. They have a medium pitch. Bronchiovesicular sounds are considered as the intermediate sounds between the bronchial and vesicular breathing.

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