Rales are sounds additional to respiratory sounds, due to lesions such as partial obstruction of the tracheobronchial tubes or lumen; depending on the nature of the sound, they can be divided into dry rales and wet rales. Diagnosis 1. Dry rales are a kind of additional sound of respiration with a long duration, which is produced by turbulence when air is inhaled into the head output due to narrowing or partial obstruction of the trachea or bronchi. The pathological basis for its occurrence is inflammation on the wall of trachea and bronchus, mucous membrane congestion and swelling, increased secretion, spasm of bronchial smooth muscle; tumor invasion in the lumen, foreign body or partial obstruction of secretion; or narrowing of the wall by enlarged lymph nodes and other compressions. If the snoring sound is caused by mucus retention, it disappears after coughing, and the local fixed snoring sound suggests bronchial obstruction. If the snoring sound occurs repeatedly in the same area, it should be considered that the snoring sound caused by mucus retention tumor bronchospasm due to bronchial stenosis is long and bilateral. The whistling sound is a high pitched dry rales, often described as croup, flying arrow sound, birdsong, etc. The lesions mostly occur in the bronchi or fine bronchi. 2. Wet rales, i.e., blistering sounds, are produced by the rupture of blisters formed by the passage of gas through liquid during respiration due to the presence of thinner liquids in the trachea or bronchi, such as exudate, sputum, blood, mucus, pus sputum, etc. It is mostly seen during inspiration, or more clearly at the end of inspiration, and sometimes also in early expiration, with a more constant location and nature. Due to the large diameter of the lesion bronchial lumen, or the size of the cavity, the amount of liquid is different, the sound of wet rales have coarse, medium, fine different or called large, medium, small alveolar sound, inspiration at the bottom of the lung airless area to help first close the small airway alveoli suddenly open can produce “inspiratory burst sound”, inspiratory early burst sound suggests a serious obstructive pulmonary disease, and late inspiratory burst sound can also be heard in the elderly or long-term bedridden patients after a long period of shallow breathing suddenly when the bottom of inspiration, which is due to the lung bottom of the small airways open later, does not necessarily indicate pathological conditions.