Modern understanding of lung sounds started with a historical article by Forgacs. Since then. many studies have clarified the changes of lung sounds due to airway narrowing as well as the mechanism of genesis for these sounds. Studies using bronchoprovocation have shown that an increase of the frequency and/or intensity of lung sounds was a common finding of airway narrowing and corre... https://ashleyshomestores.shop/product-category/twin-metal-hdbd-ftbd-rails/