Collapse of one side of the thorax can be caused by abscess or pleurisy, extensive pleural thickening adhesions and constriction, pulmonary atelectasis, pulmonary fibrosis, chronic fibrous tuberculosis, chronic pulmonary suppuration and other disorders. Etiology: Commonly associated with various pleural diseases and lung diseases. Such as pulmonary atelectasis, pulmonary atrophy, pulmonary fibrosis (pulmonary fibrosis, the name of the disease, that is, the interstitial tissue of the lung consists of collagen, elastin and protein glycans, when the fibroblasts are chemically or physically injured, they will secrete collagen for the repair of the interstitial tissue of the lung, which in turn causes pulmonary fibrosis; that is, after the lung is injured, the body repairs the results produced.) , extensive pleural thickening adhesions, post lobectomy, etc. Examination: Clinical manifestations vary with the primary disease, the trachea shifts to the affected side, the affected side of the thorax becomes smaller, and the spine commonly has healthy lateral convexity. Although there are some differences in the size and shape of the normal thorax between individuals, generally speaking, the anterior and posterior diameters of the normal adult thorax are shorter than the left and right diameters, and the ratio of the two is about 1:1.5. The anterior and posterior diameters of the thorax in children and the elderly are slightly smaller than the left and right diameters or almost equal, so they are cylindrical.