Collapse of one side of the thorax can be caused by abscess or pleurisy, extensive pleural thickening adhesions and contractions, pulmonary atelectasis, pulmonary fibrosis, chronic fibrous tuberculosis, chronic pulmonary suppuration and other disorders. Differential diagnosis: other thoracic abnormalities: 1, flat chest: flat chest, the front and rear diameter is less than half of the diameter of the left and right; increased inclination of the ribs, the lower edge of the ribs is low, the upper ventral angle is acute; the neck is elongated, the clavicle is prominent, the upper and lower clavicle fossa concave, trapped obviously; mostly seen in long and thin body type, also seen in chronic wasting diseases, such as tuberculosis. 2, barrel-shaped chest: the front and rear diameter is equal to or greater than the diameter of the left and right, barrel-shaped; the inclination of the rib cage is reduced almost horizontal, the rib space widened, sometimes full; the upper and lower clavicle fossa flattened or prominent, short neck and high shoulders; the upper abdominal angle increased obtuse angle; common in chronic obstructive pulmonary emphysema and bronchial asthma attacks, caused by over-inflation of the two lungs, lung volume increased; can also be seen in part of the elderly and short fat body type. 3, rickets chest: also known as “chicken chest”, for rickets caused by chest changes, mostly seen in children. The sternum is characterized by a significant convexity of the lower part of the sternum, both sides of the rib cage depression, the anterior and posterior diameter of the thorax increases while the left and right diameter decreases, the upper and lower diameter of the thorax is shorter, resembling a chicken chest and so named; sometimes the rib cage and rib cartilage junction thickens and bulges in the shape of a bead, arranged in a bead on both sides of the sternum, called rickets bead; the lower part of the anterior thorax where the diaphragm is attached, because the rib cartilage is pulled by the diaphragm for a long time can be depressed inward, while the lower rib edge is turned out to form a Horizontal deep groove, called the rib diaphragm groove; if the sternal saber is significantly sunken, sometimes together with the attached rib cartilage is sunken, resembling a funnel, called funnel chest. 4, one side of the thoracic bulge accompanied by rib space widening: if there is also restricted respiratory movement, trachea, heart to the healthy side of the displacement, seen in a large number of pleural effusion, pneumothorax, liquid pneumothorax, huge intrathoracic masses, etc.; restricted chest wall bulge seen in cardiomegaly, large pericardial effusion, aortic aneurysm, intrathoracic or chest wall tumors, chest wall inflammation, subcutaneous emphysema, etc.; 5, the thoracic deformation caused by spinal deformity: anterior convexity of the spine Most of them occur in the lumbar spine, which has no effect on the shape of the thorax; posterior convexity deformity (hunchback) of the spine occurs mostly in the thoracic spine, with the thoracic spine bulging backward, shortening the upper and lower thoracic diameter, shortening the rib cage, pulling the sternum inward, commonly seen in thoracic spine tuberculosis, the elderly, and osteochondrosis; lateral convexity deformity of the spine, with high shoulders on the convex side, widening of the rib space, and narrowing of the rib space on the opposite side, seen in thoracic spine disorders, long-term incorrect posture or developmental deformities The clinical manifestations vary with the primary disease, with the trachea shifting to the affected side, the affected side of the thorax becoming smaller, and the spine commonly having healthy lateral convexity.