Right middle lung syndrome refers to the lesion of the bronchus itself, or the compression and obstruction of extrabronchial enlarged lymph nodes, causing right middle lung lobar atelectasis, lung lobe volume reduction or complicating inflammatory solid changes. Its clinical manifestations are mainly recurrent cough, sputum, chest pain, chest tightness, etc., sometimes accompanied by fever or hemoptysis, and wet rales can be heard in the lungs. Laboratory tests often show increased white blood cell count and increased blood sedimentation. Depending on the etiology, tuberculosis, bacteria and cancer cells can sometimes be detected in the sputum. On chest imaging, right middle lobe syndrome may appear as a uniform triangular shaped shadow with the tip pointing toward the hilum, an elevation of the transverse septum anteriorly, and a decrease in the size of the middle lobe.