Diaphragmatic palsy is a paralytic rise of the diaphragm on one or both sides due to damage to the phrenic nerve and blockage of nerve impulses, resulting in impaired movement. Long-term diaphragmatic paralysis can produce atrophy of the diaphragm to form a membrane. The following is the differential diagnosis of diaphragmatic palsy: 1. Diaphragmatic bulge Diaphragmatic bulge is an abnormal rise in the position of the diaphragm caused by paralysis, underdevelopment or atrophy of the diaphragm due to incomplete muscularization of the thoracoabdominal membrane, non-myelination or atrophy resulting in a weak diaphragm forming a fibrous film and a marked rise in the position of the top of the diaphragm. It mostly occurs on the left side. Occasionally, part of the diaphragm may be involved, with the anteromedial part of the right side being common and bilateral diaphragmatic bulges rare. The disorder can occur at any age, commonly on the left side in adults and on the right side in infants. It is more common in males than females, about 2:1. 2, fluid at the base of the lungs Fluid in the lungs indicates the presence of more obvious lesions in the lungs, and if fluid in the lungs is not treated it can affect the patient’s respiratory function. There are two causes of right-sided pulmonary atelectasis, which can be caused by bronchial obstruction (including intrinsic or extrinsic factors) or by external pressure on the lung. The most common causes of intrinsic bronchial obstruction are inhaled foreign bodies, thick mucus, inflammatory exudates, bronchial tumors, bronchial inflammatory granulation tissue, or inflammatory bronchial stenosis. Extrinsic bronchial obstruction can be caused by enlarged lymph nodes (including tuberculosis, tumors, and nodular disease), peribronchial tumors, aortic aneurysms, cardiac enlargement (such as enlarged left atrium), and pericardial effusion. Pulmonary atrophy can be caused by external pressure on the lungs and can be due to larger amounts of pleural effusion or pneumothorax, intrathoracic tumors, thoracic subsidence (congenital, traumatic or post-surgical), and rising septum.