What are the main causes of sharp bilateral costophrenic angles?

Main reasons for sharp costophrenic angles bilaterally: 1. Normal condition: Sharp costophrenic angles typically indicate no pleural effusion, hemothorax, or pleural adhesions between the costophrenic angles, which is a normal finding. 2. Possible causes: Although sharp costophrenic angles generally indicate normalcy, in some situations—for example, if the patient is anxious or the costophrenic angles appear overly full—the examination results may be subject to interpretation errors. 3. Other factors: Although sharp costophrenic angles suggest normalcy, other conditions such as costochondritis or pleuritis might still be present without manifesting obvious abnormalities; therefore, other examination results and symptoms should also be considered. In most cases, sharp bilateral costophrenic angles are a normal finding, but comprehensive evaluation combining other examinations and symptoms remains essential.