Pleural Effusion & Pneumothorax

The pleural space is a virtual cavity, and the two commonest abnormal things that fill it are fluid (effusion) and air (pneumothorax). For NEET PG, the radiological recognition of these two — costophrenic angle blunting, the meniscus, the visceral pleural line, mediastinal shift direction — is among the highest-yield, most-repeated chest radiology themes. This note builds the imaging logic so you can answer both "spo…