Pleurisy can be seen on film. Pleurisy is divided into dry pleurisy and wet pleurisy. Dry pleurisy means there is no exudate, no pleural effusion, and this is when the pleural thickening can be seen on film. In wet pleurisy, the angle of the rib diaphragm is blunted and disappears. When the amount of pleural effusion is large, there will be a large dense shadow in the chest cavity. When this dense shadow reaches the lung door, the amount of pleural effusion has reached 1500ml, which is a medium amount of pleural effusion. When the amount of pleural effusion exceeds 1500ml, a large dense shadow will appear on the chest film above the lung door.