Silent Sinus :
It is the spontaneous unilateral collapse of the maxillary sinus with complete or partial opacification of the collapsed sinus.
The sinus is fully formed but fully opacified and reduced in volume with inward bowing of all four walls.
1)Inferior bowing of the roof (orbital floor) .
2)lateral bowing of the medial wall: lateral displacement of the middle and inferior turbinate.
3)posterior bowing of the anterior wall: flattening of the malar eminence.
4)anteromedial bowing of the posterolateral wall.
