If you are having any of the following: Shortness of breath, Chest pain on exertion, Suspected chest infection, Persistant or productive cough. They should not be done to view fractured ribs.
A quadrangle is any shape which has 4 angles. In order for an angle to exist, there needs to be two lines meeting at a point. If the shape is a polygon (a closed 2d shape) then 4 angles means it must...