Frontal & Anterior Ethmoid Sinuses
PA axial (Caldwell) IR Size: 8x10 LW SID: 40"" Page #'s: 2:372,318	Positioning:   • Pt seated or upright   • Pt nose rests on bucky (w/ forehead ~3/4"" from bucky)   • (or if possible angle grid 15°)	CR Entrance & Angle:   • CR _|_ exits Nasion.   • Collimation:   • Best to Determine:   • Primary-Frontal & Anterior Ethmoidal	Eval Criteria:   • NR by Equidistant lat borders of skull & orbits   • Petrous ridges in lower 1/3 of orbits   • Frontal sinuses above frontal suture   • Ethmoid cells just below frontal sinuses   • Sphenoidal sinuses thru nasal fossae just below or between ethmoidal air cells