Paranasal sinuses are the group of air filled sacs that are present around the nasal cavity. Paranasal sinuses are present four in numbers. These are maxillary sinuses, frontal sinuses, ethmoidal sinuses and sphenoidal sinuses.
The radiography of paranasal sinuses using X ray technique is helful in medical diagnosing. The erect position provides the best image for the radiography of paranasal sinuses.
The cell membrane protects the cell and keeps bad things like viruses from getting in the cell.<span>It consists of the lipid bilayer with embedded proteins.</span>
