Know Your Sinuses
The largest of the paranasal sinuses.
This line extends from the outer canthus of the eye to the external auditory meatus.
What is the OML
The presence of this finding often seen as a straight horizontal line suggests sinusitis.
What is an air-fluid level
Found between the orbits, these sinuses are made up of many small air cells.
What are the ethmoid sinuses.
This line is positioned perpendicular to the IR when performing a Waters view.
What is the MML
This projection demonstrates all four sinus groups in one image.
What is a lateral projection
These sinuses develop last and are located deep within the skull.
What are the sphenoid sinuses.
The CR exits at this landmark in the PA Caldwell Sinus projection.
What is the nasion
When the patients head is rotated on a Waters view, this midline structure appears off center.
What is the bony nasal septum
These paired sinuses lie just above the orbits.
What are the frontal sinuses.
For the SMV projection, this positioning line is parallel to the IR
What is the IOML
In the Waters view, these bony structures should appear just inferior to the maxillary sinuses.
What are the petrous ridges