Which sinuses are demonstrated by the open-mouth Waters method?

Which sinuses are demonstrated by the open-mouth Waters method?

• A. Frontal and Ethmoid
• B. Sphenoid and Ethmoid
• C. Frontal and Maxillary
• D. Sphenoid and Maxillary

Answer: (D)

The open-mouth Waters projection is designed to reveal the sphenoid sinuses in addition to the maxillary sinuses. In the standard Waters (parietoacanthial) view, the maxillary sinuses are seen well because of the angled position of the petrous ridges. Opening the mouth lowers the soft palate and reduces superimposition from the nasal cavity, allowing the sphenoid sinuses to be projected through the nasal passages. So you can visualize both the maxillary and sphenoid sinuses in this view. Frontal and ethmoid sinuses are not typically demonstrated as clearly in this projection due to their location and the overlapping bones.

The open-mouth Waters projection is designed to reveal the sphenoid sinuses in addition to the maxillary sinuses. In the standard Waters (parietoacanthial) view, the maxillary sinuses are seen well because of the angled position of the petrous ridges. Opening the mouth lowers the soft palate and reduces superimposition from the nasal cavity, allowing the sphenoid sinuses to be projected through the nasal passages. So you can visualize both the maxillary and sphenoid sinuses in this view. Frontal and ethmoid sinuses are not typically demonstrated as clearly in this projection due to their location and the overlapping bones.