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

Which two 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 paranasal sinuses by minimizing overlapping structures. When the mouth is opened, the soft palate drops away, allowing the sphenoid sinus area to project into view behind the nasal cavity, while the maxillary sinuses remain clearly visible in this same view. This combination makes the sphenoid and maxillary sinuses the ones best demonstrated with this technique. Frontal sinuses and ethmoid air cells aren’t the primary focus of this particular view, which is why they’re not the expected structures seen here.

The open-mouth Waters projection is designed to reveal the paranasal sinuses by minimizing overlapping structures. When the mouth is opened, the soft palate drops away, allowing the sphenoid sinus area to project into view behind the nasal cavity, while the maxillary sinuses remain clearly visible in this same view. This combination makes the sphenoid and maxillary sinuses the ones best demonstrated with this technique. Frontal sinuses and ethmoid air cells aren’t the primary focus of this particular view, which is why they’re not the expected structures seen here.