Which sinus groups are visible on a lateral projection?

Which sinus groups are visible on a lateral projection?

• A. Frontal sinus only
• B. Frontal, maxillary, ethmoid, and sphenoid
• C. Maxillary and frontal
• D. Sphenoid sinus only

Answer: (B)

The key idea is that a lateral skull projection allows a side view where the paranasal sinuses appear as radiolucent spaces bounded by bone, making each group identifiable. Frontal sinuses sit above the orbits, maxillary sinuses are in the cheek area, ethmoid sinuses are a maze of air cells between the orbits, and the sphenoid sinus lies deeper in the skull behind the ethmoids. In this view, their outlines can be seen without being obscured by other structures, so all four sinus groups can be visualized. This is why the best choice includes frontal, maxillary, ethmoid, and sphenoid sinuses. Other views may show only some sinuses or have overlapping that hides others.

The key idea is that a lateral skull projection allows a side view where the paranasal sinuses appear as radiolucent spaces bounded by bone, making each group identifiable. Frontal sinuses sit above the orbits, maxillary sinuses are in the cheek area, ethmoid sinuses are a maze of air cells between the orbits, and the sphenoid sinus lies deeper in the skull behind the ethmoids. In this view, their outlines can be seen without being obscured by other structures, so all four sinus groups can be visualized. This is why the best choice includes frontal, maxillary, ethmoid, and sphenoid sinuses. Other views may show only some sinuses or have overlapping that hides others.