Final answer:
The nasal conchae are the structures that form a ring around the nasal cavities, with three types: superior, middle, and inferior conchae. These bony projections help in filtering, warming, and moisturizing the air we breathe.
Step-by-step explanation:
Structures that form a ring around the nasal cavities are the nasal conchae. Specifically, the superior, middle, and inferior nasal conchae are bony projections from the lateral walls of the nasal cavity. These structures serve to increase the surface area within the nasal cavity, aiding in warming, moisturizing, and filtering the air as it passes through. They are partly responsible for the turbulence created in the incoming air, which helps trap particles in the mucus. Among the nasal conchae, the inferior concha is the largest and can be seen when looking into the anterior nasal opening. The middle and superior conchae are parts of the ethmoid bone, with the superior nasal concha being well hidden above and behind the middle concha.