Final answer:
The paranasal sinuses are air-filled spaces located in the skull bones, serving to warm, humidify, and filter the air we breathe. They consist of the frontal, maxillary, ethmoid, and sphenoid sinuses, which also help to lighten the skull. The nasal cavity is divided by the nasal septum, formed by the ethmoid bone and the vomer bone.
Step-by-step explanation:
Paranasal Sinuses Anatomy
The paranasal sinuses are air-filled spaces within the bones of the skull that play a vital role in warming and humidifying the air we breathe in. Among these sinuses, the frontal sinus is positioned above the eyebrows, in the frontal bone, making it the most anterior sinus. The maxillary sinus, which is the largest and prone to infections, is found within the right and left maxillary bones just below the orbits. Behind the superior nasal conchae are the ethmoid air cells, part of the ethmoid bone that is divided into multiple small spaces. The sphenoid sinus is located near the center of the skull's sphenoidal bone, making it the most posterior sinus.
The sinuses are lined with mucosa and produce mucus that helps to trap dirt and pathogens, and they also lighten the skull's weight. Structurally, the ethmoid bone contains the ethmoid air cells and contributes to the formation of the upper nasal cavity walls. The nasal cavity itself is divided into two parts by the nasal septum, with the upper part formed by the perpendicular plate of the ethmoid bone and the lower part by the vomer bone.