Final answer:
The paranasal sinuses are air-filled spaces located within the frontal, maxillary, sphenoid, and ethmoid bones of the skull, each named for the bone it occupies. They are involved in respiratory functions and are connected to the nasal cavity, with the frontal sinus being the most anterior and the sphenoid sinus being the most posterior.
Step-by-step explanation:
The paranasal sinuses are hollow, air-filled spaces located in several bones of the skull. Specifically, they are found in the frontal, maxilla (maxillary), sphenoid, and ethmoid bones. They are named for the skull bone each occupies. The frontal sinus is the most anteriorly located, found in the frontal bone just above the eyebrows. The maxillary sinuses are the largest and are located within the maxillary bones just below the orbits. The sphenoid sinus is the most posterior, found in the sphenoid bone below the sella turcica. The ethmoid air cells, or ethmoid sinuses, consist of multiple small spaces within the ethmoid bone, found between the orbit and the nasal cavity. These sinuses are crucial for respiratory functions and are often involved in sinus infections.
The paranasal sinuses are divided at the midline by the nasal septum, which is formed by the perpendicular plate of the ethmoid bone, the vomer bone, and the septal cartilage. These sinuses are connected to the nasal cavity and play a role in conditioning the air we breathe.