The structure dividing the nasal cavity into left and right sides is the?

• A. Inferior nasal concha
• B. Nasal bone
• C. Nasal septum
• D. Superior nasal concha

Answer: (C)

Dividing the nasal cavity into left and right sides is accomplished by the nasal septum. This midline wall is formed mainly by the perpendicular plate of the ethmoid bone and the vomer, with cartilage at the front. Its role is to create two separate nasal passages so airflow, mucous membranes, and olfactory regions on each side function independently. The superior and inferior nasal conchae are bony shelves on the side walls that help direct air and humidify it, but they do not separate the cavities. The nasal bone relates to the external nose, not the internal separation.