The nasal septum is the dividing wall between the right and left nasal cavities. The nasal septum is made up of cartilage and bone. The quadrangular cartilage makes up the front part of the nasal septum, and the ethmoid and vomer bones make up the paper-thin back part of the septum. The main function of the septum is to provide structural support for the nose and to help regulate and ensure smooth laminar airflow through the nasal cavities. The surface of the septum and the rest of the nasal cavity are covered by a lining called mucosa which secretes mucus and helps keep the nasal cavity moist.
The nasal turbinates are sets of three swellings on the side of both the right and left nasal cavity that help to humidify and heat the air entering the nose and to ensure smooth laminar (straight) airflow through the nasal cavity. There are inferior, middle, and superior turbinates. The inferior turbinate is the one of the major regulators of airflow into the nasal cavity. The middle turbinate overlies the entrance to the sinuses and swelling or displacement of this turbinate can lead to chronic sinus disorders like sinusitis. The superior turbinate and the highest portion of the nasal septum are also covered by special smell receptors that relay sense of smell to the brain. Blockage of these areas can lead to a diminished sense of smell.