The nose is made up of several bones and soft tissue. When we breathe in through our nose, our lungs are automatically engaged in what is called nasal resistance, the force that the lungs pull on to draw air into our bodies. For the lungs to work optimally, the nose and sinuses have to provide perfect resistance, which is enabled through their unique design.
The tip of the nose is flexible and made of two cartilages (called the upper and lower lateral cartilages), and the upper part of the nose is made of bone (). The middle part of the nose consists of a wall that separates the nose into two discrete sides. This wall, or partition, is called the nasal septum. The front portion of the septum is cartilage, and this part of the nose is flexible. The back third of the septum is bone. The nasal septum is not the only wall that is housed in the nose. There are many septae (plural for septum), or walls, that divide the sinuses.
On each side of the nasal septum exists a nasal passageway, made up of five areas, the most critical being the nasal valve (). The
nasal valve is a triangle formed where the cartilaginous septum meets the junction of the two lateral cartilages, the upper and lower lateral cartilages. This triangle of cartilage forms the narrowest and most critical area for the passage of air within your nose and is flexible. When you pinch the tip of your nose, you close the nasal valve. As the nasal valve closes, you can appreciate the nasal blockage that occurs, cutting off a significant amount of your nasal airway When this area is closed naturally or as a result of trauma, scarring, or infection, it becomes significantly difficult to breathe through your nose.
When any or all of the five areas of the nasal passageway are obstructed, the air flow through the nose becomes blocked. The magnitude of nasal obstruction depends on which area or combination of areas are affected and the extent to which each of these areas is blocked. The first, the vestibular area is located at the tip of the nose, at the entrance behind the nostrils. The second area is the nasal valve. The third area is called the attic, which lies between the septum and the nasal bones. Area four is located between the septum and the turbinates. Area five, called the choana, lies between the septum and the back of the nose.
A straight nasal septum allows for good air flow. When it is deviated or crooked, the septum can significantly obstruct breathing, limiting our air intake. The extent of the decrease in airflow depends on the amount and location of the deviation. For instance, a major deviation in the back of the nose may not cause as much obstruction as a deviation in the nasal valve area. Typically, blockage in any of these areas will reduce the airflow through the nose, and it will become necessary for you to breathe partially through your mouth to get enough air into your lungs.