The nasal septum is the thin wall of cartilage and bone that divides your nasal cavity into left and right sides. Ideally, it should sit in the center. However, when it is significantly off-center, this condition is known as a deviated septum.
Some people are born with a deviated septum, while others develop one due to injury or trauma. As we age, natural changes in the nasal structure can also cause or worsen septal deviation.