The nasal septum is the wall between the nostrils that separates the nasal passages. The septum is made of cartilage and thin bone. If the nasal septum is crooked, it is called a deviated nasal septum. A deviated septum may be caused by injury or surgery to the nose.

A deviated nasal septum may not cause symptoms. When present, symptoms may include a crooked nose, trouble breathing through the nose (especially on one side), or a runny nose.