The septum is a sheet of cartilage and bone that divides the nose into left and right chambers. A deviated septum is a condition where the septum is severely shifted away from the midline, bent, crooked, or misshapen. Some degree of deviation is quite common, because roughly 80 percent of all nasal septums are deviated.
The most common symptoms caused by a deviated septum are nasal congestion, nasal obstruction, difficulty breathing through the nose, and snoring. Nasal congestion and breathing symptoms may occur all day or primarily at night and may be worse on one side, or alternate sides. In some patients, sinuses drainage is inhibited, causing repeated sinus infections or post-nasal drip. A deviated septum may be present at birth, caused by an injury or result from damage from previous treatments or surgery.