What Causes a Deviated Septum? The nasal cavity is divided into the right and left nostrils through a thin wall known as the septum. At times, congenital or traumatic factors can lead to its displacement from the middle of the nose. This condition is called a 'deviated septum' or 'nasal septum deviation.' The nasal septum of almost all people deviates more towards the right. So, a minor...