The nasal septum is a thin piece of cartilage and bone inside the nose. It divides the left and right nostrils. Nobody has a completely straight septum but in some people the septum is significantly bent which can block the nose. Sometimes this is owing to a previous injury but sometimes it just grows that way.
An operation called a Septoplasty can straighten the septum and unblock the nose.
This is performed with the patient asleep and most people go home the same day.
It can take several weeks for the nose to become fully clear after surgery.