Nasal septum deviation is a structural abnormality where the cartilage or bone of the nasal septum leans towards one or both sides of the nasal cavities. Clinically, a perfectly vertical nasal septum does not exist; there is always some degree of deviation, but the extent can vary significantly. If nasal septum deviation is accompanied by symptoms such as nasal congestion, nosebleeds, or even headaches, a sinus CT scan should be conducted to assess the degree of deviation. If the deviation is severe, then surgery is definitely necessary. For cases with no clinical symptoms and only minor deviation, surgery is not required.