Deviated nasal septum refers to the fracture of the cartilage of the nasal septum, deviating toward one or both nasal cavities. Patients with a deviated nasal septum are prone to bleeding, and this bleeding tends to recur. This is because after the cartilage of the nasal septum deviates toward one side of the nasal cavity, continuous breathing causes the airflow to rub against the protruding nasal mucosal tissue of the deviated side. Additionally, after the deviation, the nasal mucosal tissue itself becomes thinner. Under these conditions, the thinner mucosal tissue at the deviated part is more likely to rupture and get damaged, making it prone to erosion and bleeding, and the blood vessels are also more likely to rupture, leading to bleeding. In summary, a deviated nasal septum can lead to nosebleeds.