Nasal spray oil are also available. There is however no trial-verified evidence that they have a measurable effect on symptoms. Decongestant nasal sprays are available over-the-counter in many countries. They work to very quickly open up nasal passages by constricting blood vessels in the lining of the nose. Prolonged use of these types of sprays can damage the delicate mucous membranes in the nose. This causes increased inflammation, an effect known as rhinitis medicamentosa or the rebound effect. Decongestant nasal sprays are advised for short-term use only, preferably 5 to 7 days at maximum. Some doctors advise to use them 3 days
Nasal cavity blends, via the choanae, into the nasopharynx. The nasal cavity is divided in two by a vertical fin called the nasal septum. On the sides of the nasal cavity are three horizontal outgrowths called nasal conchae (singular "concha") or turbinates. These turbinates disrupt the airflow, directing air toward the olfactory epithelium on the surface of the turbinates and the septum. The vomeronasal organ is located at the back of the septum and has a role in pheromone detection. The nasal cavity is divided into two segments: the respiratory segment and the olfactory segment. There is a rich blood supply to