Otolaryngology or ENT (ear, nose and throat) specialises in the diagnosis and treatment of ear, nose, throat, and head and neck diseases and disorders. The sinuses are air-filled spaces in the skull behind the forehead, nasal bones, cheeks and eyes that are lined with mucus membranes. Normally, mucus is able to drain out and air can circulate. But when the sinus openings become blocked or too much mucus builds up, a viral, bacterial or fungal infection may occur. Sinusitis refers to inflammation of the lining membrane that occurs with such an infection. Treatment usually includes antibiotics, decongestants and pain relievers. Surgery may be required to remove blockages in sinuses. Nose disorders (or nasal disorders) may include: deviated septum (a problem with the wall that divides the nasal cavity into halves) and other defects; nasal polyps (soft growths that develop on the lining of your nose or sinuses); frequent nosebleeds; and rhinitis (inflammation of the nose and sinuses, sometimes caused by allergies). Cancer of the nasal cavity and sinuses is rare. Surgery may be required to treat some of these problems.