paranasalisiin

Paranasal sinuses, also known as para-nasal sinuses, are a group of air-filled cavities within the skull bones around the nasal cavity. In humans, the four paired sinuses are the maxillary, frontal, ethmoid, and sphenoid sinuses. They are lined by a ciliated mucous membrane and communicate with the nasal cavity through small openings, allowing drainage of mucus.

Anatomy and drainage: The maxillary sinuses drain into the middle meatus, the frontal sinuses into the frontal recess, the anterior and middle ethmoid air cells into the middle meatus, the posterior ethmoid cells into the superior meatus, and the sphenoid sinuses into the sphenoethmoidal recess. The mucous produced by the sinus lining helps humidify and filter inhaled air. The size and shape of the sinuses vary among individuals and can change with age and development.

Development and function: Paranasal sinuses develop postnatally and continue to grow during adolescence. They are thought to reduce skull weight, participate in conditioning of inhaled air, contribute to voice resonance, and protect vital structures from trauma. The sinus lining performs mucociliary clearance, moving mucus toward the nasal cavity.

Clinical considerations: Sinus-related disorders commonly include sinusitis, caused by infection, inflammation, or obstruction of sinus drainage. Risk factors include allergic rhinitis, dental infections, nasal polyps, and anatomical variations. Diagnosis often involves clinical evaluation and imaging such as CT or MRI. Treatments range from saline irrigation and intranasal corticosteroids to antibiotics for bacterial infections and, in some cases, functional endoscopic sinus surgery to restore drainage and ventilation.