A sinus is a cavity or hollow space within a bone or other tissue. The term is most often used to refer to the paranasal sinuses, which are a group of four paired air-filled spaces surrounding the nasal cavity. These include:
1. **Maxillary Sinuses**: Located in the cheekbones. 2. **Frontal Sinuses**: Found in the low-center of the forehead. 3. **Ethmoid Sinuses**: Located between the eyes. 4. **Sphenoid Sinuses**: Found behind the eyes, deeper in the skull.
The main functions of the sinuses include:
- **Humidifying and warming inhaled air**: They help condition the air we breathe in. - **Enhancing our voices**: They act as resonance chambers. - **Reducing the weight of the skull**: Being air-filled, they make the skull lighter. - **Producing mucus**: This helps trap and clear out particles and pathogens from the nasal passages.
Sinus-related issues can include sinusitis (inflammation of the sinus lining), sinus infections, and nasal polyps. Symptoms might include facial pain, nasal congestion, and a reduction in the sense of smell. Treatment may involve medications, saline nasal sprays, or, in some cases, surgery.