Among these important structures are the sphenoid sinuses, a pair of cavities nestled deep within the head. This article explores the precise location of the sphenoid sinus, its various functions, and the common problems that can arise when it is affected.
Where the Sphenoid Sinus Is Located
The sphenoid sinuses are situated in a central and deep area of the skull, specifically within the sphenoid bone. This butterfly-shaped bone is positioned between the bones of the face and other deeper cranial bones, placing the sphenoid sinuses behind the upper part of the nasal cavity. They are located behind the eyes and nose, making them the farthest back of all the paranasal sinuses.
Their profound location means the sphenoid sinuses are intimately close to several important structures. These include the optic nerves and the pituitary gland. The internal carotid arteries also lie in close proximity to the sphenoid sinuses. Each individual typically has two sphenoid sinus cavities, a left and a right, separated by a bony wall that is often asymmetrical, meaning one sinus might be larger than the other.
Key Roles of the Sphenoid Sinus
The sphenoid sinus performs several functions. One of its primary roles involves reducing the overall weight of the skull. As air-filled cavities, these sinuses decrease the amount of solid bone in the head, making it lighter and easier to support.
Another function of the sphenoid sinus is its contribution to voice resonance. The air within these cavities acts as a resonating chamber, which helps shape the sound and quality of the human voice. Additionally, the sphenoid sinus plays a part in conditioning the air we breathe. It helps to warm and humidify inhaled air before it reaches the lungs.
The sphenoid sinus also offers a degree of protection for delicate brain structures. By absorbing some of the impact during head injuries, it can help prevent skull bones from breaking and shield structures like the pituitary gland. Furthermore, the lining of the sphenoid sinuses produces mucus, which traps airborne particles, germs, and allergens. This mucus then drains into the nasal cavity, flushing out harmful substances.
When the Sphenoid Sinus Causes Problems
The most common issue affecting the sphenoid sinus is sphenoid sinusitis, which refers to inflammation or infection of these air-filled cavities. Due to its deep and central location, sphenoid sinusitis can present with symptoms that differ from those of other sinus infections, often making it challenging to diagnose.
Headaches are a frequent symptom, typically felt behind the eyes, or in the forehead, temples, vertex, or back of the head. These headaches can worsen when lying down. Facial pressure or pain is also commonly reported.
Because of the sphenoid sinus’s close proximity to the optic nerves, inflammation can lead to visual disturbances. Individuals might experience changes in vision, such as double vision (diplopia), vision loss, or increased sensitivity to light (photophobia). Other symptoms can include post-nasal drip or nasal discharge, and sometimes neck pain, fever, fatigue, or dizziness. These symptoms arise from pressure and inflammation building within the sinus cavity, which can block normal drainage. While sphenoid sinusitis can occur in isolation, it is often accompanied by inflammation in other paranasal sinuses.