sphenoid sinus
Meaning of sphenoid sinus: Its position deep within the skull places the sphenoid sinus in close proximity to structures such as the pituitary gland and nearby nerves.
Definition of sphenoid sinus
The sphenoid sinus is one of the paranasal sinuses, air filled spaces located within certain bones surrounding the nasal cavity. It sits within the sphenoid bone, a bone positioned deep in the skull behind the nasal cavity and roughly between the two eyes, making it the most posteriorly located of the paranasal sinuses.
Like the other paranasal sinuses, the sphenoid sinus is lined with a mucus producing membrane and connects to the nasal cavity through a small opening, allowing mucus produced within the sinus to drain normally and air to pass in and out.
Because of its deep location, the sphenoid sinus lies close to several important structures, including the pituitary gland, the optic nerves, and major blood vessels supplying the brain, a relationship used surgically, since certain pituitary operations are performed by passing instruments through the sphenoid sinus rather than through the skull directly.
Used in a sentence
Imaging showed mucosal thickening within the sphenoid sinus.
Good to know
The sphenoid sinus's deep location near the pituitary gland is used to surgical advantage, providing a natural route for reaching the pituitary gland without an incision through the skull.
Word origin
Where “sphenoid sinus” comes from
Formed from Greek sphenoeides, meaning wedge shaped, from sphen, meaning wedge, and eidos, meaning form, combined with Latin sinus, meaning a curve, fold, or hollow.