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Sphenoid Sinus

sinus sphenoidalis

The sphenoid sinus occupies the body of the sphenoid bone and is divided by an asymmetric intersphenoid septum. It is intimately related to the pituitary gland in the sella turcica superiorly, the optic canals and optic chiasm superolaterally, the cavernous sinuses laterally, and the internal carotid arteries in their cavernous course laterally. It drains into the sphenoethmoidal recess of the nasal cavity.

Region: Head & Skull

Clinical Relevance

Clinical Notes

Sphenoiditis produces deep retro-orbital and vertex headache. The sphenoid sinus provides the transsphenoidal surgical corridor to the pituitary gland: the endoscopic endonasal approach enters through the sphenoethmoidal recess, removes the anterior sinus wall, and drills through the sinus floor to the sella. Inadvertent drilling lateral to the intersphenoidal septum risks the optic nerve or carotid artery. The sinus may be pneumatised to varying degrees, and its anatomy dictates approach feasibility.

Pathology

Common Injuries & Conditions

Carotid Artery Injury in Transsphenoidal Surgery

Drilling the lateral wall of the sphenoid sinus during transsphenoidal pituitary surgery risks injury to the cavernous ICA that forms an impression on the lateral sinus wall, producing catastrophic arterial haemorrhage requiring immediate packing, balloon occlusion, and endovascular sacrifice or repair.

Isolated Sphenoid Sinusitis

Isolated sphenoiditis produces deep non-specific headache and is frequently missed without targeted imaging; CT or MRI confirms the diagnosis, and serious complications including cavernous sinus thrombosis and optic neuritis may develop if treatment is delayed.