Sphenoid sinus

The sphenoid sinus is the most posterior paranasal sinus. It lies anteroinferior to the sella. It is important to look for the variable pneumatisation of this sinus and to report the relationship with neurovascular structures. The sinus is often divided by a central septum, and in this context some radiologists employ the term sphenoid hemisinus for each portion. 

Pneumatisation starts at around 2 year of age and it develops more slowly than the other paranasal sinuses.

  • location: the central body of the sphenoid bone anteroinferior to the sella turcica
  • blood supply: posterior ethmoidal and sphenopalatine arteries
  • innervation: posterior ethmoidal nerve and orbital branch of pterygopalatine fossa

The sphenoid sinuses are paired spaces formed within the body of the sphenoid bone, communicating with the roof of the nasal cavity via the spheno-ethmoidal recess in its anterior wall. The two sinuses are separated by a septum which may or may not be in the midline. 

A large sinus can show a number of ridges and depressions related to closely adjacent structures. These can include the pituitary gland, optic nerve and internal carotid artery.

  • conchal
  • lateral recess
  • presellar
  • sellar (which can be incomplete or complete)

Lymph drainage occurs via afferent vessels leading into the retropharyngeal nodes

With respect to optic nerve relationship:

  • type 1: adjacent to sphenoid sinus
  • type 2: indenting the sinus
  • type 3: traversing the sinus
  • type 4: adjacent to posterior ethmoid sinus
Head and neck anatomy
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Article information

rID: 24668
System: Head & Neck
Section: Anatomy
Tags: cases, cases, refs
Synonyms or Alternate Spellings:
  • Sphenoid sinuses
  • Sphenoidal sinus
  • Sphenoidal sinuses

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Cases and figures

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    Figure 1: in green on annotated CT
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    Case 1: sphenoid sinus aplasia
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