Sphenoid bone

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Done

Parent item

Skull

 

• Abbreviation
• A., artery; Ant., anterior; Car., carotid; Cav., cavernous; Clin., clinoid; CN, cranial nerve; Fiss., fissure; For., foramen; Gang., ganglion; Gr., greater; Lat., lateral; Less., lesser; Ling., lingual; Max., maxillary; Med., medial; N., nerve; Opticocar., opticocarotid; Orb., orbital; Pet., petrous; Pit., pituitary; Proc., process; Pteryg., pterygoid; Pterygopal., pterygopalatine; Seg., segment; Sphen., sphenoid; Sup., superior; Tuberc., tuberculum.

• The foramen rotundum is positioned superolateral to the vidian canal.

• The vidian canal passes posteriorly along the floor of the sphenoid sinus.

• The maxillary nerve, posterior to the extracranial end of the foramen rotundum, often underlies a prominence in the lateral wall of the sinus.

• The lateral and anterior walls of the sphenoid sinus and the anterior wall of the sella have been removed to expose the petrous and cavernous segments of the carotid artery and the pituitary gland, all of which underlie bony prominences in the sinus wall.

• The posterior wall of the maxillary sinus has been removed to expose the pterygopalatine fossa.

• The vidian nerve enters the posterior margin of the pterygopalatine ganglion, which sits just anterior to the vidian canal in the pterygopalatine fossa.

• The maxillary nerve exits the foramen rotundum to enter the pterygopalatine fossa superolaterally to the vidian canal.

• Branches of the maxillary artery cross the pterygopalatine fossa on the anterior surface of the pterygoid process.

• Sinus pneumatization can extend posterior to the posterior sella wall to the clivus, upward into the tuberculum sellae and/or dorsum, laterally through the optic strut into the anterior clinoid process, and laterally or inferiorly between the foramen rotundum and vidian canal into the greater wing or pterygoid process.

• The sphenoid bone is the foundation of the central skull base.

• The shape of the sphenoid bone resembles that of a bird with wings outstretched.

• It consists of:
• A central body
• Two sets of wings – the greater and lesser, which course laterally
• Two pterygoid processes, which are directed inferiorly.

 

• The bone between V2 and V3 was removed to expose the mucosa lining the lateral wall of a sphenoid sinus that extended below the V2 to the medial edge of V3.

Variable pneumatisation

• The pneumatisation did not extend lateral to a line connecting the medial edge of the vidian canal and foramen rotundum (VR line).

• The pneumatisation extends laterally between the vidian canal and foramen rotundum.

• The anterolateral wall of the sphenoid sinus has been preserved. The pneumatization extends from the body of the sphenoid bone, through the optic strut, and into the anterior clinoid process.

• Superior view of another sphenoid bone in which the left lesser wing, anterior base of the anterior clinoid, and roof of the optic canal and sphenoid sinus have been removed.

• The remaining part of the anterior clinoid is held in place by its attachment to the optic strut.

• Pneumatization extended from the sphenoid sinus through the strut into the anterior clinoid process.

• Different types of sphenoidal pneumotisation