(1) The maxillary sinus is most commonly involved; however, most patients with radiologic maxillary sinusitis have abnormalities of the ethmoid and sphenoid sinuses.(2) Its accuracy, however, is questionable in suspected ethmoid, frontal, or sphenoid involvement.(3) A large groove (sinus of Breschet) may occur on the intracranial face, parallel to the coronal suture and extending from the bregma to the lesser wing of the sphenoid .(4) Further CT scans have not demonstrated any additional sphenoid sinus or skull base erosion nor recurrent tumour five years after surgery.(5) It is attached superiorly to the spine of the sphenoid and the region of the petrotympanic fissure.(6) Magnetic resonance imaging showed a mass bilaterally in the nasopharynx and the sphenoid sinuses.(7) Another such feature are the deep internasal cavities on either side of the sphenoid .(8) In 1998, the tumor recurred with involvement of the nasal cavity and sphenoid and ethmoid sinuses.(9) Metastasis to the brain can occur by way of Batson's plexus or by direct extension from adjacent structures such as the sphenoid bone or sinuses.(10) Somewhat further back, the dura has been separated from the body of the sphenoid bone .(11) The middle meningeal gives rise, in about 50% of cases, to an accessory meningeal artery, which also enters the skull via the foramen ovale, or the emissary sphenoidal foramen.(12) Faint, anteriorly convergent ridges extend from the sphenoidal bridge and define the shallow basisphenoid fossa.(13) Branches of the nasal nerve have been described passing to the frontal, ethmoidal, and sphenoidal sinuses.(14) The sphenoidal bridge is broad anteriorly, constricted posteriorly.(15) The ophthalmic artery may be associated with the development of a branch of the lacrimal artery that passes through the sphenoidal fissure to anastomose with the middle meningeal artery.
