Anatomy of sphenoid
Anatomical points
- Body lies centrally
- superior surface of body lies horizontally
- Two greater wings & two lesser wings project laterally from the sides of the body
- Superior surfaces of greater wings are deeply concave
- Two pterygoid processes are directed downwards from adjoining parts of the body and greater wings Morphological type of bone: pneumatic irregular bone
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Parts of sphenoid bone
Body
Two greater wings
Two lesser wings
Two pterygoid processes
Body: It has six surfaces : superior , inferior , anterior , posterior and two lateral surfaces
Shape : cuboid
It contains two large air sinuses which are separated from each other by a septum
Superior or cerebral surface
Articulates with ethmoid bone anteriorly and basilar part of occipital bone posteriorly. It shows:
Ethmoidal spine : it is articulate with posterior border of cribriform plate of ethmoid bon
Jugum sphenoidale: smooth area which is the part of anterior cranial fossa . this part is related with gyri recti of cerebrum and olfactory tracts
Sulcus chiasmaticus: it is a groove which connects both optic canal . it lodges optic chiasm
Tuberculum sellae: round elevation it bears middle clinoid processe
Sella turcica: deep depression behind the tuberculum sellae . deepest part of sella turcica is
known as hypophyseal fossa
Dorsum sellae: square shape bone which form posterior boundary of sella turcica . it bear
posterior clinoid processes
Clivus: slopping area behind dorsum sellae . it continue with basilar part of occipital bone this part is related with pons
Inferior surface
Rostrum of sphenoid
Sphenoidal conchae
Vaginal processes of medial pterygoid plate
Anterior surface
Sphenoidal crest articulates with the perpendicular plate of ethmoid leading to formation of a part of the septum of nose.
Posterior surface: Basilar part of occipital bone
Lateral surface
- It is united with the greater wing and medial pterygoid plate ,
Carotid sulcus is present in the lateral surface which is extend from superior orbital fissure to foramen lacerum s lodging cavernous sinus and internal carotid - Development:
- up to rostral half of sella turcica is developed from neural crest
- caudal half of sella turcica is developed from paraxial mesoderm
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