Body of sphenoid bone

Body of sphenoid bone
Body of sphenoid bone
	Figure 2:Sphenoid bone,anterior and inferior surfaces.
	Figure 3: Sphenoid bone, upper and posterior surfaces.
Details
Identifiers
Latin	corpus ossis sphenoidalis
TA98	A02.1.05.002
TA2	585
FMA	52867
	Anatomical terms of bone [edit on Wikidata]

Thebody of thesphenoid bone,more or lesscubicalin shape, is hollowed out in its interior to form two large cavities, thesphenoidal sinuses,which are separated from each other by aseptum.^[1]

Superior surface

Thesuperior surfaceof the body [Fig. 1] presents in front a prominent spine, theethmoidal spine,for articulation with thecribriform plateof theethmoid bone;behind this is a smooth surface slightly raised in the middle line, and grooved on either side for theolfactory lobesof thebrain.

This surface is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, theprechiasmatic groove,above and behind which lies theoptic chiasma;the groove ends on either side in theoptic foramen,which transmits theoptic nerveandophthalmic arteryinto theorbital cavity.

Behind the chiasmatic groove is an elevation, thetuberculum sellae;and behind this is a deep depression, the saddle-shapedsella turcica(Turkish seat), the deepest part of which, thehypophyseal fossa,lodges thepituitary gland.

The anterior boundary of thesella turcicais completed by two small eminences, one on either side, called themiddle clinoid processes,while the posterior boundary is formed by a square-shaped plate of bone, thedorsum sellae,ending at its superior angles in two tubercles, the posterior clinoid processes, the size and form of which vary considerably in different individuals.

The posterior clinoid processes deepen the sella turcica, and give attachment to thetentorium cerebelli.

On either side of the dorsum sellae is a notch for the passage of theabducent nerve,and below the notch a sharp process, the petrosal process, which articulates with the apex of the petrous portion of thetemporal bone,and forms the medial boundary of theforamen lacerum.

Behind the dorsum sellae is a shallow depression, theclivus,which slopes obliquely backward, and is continuous with the groove on the basilar portion of theoccipital bone;it supports the upper part of thepons.

Lateral surfaces

Thelateral surfacesof the body are united with thegreater wings of the sphenoidand themedial pterygoid plates.

Above the attachment of each greater wing is a broad groove, curved something like the italic letter f; it lodges theinternal carotid arteryand thecavernous sinus,and is named thecarotid sulcus.

Along the posterior part of the lateral margin of this groove, in the angle between the body and greater wing, is a ridge of bone, called thesphenoidal lingula.

Posterior surfaces

Theposterior surface,quadrilateral in form [Fig. 3], is joined, during infancy and adolescence, to the basilar part of the occipital bone by a plate of cartilage.

Between the eighteenth and twenty-fifth years this becomes ossified, ossification commencing above and extending downward.

Anterior surface

Theanterior surfaceof the body [Fig. 2] presents, in the middle line, a vertical crest, the sphenoidal crest, which articulates with the perpendicular plate of theethmoid,and forms part of thenasal septum.

On either side of the crest is an irregular opening leading into the correspondingsphenoidal air sinus.

These sinuses are two large, irregular cavities hollowed out of the interior of the body of the bone, and separated from one another by a bonyseptum,which is commonly bent to one or the other side.

They vary considerably in form and size, are seldom symmetrical, and are often partially subdivided by irregular bony laminae.

Occasionally, they extend into thebasilarpart of theoccipital bonenearly as far as theforamen magnum.They begin to be developed before birth, and are of a considerable size by the age of six.

They are partially closed, in front and below, by two thin, curved plates of bone, thesphenoidal conchae,leaving in the articulated skull a round opening at the upper part of each sinus by which it communicates with the upper and back part of the nasal cavity and occasionally with the posterior ethmoidal air cells.

The lateral margin of the anterior surface is serrated, and articulates with thelamina papyraceaof theethmoid,completing the posterior ethmoidal cells; the lower margin articulates with the orbital process of the palatine bone, and the upper with the orbital plate of the frontal bone.

Inferior surface

Theinferior surfacepresents, in the middle line, a triangular spine, thesphenoidal rostrum,which is continuous with the sphenoidal crest on the anterior surface, and is received in a deep fissure between the alæ of the vomer.

On either side of the rostrum is a projecting lamina, the vaginal process, directed medialward from the base of themedial pterygoid plate,with which it will be described.