Structures in the Cranial Fossae

Structures in the Cranial Fossae

A) Foramen cecum

• Is a small pit in front of the crista galli between the ethmoid and frontal bones.
• May transmit an emissary vein from the nasal mucosa and the frontal sinus to the superior sagittal sinus.

B) Crista galli

• Is the triangular midline process of the ethmoid bone extending upward from the cribriform plate.
• Provides attachment for the falx cerebri.

C) Cribriform plate of the ethmoid bone

• Is perforated by 15 to 20 foramina, supports the olfactory bulb, and transmits olfactory nerves from the olfactory mucosa to the olfactory bulb.

D) Anterior clinoid processes

• Are two anterior processes of the lesser wing of the sphenoid bone, which are located in the middle cranial fossa.
• Provide attachment for the free border of the tentorium cerebelli.

E) Middle clinoid process

• Is a small inconstant eminence on the body of the sphenoid, posterolateral to the tuberculum sellae.

F) Posterior clinoid processes

• Are two tubercles from each side of the dorsum sellae.
• Provide attachment for the attached border of the tentorium cerebelli.

G) Lesser wing of the sphenoid bone

• Forms the anterior boundary of the middle cranial fossa.
• Forms the sphenoidal ridge separating the anterior from the middle cranial fossa.
• Forms the boundary of the superior orbital fissure (the space between the lesser and greater wings).

H) Greater wing of the sphenoid bone

• Forms the anterior wall and the floor of the middle cranial fossa.
• Presents several openings: the foramen rotundum, foramen ovale , and foramen spinosum.

I) Sella turcica (Turk's saddle) of the sphenoid bone

• Is bounded anteriorly by the tuberculum sellae and posteriorly by the dorsum sellae.
• Has a deep central depression known as the hypophyseal fossa , which accommodates the pituitary gland or the hypophysis.
• Lies directly above the sphenoid sinus located within the body of the sphenoid bone; its dural roof is formed by the diaphragma sellae.

J) Jugum sphenoidale

• Is a portion of the body of the sphenoid bone connecting the two lesser wings, and forms the roof for the sphenoidal air sinus.

K) Clivus

• Is the downward sloping surface from the dorsum sellae to the foramen magnum.
• Is formed by a part of the body of the sphenoid and a portion of the basilar part of the occipital bone.

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