Cranial cavity Flashcards
(42 cards)
What is housed in the cranial cavity?
brain, cerebral vessels, meninges, meningeal vessels, intracranial portions of cranial nerves
What can the base of the cranial cavity be divided into for descriptive purposes?
three fossae: anterior, middle and posterior
What are the limits of the anterior cranial fossa?
front and laterally by the frontal bone, posteriorly by the lesser wing of the sphenoid
What 3 bone parts form the floor of the anterior cranial fossa?
- orbital plate of the frontal bone
- cribriform plate of the ethmoid (with a median crest-like ridge, the crista galli)
- lesser wings and anterior part of the body (jugum) of the sphenoid
What attaches ot the crista galli of the cribriform plate of the ethmoid bone?
anterior attachment of the falx cerebri
What is transmitted within the perforations of the cribriform plate of the ethmoid bone?
olfactory nerves
What does the orbital plate of the frontal bone separate?
orbit below from the frontal lobes of the cerebral hemispheres above
What are the anterior clinoid processes?
posterior projections from the lesser wings of the sphenoid, that overhang the middle cranial fossa and give attachment to the free edge of the tentorium cerebelli
What attaches to the anterior clinoid processes?
free edge of the tentorium cerebelli
How does the middle cranial fossa lie in relation to the anterior and posterior cranial fossae?
lies at a lower plane than the anterior cranial fossa but higher than the posterior cranial fossa
What is the shape of the middle cranial fossa?
floor shaped like a butterfly, with narrow central or median part and expanded lateral parts
What are the boundaries of the middle cranial fossa anteriorly, laterally and posteriorly?
- anteriorly: posterior free edge of the lesser wing of the sphenoid, anterior clinoid processes and anterior margin of the sulcus chiasmaticus
- laterally: squamous part of the temporal bone
- posteriorly: extends to the superior borders of the petrous temporal bones and dorsum sellae of the sphenoid
What is another name for the pituitary fossa?
hypophyseal fossa
What is the pituitary fossa?
indentation in the roof of the body of the sphenoid bone in the middle cranial fossa
What are the bony borders of the hypophyseal fossa?
- anteriorly: tuberculum sellae, in front of which lies the sulcus chiasmatica
- posteriorly: dorsum sellae, ridge of bone at either end of which lies the posterior clinoid processes
What is housed by the hypophyseal fossa?
pituitary gland (or hypophysis cerebri)
What connects the pituitary gland to the brain?
thin stalk called tuber cinereum
What is the roof of the pituitary fossa?
sheet of dura mater, the diaphragma sella, which is attached in front to the tuberculum and behind to the dorsum sellae
What are important lateral relations to the pituitary fossa?
right and left cavernous sinuses
What are 10 important features on the floor of the middle cranial fossa?
- Sulcus chiasmaticus
- Sella turcica (Turkish saddle)
- Optic canal
- Superior orbital fissure
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Foramen lacerum
- Trigeminal impression
- Tegmen tympani and arcuate eminence
What is the location of the sulcus chiasmaticus within the middle cranial fossa floor?
between the two optic canals anterior to tuberculum sella
What is the relevance of the sulcus chiasmaticus (feature of the middle cranial fossa floor)?
Optic chiasma rarely lies in contact with this region
What is the position of the sella turcica (Turkish saddle) within the middle cranial fossa floor?
central part of the sphenoid body between the two cavernous sinuses
What is the relevance of the sella turcica?
central hollow, the hypophyseal fossa, houses the pituitary gland. Anterior and posterior clinoid processes give attachment to the free and attached margins of the tentorium cerebelli
