Cranial Contents 1

Question 1

How is the dural venous sinus formed?

Answer 1

by the separation of dural layers: sides of the meningeal layer and the top-endosteal layer

Question 2

what is the function of the dural venous sinus?

Answer 2

it collects blood of the scalp (emissary vv) from the thin bone of the calvarium (diploic vv) as well as the superficial cerebral vv and deep cerebral vv that drain the brain and brainstem.

Question 3

what is the function of an arachnoid villus?

Answer 3

filtering CSF into the blood to prevent its buildup in the subarachnoid space due to its constant production by the choroid plexus of the ventricular system

Question 4

how is an arachnoid villus formed?

Answer 4

the meningeal layer of the dura forming the later walls of the venous sinus is frequently pierced by papilla-like process of arachnoid

Question 5

what is an arachnoid granulation?

Answer 5

continued growth of the arachnoid villi thru the sinus results in their penetration into the overlying bone

Question 6

into what bony structure do the arachnoid granulations embed themselves?

Answer 6

the inner bony diploe (plate) of the calvarium (temporal/occipital)

Question 7

trace the pathway of the flow of the venous blood within the dural venous sinus

Answer 7

anterior region of the superior sagittal sinus–drains posteriorly to the confluence of the sinuses. blood from occipital sinus comes up from below to the confluence. blood from the inferior sagittal sinus and deep cerebral vein pass back to the confluence via the straight sinus. from the confluence–all blood passes anteriorly in a horizontal fashion along the right and left transverse sinuses down the sigmoid sinus to the jugular foramen

Question 8

where does the venous blood leave the cranial cavity? what vessel forms at the point of exit?

Answer 8

via the jugular foramen–internal jugular vein

Question 9

what two sinuses drain from the cavernous sinus? to where specifically?

Answer 9

superior (transverse) and inferior (sigmoid) petrosal

Question 10

what two venous pathways flow to the cavernous sinus?

Answer 10

sphenoparietal sinus and opthalmic vein

Question 11

why is the venous pathway from the face clinically important?

Answer 11

infection form the face can flow posteriorly thru the valveless veins back into the cavernous sinus

Question 12

how is the dural fold formed?

Answer 12

the meningeal layers of dura separated at venous sinuses come together to form dural folds

Question 13

list the 4 dural folds within the cranial cavity and what components of the CNS that they separate

Answer 13

falx cerebrum, falx cerebelli, tentorium cerebelli, diaphragma sellae

Question 14

what sinus is formed in the attached margin of each dural fold?

Answer 14

falx cerebrum–superior sagittal sinus
falx cerebelli–occipital sinus
tentorium cerebelli–right and left transverse sinus
diaphragma sellae–none

Question 15

what is formed by the free edge of the tentorium cerebelli? what is found within this opening?

Answer 15

tentorial notch—midbrain, brainstem

Question 16

which cranial nerve is found just under the free edge of the tentorium cerebelli?

Answer 16

CN IV (trochlear)

Question 17

what sinus is found within the junction of the falx cerebri with the tentorium?

Answer 17

straight sinus

Question 18

what is the function of the straight sinus?

Answer 18

it drains venous blood from the inferior sagittal sinus (in the free edfe of the falx cerebri) as well as from the deep brain regions via the deep cerebral vein (of Galen).

Question 19

where does the falx cerebri attach anteriorly

Answer 19

crista Gali of ethmoid

Question 20

to what 4 structures does the diaphragma sellae attach?

Answer 20

anterior/posterior clinoid processes