Neuroanatomy 1 - Meninges & Dural Venous Sinuses

Question 1

which of the meninges is the tough, outermost layer? what layers does it consist of & what does it do?

Answer 1

dura mater - consists of endosteal/ outer and meningeal/inner layer

protection for the brain and spinal cord

Question 2

which of the layers of the dura mater is continuous with the spinal cord?

Answer 2

inner/ meningeal layer

Question 3

what is the arachnoid mater? what does it do?

Answer 3

middle web-like layer - creates the subarachnoid space where CSF circulates to cushion the brain & spinal cord

Question 4

what is the pia mater? what does it to

Answer 4

thin delicate inner layer that adheres to the surface of the CNS - provides nourishment via a rich blood supply

Question 5

blood venous drainage occurs first through smaller venules, which drain into larger veins and ultimately empty into WHAT?

Answer 5

dural venous sinuses - sinus spaces between the dura mater layers

Question 6

what is the anatomical basis for headaches?

Answer 6

the sensitive stretching of the dura mater

Question 7

which reflection of the dura mater separates the two cerebral hemispheres?

Answer 7

falx cerebri

Question 8

which reflection of the dura mater separates the two cerebellar hemispheres?

Answer 8

falx cerebelli

Question 9

which dura mater reflection forms the roof over the posterior cranial fossa?

Answer 9

tentorium cerebelli

Question 10

what is the diaphragm sellae? what does it allow?

Answer 10

small circular fold of dura mater that covers the hypophyseal fossa - allows the infundibulum of the pituitary gland to pass through

Question 11

function of the tentorial notch?

Answer 11

it’s the anterior free margin of the tentorium cerebelli - allows the passage of the midbrain inferiorly

Question 12

what does the tentorial notch allow?

Answer 12

the passage of the midbrain inferiorly

Question 13

which reflection of the dura mater covers the hypophyseal fossa?

Answer 13

diaphragm sellae

Question 14

what sinuses are contained within the falx cerebri?

Answer 14

superior sagittal sinus
inferior sagittal sinus
straight sinus (at junction with tentorium cerbelli)

Question 15

what does the tentorium cerebelli separate?

Answer 15

separates cerebrum from cerebellum

Question 16

sinuses associated with the tentorium cerbelli?

Answer 16

straight sinus
transverse sinus
superior petrosal sinus

Question 17

which sinus does the falx cerebelli contain?

Answer 17

occipital sinus

Question 18

what sinuses are associated with the diaphragm sellae?

Answer 18

anterior & posterior intercavernous sinuses

Question 19

(!!) A midline sagittal MRI shows a sickle-shaped structure extending between the two cerebral hemispheres. Identify the structure and the sinus it contains along its superior margin.

Answer 19

falx cerebri - contains superior sagittal sinus

Question 20

(!!) If there is a blockage in the straight sinus, which dural reflection and associated sinuses would likely be affected in terms of venous drainage?

Answer 20

falx cerebri - inferior sagittal sinus
tentorium cerebelli - straight sinus

Question 21

what are the two margins of the tentorium cerbelli?

Answer 21

attached to the posterior cranial fossa & a free margin (tentorial notch)

Question 22

what sinus is contained at the junction between the tentorium cerebelli and falx cerebri?

Answer 22

straight sinus

Question 23

which reflection of the dura mater contains the intercavernous sinuses?

Answer 23

diaphragm sellae

Question 24

functions of the CSF?

Answer 24

1. protection - cushions brain & spinal cord against sudden impact and helps prevent injury
2. buoyancy - brain is suspended in CSF, reducing its effective weight & pressure against the base of the brain and blood vessels
3. waste removal from brain - circulates to venous system
4. nutrient transport to CNS and ensures proper nerve cell function
5. maintains homeostasis around brain for optimal nerve cell activity

Question 25

what produces CSF?

Answer 25

choroid plexus in brain ventricles

Question 26

describe the production & drainage of CSF

Answer 26

production - produced by specialised cells of the choroid plexus which line the ventricular system - CSF enters lateral ventricles

enters 3rd ventricle via interventricular foramen –> enters 4th ventricle via cerebral aqueduct

leaves via median (Magendie) and lateral (Luschka) apertures to enter subarachnoid space and surround SC

projections of the arachnoid mater (granulations and villi) pierce the dura mater and communicate with venous sinuses to drain CSF into dural venous sinuses

Question 27

differentiate extradural & subdural haematomas

Answer 27

extradural - often arterial, need emergency surgical management, lime-shaped/biconcave lesion

subdural - often venous, treatment depends on size/shape/severity, banana-shaped lesion