3.2.1 Meningeal Layers and Dural Venous Sinuses

Question 1

What are the 3 meningeal layers?

Answer 1

Pia mater
Arachnoid mater
Dura mater

Question 2

What meningeal layers make up the leptomeninges?

Answer 2

Pia and arachnoid

Inflammation of the leptomeninges causes meningitis

Question 3

What is the structure of the dura?

Answer 3

Tough fibrous membrane, has a potential space with the arachnoid (CSF pushes arachnoid against the dura)

Periosteal layer, against the inner table

Meningeal layer (in contact with arachnoid)

Appears as a single layer

Question 4

What is the structure of the arachnoid mater?

Answer 4

Soft, fibrous translucent membrane, extends only in the longitudinal fissure

Question 5

What is in the subarachnoid space?

Answer 5

-CSF, pushes arachnoid against the dura
-Cerebral vessels (supplying and draining brain)

This is where we get CSF in a lumbar puncture at level of cauda equina

Some -Skin
Serious -Superficial fascia
Strep -Supraspinous ligament
Infections -Intraspinous ligament
Love -Ligamentum flavum
Ensuring -Epidural layer
Death -Dura mater
Always -Arachnoid mater
Swiftly -Sub-arachnoid space
SSS ILEDAS

Question 6

What is the structure of the pia?

Answer 6

Adhered to every irregularity (fold, fissure etc) of the brain

Microscopic layer so cannot be removed like arachnoid or dura

Question 7

What is formed when the periosteal and meningeal layers of the dura separate?

Answer 7

Dural folds
Dural venous sinuses (spaces which are filled with venous blood)

Question 8

What does the dura fuse with to form the outer periosteal layer?

Answer 8

Periosteum of the inner table, covers all surfaces of bone

Question 9

What dural fold separates the two hemispeheres of the brain in the longitudinal fissure?

Answer 9

Falx Cerebri, attached to the cristal galli anteriorly and tentorium cerebelli posteriorly

Question 10

What dural fold separates the brain horizontally?

Answer 10

Tentorium cerebelli
Anteriorly- attached to anterior and posterior clinoid processes
Posteriorly- attached to grooves for transverse sinus
Laterally- petrous bone

Question 11

Label the image

Answer 11

Question 12

Label the image

Answer 12

Question 13

What is the function of the dural folds?

Answer 13

Stabilise the brain and act as rigid dividers

Falx cerebri-prevents side to side movement

Tentorium cerebelli- prevents the brain from going up and down

Question 14

What can a rise in pressure in the skull cause (due to dural folds)?

Answer 14

Compression and herniation of the brain

Parts of the brain pushed against rigid dural folds brain can even herniate through foramen magnum

Question 15

What is a dural venous sinus?

Answer 15

Venous blood filled space created by separation of meningeal layer from periosteal layer of dura

Question 16

Where do dural venous sinuses recieve blood from?

Answer 16

Recieve blood from cerebral veins (draining veins)

Connected to eachother, therefore recieve blood from eachother

Question 17

Where do dural venous sinuses drain?

Answer 17

Drain into IJV

Question 18

Label the image

Answer 18

Question 19

Label the image

Answer 19

Question 20

What do dural venous sinuses connect to?

Answer 20

Cerebral veins -via bridging veins (brain veins)

Scalp veins- via emissary veins

IJV

Question 21

How does the brain drain into dural venous sinuses?

Answer 21

Cerebral veins via bridging veins

Located in subarachnoid space then traverse the subdural space to drain into dvs

Question 22

How does the scalp drain into dural venous sinuses?

Answer 22

Scalp veins (not inside the skull) drain via emissary veins to the inside of the skull
(think of an emissary sent from one place to another)

Can transmit infection from the skull intracranially