5 Meningeal Layers, Dural Folds and Dural Venous Sinuses

Question 1

Name the 3 membranous layers (meninges) that surround and protect the brain and spinal cord.

Answer 1

Pia mater

Arachnoid mater

Dura mater

Question 2

What are the leptomeninges? What is the clinical significance?

Answer 2

Leptomeninges=

• Pia mater
• Arachnoid mater

These layers= affected by meningitis

Question 3

What is the subarachnoid space filled with?

Answer 3

• CSF: cerebrospinal fluid
• Cerebral vessels supplying/draining brain

Question 4

Describe the structure of each of the membranous layers surrounding the brain and spinal cord (Pia mater, Arachnoid mater, Dura mater).

Answer 4

Pia: Microscopically thin, follows every fold, delicate adherence

Arachnoid: soft, translucent

Dura: tough fibrous membrane

Question 5

Whilst its within the skull, the dura effectively has 2 layers which appear as a single sheet. What are these two layers and what does the separation of the 2 layers create?

Answer 5

Periosteal layer= periosteum (against inner table of bone)

Meningeal layer= adjacent to arachnoid

Separation of 2 layers forms:

• Dural folds
• Dural venous sinuses

Question 6

Label the 2 dural folds:

Answer 6

Question 7

Label the superior and inferior sagittal sinuses:

Answer 7

Question 8

Fill in the missing labels:

Answer 8

Question 9

What is the function of dural folds?

Answer 9

• Help to stabilise brain
• Rigid dividers

Question 10

What can a rise in pressure inside the skull (eg secondary to bleed) cause?

Answer 10

Compression and herniation (displacement) of parts of brain:

• Under rigid dural folds
• Through foramen magnum

Question 11

Describe dural venous sinuses.

Answer 11

Venous blood filled spaces created by separation of menigeal layer of dura mater from periosteal layer of dura.

Receive blood from cerebral veins, connect to each other

Question 12

Where do dural venous sinuses eventually drain into?

Answer 12

Internal jugular vein

Question 13

Label the sinuses on the following image:

Answer 13

Question 14

Fill in the missing labels:

Answer 14

Question 15

Cerebral veins tranverse the subdural space. What do they connect?

Answer 15

Connect cerebral veins in subarachnoid space to dural venous sinuses

Question 16

What do emissary veins do?

Answer 16

Connect dural venous sinous to scalp vessels

Pass through bone

Question 17

Name three areas where accumulation of blood can occur due to an intracranial haemorrhage.

Answer 17

1. Extradural (arterial)
2. Subdural (venous)
3. Subarachnoid (arterial)

Question 18

Differentiate between an intracranial and intracerebral haemorrhage.

Answer 18

Intracerebral= within brain tissue itself

Intracranial= in spaces between meningeal layers

(both can cause damge to important brain tissue due to increased pressure)

Question 19

What sort of intracranial haemorrhage is shown in this image?

Answer 19

Question 20

Why are subdural haemorrhages more common in older people?

Answer 20

Older people- brain shrinks

Venous bleed- usually from bridging veins

(See image)

Question 21

Describe what may cause a subarachnoid haemorrhage.

Answer 21

Secondary to:

trauma

spontaneous blood vessel rupture eg aneurysm

Usually branch of circle of willis

Blood leaks into subarachnoid space- mixes with CSF

Question 22

Why would we see similar symptoms to meningitis as will a subarachnoid haemorrhage?

Answer 22

Blood irritating pia mater