Meninges

Question 1

Meninges

Answer 1

3 layers of protective tissue that cover the brain

Question 2

The 3 meninges layers:

Answer 2

1. Dura mater
2. Arachnoid Mater
3. Pia mater

(Outermost to innermost)

Question 3

Dura Mater

Answer 3

Thickest, outermost layer, protective, impermeable

1. Periosteal Layer
2. Meningeal Layer

Question 4

Periosteal Layer

Answer 4

• Attached to inner surface of skull (outer)
• Adheres tightly to the inner skull
• Continuous with periosteum on outside of skull bones and sutures
• Not continuous with dura mater of spinal cord

Question 5

Meningeal Layer

Answer 5

Protective layer covering brain (inner)

• penetrate spaces in cerebral hemispheres
• continuous with dura mater of spinal cord and epineurium of cranial nerve

Question 6

Meningeal layers has two partitions:

Answer 6

1. Falx Cerebri

2. Tentorium Cerebelli

Question 7

Arachnoid mater

Answer 7

Middle layer, impermeable, connects dura

• separated from Pia mater by subarachnoid space that’s filled with CSF

Question 8

Pia Mater

Answer 8

Delicate, permeable, innermost, testing on brain surface

• vascular membrane that adheres closely to the brain
• arteries carry sheath of Pia as enter parenchyma
• fuses with ependymal choroid plexus

Question 9

Venous sinus

Answer 9

Large, low pressure blood vessel return path of cerebral venous blood

Question 10

Falx Cerebri

Answer 10

Sickle-shaped fold that separates cerebral hemispheres

• superior convex border forms floor of superior Sagittal sinus
• inferior border houses inferior sagittal sinus

Question 11

Tentorium Cerebelli

Answer 11

Fits between the cerebellum and the occipital lobes

• separates posterior cranial fossa from rest of cranial vault
• arches upward along median line to become continuous with Falx cerebri to form straight venous sinus

Question 12

Falx Cerebri & Tentorium Cerebelli function:

Answer 12

Restrict brain displacement associated with acceleration and deceleration

• hold the brain in place so it doesn’t move
• they are part of the meningeal layer

Question 13

Epidural space + hemorrhage/hematoma:

Answer 13

Location: tight space between the dura mater and the skull

Cause: rupture of the middle (meningeal) artery during head trauma

Symptoms: no symptoms at first, there’s a lucid interval. But within a few hours, the hematoma compresses the brain and causes an increase in intracranial pressure. This results on herniation and death, unless surgery.

Question 14

Subdural space + Hemorrhage/hematoma

Answer 14

Location: between the dura mater and the loosely adherent arachnoid mater

Cause: rupture of the bridging veins that pass through en-route to Durham sinuses. Vulnerable to shear injury.

Question 15

Acute Hematoma

Answer 15

Occurs with high velocity impact

Question 16

Chronic Hematoma

Answer 16

In elderly. Brain atrophy allows brain to move freely in cranial vault making bridging veins more susceptible to injury. Slow bleeding over weeks/months allows brain to accommodate so symptoms are often vague (headache, cognitive impairment, unsteady gait)

Question 17

Subarachnoid space

Answer 17

Separates arachnoid mater from Pia mater

• cerebral arteries and veins lie in this space and send off branches into the brain
• the branches that go into the brain are aneurysm sites that may hemorrhage

Question 18

Trabeculae

Answer 18

Delicate threads that connect arachnoid to Pia

Question 19

Arachnoid granulations

Answer 19

The site where CSF diffuse into the venous sinuses

Question 20

Headaches

Answer 20

Brain doesn’t have any pain receptors, so pain that causes headache comes from trigeminal and 3 cervical nerve innervating the meninges and vasculature

Question 21

Dura above tentorium

Answer 21

Innervating by trigeminal; forehead and face

Question 22

Dura below tentorium

Answer 22

Innervating by C1-3; back of head and neck

Question 23

Space occupying lesions

Answer 23

Raise intracranial pressure; irritation, stretching of dura

Question 24

Timor located above tentorium:

Answer 24

Front of head

Question 25

Tumor locate below tentorium:

Answer 25

Back of head

Question 26

Lesions are an example of

Answer 26

Why pain originates, ex. Tumor

Question 27

Migraine headaches

Answer 27

Depend on activation of trigeminal afferents that densely innervate the meninges

Question 28

Examples of tumors

Answer 28

Lesions, meningitis, meningioma’s

Question 29

Meningioma

Answer 29

Tumor in the meninges

Question 30

Meningitis

Answer 30

Inflammation of meninges. Global pain.

Question 31

Hangover

Answer 31

Multifactorial, but involves direct toxic effect on meninges

Question 32

Cluster headaches

Answer 32

Lancinating/boring periorbital pain. More severe than childbirth.