Lectures 24-25: Part 3

Question 1

Cranial Meninges (deep to superficial)

Answer 1

• Pia mater
• Subarachnoid space
• Arachnoid
• Subdural space
• Dura mater
• Tentorium cerebellum
• Cerebral falx

Question 2

Pia mater

Answer 2

• “tender mother”

- fine layer formed by the process of glial cells which tightly invest the gray matter

Question 3

Arachnoid

Answer 3

• “spider web”

- filmy layer which forms a loose covering over the brain and pia mater

Question 4

Dura mater

Answer 4

• “tough mother”
• fibrous layer which surrounds the brain, pia mater, and subarachnoid, and in the cranium is continuous with the periosteum of the skull

Question 5

Tentorium Cerebelli

Answer 5

• extension of dura mater

- covers the posterior cranial fossa

Question 6

Subarachnoid space

Answer 6

between pia mater and arachnoid and contains CSF

Question 7

Subdural space

Answer 7

between the arachnoid and dura mater and contains the terminations of the superficial cerebral veins

Question 8

Tentorium cerebellum

Answer 8

Perpendicular to cerebral falx

Question 9

Cerebral falx

Answer 9

• separates hemispheres
• attaches rostrally to the crista galli
• lies within the medial longitudinal fissure

Question 10

Is there epidural space in the cranium?

Answer 10

No, it’s simply potential space there

Question 11

From where does the CNS circulation derive?

Answer 11

• Anterior circulation
• Posterior circulation
• these two form the “Circle of Willis”

Question 12

Anterior circulation of the cranium

Answer 12

• common carotid artery

- internal carotid artery

Question 13

Posterior circulation of cranium

Answer 13

Vertebral arteries

Question 14

Basilar artery (where does it come from and what does it divide into?)

Answer 14

• emerges from two vertebral arteries

- divides into posterior cerebral arteries

Question 15

What do the posterior cerebral arteries give off?

Answer 15

posterior communicating arteries

Question 16

What do the posterior communicating arteries join?

Answer 16

internal carotid arteries

Question 17

Posterior inferior cerebellar artery: what does it supply?

Answer 17

• lower surface of the cerebellum

- lower brainstem

Question 18

Anterior inferior cerebellar artery: what does it supply?

Answer 18

• upper inferior surface of cerebellum

- upper brainstem

Question 19

Superior cerebellar artery: what does it supply?

Answer 19

• superior surface of the cerebellum

- midbrain

Question 20

Posterior cerebral artery: what does it supply?

Answer 20

• occipital lobe

- inferior temporal lobe

Question 21

Middle cerebral artery: what does it supply?

Answer 21

• subcortical structures
• frontal, parietal, and temporal lobes (lateral side of brain)
• runs through lateral fissure
• most strokes occur at this artery

Question 22

Anterior cerebral artery: what does it supply?

Answer 22

• frontal and parietal lobes (medial cerebral cortex)

- runs in medial longitudinal fissure

Question 23

Blood is returned from the cranial cavity and brain via the…

Answer 23

dural venous sinuses

Question 24

The dural venous sinuses receive blood from the…

Answer 24

superficial cerebral veins

Question 25

The venous sinuses converge in the _________ region to eventually drain bilaterally into the _____________

Answer 25

occipital; internal jugular vein

Question 26

Superior Cerebral Veins

Answer 26

pierces arachnoid and attaches to superior sagittal sinus in subdural space

Question 27

Subdural Hematoma

Answer 27

- slow venous bleed (superficial cerebral veins) | - in babies, it's caused by head trauma/abuse

Question 28

Superior sagittal sinus

Answer 28

- lies within the cerebral flax superiorly | - found where 2 hemispheres come together

Question 29

Inferior sagittal sinus

Answer 29

lies within the inferior edge of the cerebral falx

Question 30

Great cerebral vein of Galen

Answer 30

- drains the diencephalic area - joins inferior sagittal sinus to form straight sinus - joins superior sagittal sinus and occipital protuberance

Question 31

Occipital sinus

Answer 31

drains the cerebellum and brainstem

Question 32

Confluence of sinuses

Answer 32

where all the veins run together

Question 33

Transverse sinus

Answer 33

- lies within the groove for the transverse sinus | - carries blood from the convergence of sinuses on the occipital region toward the exit

Question 34

Sigmoid sinus

Answer 34

- lies within the groove for the sigmoid sinus | - continuation of the transverse sinus toward the jugular foramen exit from the skull

Question 35

Cavernous sinus

Answer 35

venous "pool" lying on either side of the body of the sphenoid

Question 36

From what veins does the cavernous sinus receive drainage?

Answer 36

inferior and superior opthalmic veins

Question 37

Into what does the cavernous sinus drain?

Answer 37

- pterygoid plexus of veins | - greater/lesser petrosal sinuses

Question 38

Where is cerebrospinal fluid (CSF) produced?

Answer 38

- two lateral ventricles - 3rd ventricle - 4th ventricle

Question 39

Where is the 3rd ventricle found?

Answer 39

between the two lobes of the thalamus

Question 40

How much CSF is present at any one moment in the average adult?

Answer 40

150-200 ml

Question 41

Within the ventricles, WHAT produces the CSF?

Answer 41

The choroid plexus (1200ml/24 hours), which consists of capillaries covered by ependymal cells

Question 42

What is the path of the CSF?

Answer 42

produced in lateral ventricles --> 3rd ventricle (via inter ventricular foramina) --> cerebral/Sylvius aqueduct --> 4th ventricle --> subarachnoid space

Question 43

How does the CSF get from 4th ventricle to subarachnoid space ?

Answer 43

- foramen of Magendie | - 2 foramina of Luschka

Question 44

Where does the CSF eventually return to the blood vascular system?

Answer 44

superior sagittal sinus

Question 45

What is Arachnoid Villi (Arachnoid Granulations)?

Answer 45

- small extensions of the subarachnoid space that protrude into the superior sagittal sinus - CSF is absorbed into the venous circulation across the thin walls of the arachnoid villi