Dissection 13

Question 1

Parts of the cranial meninges

Answer 1

Dura Mater Arachnoid Pia Mater

Question 2

Parts of the dura mater

Answer 2

Periosteal dura

Meningeal dura

Question 3

Three major dural reflections

Answer 3

1. Falx Cerebri
2. Tentorium Cerebelli
3. Falx cerebelli

Question 4

Arachnoid Barrier

Answer 4

Occulding junctions that prevent harmful substances from reaching the subarachnoid space

Question 5

Subarachnoid Space

Answer 5

Filled with CSF which holds the arachnoid against the dura mater

Question 6

Two components of the arachnoid

Answer 6

1. Arachnoid Barrier
2. Trabeculae that attach to pia mater

Question 7

Arachnoid Trabeculae

Answer 7

Support blood vessels in the subarachnoid space

Question 8

Arachnoid Granulations/Villi

Answer 8

Serve as one way valves for CSF to return to the circulatory system especially at the superior saggital sinus (but in all sinuses)

Question 9

Where is the pia mater?

Answer 9

Attached to the brain; follows all contours

Question 10

Cistern

Answer 10

Space between arachnoid and pia mater where the brain contour changes suddenly

Question 11

Largest cistern of the brain

Answer 11

Cisterna Magna

Question 12

Ratio of arterial pressure to CSF pressure

Answer 12

13

Question 13

Epidural hematoma

Answer 13

Arterial bleeding occurs into space between bone and dura mater. Can compress braintem and cause death.

Question 14

Subdural hematoma

Answer 14

Caused by venous bleeding into the subdural space

Most commonly caused by rupture of surface vein or perhaps arteries

Question 15

Where does venous blood from the outer hemispheres drain?

Answer 15

• Superiorly to superior sagittal sinus
• Inferiorly and anteriorly to cavernous sinus
• Posteriorly and inferiorly to transverse sinus
• Deep cerebral veins empty to straight sinus

Question 16

What cranial nerves pass through the cavernous sinus?

Answer 16

III, IV, V1, V2, VI

May be injured from internal carotid artery aneurysm

Question 17

Label parts of the cavernous sinus (picture)

Answer 17

Question 18

What connects the eyes to the cavernous sinus?

Answer 18

Angular and ophthalmic veins

Question 19

Where do the cranial nerves pierce the dura?

Answer 19

• Anterior- I
• Middle- II
• Posterior- III-XII

Question 20

In which fossa do the cranial nerves exit the skull?

Answer 20

• Anterior- I
• Middle- II-VI
• Posterior- VII-XII

Question 21

Cranial nerve with the longest intradural course

Answer 21

VI

Question 22

Label the circle of Willis (picture)

Answer 22

Question 23

Purpose of CSF

Answer 23

• Shock absorption
• Decreases weight of brain
• Provide nutrients
• Remove wastes
• Like lymph fluid for the brain

Question 24

CSF flow order

Answer 24

1. Lateral ventricles
2. interventricular foramina of Monro
3. Third ventricle
4. Cerebral aqueduct of Silvius
5. Fourth ventricle
6. Apertures of the fourth ventricle or central canal spinal cord
7. Subarachnoid space
8. Midline
9. Arachnoid villi in superior sagittal sinus
10. Returns to circulation

Question 25

Hydrocephaly

Answer 25

CSF build-up; usually due to block in cerebral aqueduct

Question 26

What do the dural reflections most importantly contain?

Answer 26

Venous sinuses

Question 27

What nerves innervate the dura mater?

Answer 27

V1, V2, V2, upper cervical nerves

Question 28

What are arachnoid and pia mater derived from?

Answer 28

Neural Crest Cells

Question 29

How is CSF made?

Answer 29

* In **choroid plexus** * Capillaries embedded in special pia mater * Fluid leaks from capillaries through occluding junctions in ependymal cells

Question 30

Name and locate the dural sinuses

Answer 30

* Superior sagittal sinus * Straight sinus * Transverse sinus * Sigmoid sinus * 1-3 form confluence of sinuses

Question 31

Describe the cavernous sinus drainage pathways

Answer 31

Question 32

Arteriovenous fistula between internal carotid and cavernous sinus

Answer 32

* Very red eyes * Damage to cranial nerves in the sinus * Can be caused by trauma or aneurysm

Question 33

Name the three (potential) spaces of the meninges and what they contain

Answer 33

Question 34

What vessel mainly supplies blood to the dura mater and where does it run?

Answer 34

Middle meningial artery; Epidural space by pterion

Question 35

What bones make up the anterior cranial fossa?

Answer 35

* Frontal * Sphenoid * Ethmoid

Question 36

What bones make up the middle cranial fossa?

Answer 36

* Sphenoid, Temporal, Parietal

Question 37

What bones make up the posterior cranial fossa?

Answer 37

* Temporal, Occipital, Sphenoid, Parietal * Covered by tentorium cerebelli

Question 38

Foramen where cranial nerve I exits the skull

Answer 38

Cribriform plate of ethmoid bone

Question 39

Foramen where cranial nerve II exits the skull

Answer 39

Optic canal

Question 40

Foramen where cranial nerve III exits the skull

Answer 40

Superior orbital fissure

Question 41

Foramen where cranial nerve IV exits the skull

Answer 41

Superior orbital fissure

Question 42

Foramen where cranial nerve V1 exits the skull

Answer 42

Superior orbital fissure

Question 43

Foramen where cranial nerve V2 exits the skull

Answer 43

Foramen rotundum

Question 44

Foramen where cranial nerve V3 exits the skull

Answer 44

Foramen ovale

Question 45

Foramen where cranial nerve VI exits the skull

Answer 45

Superior orbital fissure

Question 46

Foramen(foramina) where cranial nerve VII exits the skull

Answer 46

* Internal acoustic meatus * Pterygoid canal * Facial canal * Petrotympanic fissure * Stylomastoid foramen

Question 47

Foramen where cranial nerve VIII exits the skull

Answer 47

Internal acoustic meatus

Question 48

Foramen where cranial nerve IX exits the skull

Answer 48

* Jugular foramen * Tympanic canaliculus * Foramen ovale

Question 49

Foramen where cranial nerve X exits the skull

Answer 49

Jugular foramen

Question 50

Foramen where cranial nerve XI exits the skull

Answer 50

* Foramen magnum * Jugular foramen

Question 51

Foramen where cranial nerve XII exits the skull

Answer 51

Hypoglossal canal