Week 1 Dry

Question 1

Describe the circle of willis?

Answer 1

Basilar artery formed from vertebral arteries.
It connects to the ICAs via the post. communicating artery.

Post cerebral comes off basilar/post communicating

Middle cerebral comes off ICA

Ant cerebral comes off ICA and are joined to eachother by ant communicating

Question 2

What arteryies come off the vertebral and basilar arteries?

Answer 2

Post inf cerebellar and Ant spinal arteries come off the vertebral arteries

Ant Inf, Labyrinthine and sup cerebellar come off the basilar (in that order)

Question 3

Where do the vertebral arteries arise?

Answer 3

Subclavians

Question 4

Which part of the brainstem is the basilar artery most close to?

Answer 4

Pons

Question 5

Which surface of the brain is supplied by which cerebral arteru?

Answer 5

Ant - Superior/medial, runs in the longitudinal fissure

Middle - Most of Lateral, runs in the sylvian fissure

Posterior - Posterior, runs in calcarine fissure

Question 6

What cerebral artery supplies Primary motor cortex?

Answer 6

Ant and middle

Question 7

What cerebral artery supplies Primary sensory cortex?

Answer 7

Ant & Middle

Question 8

What cerebral artery supplies Primary Visual Cortex?

Answer 8

Post

Question 9

What cerebral artery supplies Primary Auditory Cortex?

Answer 9

Middle

Question 10

What cerebral artery supplies the area of olfaction?

Answer 10

Middle

Question 11

Which cranial nerve & major Art are closely related to the sup cerebellar artery and how?
Why is this relevant clinically?

Answer 11

Oculomotor & Post Cerebral artery both run just above the Superior Cerebellar Art.

Aneurysms are common here causing III nerve palsy

Question 12

What pieces of nervous tissue are involved in controlling blood supply to the brain?

Answer 12

Carotid Sinus - Detects pressure in ICA
Carotid Body - Detects Anoxia in ICA
Sympathetic motor nerves also form a plexus around the ICA

Question 13

What nerves do the Carotid sinus and body connect to?

Answer 13

Both have sensory fibres in the glossopharyngeal nerve

Carotid sinus also uses Vagus

Question 14

Where do intracranial veins drain to?

Answer 14

Dural venous sinuses between the periocranium and cranial dura

Question 15

List the important Dural venous sinuses?

Answer 15

Opthalmic Veins -> Cavernous sinus -> IJV
Sup/Inf Petrosal Sinuses -> IJV

Also Inf sagittal -> Straight sinus (joins with Sup sagittal) -> Confluence of sinuses -> Transverse sinus -> Sigmoid sinus -> IJV

Question 16

What are the important connection between veins outside and inside the cranium, and why?

Answer 16

# Sup Opthalmic Vein is continuous with the facial vein outside and cavernous sinus inside.
# Emissary veins are continuous with dural sinuses -> Diploe of bone -> veins of scalp
# Inf Petrosal Sinus are connected left-right by the basilar sinus

All of these are potential routes of intracranial infection

Question 17

What is the 2 most important grooves in the skull base due to arteries?

Answer 17

Carotid groove one either side of the sella turcica

Groove for middle meningeal artery just lateral to foramen spinosum

Question 18

What drains into the cavernous sinus?

Answer 18

• Opthalmic Veins
• Superficial and middle cerebral veins
• Sphenoparietal veins

Question 19

What neurovascular structures pass through the cavernous sinus?

Answer 19

• ICA
• Cr Nerves III, IV, V2, V3 & 6
• Cr Nerve II passes just behind the cavernous sinus medially

Question 20

How does Cavernous Sinus Thrombosis occur and what does it cause?

Answer 20

CST results from infection spreading from the nose, sinuses, ears or teeth.
The sinus thromboses causing oedema & blood to back up
So your eyes bulge and you get cranial nerve palsies of II, III, IV, V2/3 & VI

Question 21

Explain the blood supply of the Spinal Cord??

Answer 21

You have 1 anterior and 2 posterior spinal arteries which give of multiple segmental spinal arteries

Question 22

What arteries form the anterior spinal artery?

Answer 22

The two vertebral arteries give off branches which become the Ant Spinal Art, just before they form basilar artery.

Question 23

What arteries form the posterior spinal arteries?

Answer 23

Branches of the post inf cerebellar art

Question 24

Explain the venous drainage of the spinal cord?

Answer 24

Ant & Post spinal veins drain into the Internal vertebral (epidural) venous plexus.

In turn the Internal Vertebral Venous Plexus communicates with its external counterpart outside the vertebral canal.

Then it reaches up into the cranium and drains into the intracranial venous sinsues

Question 25

What are the important Dural folds?

Answer 25

Falx Cerebri
Tentorium Cerebelli
Falx Cerebelli
Diaphragma Selli

Question 26

What does the falx cerebri attach to?

Answer 26

Anteriorly — Crista Galli & Frontal Crest

Posteriorly — Tentorium Cerebelli

Question 27

What dural sinuses run within and along the falx cerebri?

Answer 27

Inf Saggital Sinus runs within the upper border of the falx cerebri

Sup Sagittal Sinus runs along the upper border of the falx cerebri

Question 28

Where does the tentorium cerebelli attach?

Answer 28

Ant/Post Clinoid processes of the sphenoid bones

Question 29

How does the straight sinus relate to the dural folds?

Answer 29

IT runs along where the falx cerebri joins the tentorium cerebelli

Question 30

Where does the middle meningeal artery come from?

Answer 30

The maxillary Art through the foramen spinosum

Question 31

What embryological structures are the ventricles formed from?

Answer 31

Neural Tube Vesicles

Question 32

What are the parts of the lateral ventricle and in what part of the brain does each lie in?

Answer 32

Anterior Horn - Frontal Lobe
Body - Parietal Lobe
Posterior Horn - Occipital Lobe
Inferior horn - Temporal Lobe

Question 33

What parts of the brain are the other ventricles (not lateral) found in?

Answer 33

Interventricular Foramen - Temporal
3rd Ventricle - Diencephalon
Cerebral Aqueduct - Midbrain
4th Ventricle - Between Brainstem and cerebellum

Question 34

What produces CSF?

Answer 34

Choroid plexus which is found within the ventricles

Question 35

How does CSF reach the subarachnoid space from the 4th ventricle?

Answer 35

Through the two lateral apertures or 1 midline aperture

Question 36

How is CSF reabsorbed into venous sinuses?

Answer 36

Through arachnoid villi

Question 37

What are the indentations in the skull cap around the sup sagitall sinus groove?

Answer 37

Indentations of the arachnoid villi in the developing skull