Ventricular System & Blood Supply

Question 1

What makes up the cranial meninges?

Answer 1

1. Dura Mater
   - Tough, fibrous loose membrane
   - (Flax cerebri; tentorium cerebelli)
2. Arachnoid Mater
   - Soft, loose membrane (arachnoid villi)
3. Pia Mater
   - Very thin, adheres to the brain

Question 2

State and locate where the following are:
1. Arachnoid Matter
2. Arachnoid granulation
3. Superior sagittal sinus
4. Pia mater
5. Dura mater

6. Subarachnoid space
7. Arachnoid trabeculae
8. Perivascular space
9. Cerebral cortex
10. White matter

Answer 2

Check slide 4 for image and labelling

Question 3

Name & label the ventricular system.

Answer 3

1. Lateral ventricles
2. Third ventricle
3. Cerebral aqueduct
4. Fourth ventricle
5. Central canal

-circulating CSF produced by choroid plexus in lateral ventricles

Check slide 5 for labelling

Question 4

Name, label and explain how the circulating CSF works.

Answer 4

1. Arachnoid
2. Dura mater
3. Superior sagittal sinus
4. Arachnoid Villi or granulations
5. Middle cranial fossa
6. Subarachnoid space filled with spinal fluid
7. Anterior cranial fossa
8. Choroid plexus of lateral ventricle
9. Choroid plexus of the 4th ventricle
10. Posterior cranial fossae

Question 5

Explain the differences between:
Meningitis, Haematoma & Hydrocephalus.

Answer 5

Meningitis:
-Viral, bacterial, chemical reaction
Haematoma:
- Intracerebral
- Subarachnoid (e.g. aneurysm, haem. stroke)
- Subdural (e.g. “shaken baby syndrome”)
- Extradural (e.g. trauma, MMA rupture)
Hydrocephalus:
- Increased fluid pressure due to obstruction to flow of CSF

Question 6

Explain the flow of blood in CNS blood supply

Answer 6

• Common carotid  internal & external carotid
• Internal carotid  posterior communicating artery; middle cerebral
  artery; anterior cerebral artery
• Anterior communicating artery connects two anterior cerebral
  arteries across midline
• Vertebral artery -> posterior inferior cerebellar artery (PICA)
• Vertebral arteries -> basilar artery
• Basilar artery -> anterior inferior cerebellar artery (PICA); superior
  cerebellar artery (SCA); posterior cerebral artery as it joins posterior
  communicating artery

Summarised:

• ICA -> MCA; ACA; PCA
• ACA’s -> Ant cerebral
• VA -> PICA; BA
• BA -> AICA; SCA; post cerebral (PCA)

check slide 9

Question 7

Explain the distribution of cerebral arteries.

Answer 7

1. Lateral surface of the brain
   - mainly Middle Cerebral Artery (MCA) and Anterior Cerebral Artery (ACA)
   - Posterior Cerebral Artery (PCA) = visual cortex and inferior temporal lobe
2. Medial surface of the brain
   - Mainly ACA & also PCA
   - Very little MCA

Question 8

State the vessels used for venous drainage in the brain.

Answer 8

Occurs via:

1. Superficial veins (in subarachnoid space)
2. Deep veins (internal structures, to great cerebral vein)
3. Dural venous sinuses (channels between 2 layers of dura mater)

Lateral surface:
- Superior anastomotic vein
- Superior sagittal sinus
- Superficial middle cerebral vein
- Inferior anatomic vein
- Transverse sinus
- Confluence of the sinuses

Medial surface:
- Superior sagittal sinus
- Inferior sagittal sinus
- Greater cerebral vein
- Straight sinus
- Confluence of the sinuses

Question 9

State the pathway of blood in venous drainage.

Answer 9

Superior sagital sinus + inferior sagittal sinus + great cerebral vein (of Galen) + Occiptal sinus all empty into the straight sinus.

The straight sinus then empties into the confluence of sinuses, which empties into the transverse sinus which empties into the sigmoid sinus, which then empties into the internal jugular vein.

Question 10

Describe the deep cerebral structures

Answer 10

1. Anterior circulation: MCA and ACA
2. Branches penetrate basal brain surface
3. Supply deep cortical structures (basal ganglia, internal capsule, thalamus)
4. Lenticulostriate arteries
5. Middle cerebral artery
6. Internal carotid artery
7. Anterior communicating artery
8. Anterior cerebral artery

Question 11

State the different clinical disorders associate with the brain vessels.

Answer 11

1. Stroke:
   - Infarction: occlusion of cerebral artery
   - Rupture of a blood vessel: cerebral haemorrhage
2. Aneurysm:
   - Subarachnoid haemorrhage
   - Intracerebral haemorrhage
3. Anterlovenous malformation
   - Congenital abnormality
   - Swollen blood vessels

What is a stroke: https://www.youtube.com/watch?v=LZJlGSDfNr4